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  • Built-in GZip/Deflate Compression on IIS 7.x

    - by Rick Strahl
    IIS 7 improves internal compression functionality dramatically making it much easier than previous versions to take advantage of compression that’s built-in to the Web server. IIS 7 also supports dynamic compression which allows automatic compression of content created in your own applications (ASP.NET or otherwise!). The scheme is based on content-type sniffing and so it works with any kind of Web application framework. While static compression on IIS 7 is super easy to set up and turned on by default for most text content (text/*, which includes HTML and CSS, as well as for JavaScript, Atom, XAML, XML), setting up dynamic compression is a bit more involved, mostly because the various default compression settings are set in multiple places down the IIS –> ASP.NET hierarchy. Let’s take a look at each of the two approaches available: Static Compression Compresses static content from the hard disk. IIS can cache this content by compressing the file once and storing the compressed file on disk and serving the compressed alias whenever static content is requested and it hasn’t changed. The overhead for this is minimal and should be aggressively enabled. Dynamic Compression Works against application generated output from applications like your ASP.NET apps. Unlike static content, dynamic content must be compressed every time a page that requests it regenerates its content. As such dynamic compression has a much bigger impact than static caching. How Compression is configured Compression in IIS 7.x  is configured with two .config file elements in the <system.WebServer> space. The elements can be set anywhere in the IIS/ASP.NET configuration pipeline all the way from ApplicationHost.config down to the local web.config file. The following is from the the default setting in ApplicationHost.config (in the %windir%\System32\inetsrv\config forlder) on IIS 7.5 with a couple of small adjustments (added json output and enabled dynamic compression): <?xml version="1.0" encoding="UTF-8"?> <configuration> <system.webServer> <httpCompression directory="%SystemDrive%\inetpub\temp\IIS Temporary Compressed Files"> <scheme name="gzip" dll="%Windir%\system32\inetsrv\gzip.dll" staticCompressionLevel="9" /> <dynamicTypes> <add mimeType="text/*" enabled="true" /> <add mimeType="message/*" enabled="true" /> <add mimeType="application/x-javascript" enabled="true" /> <add mimeType="application/json" enabled="true" /> <add mimeType="*/*" enabled="false" /> </dynamicTypes> <staticTypes> <add mimeType="text/*" enabled="true" /> <add mimeType="message/*" enabled="true" /> <add mimeType="application/x-javascript" enabled="true" /> <add mimeType="application/atom+xml" enabled="true" /> <add mimeType="application/xaml+xml" enabled="true" /> <add mimeType="*/*" enabled="false" /> </staticTypes> </httpCompression> <urlCompression doStaticCompression="true" doDynamicCompression="true" /> </system.webServer> </configuration> You can find documentation on the httpCompression and urlCompression keys here respectively: http://msdn.microsoft.com/en-us/library/ms690689%28v=vs.90%29.aspx http://msdn.microsoft.com/en-us/library/aa347437%28v=vs.90%29.aspx The httpCompression Element – What and How to compress Basically httpCompression configures what types to compress and how to compress them. It specifies the DLL that handles gzip encoding and the types of documents that are to be compressed. Types are set up based on mime-types which looks at returned Content-Type headers in HTTP responses. For example, I added the application/json to mime type to my dynamic compression types above to allow that content to be compressed as well since I have quite a bit of AJAX content that gets sent to the client. The UrlCompression Element – Enables and Disables Compression The urlCompression element is a quick way to turn compression on and off. By default static compression is enabled server wide, and dynamic compression is disabled server wide. This might be a bit confusing because the httpCompression element also has a doDynamicCompression attribute which is set to true by default, but the urlCompression attribute by the same name actually overrides it. The urlCompression element only has three attributes: doStaticCompression, doDynamicCompression and dynamicCompressionBeforeCache. The doCompression attributes are the final determining factor whether compression is enabled, so it’s a good idea to be explcit! The default for doDynamicCompression='false”, but doStaticCompression="true"! Static Compression is enabled by Default, Dynamic Compression is not Because static compression is very efficient in IIS 7 it’s enabled by default server wide and there probably is no reason to ever change that setting. Dynamic compression however, since it’s more resource intensive, is turned off by default. If you want to enable dynamic compression there are a few quirks you have to deal with, namely that enabling it in ApplicationHost.config doesn’t work. Setting: <urlCompression doDynamicCompression="true" /> in applicationhost.config appears to have no effect and I had to move this element into my local web.config to make dynamic compression work. This is actually a smart choice because you’re not likely to want dynamic compression in every application on a server. Rather dynamic compression should be applied selectively where it makes sense. However, nowhere is it documented that the setting in applicationhost.config doesn’t work (or more likely is overridden somewhere and disabled lower in the configuration hierarchy). So: remember to set doDynamicCompression=”true” in web.config!!! How Static Compression works Static compression works against static content loaded from files on disk. Because this content is static and not bound to change frequently – such as .js, .css and static HTML content – it’s fairly easy for IIS to compress and then cache the compressed content. The way this works is that IIS compresses the files into a special folder on the server’s hard disk and then reads the content from this location if already compressed content is requested and the underlying file resource has not changed. The semantics of serving an already compressed file are very efficient – IIS still checks for file changes, but otherwise just serves the already compressed file from the compression folder. The compression folder is located at: %windir%\inetpub\temp\IIS Temporary Compressed Files\ApplicationPool\ If you look into the subfolders you’ll find compressed files: These files are pre-compressed and IIS serves them directly to the client until the underlying files are changed. As I mentioned before – static compression is on by default and there’s very little reason to turn that functionality off as it is efficient and just works out of the box. The one tweak you might want to do is to set the compression level to maximum. Since IIS only compresses content very infrequently it would make sense to apply maximum compression. You can do this with the staticCompressionLevel setting on the scheme element: <scheme name="gzip" dll="%Windir%\system32\inetsrv\gzip.dll" staticCompressionLevel="9" /> Other than that the default settings are probably just fine. Dynamic Compression – not so fast! By default dynamic compression is disabled and that’s actually quite sensible – you should use dynamic compression very carefully and think about what content you want to compress. In most applications it wouldn’t make sense to compress *all* generated content as it would generate a significant amount of overhead. Scott Fortsyth has a great post that details some of the performance numbers and how much impact dynamic compression has. Depending on how busy your server is you can play around with compression and see what impact it has on your server’s performance. There are also a few settings you can tweak to minimize the overhead of dynamic compression. Specifically the httpCompression key has a couple of CPU related keys that can help minimize the impact of Dynamic Compression on a busy server: dynamicCompressionDisableCpuUsage dynamicCompressionEnableCpuUsage By default these are set to 90 and 50 which means that when the CPU hits 90% compression will be disabled until CPU utilization drops back down to 50%. Again this is actually quite sensible as it utilizes CPU power from compression when available and falling off when the threshold has been hit. It’s a good way some of that extra CPU power on your big servers to use when utilization is low. Again these settings are something you likely have to play with. I would probably set the upper limit a little lower than 90% maybe around 70% to make this a feature that kicks in only if there’s lots of power to spare. I’m not really sure how accurate these CPU readings that IIS uses are as Cpu usage on Web Servers can spike drastically even during low loads. Don’t trust settings – do some load testing or monitor your server in a live environment to see what values make sense for your environment. Finally for dynamic compression I tend to add one Mime type for JSON data, since a lot of my applications send large chunks of JSON data over the wire. You can do that with the application/json content type: <add mimeType="application/json" enabled="true" /> What about Deflate Compression? The default compression is GZip. The documentation hints that you can use a different compression scheme and mentions Deflate compression. And sure enough you can change the compression settings to: <scheme name="deflate" dll="%Windir%\system32\inetsrv\gzip.dll" staticCompressionLevel="9" /> to get deflate style compression. The deflate algorithm produces slightly more compact output so I tend to prefer it over GZip but more HTTP clients (other than browsers) support GZip than Deflate so be careful with this option if you build Web APIs. I also had some issues with the above value actually being applied right away. Changing the scheme in applicationhost.config didn’t show up on the site  right away. It required me to do a full IISReset to get that change to show up before I saw the change over to deflate compressed content. Content was slightly more compressed with deflate – not sure if it’s worth the slightly less common compression type, but the option at least is available. IIS 7 finally makes GZip Easy In summary IIS 7 makes GZip easy finally, even if the configuration settings are a bit obtuse and the documentation is seriously lacking. But once you know the basic settings I’ve described here and the fact that you can override all of this in your local web.config it’s pretty straight forward to configure GZip support and tweak it exactly to your needs. Static compression is a total no brainer as it adds very little overhead compared to direct static file serving and provides solid compression. Dynamic Compression is a little more tricky as it does add some overhead to servers, so it probably will require some tweaking to get the right balance of CPU load vs. compression ratios. Looking at large sites like Amazon, Yahoo, NewEgg etc. – they all use Related Content Code based ASP.NET GZip Caveats HttpWebRequest and GZip Responses © Rick Strahl, West Wind Technologies, 2005-2011Posted in IIS7   ASP.NET  

