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  • Python - Polymorphism in wxPython, What's wrong?

    - by Wallter
    I am trying to wright a simple custom button in wx.Python. My code is as follows, an error is thrown on line 19 of my "Custom_Button.py" - What is going on? I can find no help online for this error and have a suspicion that it has to do with the Polymorphism. (As a side note: I am relatively new to python having come from C++ and C# any help on syntax and function of the code would be great! - knowing that, it could be a simple error. thanks!) Error def __init__(self, parent, id=-1, NORM_BMP, PUSH_BMP, MOUSE_OVER_BMP, **kwargs): SyntaxError: non-default argument follows default argument Main.py class MyFrame(wx.Frame): def __init__(self, parent, ID, title): wxFrame.__init__(self, parent, ID, title, wxDefaultPosition, wxSize(400, 400)) self.CreateStatusBar() self.SetStatusText("Program testing custom button overlays") menu = wxMenu() menu.Append(ID_ABOUT, "&About", "More information about this program") menu.AppendSeparator() menu.Append(ID_EXIT, "E&xit", "Terminate the program") menuBar = wxMenuBar() menuBar.Append(menu, "&File"); self.SetMenuBar(menuBar) self.Button1 = Custom_Button(self, parent, -1, "D:/Documents/Python/Normal.bmp", "D:/Documents/Python/Clicked.bmp", "D:/Documents/Python/Over.bmp", "None", wx.Point(200,200), wx.Size(300,100)) EVT_MENU(self, ID_ABOUT, self.OnAbout) EVT_MENU(self, ID_EXIT, self.TimeToQuit) def OnAbout(self, event): dlg = wxMessageDialog(self, "Testing the functions of custom " "buttons using pyDev and wxPython", "About", wxOK | wxICON_INFORMATION) dlg.ShowModal() dlg.Destroy() def TimeToQuit(self, event): self.Close(true) class MyApp(wx.App): def OnInit(self): frame = MyFrame(NULL, -1, "wxPython | Buttons") frame.Show(true) self.SetTopWindow(frame) return true app = MyApp(0) app.MainLoop() Custom Button import wx from wxPython.wx import * class Custom_Button(wx.PyControl): ############################################ ##THE ERROR IS BEING THROWN SOME WHERE IN HERE ## ############################################ # The BMP's Mouse_over_bmp = wx.Bitmap(0) # When the mouse is over Norm_bmp = wx.Bitmap(0) # The normal BMP Push_bmp = wx.Bitmap(0) # The down BMP Pos_bmp = wx.Point(0,0) # The posisition of the button def __init__(self, parent, id=-1, NORM_BMP, PUSH_BMP, MOUSE_OVER_BMP, text="", pos, size, **kwargs): wx.PyControl.__init__(self,parent, id, **kwargs) # Set the BMP's to the ones given in the constructor self.Mouse_over_bmp = wx.Bitmap(MOUSE_OVER_BMP) self.Norm_bmp = wx.Bitmap(NORM_BMP) self.Push_bmp = wx.Bitmap(PUSH_BMP) self.Pos_bmp = pos ############################################ ##THE ERROR IS BEING THROWN SOME WHERE IN HERE ## ############################################ self.Bind(wx.EVT_LEFT_DOWN, self._onMouseDown) self.Bind(wx.EVT_LEFT_UP, self._onMouseUp) self.Bind(wx.EVT_LEAVE_WINDOW, self._onMouseLeave) self.Bind(wx.EVT_ENTER_WINDOW, self._onMouseEnter) self.Bind(wx.EVT_ERASE_BACKGROUND,self._onEraseBackground) self.Bind(wx.EVT_PAINT,self._onPaint) self._mouseIn = self._mouseDown = False def _onMouseEnter(self, event): self._mouseIn = True def _onMouseLeave(self, event): self._mouseIn = False def _onMouseDown(self, event): self._mouseDown = True def _onMouseUp(self, event): self._mouseDown = False self.sendButtonEvent() def sendButtonEvent(self): event = wx.CommandEvent(wx.wxEVT_COMMAND_BUTTON_CLICKED, self.GetId()) event.SetInt(0) event.SetEventObject(self) self.GetEventHandler().ProcessEvent(event) def _onEraseBackground(self,event): # reduce flicker pass def _onPaint(self, event): dc = wx.BufferedPaintDC(self) dc.SetFont(self.GetFont()) dc.SetBackground(wx.Brush(self.GetBackgroundColour())) dc.Clear() dc.DrawBitmap(self.Norm_bmp) # draw whatever you want to draw # draw glossy bitmaps e.g. dc.DrawBitmap if self._mouseIn: # If the Mouse is over the button dc.DrawBitmap(self, self.Mouse_over_bmp, self.Pos_bmp, useMask=False) if self._mouseDown: # If the Mouse clicks the button dc.DrawBitmap(self, self.Push_bmp, self.Pos_bmp, useMask=False)

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  • How can I decompress a gzip stream with zlib?

    - by Greg Hewgill
    Gzip format files (created with the gzip program, for example) use the "deflate" compression algorithm, which is the same compression algorithm as what zlib uses. However, when using zlib to inflate a gzip compressed file, the library returns a Z_DATA_ERROR. How can I use zlib to decompress a gzip file?

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  • Groovy Grails, How do you stream or buffer a large file in a Controller's response?

    - by Julian Noye
    Hi Guys I have a controller that makes a connection to a url to retrieve a csv file. I am able to send the file in the response using the following code, this works fine. def fileURL = "www.mysite.com/input.csv" def thisUrl = new URL(fileURL); def connection = thisUrl.openConnection(); def output = connection.content.text; response.setHeader "Content-disposition", "attachment; filename=${'output.csv'}" response.contentType = 'text/csv' response.outputStream << output response.outputStream.flush() However I don't think this method is inappropriate for a large file, as the whole file is loaded into the controllers memory. I want to be able to read the file chunk by chunk and write the file to the response chunk by chunk. Any ideas?

