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CodePlex Daily Summary for Saturday, January 22, 2011

CodePlex Daily Summary for Saturday, January 22, 2011Popular ReleasesMinecraft Tools: Minecraft Topographical Survey 1.3: MTS requires version 4 of the .NET Framework - you must download it from Microsoft if you have not previously installed it. This version of MTS adds automatic block list updates, so MTS will recognize blocks added in game updates properly rather than drawing them in bright pink. New in this version of MTS: Support for all new blocks added since the Halloween update Auto-update of blockcolors.xml to support future game updates A splash screen that shows while the program searches for upd...StyleCop for ReSharper: StyleCop for ReSharper 5.1.14996.000: New Features: ============= This release is just compiled against the latest release of JetBrains ReSharper 5.1.1766.4 Previous release: A considerable amount of work has gone into this release: Huge focus on performance around the violation scanning subsystem: - caching added to reduce IO operations around reading and merging of settings files - caching added to reduce creation of expensive objects Users should notice condsiderable perf boost and a decrease in memory usage. Bug Fixes...TweetSharp: TweetSharp v2.0.0.0 - Preview 9: Documentation for this release may be found at http://tweetsharp.codeplex.com/wikipage?title=UserGuide&referringTitle=Documentation. Note: This code is currently preview quality. Preview 9 ChangesAdded support for lists and suggested users Fixes based on user feedback Third Party Library VersionsHammock v1.1.6: http://hammock.codeplex.com Json.NET 4.0 Release 1: http://json.codeplex.comjqGrid ASP.Net MVC Control: Version 1.2.0.0: jqGrid 3.8 support jquery 1.4 support New and exciting features Many bugfixes Complete separation from the jquery, & jqgrid codeMediaScout: MediaScout 3.0 Preview 4: Update ReleaseCoding4Fun Tools: Coding4Fun.Phone.Toolkit v1: Coding4Fun.Phone.Toolkit v1MFCMAPI: January 2011 Release: Build: 6.0.0.1024 Full release notes at SGriffin's blog. If you just want to run the tool, get the executable. If you want to debug it, get the symbol file and the source. The 64 bit build will only work on a machine with Outlook 2010 64 bit installed. All other machines should use the 32 bit build, regardless of the operating system. Facebook BadgeAutoLoL: AutoLoL v1.5.4: Added champion: Renekton Removed automatic file association Fix: The recent files combobox didn't always open a file when an item was selected Fix: Removing a recently opened file caused an errorDotNetNuke® Community Edition: 05.06.01: Major Highlights Fixed issue to remove preCondition checks when upgrading to .Net 4.0 Fixed issue where some valid domains were failing email validation checks. Fixed issue where editing Host menu page settings assigns the page to a Portal. Fixed issue which caused XHTML validation problems in 5.6.0 Fixed issue where an aspx page in any subfolder was inaccessible. Fixed issue where Config.Touch method signature had an unintentional breaking change in 5.6.0 Fixed issue which caused...MiniTwitter: 1.65: MiniTwitter 1.65 ???? ?? List ????? in-reply-to ???????? ????????????????????????? ?? OAuth ????????????????????????????ASP.net Ribbon: Version 2.1: Tadaaa... So Version 2.1 brings a lot of things... Have a look at the homepage to see what's new. Also, I wanted to (really) improve the Designer. I wanted to add great things... but... it took to much time. And as some of you were waiting for fixes, I decided just to fix bugs and add some features. So have a look at the demo app to see new features. Thanks ! (You can expect some realeses if bugs are not fixed correctly... 