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  • IIS7 Compression CSS files only compressed when dynamic compression is enabled

    - by Paul
    If anyone can help it would be appreciated. I would like to enable compression for static files within IIS7 (for the sake of simplicity I'll just refer to static css files for the time being). The problem I'm getting is that css files are only compressed when both dynamic and static compression is enabled in IIS for the website. What I really want to achieve is css compression (static file) whilst leaving the dynamic (aspx) pages as uncompressed for the time being (to avoid unnecessary CPU load). I am puzzled as to why just leaving 'static compression' enabled causes css files to be returned uncompressed. My applicationHost.config file has not be altered and looks like this: <httpCompression directory="%SystemDrive%\inetpub\temp\IIS Temporary Compressed Files"> <scheme name="gzip" dll="%Windir%\system32\inetsrv\gzip.dll" /> <staticTypes> <add mimeType="text/*" enabled="true" /> <add mimeType="message/*" enabled="true" /> <add mimeType="application/javascript" enabled="true" /> <add mimeType="*/*" enabled="false" /> </staticTypes> <dynamicTypes> <add mimeType="text/*" enabled="true" /> <add mimeType="message/*" enabled="true" /> <add mimeType="application/x-javascript" enabled="true" /> <add mimeType="*/*" enabled="false" /> </dynamicTypes> </httpCompression> The server-wide compression setting within IIS is set to 'Dynamic Disabled' and 'Static Enabled' from the Server Features Compression page. The web-site compression setting (Server Sites MyWebsite Features Compression) is where I am enabling and disabling dynamic compression as detailed above. Any help would be really help me get unstuck on this. Thanks

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  • Yes, you can benefit from both data and backup compression

    - by AaronBertrand
    Earlier today, MSSQLTips posted a backup compression tip by Thomas LaRock ( blog | twitter ). In that article, Tom states: "If you are already compressing data then you will not see much benefit from backup compression." I don't want to argue with a rock star, and I will concede that he may be right in some scenarios. Nonetheless, I tweeted that "it depends;" Thomas then asked for "an example where you have data comp and you also see a large benefit from backup comp?" My initial reaction came about...(read more)

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  • Tömörítés becslése - Compression Advisor