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  • Python - wxPython custom button -> unbound method __init__()? what?

    - by Wallter
    After looking at questions like this it doesn't make sense that my __init__(self, parrent, id) would be throwing a unbound error? help? main.py import wx from customButton import customButton from wxPython.wx import * class MyFrame(wx.Frame): def __init__(self, parent, ID, title): wxFrame.__init__(self, parent, ID, title, wxDefaultPosition, wxSize(400, 400)) # Non-important code here... # This is the first declaration of the Button1 # This is also where the ERROR is thrown. # Omitting this line causes the window to execute # flawlessly. self.Button1 = customButton.__init__(self, parent, -1) # ... finishes in a basic wx.program style... customButton.py # I've included all of the code in the file # because have no idea where the bug/error happens import wx from wxPython.wx import * class Custom_Button(wx.PyControl): # The BMP's Over_bmp = None #wxEmptyBitmap(1,1,1) # When the mouse is over Norm_bmp = None #wxEmptyBitmap(1,1,1) # The normal BMP Push_bmp = None #wxEmptyBitmap(1,1,1) # The down BMP def __init__(self, parent, id, **kwargs): wx.PyControl.__init__(self,parent, id, **kwargs) # Set the BMP's to the ones given in the constructor #self.Over_bmp = wx.Bitmap(wx.Image(MOUSE_OVER_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) #self.Norm_bmp = wx.Bitmap(wx.Image(NORM_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) #self.Push_bmp = wx.Bitmap(wx.Image(PUSH_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) #self.Pos_bmp = self.pos self.Bind(wx.EVT_LEFT_DOWN, self._onMouseDown) self.Bind(wx.EVT_LEFT_UP, self._onMouseUp) self.Bind(wx.EVT_LEAVE_WINDOW, self._onMouseLeave) self.Bind(wx.EVT_ENTER_WINDOW, self._onMouseEnter) self.Bind(wx.EVT_ERASE_BACKGROUND,self._onEraseBackground) self.Bind(wx.EVT_PAINT,self._onPaint) self._mouseIn = self._mouseDown = False def _onMouseEnter(self, event): self._mouseIn = True def _onMouseLeave(self, event): self._mouseIn = False def _onMouseDown(self, event): self._mouseDown = True def _onMouseUp(self, event): self._mouseDown = False self.sendButtonEvent() def sendButtonEvent(self): event = wx.CommandEvent(wx.wxEVT_COMMAND_BUTTON_CLICKED, self.GetId()) event.SetInt(0) event.SetEventObject(self) self.GetEventHandler().ProcessEvent(event) def _onEraseBackground(self,event): # reduce flicker pass def _onPaint(self, event): dc = wx.BufferedPaintDC(self) dc.SetFont(self.GetFont()) dc.SetBackground(wx.Brush(self.GetBackgroundColour())) dc.Clear() dc.DrawBitmap(self.Norm_bmp) # draw whatever you want to draw # draw glossy bitmaps e.g. dc.DrawBitmap if self._mouseIn: # If the Mouse is over the button dc.DrawBitmap(self, self.Mouse_over_bmp, self.Pos_bmp, useMask=False) if self._mouseDown: # If the Mouse clicks the button dc.DrawBitmap(self, self.Push_bmp, self.Pos_bmp, useMask=False)

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  • How does Bitmap.Save(Stream, ImageFormat) format the data?

    - by Matt Jacobsen
    I have a non transparent, colour bitmap with length 2480 and width 3507. Using Bitmap.GetPixel(int x, int y) I am able to get the colour information of each pixel in the bitmap. If I squirt the bitmap into a byte[]: MemoryStream ms = new MemoryStream(); bmp.Save(ms, ImageFormat.Bmp); ms.Position = 0; byte[] bytes = ms.ToArray(); then I'd expect to have the same information, i.e. I can go to bytes[1000] and read the colour information for that pixel. It turns out that my array of bytes is larger than I anticipated. I thought I'd get an array with 2480 x 3507 = 8697360 elements. Instead I get an array with 8698438 elements - some sort of header I presume. In what format the bytes in my array stored? Is there a header 1078 bytes long followed by Alpha, Red, Green, Blue values for every byte element, or something else?

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  • FFMPEG Segfault Solutions