2.2, 2.3, 2.4....)iTracker Asp.Net Starter Kit: Version 3.0.0: This is the inital release of the version 3.0.0 Visual Studio 2010 (.Net 4.0) remake of the ITracker application. I connsider this a working, stable application but since there are still some features missing to make it "complete" I'm leaving it listed as a "beta" release. I am hoping to make it feature complete for v3.1.0 but anything is possible.ASP.NET MVC Project Awesome, jQuery Ajax helpers (controls): 1.6.1: A rich set of helpers (controls) that you can use to build highly responsive and interactive Ajax-enabled Web applications. These helpers include Autocomplete, AjaxDropdown, Lookup, Confirm Dialog, Popup Form, Popup and Pager changes: RenderView controller extension works for razor also live demo switched to razorBloodSim: BloodSim - 1.3.3.1: - Priority update to resolve a bug that was causing Boss damage to ignore Blood Shields entirelyRawr: Rawr 4.0.16 Beta: Rawr is now web-based. The link to use Rawr4 is: http://elitistjerks.com/rawr.phpThis is the Cataclysm Beta Release. More details can be found at the following link http://rawr.codeplex.com/Thread/View.aspx?ThreadId=237262 As of this release, you can now also begin using the new Downloadable WPF version of Rawr!This is a pre-alpha release of the WPF version, there are likely to be a lot of issues. If you have a problem, please follow the Posting Guidelines and put it into the Issue Tracker. W...MvcContrib: an Outer Curve Foundation project: MVC 3 - 3.0.51.0: Please see the Change Log for a complete list of changes. MVC BootCamp Description of the releases: MvcContrib.Release.zip MvcContrib.dll MvcContrib.TestHelper.dll MvcContrib.Extras.Release.zip T4MVC. The extra view engines / controller factories and other functionality which is in the project. This file includes the main MvcContrib assembly. Samples are included in the release. You do not need MvcContrib if you download the Extras.Yahoo! UI Library: YUI Compressor for .Net: Version 1.5.0.0 - Jalthi: Updated solution to VS2010. New: Work Item #4450 - Optional MSBuild task parameter :: Do not error if no files were found. Fixed: Work Item #5028 - Output file encoding is the same as the optional MSBuild task encoding argument. Fixed: Work Item #5824 - MSBuilds where slow, after the first build due to the Current Thread being forced to en-gb, on none en-gb systems. Changed: Work Item #6873 - Project license changed from MS-PL to GPLv2. New: Added all the unit tests from the Java YU...N2 CMS: 2.1.1: N2 is a lightweight CMS framework for ASP.NET. It helps you build great web sites that anyone can update. 2.1.1 Maintenance release List of changes 2.1 Major Changes Support for auto-implemented properties ({get;set;}, based on contribution by And Poulsen) File manager improvements (multiple file upload, resize images to fit) New image gallery Infinite scroll paging on news Content templates First time with N2? Try the demo site Download one of the template packs (above) and open...DNN Menu Provider: 01.00.00 (DNN 5.X and newer): DNN Menu Provider v1.0.0Our first release build is a stable release. It requires at least DotNetNuke 5.1.0. Previous DNN versions are not suported. Major Highlights: Easy to use template system build on a selfmade and powerful engine. Ready for multilingual websites. A flexible translation integration based on the ASP.NET Provider Model as well as an build in provider for DNN Localization (DNN 5.5.X > required) and an provider for EALO Translation API. Advanced in-memory caching function...VidCoder: 0.8.1: Adds ability to choose an arbitrary range (in seconds or frames) to encode. Adds ability to override the title number in the output file name when enqueing multiple titles. Updated presets: Added iPhone 4, Apple TV 2, fixed some existing presets that should have had weightp=0 or trellis=0 on them. Added {parent} option to auto-name format. Use {parent:2} to refer to a folder 2 levels above the input file. Added {title:2} option to auto-name format. Adds leading zeroes to reach the sp...New Projectsagap: Système de gestion d'application.Blog in Silverlight With BlogEngine: I love silverlight and want to build my blog in silverlight base on BlogEngine.NETCavemanTools: Easy to use toolkit with extension methods and special goodies for faster development, written in C# on .Net 3.5. CloudCompanion: Windows Azure performance measurement & analytics tools.Delivery Madness: XNA Game Development ExampledFactor: Visual Studio Add-in. Provides extended refactoring options.GpSpotMe: El objetivo