    - by lsarecz
    Az Oracle Database 11g verziójától már OLTP adatbázisok is hatékonyan tömöríthetok az Advanced Compression funkcióval. Nem csak a tárolandó adatok mennyisége csökken ezáltal felére, vagy akár negyedére, de az adatbázis teljesítménye is javulhat, amennyiben I/O korlátos a rendszer (és általában az). Hogy pontosan mekkora tömörítés várható az Advanced Compression bevezetésével, az kiválóan becsülheto a Compression Advisor eszközzel. Ez nem csak az OLTP tömörítés mértékét, de 11gR2 verziótól kezdve a HCC tömörítés arányát is becsülni tudja, amely Exadata Database Machine, Pillar Axiom illetve ZFS Storage alkalmazásával érheto el. A HCC tömörítés becsléséhez csak 11gR2 adatbázisra van szükség, nem kell hozzá a speciális célhardver (Exadata, Pillar, ZFS). A Compression Advisor valójában a DBMS_COMPRESSION package használatával érheto el. A package-hez tartozik 6 konstans, amellyel a kívánt tömörítési szintek választhatók ki: Constant Type Value Description COMP_NOCOMPRESS NUMBER 1 No compression COMP_FOR_OLTP NUMBER 2 OLTP compression COMP_FOR_QUERY_HIGH NUMBER 4 High compression level for query operations COMP_FOR_QUERY_LOW NUMBER 8 Low compression level for query operations COMP_FOR_ARCHIVE_HIGH NUMBER 16 High compression level for archive operations COMP_FOR_ARCHIVE_LOW NUMBER 32 Low compression level for archive operations A GET_COMPRESSION_RATIO tárolt eljárás elemzi a tömöríteni kívánt táblát. Mindig csak egy táblát, vagy opcionálisan annak egy partícióját tudja elemezni úgy, hogy a tábláról készít egy másolatot egy külön erre a célra kijelölt/létrehozott táblatérre. Amennyiben az elemzést egyszerre több tömörítési szintre futtatjuk, úgy a tábláról annyi másolatot készít. A jó közelítésu becslés (+-5%) feltétele, hogy táblánként/partíciónként minimum 1 millió sor legyen. 11gR1 esetében még a DBMS_COMP_ADVISOR csomag GET_RATIO eljárása volt használatos, de ez még nem támogatta a HCC becslést. Érdemes még megnézni és kipróbálni a Tyler Muth blogjában publikált formázó eszközt, amivel a compression advisor kimenete alakítható jól értelmezheto formátumúvá. Végül összegezném mit is tartalmaz az Advanced Compression opció, mivel gyakran nem világos a felhasználóknak miért kell fizetni: Data Guard Network Compression Data Pump Compression (COMPRESSION=METADATA_ONLY does not require the Advanced Compression option) Multiple RMAN Compression Levels (RMAN DEFAULT COMPRESS does not require the Advanced Compression option) OLTP Table Compression SecureFiles Compression and Deduplication Ez alapján RMAN esetében például a default compression (BZIP2) szint ingyen használható, viszont az új ZLIB Advanced Compression opciót igényel. A ZLIB hatékonyabban használja a CPU-t, azaz jóval gyorsabb, viszont kisebb tömörítési arány érheto el vele.

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  • Enabling Http caching and compression in IIS 7 for asp.net websites

    - by anil.kasalanati
    Caching – There are 2 ways to set Http caching 1-      Use Max age property 2-      Expires header. Doing the changes via IIS Console – 1.       Select the website for which you want to enable caching and then select Http Responses in the features tab       2.       Select the Expires webcontent and on changing the After setting you can generate the max age property for the cache control    3.       Following is the screenshot of the headers   Then you can use some tool like fiddler and see 302 response coming from the server. Doing it web.config way – We can add static content section in the system.webserver section <system.webServer>   <staticContent>             <clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="365.00:00:00" />   </staticContent> Compression - By default static compression is enabled on IIS 7.0 but the only thing which falls under that category is CSS but this is not enough for most of the websites using lots of javascript.  If you just thought by enabling dynamic compression would fix this then you are wrong so please follow following steps –   In some machines the dynamic compression is not enabled and following are the steps to enable it – Open server manager Roles > Web Server (IIS) Role Services (scroll down) > Add Role Services Add desired role (Web Server > Performance > Dynamic Content Compression) Next, Install, Wait…Done!   ?  Roles > Web Server (IIS) ?  Role Services (scroll down) > Add Role Services     Add desired role (Web Server > Performance > Dynamic Content Compression)     Next, Install, Wait…Done!     Enable  - ?  Open server manager ?  Roles > Web Server (IIS) > Internet Information Services (IIS) Manager   Next pane: Sites > Default Web Site > Your Web Site Main pane: IIS > Compression         Then comes the custom configuration for encrypting javascript resources. The problem is that the compression in IIS 7 completely works on the mime types and by default there is a mismatch in the mime types Go to following location C:\Windows\System32\inetsrv\config Open applicationHost.config The mimemap is as follows  <mimeMap fileExtension=".js" mimeType="application/javascript" />   So the section in the staticTypes should be changed          <add mimeType="application/javascript" enabled="true" />     Doing the web.config way –   We can add following section in the system.webserver section <system.webServer> <urlCompression doDynamicCompression="false"  doStaticCompression="true"/> More Information/References – ·         http://weblogs.asp.net/owscott/archive/2009/02/22/iis-7-compression-good-bad-how-much.aspx ·         http://www.west-wind.com/weblog/posts/98538.aspx  

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  • Converting linear colors to SRGB shows banding in FFmpeg