    - by Brentley_11
    I'm trying to convert a bunch of movies into h.264 mp4's using FFMPEG. These movies are sourced from various portable camcorders such as the Flip Mino HD and the Kodak ZI8. One issue I'm having with video from the ZI8 is it seems to be causing FFMPEG to segfault. Here is my command: ffmpeg -i 'XmasSailor720p60fps.MOV' -threads 2 -acodec libfaac -ab 96kb -vcodec libx264 -vpre hq -b 500kb -s 484x272 XmasSailor.mp4 Here is the output: FFmpeg version SVN-r20668, Copyright (c) 2000-2009 Fabrice Bellard, et al. built on Dec 2 2009 18:37:34 with gcc 4.2.4 (Ubuntu 4.2.4-1ubuntu4) configuration: --enable-libfaac --enable-libfaad --enable-libmp3lame --enable-libx264 --enable-gpl --enable-nonfree --enable-postproc --enable-pthreads --enable-shared libavutil 50. 5. 1 / 50. 5. 1 libavcodec 52.42. 0 / 52.42. 0 libavformat 52.39. 2 / 52.39. 2 libavdevice 52. 2. 0 / 52. 2. 0 libswscale 0. 7. 2 / 0. 7. 2 libpostproc 51. 2. 0 / 51. 2. 0 Seems stream 0 codec frame rate differs from container frame rate: 59.94 (60000/1001) -> 29.97 (30000/1001) Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'XmasSailor720p60fps.MOV': Duration: 00:00:05.37, start: 0.000000, bitrate: 12021 kb/s Stream #0.0(eng): Video: h264, yuv420p, 1280x720 [PAR 1:1 DAR 16:9], 11994 kb/s, 29.97 tbr, 90k tbn, 59.94 tbc Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16, 128 kb/s Metadata major_brand : qt minor_version : 0 compatible_brands: qt comment : KODAK Zi8 Pocket Video Camera comment-eng : KODAK Zi8 Pocket Video Camera [libx264 @ 0x99e1020]using SAR=1/1 [libx264 @ 0x99e1020]using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.1 Cache64 [libx264 @ 0x99e1020]profile High, level 2.1 Output #0, mp4, to 'XmasSailor.mp4': Stream #0.0(eng): Video: libx264, yuv420p, 484x272 [PAR 1:1 DAR 121:68], q=10-51, 500 kb/s, 30k tbn, 29.97 tbc Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16, 96 kb/s Metadata comment : Encoded with the Statusfirm Video Transcoder Stream mapping: Stream #0.0 -> #0.0 Stream #0.1 -> #0.1 Press [q] to stop encoding [h264 @ 0x99de950]B picture before any references, skipping [h264 @ 0x99de950]decode_slice_header error [h264 @ 0x99de950]no frame! Error while decoding stream #0.0 [h264 @ 0x99de950]B picture before any references, skipping [h264 @ 0x99de950]decode_slice_header error [h264 @ 0x99de950]no frame! Error while decoding stream #0.0 frame= 20 fps= 0 q=13797729.0 size= 0kB time=0.66 bitrate= 0.6kbits/s frame= 39 fps= 37 q=13797729.0 size= 0kB time=1.30 bitrate= 0.3kbits/s frame= 48 fps= 30 q=33.0 size= 11kB time=0.10 bitrate= 903.0kbits/s frame= 58 fps= 27 q=31.0 size= 22kB time=0.43 bitrate= 421.0kbits/s frame= 67 fps= 25 q=29.0 size= 41kB time=0.73 bitrate= 462.6kbits/s frame= 75 fps= 23 q=29.0 size= 59kB time=1.00 bitrate= 486.7kbits/s frame= 83 fps= 22 q=29.0 size= 81kB time=1.27 bitrate= 521.9kbits/s frame= 90 fps= 21 q=29.0 size= 97kB time=1.50 bitrate= 530.1kbits/s frame= 98 fps= 20 q=29.0 size= 114kB time=1.77 bitrate= 526.9kbits/s frame= 106 fps= 20 q=29.0 size= 134kB time=2.04 bitrate= 537.7kbits/s frame= 114 fps= 19 q=29.0 size= 150kB time=2.30 bitrate= 533.7kbits/s frame= 122 fps= 19 q=29.0 size= 172kB time=2.57 bitrate= 547.8kbits/s frame= 130 fps= 19 q=29.0 size= 193kB time=2.84 bitrate= 557.5kbits/s frame= 136 fps= 18 q=29.0 size= 211kB time=3.04 bitrate= 570.0kbits/s frame= 144 fps= 18 q=29.0 size= 242kB time=3.30 bitrate= 599.5kbits/s frame= 152 fps= 17 q=30.0 size= 261kB time=3.57 bitrate= 598.6kbits/s frame= 157 fps= 15 q=-1.0 Lsize= 368kB time=5.21 bitrate= 579.3kbits/s video:302kB audio:61kB global headers:0kB muxing overhead 1.416371% [libx264 @ 0x99e1020]frame I:1 Avg QP:27.22 size: 8720 [libx264 @ 0x99e1020]frame P:48 Avg QP:25.15 size: 3759 [libx264 @ 0x99e1020]frame B:108 Avg QP:30.10 size: 1105 [libx264 @ 0x99e1020]consecutive B-frames: 0.6% 11.5% 28.8% 59.0% [libx264 @ 0x99e1020]mb I I16..4: 28.5% 47.6% 23.9% [libx264 @ 0x99e1020]mb P I16..4: 0.8% 1.3% 0.5% P16..4: 50.6% 17.7% 13.1% 0.0% 0.0% skip:15.9% [libx264 @ 0x99e1020]mb B I16..4: 0.2% 0.3% 0.1% B16..8: 44.0% 1.2% 2.6% direct: 5.1% skip:46.5% L0:45.5% L1:51.0% BI: 3.5% [libx264 @ 0x99e1020]final ratefactor: 23.51 [libx264 @ 0x99e1020]8x8 transform intra:49.9% inter:67.9% [libx264 @ 0x99e1020]direct mvs spatial:98.1% temporal:1.9% [libx264 @ 0x99e1020]coded y,uvDC,uvAC intra: 54.7% 76.1% 41.4% inter: 17.1% 24.4% 7.8% [libx264 @ 0x99e1020]i16 v,h,dc,p: 18% 52% 5% 25% [libx264 @ 0x99e1020]i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 12% 22% 9% 7% 10% 10% 9% 8% 13% [libx264 @ 0x99e1020]i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 13% 18% 8% 8% 10% 13% 10% 9% 12% [libx264 @ 0x99e1020]Weighted P-Frames: Y:10.4% [libx264 @ 0x99e1020]ref P L0: 60.2% 15.3% 11.0% 7.6% 5.2% 0.7% [libx264 @ 0x99e1020]ref B L0: 72.6% 15.6% 11.8% [libx264 @ 0x99e1020]kb/s:471.17 Segmentation fault I'm wondering if anyone else has ran into similar issues. I wasn't able to find anything helpful via Google. Another question I have is if anyone knows of a company that offers paid support for FFMPEG. Thank you for your time.

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  • dead keys not working in java app

    - by jippie
    The Arduino IDE is based on a java application called processing. While typing text into processing, it refuses to accept any of the characters under dead keys like " ' ^. As a work around I: Open another window (usually my browser or mail client); I type the character I need; Select and copy the character onto my clip board; Copy the character into processing. What do I have to do to make processing accept characters under dead keys? Disabling dead keys is not an option.

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  • How would you sample a real-time stream of coordinates to create a Speed Graph?