final de GPSmapPoint es mostrar la posición del usuario sobre un mapa topográfico, pero eso no es mas que una escusa para aprender y divertirse programando. Esta desarrollado en C# sobre .NET Compact Framework 3.5 y puede ser usado en teléfonos con Windows Mobile 6.xInvestment Calculator: Allows you to evaluate how much money you could have today if you invested to one of the predefined investment opportunities in the database at a given date.jbucknor: jbucknorLoad Generation: Generates load according to a given pattern over a long period of time for the given number of users. It can vary the load in different patters such as linear, exponential etc. Load can be generated on custom or standard protocol Orchard Profile Module: Provides user profilesOrchard Super Classic Theme: This Orchard Theme is used to demonstrate the dynamic themes capabilities offered by Orchard. Based on the Classic Theme for Orchard, you can chose among different variations from the Dashboard.Orchard Youtube Field Module: Youtube field for orchard.Osac DataLayer: Database layer to simplify the use of database connection, sql queries and commands. Powerd by OSAC. http://www.osac.nlPascal Design: Pascal Design. pascal design is for users writing pascal application or to students learning pascal and don't need to workout the design and want to make same fast "screens". it's developed in C#PathEditor: This tool simplified the access to the environment path variable. No long line, a nice grid for editing easy and secure with directory checking. PLG Graphic File Analyzer: PLG Analyzer is an application that loads a graphic scene described in PLG format, parses the file and displays the information in it on the screen in 3D coordinates using OpenTK for C#. This project is a university project (homework, not final project) so please bear in mind :)Read Application Cofiguration in Javascript: Would it be good , if "AppSettings" is accessed with "Javascript.Configuration.ConfigurationManager.AppSettings["ServiceUrl"]"?Route#: A Microsoft .NET 4.0 C#/F# application to load routes and find minimal paths. The application is meant to let user create a network of nodes and connections representing a web to route. Starting from a point A the application will find the minimal path to B.Send SMS: Send SMS allows you to send SMS (Short Messaging Service) to all mobile operators across India. It allows you to send SMS through popular service providers like Way2SMS, Full On Sms, Tezsms, Sms Inside and more.SocialMe: This is a simple Facebook, MySpace & Twitter client, but small!StockViewer: This is an interactive way to browse stocks.Thailand IC2011 Training: Using for IC2011 training at KU. Topic. Windows Presentation Foundation Silverlight Windows Phone 7 TipTip: Online oblozuvanjeWeb Content Compressor: The objective of this project is to compress any Javascript (js file or inline script at some web files) and Cascading Style Sheets to an efficient level that works exactly as the original source, before it was minified. The library also is integrated with MSBuildwuyuhu: wuyuhuXaml Mvp: With Xaml Mvp you can create Windows Phone 7 applications based on the MVP pattern. By seperating Data from Behaviour you still get the benefit of MVVM without your View Model becoming a fat-controller. Silverlight and WPF coming soon! Developed using C#XnaWavPack: Native C# wavpack decoder, intended for use with the dynamic sound API in XNA4.

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c++ to vb.net , problem with callback function

- by johan