    - by user1863947
    When I convert an EXR file sequence with x264 using FFmpeg and convert the colorspace from linear to SRGB (with gamma 0.45454545) I get some heavy banding issues (most visible on a dark gradient). Here is the ffmpeg command I use: C:/ffmpeg.exe -y -i C:/seq_v001.%04d.exr -vf lutrgb=r=gammaval(0.45454545):g=gammaval(0.45454545):b=gammaval(0.45454545) -vcodec libx264 -pix_fmt yuv420p -preset slow -crf 18 -r 25 C:/out.mov Here is the output: ffmpeg version N-47062-g26c531c Copyright (c) 2000-2012 the FFmpeg developers built on Nov 25 2012 12:25:21 with gcc 4.7.2 (GCC) configuration: --enable-gpl --enable-version3 --disable-pthreads --enable-runtime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libnut --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib libavutil 52. 9.100 / 52. 9.100 libavcodec 54. 77.100 / 54. 77.100 libavformat 54. 37.100 / 54. 37.100 libavdevice 54. 3.100 / 54. 3.100 libavfilter 3. 23.102 / 3. 23.102 libswscale 2. 1.102 / 2. 1.102 libswresample 0. 17.101 / 0. 17.101 libpostproc 52. 2.100 / 52. 2.100 Input #0, image2, from 'C:/seq_v001.%04d.exr': Duration: 00:00:09.60, start: 0.000000, bitrate: N/A Stream #0:0: Video: exr, rgb48le, 960x540 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 25 tbn, 25 tbc [libx264 @ 0000000004d11540] using SAR=1/1 [libx264 @ 0000000004d11540] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2 [libx264 @ 0000000004d11540] profile High, level 3.1 [libx264 @ 0000000004d11540] 264 - core 128 r2216 198a7ea - H.264/MPEG-4 AVC codec - Copyleft 2003-2012 - http://www.videolan.org/x264.html - options: cabac=1 ref=5 deblock=1:0:0 analyse=0x3:0x113 me=umh subme=8 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=18 lookahead_threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=2 b_bias=0 direct=3 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=50 rc=crf mbtree=1 crf=18.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00 Output #0, mov, to 'C:/out.mov': Metadata: encoder : Lavf54.37.100 Stream #0:0: Video: h264 (avc1 / 0x31637661), yuv420p, 960x540 [SAR 1:1 DAR 16:9], q=-1--1, 12800 tbn, 25 tbc Stream mapping: Stream #0:0 -> #0:0 (exr -> libx264) Press [q] to stop, [?] for help [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute frame= 16 fps=0.0 q=0.0 size= 0kB time=00:00:00.00 bitrate= 0.0kbits/s Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute frame= 34 fps= 33 q=0.0 size= 0kB time=00:00:00.00 bitrate= 0.0kbits/s Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute frame= 52 fps= 34 q=0.0 size= 0kB time=00:00:00.00 bitrate= 0.0kbits/s Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute frame= 68 fps= 34 q=0.0 size= 0kB time=00:00:00.00 bitrate= 0.0kbits/s Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute frame= 85 fps= 33 q=23.0 size= 47kB time=00:00:00.44 bitrate= 867.5kbits/s Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute frame= 104 fps= 34 q=23.0 size= 94kB time=00:00:01.20 bitrate= 640.3kbits/s Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute frame= 121 fps= 34 q=23.0 size= 133kB time=00:00:01.88 bitrate= 577.8kbits/s Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute frame= 139 fps= 34 q=23.0 size= 172kB time=00:00:02.60 bitrate= 543.4kbits/s Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute frame= 157 fps= 34 q=23.0 size= 213kB time=00:00:03.32 bitrate= 525.6kbits/s Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute frame= 175 fps= 34 q=23.0 size= 254kB time=00:00:04.04 bitrate= 516.0kbits/s Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute frame= 193 fps= 35 q=23.0 size= 287kB time=00:00:04.76 bitrate= 494.6kbits/s Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute frame= 211 fps= 35 q=23.0 size= 332kB time=00:00:05.48 bitrate= 496.4kbits/s Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute [exr @ 000000000dffa660] Found more than one compression attribute [exr @ 000000000dffaaa0] Found more than one compression attribute [exr @ 000000000dffaf00] Found more than one compression attribute [exr @ 000000000dffb340] Found more than one compression attribute [exr @ 000000000dffb7a0] Found more than one compression attribute [exr @ 000000000dffbbe0] Found more than one compression attribute [exr @ 000000000dffc040] Found more than one compression attribute [exr @ 000000000dff8c40] Found more than one compression attribute [exr @ 000000000dff90c0] Found more than one compression attribute [exr @ 000000000dff9520] Found more than one compression attribute [exr @ 000000000dff9960] Found more than one compression attribute [exr @ 000000000dff9dc0] Found more than one compression attribute [exr @ 000000000dffa200] Found more than one compression attribute frame= 228 fps= 34 q=23.0 size= 421kB time=00:00:06.16 bitrate= 559.8kbits/s frame= 240 fps= 32 q=-1.0 Lsize= 708kB time=00:00:09.52 bitrate= 609.3kbits/s video:705kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.505636% [libx264 @ 0000000004d11540] frame I:2 Avg QP:15.07 size: 18186 [libx264 @ 0000000004d11540] frame P:73 Avg QP:16.51 size: 3719 [libx264 @ 0000000004d11540] frame B:165 Avg QP:18.38 size: 2502 [libx264 @ 0000000004d11540] consecutive B-frames: 2.5% 3.3% 42.5% 51.7% [libx264 @ 0000000004d11540] mb I I16..4: 46.2% 33.3% 20.4% [libx264 @ 0000000004d11540] mb P I16..4: 6.8% 2.0% 0.6% P16..4: 29.4% 10.5% 4.6% 0.0% 0.0% skip:46.1% [libx264 @ 0000000004d11540] mb B I16..4: 1.8% 0.7% 0.2% B16..8: 40.9% 6.5% 0.3% direct: 1.2% skip:48.5% L0:52.0% L1:47.5% BI: 0.5% [libx264 @ 0000000004d11540] 8x8 transform intra:24.7% inter:81.3% [libx264 @ 0000000004d11540] direct mvs spatial:93.3% temporal:6.7% [libx264 @ 0000000004d11540] coded y,uvDC,uvAC intra: 10.7% 31.4% 24.9% inter: 2.3% 9.0% 2.9% [libx264 @ 0000000004d11540] i16 v,h,dc,p: 83% 11% 6% 1% [libx264 @ 0000000004d11540] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 9% 9% 52% 6% 4% 4% 5% 5% 5% [libx264 @ 0000000004d11540] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 22% 11% 44% 5% 4% 3% 3% 4% 3% [libx264 @ 0000000004d11540] i8c dc,h,v,p: 69% 15% 15% 2% [libx264 @ 0000000004d11540] Weighted P-Frames: Y:0.0% UV:0.0% [libx264 @ 0000000004d11540] ref P L0: 48.9% 0.1% 16.8% 17.0% 11.3% 5.8% [libx264 @ 0000000004d11540] ref B L0: 57.7% 21.9% 13.9% 6.4% [libx264 @ 0000000004d11540] ref B L1: 82.4% 17.6% [libx264 @ 0000000004d11540] kb/s:600.61 For me it looks like it converts the video first and afterwards applies the gamma correction on 8-bit clipped video. Does someone have an idea?