    - by Andrew Johnson
    I have a GPS device, and I am receiving continuous points, which I store in an array. These points are time stamped. I would like to graph distance/time (speed) vs. distance in real-time; however, I can only plot 50 of the points because of hardware constraints. How would you select points from the array to graph? For example, one algorithm might be to select every Nth point from the array, where N results in 50 points total. Code: float indexModifier = 1; if (MIN(50,track.lastPointIndex) == 50) { indexModifier = track.lastPointIndex/50.0f; } index = ceil(index*indexModifier); Another algorithm might be to keep an array of 50 points, and throw out the point with the least speed change each time you get a new point.

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  • What HTTP headers do I need to stream an ASF file?

    - by SoaperGEM
    I have a simple PHP script that will either serve up a streaming ASF file or not, depending on whether you're logged in and have access to the file. It basically does this: <?php header('Content-Type: video/x-ms-asf'); header('Content-Disposition: inline; filename="file.asf"'); readfile('file.asf'); ?> This already works fine in Firefox; when you navigate to this file it starts the video streaming right away. But Internet Explorer is a different story. When I go to this link in IE, it consistently tries to download the file as if it were an attachment rather than streaming it in the browser. What I am missing that IE's getting hung up on?

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  • How do I get a ComboBox SelectionChanged event to fire from a nested ListBoxItem?

    - by Stephen McCusker
    This is a rather complex problem that has me really confused right now. Any help would be greatly appreciated. The Setup: ListBox of Type A UserControls -ListBoxItem of Type A UserControl --ListBox of Type B UserControls ---ListBoxItem of Type B UserControl ----ListBox of Type C UserControls -----ListBoxItem of Type C UserControl (contains the ComboBox) In other words, the Type A control has a ListBox of Type B controls that has a ListBox of Type C controls. All of the controls are hierarchical in nature. Type A contains the data that's needed to load the Type B controls and the Type B contains the data that's needed to load the Type C controls. The Type C control has a standard ComboBox in it for changing the values of the present items. In addition to the above structure, I have drag and dropping tied to the PreviewMouseLeftButtonDown event on both the Type A and Type B UserControl levels to handle reordering/deleting/etc commands in the GUI. All of this is working as intended. The Problem: When I attempt to change the value in the ComboBox, the SelectionChanged event never fires on the Type C "level" unless I'm careful enough to click on the borders/spacing in between any Type A or B controls. This happens when my ComboBox popout menu overlaps on either a Type A or B control located below itself. The selection events for Type A or B are firing instead of the Type C events, so the ComboBox is never changing its value reliably. In the debugger, the code for handling the drag and drop is triggering on the next ListBoxItem that's located underneath the ComboBox. Thoughts: Is there a way I can make my ComboBox popup take prevalence over the items behind it while double-nested in a ListBox (ie, ignore anything behind it while it's open)? Is there some way to reroute the incorrectly firing SelectionChanged events down to the ComboBox that's supposed to be triggering them?

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  • Design Technique: How to design a complex system for processing orders, products and units.

    - by Shyam
    Hi, Programming is fun: I learned that by trying out simple challenges, reading up some books and following some tutorials. I am able to grasp the concepts of writing with OO (I do so in Ruby), and write a bit of code myself. What bugs me though is that I feel re-inventing the wheel: I haven't followed an education or found a book (a free one that is) that explains me the why's instead of the how's, and I've learned from the A-team that it is the plan that makes it come together. So, armed with my nuby Ruby skills, I decided I wanted to program a virtual store. I figured out the following: My virtual Store will have: Products and Services Inventories Orders and Shipping Customers Now this isn't complex at all. With the help of some cool tools (CMapTools), I drew out some concepts, but quickly enough (thanks to my inferior experience in designing), my design started to bite me. My very first product-line were virtual "laptops". So, I created a class (Ruby): class Product attr_accessor :name, :price def initialize(name, price) @name = name @price = price end end which can be instantiated by doing (IRb) x = Product.new("Banana Pro", 250) Since I want my virtual customers to be able to purchase more than one product, or various types, I figured out I needed some kind of "Order" mechanism. class Order def initialize(order_no) @order_no = order_no @line_items = [] end def add_product(myproduct) @line_items << myproduct end def show_order() puts @order_no @line_items.each do |x| puts x.name.to_s + "\t" + x.price.to_s end end end that can be instantiated by doing (IRb) z = Order.new(1234) z.add_product(x) z.show_order Splendid, I have now a very simple ordering system that allows me to add products to an order. But, here comes my real question. What if I have three models of my product (economy, business, showoff)? Or have my products be composed out of separate units (bigger screen, nicer keyboard, different OS)? Surely I could make them three separate products, or add complexity to my product class, but I am looking for are best practices to design a flexible product object that can be used in the real world, to facilitate a complex system. My apologies if my grammar and my spelling are with error, as english is not my first language and I took the time to check as far I could understand and translate properly! Thank you for your answers, comments and feedback!

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  • Updating a Progress Bar within the Status Bar [migrated]

    - by Muhnamana
    I'm trying to figure out how to incorporate a progress bar within the status bar to show how much processing is completed. Below is my example of updating the progress bar (not sure if this is the correct way or not) Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick ToolStripProgressBar1.Value = ToolStripProgressBar1.Value + 2 If ToolStripProgressBar1.Value = 100 Then ToolStripProgressBar1.Value = 0 ToolStripProgressBar1.Value = ToolStripProgressBar1.Value + 2 Timer1.Enabled = True End If End Sub Here is the code within the button. Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1Run.Click ToolStripStatusLabel1.Text = "Processing..." Timer1.Enabled = True 'more code to be inserted here End Sub What I'm not sure is how to update the progress bar based on the amount of code you have and once the processing is complete, update the ToolStripStatusLabel1 to show "Processing...Complete!".