I'm having a hard time here trying to find a solution for my problem. I'm trying to convert a client API funktion from C++ to VB.NET, and i think have some problems with the callback function. parts of the C++ code: typedef struct{ BYTE m_bRemoteChannel; BYTE m_bSendMode; BYTE m_nImgFormat; // =0 cif ; = 1 qcif char *m_sIPAddress; char *m_sUserName; char *m_sUserPassword; BOOL m_bUserCheck; HWND m_hShowVideo; }CLIENT_VIDEOINFO, *PCLIENT_VIDEOINFO; CPLAYER_API LONG __stdcall MP4_ClientStart(PCLIENT_VIDEOINFO pClientinfo,void(CALLBACK *ReadDataCallBack)(DWORD nPort,UCHAR *pPacketBuffer,DWORD nPacketSize)); void CALLBACK ReadDataCallBack(DWORD nPort,UCHAR *pPacketBuffer,DWORD nPacketSize) { TRACE("%d\n",nPacketSize); } ..... aa5.m_sUserName = "123"; aa5.m_sUserPassword="w"; aa5.m_bUserCheck = TRUE; MP4_ClientSetTTL(64); nn1 = MP4_ClientStart(&aa5,ReadDataCallBack); if (nn1 == -1) { MessageBox("error"); return; } SDK description: MP4_ClientStart This function starts a connection. The format of the call is: LONG __stdcall MP4_ClientStart(PCLIENT_VIDEOINFO pClientinfo, void(*ReadDataCallBack)(DWORD nChannel,UCHAR *pPacketBuffer,DWORD nPacketSize)) Parameters pClientinfo holds the information. of this connection. nChannel holds the channel of card. pPacketBuffer holds the pointer to the receive buffer. nPacketSize holds the length of the receive buffer. Return Values If the function succeeds the return value is the context of this connection. If the function fails the return value is -1. Remarks typedef struct{ BYTE m_bRemoteChannel; BYTE m_bSendMode; BYTE m_bImgFormat; char *m_sIPAddress; char *m_sUserName; char *m_sUserPassword; BOOL m_bUserCheck; HWND m_hShowVideo; } CLIENT_VIDEOINFO, * PCLIENT_VIDEOINFO; m_bRemoteChannel holds the channel which the client wants to connect to. m_bSendMode holds the network mode of the connection. m_bImgFormat : Image format, 0 is main channel video, 1 is sub channel video m_sIPAddress holds the IP address of the server. m_sUserName holds the user’s name. m_sUserPassword holds the user’s password. m_bUserCheck holds the value whether sends the user’s name and password or not. m_hShowVideo holds Handle for this video window. If m_hShowVideo holds NULL, the client can be record only without decoder. If m_bUserCheck is FALSE, we will send m_sUserName and m_sUserPassword as NULL, else we will send each 50 bytes. The length of m_sIPAddress and m_sUserName must be more than 50 bytes. ReadDataCallBack: When the library receives a packet from a server, this callback is called. My VB.Net code: Imports System.Runtime.InteropServices Public Class Form1 Const WM_USER = &H400 Public Structure CLIENT_VIDEOINFO Public m_bRemoteChannel As Byte Public m_bSendMode As Byte Public m_bImgFormat As Byte Public m_sIPAddress As String Public m_sUserName As String Public m_sUserPassword As String Public m_bUserCheck As Boolean Public m_hShowVideo As Long 'hWnd End Structure Public Declare Function MP4_ClientSetNetPort Lib "hikclient.dll" (ByVal dServerPort As Integer, ByVal dClientPort As Integer) As Boolean Public Declare Function MP4_ClientStartup Lib "hikclient.dll" (ByVal nMessage As UInteger, ByVal hWnd As System.IntPtr) As Boolean <DllImport("hikclient.dll")> Public Shared Function MP4_ClientStart(ByVal Clientinfo As CLIENT_VIDEOINFO, ByRef ReadDataCallBack As CALLBACKdel) As Long End Function Public Delegate Sub CALLBACKdel(ByVal nPort As Long, <MarshalAs(UnmanagedType.LPArray)> ByRef pPacketBuffer As Byte(), ByVal nPacketSize As Long) Public Sub CALLBACK(ByVal nPort As Long, <MarshalAs(UnmanagedType.LPArray)> ByRef pPacketBuffer As Byte(), ByVal nPacketSize As Long) End Sub Public mydel As New CALLBACKdel(AddressOf CALLBACK) Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Dim Clientinfo As New CLIENT_VIDEOINFO() Clientinfo.m_bRemoteChannel = 0 Clientinfo.m_bSendMode = 0 Clientinfo.m_bImgFormat = 0 Clientinfo.m_sIPAddress = "193.168.1.100" Clientinfo.m_sUserName = "1" Clientinfo.m_sUserPassword = "a" Clientinfo.m_bUserCheck = False Clientinfo.m_hShowVideo = Me.Handle 'Nothing MP4_ClientSetNetPort(850, 850) MP4_ClientStartup(WM_USER + 1, Me.Handle) MP4_ClientStart(Clientinfo, mydel) End Sub End Class here is some other examples of the code in: C# http://blog.csdn.net/nenith1981/archive/2007/09/17/1787692.aspx VB ://read.pudn.com/downloads70/sourcecode/graph/250633/MD%E5%AE%A2%E6%88%B7%E7%AB%AF%28VB%29/hikclient.bas__.htm ://read.pudn.com/downloads70/sourcecode/graph/250633/MD%E5%AE%A2%E6%88%B7%E7%AB%AF%28VB%29/Form1.frm__.htm Delphi ://read.pudn.com/downloads91/sourcecode/multimedia/streaming/349759/Delphi_client/Unit1.pas__.htm

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Can anyone help me with this VHDL code (currently malfunctioning)?