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  • What should developers know about Windows executable binary file compression?

    - by Peter Turner
    I'd never heard of this before, so shame on me, but programs like UPX can compress my files by 80% which is totally sweet, but I have no idea what the the disadvantages are in doing this. Or even what the compressor does. Website linked above doesn't say anything about dynamically linking DLLs but it mentions about compressing DESCENT 2 and about compressing Netscape 4.06. Also, it doesn't say what the tradeoffs are, only the benefits. If there weren't tradeoffs why wouldn't my linker compress the file? If I have an environment where I have one executable and 20-30 DLL's, some of which are dynamically loaded an unloaded fairly arbitrarily, but not in loops (hopefully), do I take a big hit in processing time decompressing these DLL's when they're used?

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  • IIS7 Compression Configuration

    - by Level1Coder
    Hi, Previously when I used IIS6, I used IIS6 Metabase Explorer to edit Metabase.xml and manually turned on compression, specified the compression level and the file extensions to compress. IIS7 seems a bit different, there is no Metabase.xml file in the system32\inetsrv folder. Enabling compression is easy to turn on by checking the checkbox in the Compression module. But how do I manually tweak and set the compression levels and file extensions to compress? I also ran across an article saying that IIS7 also automatically throttles the compression if your CPU load is 50% then compression is turned off. Where are all these settings located?

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  • .NET Multipage Tiff with Lossy Compression

    - by Adam Berent
    I need a way to take several jpgs and convert them into a single multi page Tiff. I have that working using GDI+ however it only works with the compression LZW which is lossless. This means that my 3 50KB Jpgs turn into 3MB multipage Tiff file. This is not something I can accept for the software that I am working on. I know that Tiff Image format can use a JPG compression scheme but GDI+ does not seem to support this. If anyone knows how to do this in .NET (C#) or of any component that does this conversion.

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  • Avoid double compression of resources

    - by user1095108
    I am using .pngs for my textures and am using a virtual file system in a .zip file for my game project. This means my textures are compressed and decompressed twice. What are the solutions to this double compression problem? One solution I've heard about is to use .tgas for textures, but it seems ages ago, since I've heard that. Another solution is to implement decompression on the GPU and, since that is fast, forget about the overhead.

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  • How to disable Apache http compression (mod_deflate) when SSL stream is compressed

    - by Mohammad Ali
    I found that Goggle Chrome supports ssl compression and Firefox should support it soon. I'm trying to configure Apache to to disable http compression if the ssl compression is used to prevent CPU overhead with the configuration option: SetEnvIf SSL_COMPRESS_METHOD DEFLATE no-gzip While the custom log (using %{SSL_COMPRESS_METHOD}x) shows that the ssl layer compression method is DEFLATE, the above option did not work and the http response content is still being compressed by Apache. I had to use the option: BrowserMatchNoCase ".Chrome." no-gzip' I prefer if there are more general method in case other browsers supports ssl compression or some has a version of chrome that does not have ssl compression.

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  • New Whitepaper: Advanced Compression 11gR1 Benchmarks with EBS 12

    - by Steven Chan
    In my opinion, if there's any reason to upgrade an E-Business Suite environment to the 11gR1 or 11gR2 database, it's the Advanced Compression database option.  Oracle Advanced Compression was introduced in Oracle Database 11g, and allows you to compress structured data (numbers, characters) as well as unstructured data (documents, spreadsheets, XML and other files).  It provides enhanced compression for database backups and also includes network compression for faster synchronization with standby databases.In other words, the promise of Advanced Compression is that it can make your E-Business Suite database smaller and faster.  But how well does it actually deliver on that promise?Apps 12 + Advanced Compression Benchmarks now availableThree of my colleagues, Uday Moogala, Lester Gutierrez, and Andy Tremayne, have been benchmarking Oracle E-Business Suite Release 12 with Advanced Compression 11gR1.  They've just released a detailed whitepaper with their benchmarking results and recommendations.This whitepaper is available in two locations:Oracle E-Business Suite Release 12.1 with Oracle Database 11g Advanced Compression (Note 1110648.1) (requires My Oracle Support access)Oracle E-Business Suite Release 12.1 with Oracle Database 11g Advanced Compression (Applications Benchmark website, PDF, 500K)