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  • Ruby on Rails - where to write business logic while processing a request? (newbie)

    - by Genadinik
    I am learning Ruby on Rails. I made a simple link like this: <%= link_to "Alex Link", alexes_path(@alex) %> then I routed it in routes.rb like this: resources :alexes get "home/index" then I am a bit unclear, but I think it goes to this part of the controller: def index #@alexes = Alex.all respond_to do |format| format.html # index.html.erb format.json { render json: @alexes } end end Am I correct that it goes to this part of the controller? Then nothing much happens and it goes to the next page which is index.html.rb under views\alexes So what I am wondering is - if I needed to do some business logic, would I write that in the controller snippet? Where inside the snippet? An example would be nice to take a look. Also, I would like to connect to a MongoDb database. Would I also write that in the middle of the controller? Thanks!

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  • Why is processing a sorted array faster than an unsorted array?

    - by GManNickG
    Here is a piece of code that shows some very peculiar performance. For some strange reason, sorting the data miraculously speeds up the code by almost 6x: #include <algorithm> #include <ctime> #include <iostream> int main() { // generate data const unsigned arraySize = 32768; int data[arraySize]; for (unsigned c = 0; c < arraySize; ++c) data[c] = std::rand() % 256; // !!! with this, the next loop runs faster std::sort(data, data + arraySize); // test clock_t start = clock(); long long sum = 0; for (unsigned i = 0; i < 100000; ++i) { // primary loop for (unsigned c = 0; c < arraySize; ++c) { if (data[c] >= 128) sum += data[c]; } } double elapsedTime = static_cast<double>(clock() - start) / CLOCKS_PER_SEC; std::cout << elapsedTime << std::endl; std::cout << "sum = " << sum << std::endl; } Without std::sort(data, data + arraySize);, the code runs in 11.54 seconds. With the sorted data, the code runs in 1.93 seconds. Initially I thought this might be just a language or compiler anomaly. So I tried it Java... import java.util.Arrays; import java.util.Random; public class Main { public static void main(String[] args) { // generate data int arraySize = 32768; int data[] = new int[arraySize]; Random rnd = new Random(0); for (int c = 0; c < arraySize; ++c) data[c] = rnd.nextInt() % 256; // !!! with this, the next loop runs faster Arrays.sort(data); // test long start = System.nanoTime(); long sum = 0; for (int i = 0; i < 100000; ++i) { // primary loop for (int c = 0; c < arraySize; ++c) { if (data[c] >= 128) sum += data[c]; } } System.out.println((System.nanoTime() - start) / 1000000000.0); System.out.println("sum = " + sum); } } with a similar but less extreme result. My first thought was that sorting brings the data into cache, but my next thought was how silly that is because the array was just generated. What is going on? Why is a sorted array faster than an unsorted array? The code is summing up some independent terms, the order should not matter.

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  • How to trigger the event together on each two deferent class.

    - by XBasic3000
    I have two object class on a single unit, is it posible to trigger the two events? let say the FIRSTCLASS event is fired, The SECONDCLASS also will fired? Assuming...... //{Class 1}------------------------------------------------------------- type TOnEventTrigger = procedure(Sender : Tobject; Value :integer); TMyFirstClass = Class(Tcomponent) private .... public .... OnEventTrigger : TOnEventTrigger read Fevent write Fevent; end; procedure TMyFirstClass.FEvnt(Sender : Tobject; Value :integer); begin // here is normaly triggers the event // if Assigned(OnEventTrigger) then OnEventTrigger(Self,FSomevalue); // POSTMessage(GetForegroundWindow,WM_USER+3,0,0); // this is what i did here to get the result of FSomevalue // but this is not ideal. It work only on focus window. end; //{Class 2}------------------------------------------------------------- type TOnEventTrigger = procedure(Sender : Tobject; Value :integer); TMySecondClass = Class(Tobject) private .... public .... OnEventTrigger : TOnEventTrigger; read Fevent write Fevent; end; procedure TMySecondClass.FEvnt(Sender : Tobject; Value :integer); begin // I wanted here to trigger, whenenver the above is fired // if Assigned(OnEventTrigger) then OnEventTrigger(Self,FSomevalue); end;

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  • Why is a NullReferenceException thrown when a ToolStrip button is clicked twice with code in the `Click` event handler?

    - by Patrick
    I created a clean WindowsFormsApplication solution, added a ToolStrip to the main form, and placed one button on it. I've added also an OpenFileDialog, so that the Click event of the ToolStripButton looks like the following: private void toolStripButton1_Click(object sender, EventArgs e) { openFileDialog1.ShowDialog(); } I didn't change any other properties or events. The funny thing is that when I double-click the ToolStripButton (the second click must be quite fast, before the dialog opens), then cancel both dialogs (or choose a file, it doesn't really matter) and then click in the client area of main form, a NullReferenceException crashes the application (error details attached at the end of the post). Please note that the Click event is implemented while DoubleClick is not. What's even more strange that when the OpenFileDialog is replaced by any user-implemented form, the ToolStripButton blocks from being clicked twice. I'm using VS2008 with .NET3.5. I didn't change many options in VS (only fontsize, workspace folder and line numbering). Does anyone know how to solve this? It is 100% replicable on my machine, is it on others too? One solution that I can think of is disabling the button before calling OpenFileDialog.ShowDialog() and then enabling the button back (but it's not nice). Any other ideas? And now the promised error details: System.NullReferenceException was unhandled Message="Object reference not set to an instance of an object." Source="System.Windows.Forms" StackTrace: at System.Windows.Forms.NativeWindow.WindowClass.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.PeekMessage(MSG& msg, HandleRef hwnd, Int32 msgMin, Int32 msgMax, Int32 remove) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.Run(Form mainForm) at WindowsFormsApplication1.Program.Main() w C:\Users\Marchewek\Desktop\Workspaces\VisualStudio\WindowsFormsApplication1\Program.cs:line 20 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException:

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  • Does QThread::sleep() require the event loop to be running?