- by xx77aBs

This code should be (and is) very simple, and I don't know what I am doing wrong. Here is description of what it should do: It should display a number on one 7-segment display. That number should be increased by one every time someone presses the push button. There is also reset button which sets the number to 0. That's it. Here is VHDL code: library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL; entity PWM is Port ( cp_in : in STD_LOGIC; inc : in STD_LOGIC; rst: in std_logic; AN : out STD_LOGIC_VECTOR (3 downto 0); segments : out STD_LOGIC_VECTOR (6 downto 0)); end PWM; architecture Behavioral of PWM is signal cp: std_logic; signal CurrentPWMState: integer range 0 to 10; signal inco: std_logic; signal temp: std_logic_vector (3 downto 0); begin --cp = 100 Hz counter: entity djelitelj generic map (CountTo => 250000) port map (cp_in, cp); debounce: entity debounce port map (inc, cp, inco); temp <= conv_std_logic_vector(CurrentPWMState, 4); ss: entity decoder7seg port map (temp, segments); process (inco, rst) begin if inco = '1' then CurrentPWMState <= CurrentPWMState + 1; elsif rst='1' then CurrentPWMState <= 0; end if; end process; AN <= "1110"; end Behavioral; Entity djelitelj (the counter used to divide 50MHz clock): library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL; entity PWM is Port ( cp_in : in STD_LOGIC; inc : in STD_LOGIC; rst: in std_logic; AN : out STD_LOGIC_VECTOR (3 downto 0); segments : out STD_LOGIC_VECTOR (6 downto 0)); end PWM; architecture Behavioral of PWM is signal cp: std_logic; signal CurrentPWMState: integer range 0 to 10; signal inco: std_logic; signal temp: std_logic_vector (3 downto 0); begin --cp = 100 Hz counter: entity djelitelj generic map (CountTo => 250000) port map (cp_in, cp); debounce: entity debounce port map (inc, cp, inco); temp <= conv_std_logic_vector(CurrentPWMState, 4); ss: entity decoder7seg port map (temp, segments); process (inco, rst) begin if inco = '1' then CurrentPWMState <= CurrentPWMState + 1; elsif rst='1' then CurrentPWMState <= 0; end if; end process; AN <= "1110"; end Behavioral; Debouncing entity: library IEEE; use IEEE.STD_LOGIC_1164.all; use IEEE.STD_LOGIC_ARITH.all; use IEEE.STD_LOGIC_UNSIGNED.all; ENTITY debounce IS PORT(pb, clock_100Hz : IN STD_LOGIC; pb_debounced : OUT STD_LOGIC); END debounce; ARCHITECTURE a OF debounce IS SIGNAL SHIFT_PB : STD_LOGIC_VECTOR(3 DOWNTO 0); BEGIN -- Debounce Button: Filters out mechanical switch bounce for around 40Ms. -- Debounce clock should be approximately 10ms process begin wait until (clock_100Hz'EVENT) AND (clock_100Hz = '1'); SHIFT_PB(2 Downto 0) <= SHIFT_PB(3 Downto 1); SHIFT_PB(3) <= NOT PB; If SHIFT_PB(3 Downto 0)="0000" THEN PB_DEBOUNCED <= '1'; ELSE PB_DEBOUNCED <= '0'; End if; end process; end a; And here is BCD to 7-segment decoder: library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL; entity decoder7seg is port ( bcd: in std_logic_vector (3 downto 0); segm: out std_logic_vector (6 downto 0)); end decoder7seg; architecture Behavioral of decoder7seg is begin with bcd select segm<= "0000001" when "0000", -- 0 "1001111" when "0001", -- 1 "0010010" when "0010", -- 2 "0000110" when "0011", -- 3 "1001100" when "0100", -- 4 "0100100" when "0101", -- 5 "0100000" when "0110", -- 6 "0001111" when "0111", -- 7 "0000000" when "1000", -- 8 "0000100" when "1001", -- 9 "1111110" when others; -- just - character end Behavioral; Does anyone see where I made my mistake(s) ? I've tried that design on Spartan-3 Started board and it isn't working ... Every time I press the push button, I get crazy (random) values. The reset button is working properly. Thanks !!!!