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  • Objects won't render when Texture Compression + Mipmapping is Enabled

    - by felipedrl
    I'm optimizing my game and I've just implemented compressed (DXTn) texture loading in OpenGL. I've worked my way removing bugs but I can't figure out this one: objects w/ DXTn + mipmapped textures are not being rendered. It's not like they are appearing with a flat color, they just don't appear at all. DXTn textured objs render and mipmapped non-compressed textures render just fine. The texture in question is 256x256 I generate the mips all the way down 4x4, i.e 1 block. I've checked on gDebugger and it display all the levels (7) just fine. I'm using GL_LINEAR_MIPMAP_NEAREST for min filter and GL_LINEAR for mag one. The texture is being compressed and mipmaps being created offline with Paint.NET tool using super sampling method. (I also tried bilinear just in case) Source follow: [SNIPPET 1: Loading DDS into sys memory + Initializing Object] // Read header DDSHeader header; file.read(reinterpret_cast<char*>(&header), sizeof(DDSHeader)); uint pos = static_cast<uint>(file.tellg()); file.seekg(0, std::ios_base::end); uint dataSizeInBytes = static_cast<uint>(file.tellg()) - pos; file.seekg(pos, std::ios_base::beg); // Read file data mData = new unsigned char[dataSizeInBytes]; file.read(reinterpret_cast<char*>(mData), dataSizeInBytes); file.close(); mMipmapCount = header.mipmapcount; mHeight = header.height; mWidth = header.width; mCompressionType = header.pf.fourCC; // Only support files divisible by 4 (for compression blocks algorithms) massert(mWidth % 4 == 0 && mHeight % 4 == 0); massert(mCompressionType == NO_COMPRESSION || mCompressionType == COMPRESSION_DXT1 || mCompressionType == COMPRESSION_DXT3 || mCompressionType == COMPRESSION_DXT5); // Allow textures up to 65536x65536 massert(header.mipmapcount <= MAX_MIPMAP_LEVELS); mTextureFilter = TextureFilter::LINEAR; if (mMipmapCount > 0) { mMipmapFilter = MipmapFilter::NEAREST; } else { mMipmapFilter = MipmapFilter::NO_MIPMAP; } mBitsPerPixel = header.pf.bitcount; if (mCompressionType == NO_COMPRESSION) { if (header.pf.flags & DDPF_ALPHAPIXELS) { // The only format supported w/ alpha is A8R8G8B8 massert(header.pf.amask == 0xFF000000 && header.pf.rmask == 0xFF0000 && header.pf.gmask == 0xFF00 && header.pf.bmask == 0xFF); mInternalFormat = GL_RGBA8; mFormat = GL_BGRA; mDataType = GL_UNSIGNED_BYTE; } else { massert(header.pf.rmask == 0xFF0000 && header.pf.gmask == 0xFF00 && header.pf.bmask == 0xFF); mInternalFormat = GL_RGB8; mFormat = GL_BGR; mDataType = GL_UNSIGNED_BYTE; } } else { uint blockSizeInBytes = 16; switch (mCompressionType) { case COMPRESSION_DXT1: blockSizeInBytes = 8; if (header.pf.flags & DDPF_ALPHAPIXELS) { mInternalFormat = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT; } else { mInternalFormat = GL_COMPRESSED_RGB_S3TC_DXT1_EXT; } break; case COMPRESSION_DXT3: mInternalFormat = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT; break; case COMPRESSION_DXT5: mInternalFormat = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT; break; default: // Not Supported (DXT2, DXT4 or any compression format) massert(false); } } [SNIPPET 2: Uploading into video memory] massert(mData != NULL); glGenTextures(1, &mHandle); massert(mHandle!=0); glBindTexture(GL_TEXTURE_2D, mHandle); commitFiltering(); uint offset = 0; Renderer* renderer = Renderer::getInstance(); switch (mInternalFormat) { case GL_RGB: case GL_RGBA: case GL_RGB8: case GL_RGBA8: for (uint i = 0; i < mMipmapCount + 1; ++i) { uint width = std::max(1U, mWidth >> i); uint height = std::max(1U, mHeight >> i); glTexImage2D(GL_TEXTURE_2D, i, mInternalFormat, width, height, mHasBorder, mFormat, mDataType, &mData[offset]); offset += width * height * (mBitsPerPixel / 8); } break; case GL_COMPRESSED_RGB_S3TC_DXT1_EXT: case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT: case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT: case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT: { uint blockSize = 16; if (mInternalFormat == GL_COMPRESSED_RGB_S3TC_DXT1_EXT || mInternalFormat == GL_COMPRESSED_RGBA_S3TC_DXT1_EXT) { blockSize = 8; } uint width = mWidth; uint height = mHeight; for (uint i = 0; i < mMipmapCount + 1; ++i) { uint nBlocks = ((width + 3) / 4) * ((height + 3) / 4); // Only POT textures allowed for mipmapping massert(width % 4 == 0 && height % 4 == 0); glCompressedTexImage2D(GL_TEXTURE_2D, i, mInternalFormat, width, height, mHasBorder, nBlocks * blockSize, &mData[offset]); offset += nBlocks * blockSize; if (width <= 4 && height <= 4) { break; } width = std::max(4U, width / 2); height = std::max(4U, height / 2); } break; } default: // Not Supported massert(false); } Also I don't understand the "+3" in the block size computation but looking for a solution for my problema I've encountered people defining it as that. I guess it won't make a differente for POT textures but I put just in case. Thanks.