    - by suszterpatt
    I have a simple client-server program written in Qt, where processes communicate using MPI. The basic design I'm trying to implement is the following: The first process (the "server") launches a GUI (derived from QMainWindow), which listens for messages from the clients (using repeat fire QTimers and asynchronous MPI receive calls), updates the GUI depending on what messages it receives, and sends a reply to every message. Every other process (the "clients") runs in an infinite loop, and all they are intended to do is send a message to the server process, receive the reply, go to sleep for a while, then wake up and repeat. Every process instantiates a single object derived from QThread, and calls its start() method. The run() method of these classes all look like this: from foo.cpp: void Foo::run() { while (true) { // Send message to the first process // Wait for a reply // Do uninteresting stuff with the reply sleep(3); // also tried QThread::sleep(3) } } In the client's code, there is no call to exec() anywhere, so no event loop should start. The problem is that the clients never wake up from sleeping (if I surround the sleep() call with two writes to a log file, only the first one is executed, control never reaches the second). Is this because I didn't start the event loop? And if so, what is the simplest way to achieve the desired functionality?

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  • Oh no! My padding's invalid!

    - by Simon Cooper
    Recently, I've been doing some work involving cryptography, and encountered the standard .NET CryptographicException: 'Padding is invalid and cannot be removed.' Searching on StackOverflow produces 57 questions concerning this exception; it's a very common problem encountered. So I decided to have a closer look. To test this, I created a simple project that decrypts and encrypts a byte array: // create some random data byte[] data = new byte[100]; new Random().NextBytes(data); // use the Rijndael symmetric algorithm RijndaelManaged rij = new RijndaelManaged(); byte[] encrypted; // encrypt the data using a CryptoStream using (var encryptor = rij.CreateEncryptor()) using (MemoryStream encryptedStream = new MemoryStream()) using (CryptoStream crypto = new CryptoStream( encryptedStream, encryptor, CryptoStreamMode.Write)) { crypto.Write(data, 0, data.Length); encrypted = encryptedStream.ToArray(); } byte[] decrypted; // and decrypt it again using (var decryptor = rij.CreateDecryptor()) using (CryptoStream crypto = new CryptoStream( new MemoryStream(encrypted), decryptor, CryptoStreamMode.Read)) { byte[] decrypted = new byte[data.Length]; crypto.Read(decrypted, 0, decrypted.Length); } Sure enough, I got exactly the same CryptographicException when trying to decrypt the data even in this simple example. Well, I'm obviously missing something, if I can't even get this single method right! What does the exception message actually mean? What am I missing? Well, after playing around a bit, I discovered the problem was fixed by changing the encryption step to this: // encrypt the data using a CryptoStream using (var encryptor = rij.CreateEncryptor()) using (MemoryStream encryptedStream = new MemoryStream()) { using (CryptoStream crypto = new CryptoStream( encryptedStream, encryptor, CryptoStreamMode.Write)) { crypto.Write(data, 0, data.Length); } encrypted = encryptedStream.ToArray(); } Aaaah, so that's what the problem was. The CryptoStream wasn't flushing all it's data to the MemoryStream before it was being read, and closing the stream causes it to flush everything to the backing stream. But why does this cause an error in padding? Cryptographic padding All symmetric encryption algorithms (of which Rijndael is one) operates on fixed block sizes. For Rijndael, the default block size is 16 bytes. This means the input needs to be a multiple of 16 bytes long. If it isn't, then the input is padded to 16 bytes using one of the padding modes. This is only done to the final block of data to be encrypted. CryptoStream has a special method to flush this final block of data - FlushFinalBlock. Calling Stream.Flush() does not flush the final block, as you might expect. Only by closing the stream or explicitly calling FlushFinalBlock is the final block, with any padding, encrypted and written to the backing stream. Without this call, the encrypted data is 16 bytes shorter than it should be. If this final block wasn't written, then the decryption gets to the final 16 bytes of the encrypted data and tries to decrypt it as the final block with padding. The end bytes don't match the padding scheme it's been told to use, therefore it throws an exception stating what is wrong - what the decryptor expects to be padding actually isn't, and so can't be removed from the stream. So, as well as closing the stream before reading the result, an alternative fix to my encryption code is the following: // encrypt the data using a CryptoStream using (var encryptor = rij.CreateEncryptor()) using (MemoryStream encryptedStream = new MemoryStream()) using (CryptoStream crypto = new CryptoStream( encryptedStream, encryptor, CryptoStreamMode.Write)) { crypto.Write(data, 0, data.Length); // explicitly flush the final block of data crypto.FlushFinalBlock(); encrypted = encryptedStream.ToArray(); } Conclusion So, if your padding is invalid, make sure that you close or call FlushFinalBlock on any CryptoStream performing encryption before you access the encrypted data. Flush isn't enough. Only then will the final block be present in the encrypted data, allowing it to be decrypted successfully.

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  • what is the file: C:\nppdf32Log\debuglog.txt

    - by Jesse
    Hello Everyone After I updated to 12.04, a file named " C:\nppdf32Log\debuglog.txt" occurs in my home directory, the content of the file is as the follow: NPP_Initialize : called NPP_GetValue is called NPP_SetWindow : called for instance 920c0e28 Window from browser - 77594625 NPP_SetWindow : called for instance 920c0e28 Window from browser - 77594625 NPP_SetWindow : called for instance 920c0e28 Window from browser - 77594625 NPP_NewStream : called for instance 920c0e28, stream 913403b0, URL http://www.xxxxxx.com/attachments/soft/CDGM%20Optical%20Glass%20Catalog.pdf, stream size 36177984, seekable 1 NPP_Write : called for instance 920c0e28, stream 913403b0, offset = 0, length = 16384, streamlength = 36177984 Trying for window attributes Trying for query tree NPP_Write : called for instance 920c0e28, stream 913403b0, offset = 16384, length = 16384, streamlength = 36177984 Trying for window attributes Trying for query tree ...... It seems this file is related to FireFox,what's exactly the problem? many thanks for your help!