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Little more help with writing a o buffer with libjpeg

- by Richard Knop

So I have managed to find another question discussing how to use the libjpeg to compress an image to jpeg. I have found this code which is supposed to work: Compressing IplImage to JPEG using libjpeg in OpenCV Here's the code (it compiles ok): /* This a custom destination manager for jpeglib that enables the use of memory to memory compression. See IJG documentation for details. */ typedef struct { struct jpeg_destination_mgr pub; /* base class */ JOCTET* buffer; /* buffer start address */ int bufsize; /* size of buffer */ size_t datasize; /* final size of compressed data */ int* outsize; /* user pointer to datasize */ int errcount; /* counts up write errors due to buffer overruns */ } memory_destination_mgr; typedef memory_destination_mgr* mem_dest_ptr; /* ------------------------------------------------------------- */ /* MEMORY DESTINATION INTERFACE METHODS */ /* ------------------------------------------------------------- */ /* This function is called by the library before any data gets written */ METHODDEF(void) init_destination (j_compress_ptr cinfo) { mem_dest_ptr dest = (mem_dest_ptr)cinfo->dest; dest->pub.next_output_byte = dest->buffer; /* set destination buffer */ dest->pub.free_in_buffer = dest->bufsize; /* input buffer size */ dest->datasize = 0; /* reset output size */ dest->errcount = 0; /* reset error count */ } /* This function is called by the library if the buffer fills up I just reset destination pointer and buffer size here. Note that this behavior, while preventing seg faults will lead to invalid output streams as data is over- written. */ METHODDEF(boolean) empty_output_buffer (j_compress_ptr cinfo) { mem_dest_ptr dest = (mem_dest_ptr)cinfo->dest; dest->pub.next_output_byte = dest->buffer; dest->pub.free_in_buffer = dest->bufsize; ++dest->errcount; /* need to increase error count */ return TRUE; } /* Usually the library wants to flush output here. I will calculate output buffer size here. Note that results become incorrect, once empty_output_buffer was called. This situation is notified by errcount. */ METHODDEF(void) term_destination (j_compress_ptr cinfo) { mem_dest_ptr dest = (mem_dest_ptr)cinfo->dest; dest->datasize = dest->bufsize - dest->pub.free_in_buffer; if (dest->outsize) *dest->outsize += (int)dest->datasize; } /* Override the default destination manager initialization provided by jpeglib. Since we want to use memory-to-memory compression, we need to use our own destination manager. */ GLOBAL(void) jpeg_memory_dest (j_compress_ptr cinfo, JOCTET* buffer, int bufsize, int* outsize) { mem_dest_ptr dest; /* first call for this instance - need to setup */ if (cinfo->dest == 0) { cinfo->dest = (struct jpeg_destination_mgr *) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, sizeof (memory_destination_mgr)); } dest = (mem_dest_ptr) cinfo->dest; dest->bufsize = bufsize; dest->buffer = buffer; dest->outsize = outsize; /* set method callbacks */ dest->pub.init_destination = init_destination; dest->pub.empty_output_buffer = empty_output_buffer; dest->pub.term_destination = term_destination; } /* ------------------------------------------------------------- */ /* MEMORY SOURCE INTERFACE METHODS */ /* ------------------------------------------------------------- */ /* Called before data is read */ METHODDEF(void) init_source (j_decompress_ptr dinfo) { /* nothing to do here, really. I mean. I'm not lazy or something, but... we're actually through here. */ } /* Called if the decoder wants some bytes that we cannot provide... */ METHODDEF(boolean) fill_input_buffer (j_decompress_ptr dinfo) { /* we can't do