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  • Optimal Compression for Speech

    - by ashes999
    I'm designing a game that depends heavily on audio; I will have some 300+ speech files (most of them just a word or two long). This can very quickly escalate the size of my final game. What's the optimal way to encode/compress speech files to keep the size minimal without getting audio artifacts? Please address both per-file compression/encoding, and also zipping/compressing the set of all speech files together in your answer. Because I'm not sure which (or combination of both) factors will give me the best results. Edit: I need this to run in Silverlight and Android, so I'm presumably stuck with only MP3 as my option (other than uncompressed wave files).

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  • Hardware Lossless Compression for Hard Drives?

    - by GeoffreyF67
    I happened across this article about hardware based hard drive encryption and realized that not only would this give a great way to protect your data but it would also speed up the applications that we use to encrypt that data. This lead me to wonder... Would it be possible to do the same thing for compression so that all of the data is compressed or uncompressed appropriately as it is read and written to the drive? I haven't done any firmware programming in quite some time so I'm not even sure this is technically possible. If it were, however, it could probably give quite a bit more storage space to folks. What are the pros and cons of programming such an approach to be used in the firmware? G-Man

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  • Recommened design pattern to handle multiple compression algorithms for a class hierarchy

    - by sgorozco
    For all you OOD experts. What would be the recommended way to model the following scenario? I have a certain class hierarchy similar to the following one: class Base { ... } class Derived1 : Base { ... } class Derived2 : Base { ... } ... Next, I would like to implement different compression/decompression engines for this hierarchy. (I already have code for several strategies that best handle different cases, like file compression, network stream compression, legacy system compression, etc.) I would like the compression strategy to be pluggable and chosen at runtime, however I'm not sure how to handle the class hierarchy. Currently I have a tighly-coupled design that looks like this: interface ICompressor { byte[] Compress(Base instance); } class Strategy1Compressor : ICompressor { byte[] Compress(Base instance) { // Common compression guts for Base class ... // if( instance is Derived1 ) { // Compression guts for Derived1 class } if( instance is Derived2 ) { // Compression guts for Derived2 class } // Additional compression logic to handle other class derivations ... } } As it is, whenever I add a new derived class inheriting from Base, I would have to modify all compression strategies to take into account this new class. Is there a design pattern that allows me to decouple this, and allow me to easily introduce more classes to the Base hierarchy and/or additional compression strategies?

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  • HTTP gzip compression not working for css or javascript in tomcat 6

    - by Draemon
    Connector settings: <Connector ... compression="2048" noCompressionUserAgents="gozilla, traviata" compressionMimeType="text/html,text/xml,text/plain,text/css,text/javascript"/> This seems to work for html, but not for css or javascript. compression="force" does work, but compression="on" doesn't. compression="2" doesn't work either, so I don't know what "force" is really doing. The files in question are about 6k, I've cleared the browser cache, etc.

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  • On-the-fly lossless image compression

    - by geschema
    I have an embedded application where an image scanner sends out a stream of 16-bit pixels that are later assembled to a grayscale image. As I need to both save this data locally and forward it to a network interface, I'd like to compress the data stream to reduce the required storage space and network bandwidth. Is there a simple algorithm that I can use to losslessly compress the pixel data? I first thought of computing the difference between two consecutive pixels and then encoding this difference with a Huffman code. Unfortunately, the pixels are unsigned 16-bit quantities so the difference can be anywhere in the range -65535 .. +65535 which leads to potentially huge codeword lengths. If a few really long codewords occur in a row, I'll run into buffer overflow problems.

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  • CPU-adaptive compression

    - by liori
    Hello, Let assume I need to send some data from one computer to another, over a pretty fast network... for example standard 100Mbit connection (~10MB/s). My disk drives are standard HDD, so their speed is somewhere between 30MB/s and 100MB/s. So I guess that compressing the data on the fly could help. But... I don't want to be limited by CPU. If I choose an algorithm that is intensive on CPU, the transfer will actually go slower than without compression. This is difficult with compressors like GZIP and BZIP2 because you usually set the compression strength once for the whole transfer, and my data streams are sometimes easy, sometimes hard to compress--this makes the process suboptimal because sometimes I do not use full CPU, and sometimes the bandwidth is underutilized. Is there a compression program that would adapt to current CPU/bandwidth and hit the sweet spot so that the transfer will be optimal? Ideally for Linux, but I am still curious about all solutions. I'd love to see something compatible with GZIP/BZIP2 decompressors, but this is not necessary. So I'd like to optimize total transfer time, not simply amount of bytes to send. Also I don't need real time decompression... real time compression is enough. The destination host can process the data later in its spare time. I know this doesn't change much (compression is usually much more CPU-intensive than decompression), but if there's a solution that could use this fact, all the better. Each time I am transferring different data, and I really want to make these one-time transfers as quick as possible. So I won't benefit from getting multiple transfers faster due to stronger compression. Thanks,

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  • GZip/Deflate Compression in ASP.NET MVC