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  • Changes to the LINQ-to-StreamInsight Dialect

    - by Roman Schindlauer
    In previous versions of StreamInsight (1.0 through 2.0), CepStream<> represents temporal streams of many varieties: Streams with ‘open’ inputs (e.g., those defined and composed over CepStream<T>.Create(string streamName) Streams with ‘partially bound’ inputs (e.g., those defined and composed over CepStream<T>.Create(Type adapterFactory, …)) Streams with fully bound inputs (e.g., those defined and composed over To*Stream – sequences or DQC) The stream may be embedded (where Server.Create is used) The stream may be remote (where Server.Connect is used) When adding support for new programming primitives in StreamInsight 2.1, we faced a choice: Add a fourth variety (use CepStream<> to represent streams that are bound the new programming model constructs), or introduce a separate type that represents temporal streams in the new user model. We opted for the latter. Introducing a new type has the effect of reducing the number of (confusing) runtime failures due to inappropriate uses of CepStream<> instances in the incorrect context. The new types are: IStreamable<>, which logically represents a temporal stream. IQStreamable<> : IStreamable<>, which represents a queryable temporal stream. Its relationship to IStreamable<> is analogous to the relationship of IQueryable<> to IEnumerable<>. The developer can compose temporal queries over remote stream sources using this type. The syntax of temporal queries composed over IQStreamable<> is mostly consistent with the syntax of our existing CepStream<>-based LINQ provider. However, we have taken the opportunity to refine certain aspects of the language surface. Differences are outlined below. Because 2.1 introduces new types to represent temporal queries, the changes outlined in this post do no impact existing StreamInsight applications using the existing types! SelectMany StreamInsight does not support the SelectMany operator in its usual form (which is analogous to SQL’s “CROSS APPLY” operator): static IEnumerable<R> SelectMany<T, R>(this IEnumerable<T> source, Func<T, IEnumerable<R>> collectionSelector) It instead uses SelectMany as a convenient syntactic representation of an inner join. The parameter to the selector function is thus unavailable. Because the parameter isn’t supported, its type in StreamInsight 1.0 – 2.0 wasn’t carefully scrutinized. Unfortunately, the type chosen for the parameter is nonsensical to LINQ programmers: static CepStream<R> SelectMany<T, R>(this CepStream<T> source, Expression<Func<CepStream<T>, CepStream<R>>> streamSelector) Using Unit as the type for the parameter accurately reflects the StreamInsight’s capabilities: static IQStreamable<R> SelectMany<T, R>(this IQStreamable<T> source, Expression<Func<Unit, IQStreamable<R>>> streamSelector) For queries that succeed – that is, queries that do not reference the stream selector parameter – there is no difference between the code written for the two overloads: from x in xs from y in ys select f(x, y) Top-K The Take operator used in StreamInsight causes confusion for LINQ programmers because it is applied to the (unbounded) stream rather than the (bounded) window, suggesting that the query as a whole will return k rows: (from win in xs.SnapshotWindow() from x in win orderby x.A select x.B).Take(k) The use of SelectMany is also unfortunate in this context because it implies the availability of the window parameter within the remainder of the comprehension. The following compiles but fails at runtime: (from win in xs.SnapshotWindow() from x in win orderby x.A select win).Take(k) The Take operator in 2.1 is applied to the window rather than the stream: Before After (from win in xs.SnapshotWindow() from x in win orderby x.A select x.B).Take(k) from win in xs.SnapshotWindow() from b in     (from x in win     orderby x.A     select x.B).Take(k) select b Multicast We are introducing an explicit multicast operator in order to preserve expression identity, which is important given the semantics about moving code to and from StreamInsight. This also better matches existing LINQ dialects, such as Reactive. This pattern enables expressing multicasting in two ways: Implicit Explicit var ys = from x in xs          where x.A > 1          select x; var zs = from y1 in ys          from y2 in ys.ShiftEventTime(_ => TimeSpan.FromSeconds(1))          select y1 + y2; var ys = from x in xs          where x.A > 1          select x; var zs = ys.Multicast(ys1 =>     from y1 in ys1     from y2 in ys1.ShiftEventTime(_ => TimeSpan.FromSeconds(1))     select y1 + y2; Notice the product translates an expression using implicit multicast into an expression using the explicit multicast operator. The user does not see this translation. Default window policies Only default window policies are supported in the new surface. Other policies can be simulated by using AlterEventLifetime. Before After xs.SnapshotWindow(     WindowInputPolicy.ClipToWindow,     SnapshotWindowInputPolicy.Clip) xs.SnapshotWindow() xs.TumblingWindow(     TimeSpan.FromSeconds(1),     HoppingWindowOutputPolicy.PointAlignToWindowEnd) xs.TumblingWindow(     TimeSpan.FromSeconds(1)) xs.TumblingWindow(     TimeSpan.FromSeconds(1),     HoppingWindowOutputPolicy.ClipToWindowEnd) Not supported … LeftAntiJoin Representation of LASJ as a correlated sub-query in the LINQ surface is problematic as the StreamInsight engine does not support correlated sub-queries (see discussion of SelectMany). The current syntax requires the introduction of an otherwise unsupported ‘IsEmpty()’ operator. As a result, the pattern is not discoverable and implies capabilities not present in the server. The direct representation of LASJ is used instead: Before After from x in xs where     (from y in ys     where x.A > y.B     select y).IsEmpty() select x xs.LeftAntiJoin(ys, (x, y) => x.A > y.B) from x in xs where     (from y in ys     where x.A == y.B     select y).IsEmpty() select x xs.LeftAntiJoin(ys, x => x.A, y => y.B) ApplyWithUnion The ApplyWithUnion methods have been deprecated since their signatures are redundant given the standard SelectMany overloads: Before After xs.GroupBy(x => x.A).ApplyWithUnion(gs => from win in gs.SnapshotWindow() select win.Count()) xs.GroupBy(x => x.A).SelectMany(     gs =>     from win in gs.SnapshotWindow()     select win.Count()) xs.GroupBy(x => x.A).ApplyWithUnion(gs => from win in gs.SnapshotWindow() select win.Count(), r => new { r.Key, Count = r.Payload }) from x in xs group x by x.A into gs from win in gs.SnapshotWindow() select new { gs.Key, Count = win.Count() } Alternate UDO syntax The representation of UDOs in the StreamInsight LINQ dialect confuses cardinalities. Based on the semantics of user-defined operators in StreamInsight, one would expect to construct queries in the following form: from win in xs.SnapshotWindow() from y in MyUdo(win) select y Instead, the UDO proxy method is referenced within a projection, and the (many) results returned by the user code are automatically flattened into a stream: from win in xs.SnapshotWindow() select MyUdo(win) The “many-or-one” confusion is exemplified by the following example that compiles but fails at runtime: from win in xs.SnapshotWindow() select MyUdo(win) + win.Count() The above query must fail because the UDO is in fact returning many values per window while the count aggregate is returning one. Original syntax New alternate syntax from win in xs.SnapshotWindow() select win.UdoProxy(1) from win in xs.SnapshotWindow() from y in win.UserDefinedOperator(() => new Udo(1)) select y -or- from win in xs.SnapshotWindow() from y in win.UdoMacro(1) select y Notice that this formulation also sidesteps the dynamic type pitfalls of the existing “proxy method” approach to UDOs, in which the type of the UDO implementation (TInput, TOuput) and the type of its constructor arguments (TConfig) need to align in a precise and non-obvious way with the argument and return types for the corresponding proxy method. UDSO syntax UDSO currently leverages the DataContractSerializer to clone initial state for logical instances of the user operator. Initial state will instead be described by an expression in the new LINQ surface. Before After xs.Scan(new Udso()) xs.Scan(() => new Udso()) Name changes ShiftEventTime => AlterEventStartTime: The alter event lifetime overload taking a new start time value has been renamed. CountByStartTimeWindow => CountWindow