anything about this. This might happen if the provided buffer is either invalid with regards to its content or just a to small bufsize has been given. */ /* fail. */ return FALSE; } /* From IJG docs: "it's not clear that being smart is worth much trouble" So I save myself some trouble by ignoring this bit. */ METHODDEF(void) skip_input_data (j_decompress_ptr dinfo, INT32 num_bytes) { /* There might be more data to skip than available in buffer. This clearly is an error, so screw this mess. */ if ((size_t)num_bytes > dinfo->src->bytes_in_buffer) { dinfo->src->next_input_byte = 0; /* no buffer byte */ dinfo->src->bytes_in_buffer = 0; /* no input left */ } else { dinfo->src->next_input_byte += num_bytes; dinfo->src->bytes_in_buffer -= num_bytes; } } /* Finished with decompression */ METHODDEF(void) term_source (j_decompress_ptr dinfo) { /* Again. Absolute laziness. Nothing to do here. Boring. */ } GLOBAL(void) jpeg_memory_src (j_decompress_ptr dinfo, unsigned char* buffer, size_t size) { struct jpeg_source_mgr* src; /* first call for this instance - need to setup */ if (dinfo->src == 0) { dinfo->src = (struct jpeg_source_mgr *) (*dinfo->mem->alloc_small) ((j_common_ptr) dinfo, JPOOL_PERMANENT, sizeof (struct jpeg_source_mgr)); } src = dinfo->src; src->next_input_byte = buffer; src->bytes_in_buffer = size; src->init_source = init_source; src->fill_input_buffer = fill_input_buffer; src->skip_input_data = skip_input_data; src->term_source = term_source; /* IJG recommend to use their function - as I don't know **** about how to do better, I follow this recommendation */ src->resync_to_restart = jpeg_resync_to_restart; } All I need to do is replace the jpeg_stdio_dest in my program with this code: int numBytes = 0; //size of jpeg after compression char * storage = new char[150000]; //storage buffer JOCTET *jpgbuff = (JOCTET*)storage; //JOCTET pointer to buffer jpeg_memory_dest(&cinfo,jpgbuff,150000,&numBytes); So I need some help to incorporate the above four lines into this function which now works but writes to a file instead of a memory: int write_jpeg_file( char *filename ) { struct jpeg_compress_struct cinfo; struct jpeg_error_mgr jerr; /* this is a pointer to one row of image data */ JSAMPROW row_pointer[1]; FILE *outfile = fopen( filename, "wb" ); if ( !outfile ) { printf("Error opening output jpeg file %s\n!", filename ); return -1; } cinfo.err = jpeg_std_error( &jerr ); jpeg_create_compress(&cinfo); jpeg_stdio_dest(&cinfo, outfile); /* Setting the parameters of the output file here */ cinfo.image_width = width; cinfo.image_height = height; cinfo.input_components = bytes_per_pixel; cinfo.in_color_space = color_space; /* default compression parameters, we shouldn't be worried about these */ jpeg_set_defaults( &cinfo ); /* Now do the compression .. */ jpeg_start_compress( &cinfo, TRUE ); /* like reading a file, this time write one row at a time */ while( cinfo.next_scanline < cinfo.image_height ) { row_pointer[0] = &raw_image[ cinfo.next_scanline * cinfo.image_width * cinfo.input_components]; jpeg_write_scanlines( &cinfo, row_pointer, 1 ); } /* similar to read file, clean up after we're done compressing */ jpeg_finish_compress( &cinfo ); jpeg_destroy_compress( &cinfo ); fclose( outfile ); /* success code is 1! */ return 1; } Anybody could help me out a bit with it? I've tried meddling with it but I am not sure how to do it. I I just replace this line: jpeg_stdio_dest(&cinfo, outfile); It's not going to work. There is more stuff that needs to be changed a bit in that function and I am being a little lost from all those pointers and memory management.

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o write a C++ program to encrypt and decrypt certain codes.