    - by Rick Strahl
    A long while back I wrote about GZip compression in ASP.NET. In that article I describe two generic helper methods that I've used in all sorts of ASP.NET application from WebForms apps to HttpModules and HttpHandlers that require gzip or deflate compression. The same static methods also work in ASP.NET MVC. Here are the two routines:/// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } /// <summary> /// Sets up the current page or handler to use GZip through a Response.Filter /// IMPORTANT: /// You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() { HttpResponse Response = HttpContext.Current.Response; if (IsGZipSupported()) { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (AcceptEncoding.Contains("gzip")) { Response.Filter = new System.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "gzip"); } else { Response.Filter = new System.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "deflate"); } } // Allow proxy servers to cache encoded and unencoded versions separately Response.AppendHeader("Vary", "Content-Encoding"); } The first method checks whether the client sending the request includes the accept-encoding for either gzip or deflate, and if if it does it returns true. The second function uses IsGzipSupported() to decide whether it should encode content and uses an Response Filter to do its job. Basically response filters look at the Response output stream as it's written and convert the data flowing through it. Filters are a bit tricky to work with but the two .NET filter streams for GZip and Deflate Compression make this a snap to implement. In my old code and even now in MVC I can always do:public ActionResult List(string keyword=null, int category=0) { WebUtils.GZipEncodePage(); …} to encode my content. And that works just fine. The proper way: Create an ActionFilterAttribute However in MVC this sort of thing is typically better handled by an ActionFilter which can be applied with an attribute. So to be all prim and proper I created an CompressContentAttribute ActionFilter that incorporates those two helper methods and which looks like this:/// <summary> /// Attribute that can be added to controller methods to force content /// to be GZip encoded if the client supports it /// </summary> public class CompressContentAttribute : ActionFilterAttribute { /// <summary> /// Override to compress the content that is generated by /// an action method. /// </summary> /// <param name="filterContext"></param> public override void OnActionExecuting(ActionExecutingContext filterContext) { GZipEncodePage(); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } /// <summary> /// Sets up the current page or handler to use GZip through a Response.Filter /// IMPORTANT: /// You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() { HttpResponse Response = HttpContext.Current.Response; if (IsGZipSupported()) { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (AcceptEncoding.Contains("gzip")) { Response.Filter = new System.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "gzip"); } else { Response.Filter = new System.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "deflate"); } } // Allow proxy servers to cache encoded and unencoded versions separately Response.AppendHeader("Vary", "Content-Encoding"); } } It's basically the same code wrapped into an ActionFilter attribute, which intercepts requests MVC requests to Controller methods and lets you hook up logic before and after the methods have executed. Here I want to override OnActionExecuting() which fires before the Controller action is fired. With the CompressContentAttribute created, it can now be applied to either the controller as a whole:[CompressContent] public class ClassifiedsController : ClassifiedsBaseController { … } or to one of the Action methods:[CompressContent] public ActionResult List(string keyword=null, int category=0) { … } The former applies compression to every action method, while the latter is selective and only applies it to the individual action method. Is the attribute better than the static utility function? Not really, but it is the standard MVC way to hook up 'filter' content and that's where others are likely to expect to set options like this. In fact,  you have a bit more control with the utility function because you can conditionally apply it in code, but this is actually much less likely in MVC applications than old WebForms apps since controller methods tend to be more focused. Compression Caveats Http compression is very cool and pretty easy to implement in ASP.NET but you have to be careful with it - especially if your content might get transformed or redirected inside of ASP.NET. A good example, is if an error occurs and a compression filter is applied. ASP.NET errors don't clear the filter, but clear the Response headers which results in some nasty garbage because the compressed content now no longer matches the headers. Another issue is Caching, which has to account for all possible ways of compression and non-compression that the content is served. Basically compressed content and caching don't mix well. I wrote about several of these issues in an old blog post and I recommend you take a quick peek before diving into making every bit of output Gzip encoded. None of these are show stoppers, but you have to be aware of the issues. Related Posts GZip Compression with ASP.NET Content ASP.NET GZip Encoding Caveats© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Advanced file compression software for Mac OSX

    - by Steven Roose
    Back when I used Windows, I always used WinRAR for file compression and decompression. It had a fair amount of options like 'just storage' vs 'hard compression', password protection and archive type. Now that I use Mac OSX, the only compression possibility I have is the default Finder's Compress to Zip. I downloaded the most popular decompression software "Unarchiver". But this app can't compress other archive types either. I went for a search but there seem to be hardly any good advanced compression tools that work nice in OSX and have the options WinRAR has. (WinRAR works in OSX but command line only, I'm looking for something with a GUI.) Any ideas? I strongly prefer freeware. I found Archiver and StiffIt, but they are both commercial.

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  • Transparently decompressing data in archive to allow greater compression later

    - by Vi.
    I have, for example, filesystem image which have some compressed files (with weak compression such as gzip), for example, manpages or archives with the same uncompressed content nearby. How to pre-filter the data to "expand" compressed data to plain form (to re-compress it with strong compression) and then post-filter after decompression to restore original "semi-compressed" image? SHA-1 match is advices but not strictly required (but the resulting image must work, e.g. re-compressed files should not grow too much, be decompressible etc.) Like improving compression ratio by reversing weak compression algorithms. Are there programs for this?

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  • How come, diffrent text files become diffrent sizes after compression ?

    - by Arsheep
    I have file of some random text size = 27 gb and after compression it becomes 40 mb or so. And a 3.5 GB sql file become 45 Mb after compression. But a 109 mb text file become 72 mb after compression so what can be wrong with it. Why so less compressed, it must 10 mb or so , or i am missing something . All files as i can see is English text only and and some grammar symbols (/ , . - = + etc) Can you tell why ? If not can you tell how can i super compress a text file ? I can code in PHP , np in that.

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  • Backup Compression - time for an overhaul

    - by jchang
    Database backup compression is incredibly useful and valuable. This became popular with then Imceda (later Quest and now Dell) LiteSpeed. SQL Server version 2008 added backup compression for Enterprise Edition only. The SQL Server EE native backup feature only allows a single compression algorithm, one that elects for CPU efficiency over the degree of compression achieved. In the long ago past, this strategy was essential. But today the benefits are irrelevant while the lower compression is becoming...(read more)

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  • HTTP Compression Proxy

    - by Praveen
    I'm looking for a HTTP compression proxy. Basically, I need a proxy to compress images and text to be transferred over a slow internet connection when accessing the web. To put it into a diagram CLIENT ---/fast local network/--- HTTP COMPRESSION PROXY ---/slow internet connection/--- WEB (e.g. Facebook, Wiki, Google) I will be using Squid for caching but from what i've it does not support HTTP compresion (gzip, deflate)

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