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  • what will be the code to move to previous textfield ?

    - by rajesh
    i have the code if i press down button it goes to next textfield but to go to previous textfield what should be the code ... <html> <head> <script language="JavaScript"> function handleKeyDownEvent(elementRef,eventRef) { var charCode = (window.event) ? eventRef.keyCode : eventRef.which; //alert(charCode); // Arrow keys (37:left, 38:up, 39:right, 40:down)... if (charCode == 40) { if (window.event) window.event.keyCode = 9; else event.which = 9; return true; } return true; } </script> </head> <body> <table width="433" border="1" cellspacing="0" cellpadding="0"> <tr> <td width="235" align="center"><input type="text" onKeyDown="handleKeyDownEvent(this,event);" onKeyUp="handleKeyUpEvent(this,event);"></td> <td width="235" align="center"><input type="text" onKeyDown="handleKeyDownEvent(this,event);" onKeyUp="handleKeyUpEvent(this,event);"></td> </tr> <tr> <td width="235" align="center"><input type="text" onKeyDown="handleKeyDownEvent(this,event);" onKeyUp="handleKeyUpEvent(this,event);"></td> <td width="235" align="center"><input type="text" onKeyDown="handleKeyDownEvent(this,event);" onKeyUp="handleKeyUpEvent(this,event);"></td> </tr> <tr> <td> <input type="radio" id="check" name="check" checked> </td> <td> <input type="radio" id="check" name="check" checked> </td> </tr> <tr> <td><input type="checkbox" id="check" name="check"></td> <td><input type="checkbox" id="check" name="check"></td> </tr> </table> </body> </html>

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  • 'ia32-libs is not installed' while installing Skype on Ubuntu

    - by Vit Kos
    I downloaded skype from official site, but when installing I get this type of error (Reading database ... 100% (Reading database ... 150271 files and directories currently installed.) Unpacking skype (from .../skype-ubuntu_4.0.0.8-1_amd64.deb) ... dpkg: dependency problems prevent configuration of skype: skype depends on ia32-libs; however: Package ia32-libs is not installed. dpkg: error processing skype (--install): dependency problems - leaving unconfigured Processing triggers for desktop-file-utils ... Processing triggers for bamfdaemon ... Rebuilding /usr/share/applications/bamf.index... Processing triggers for gnome-menus ... Read about that I need to install ia32-libs. Tried to install them like this sudo apt-get install package-name:i386 But it doesn't find it. Any hint? Thx.

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  • How to seek to a specific time in a RTP stream?

    - by Cipi
    I am streaming a prerecorded H264 video that has the following structure: [I] [x] [x] [x] [I] [x] [x] [x] [I]... In between the IDR (I-s in my structure) I have 32 (only 3 presented here) other frames (all other stuff that is not IDR like SEI, SPS, PPS... X-es) Now, let assume that the timing of my frames is such: TIME: 1 2 3 4 5 6 7 8 9 FRAME: [I] [x] [x] [x] [I] [x] [x] [x] [I]... Now i want to seek to the time 4. If I seek to that frame, and send it, the picture gets messed up because the decoder needs a IDR to decode it properly, so I resorted to finding the appropriate IDR (in this case one with the time 1) and sending it as the frame with the time 4. So now the picture is decoded properly, all is well... but... If my GOV is 32, and I need to send the non IDR frame that has the index 31, and if the time span between it and the corresponding IDR is 3 seconds, I actually get 3 seconds earlier then the time I want. Now, this is not precise, because I cannot seek to the half of the GOV time span. Also, I cant set smaller GOV, so I want other ideas... My other idea was to send the last known IDR, and then send all other non IDR frames that come before the one I want, only I would set for all of them RTP-TIME to be the same as the corresponding IDR. In this case the picture gets decoded perfectly, but now in the above case, 3 seconds that follow non IDR frame with the wanted time get fast paced in the decoder/player (there is no instantaneous seek)... Any ideas? Or I can only seek to IDR-s and not the frames in between?

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