- by Amber

Step 1: Write a function int GetText(char[],int); which fills a character array from a requested file. That is, the function should prompt the user to input the filename, and then read up to the number of characters given as the second argument, terminating when the number has been reached or when the end of file is encountered. The file should then be closed. The number of characters placed in the array is then returned as the value of the function. Every character in the file should be transferred to the array. Whitespace should not be removed. When testing, assume that no more than 5000 characters will be read. The function should be placed in a file called coding.cpp while the main will be in ass5.cpp. To enable the prototypes to be accessible, the file coding.h contains the prototypes for all the functions that are to be written in coding.cpp for this assignment. (You may write other functions. If they are called from any of the functions in coding.h, they must appear in coding.cpp where their prototypes should also appear. Do not alter coding.h. Any other functions written for this assignment should be placed, along with their prototypes, with the main function.) Step 2: Write a function int SimplifyText(char[],int); which simplifies the text in the first argument, an array containing the number of characters as given in the second argument, by converting all alphabetic characters to lower case, removing all non-alpha characters, and replacing multiple whitespace by one blank. Any leading whitespace at the beginning of the array should be removed completely. The resulting number of characters should be returned as the value of the function. Note that another array cannot appear in the function (as the file does not contain one). For example, if the array contained the 29 characters "The 39 Steps" by John Buchan (with the " appearing in the array), the simplified text would be the steps by john buchan of length 24. The array should not contain a null character at the end. Step 3: Using the file test.txt, test your program so far. You will need to write a function void PrintText(const char[],int,int); that prints out the contents of the array, whose length is the second argument, breaking the lines to exactly the number of characters in the third argument. Be warned that, if the array contains newlines (as it would when read from a file), lines will be broken earlier than the specified length. Step 4: Write a function void Caesar(const char[],int,char[],int); which takes the first argument array, with length given by the second argument and codes it into the third argument array, using the shift given in the fourth argument. The shift must be performed cyclicly and must also be able to handle negative shifts. Shifts exceeding 26 can be reduced by modulo arithmetic. (Is C++'s modulo operations on negative numbers a problem here?) Demonstrate that the test file, as simplified, can be coded and decoded using a given shift by listing the original input text, the simplified text (indicating the new length), the coded text and finally the decoded text. Step 5: The permutation cypher does not limit the character substitution to just a shift. In fact, each of the 26 characters is coded to one of the others in an arbitrary way. So, for example, a might become f, b become q, c become d, but a letter never remains the same. How the letters are rearranged can be specified using a seed to the random number generator. The code can then be decoded, if the decoder has the same random number generator and knows the seed. Write the function void Permute(const char[],int,char[],unsigned long); with the same first three arguments as Caesar above, with the fourth argument being the seed. The function will have to make up a permutation table as follows: To find what a is coded as, generate a random number from 1 to 25. Add that to a to get the coded letter. Mark that letter as used. For b, generate 1 to 24, then step that many letters after b, ignoring the used letter if encountered. For c, generate 1 to 23, ignoring a or b's codes if encountered. Wrap around at z. Here's an example, for only the 6 letters a, b, c, d, e, f. For the letter a, generate, from 1-5, a 2. Then a - c. c is marked as used. For the letter b, generate, from 1-4, a 3. So count 3 from b, skipping c (since it is marked as used) yielding the coding of b - f. Mark f as used. For c, generate, from 1-3, a 3. So count 3 from c, skipping f, giving a. Note the wrap at the last letter back to the first. And so on, yielding a - c b - f c - a d - b (it got a 2) e - d f - e Thus, for a given seed, a translation table is required. To decode a piece of text, we need the table generated to be re-arranged so that the right hand column is in order. In fact you can just store the table in the reverse way (e.g., if a gets encoded to c, put a opposite c is the table). Write a function called void DePermute(const char[],int,char[], unsigned long); to reverse the permutation cypher. Again, test your functions using the test file. At this point, any main program used to test these functions will not be required as part of the assignment. The remainder of the assignment uses some of these functions, and needs its own main function. When submitted, all the above functions will be tested by the marker's own main function. Step 6: If the seed number is unknown, decoding is difficult. Write a main program which: (i) reads in a piece of text using GetText; (ii) simplifies the text using SimplifyText; (iii) prints the text using PrintText; (iv) requests two letters to swap. If we think 'a' in the text should be 'q' we would type aq as input. The text would be modified by swapping the a's and q's, and the text reprinted. Repeat this last step until the user considers the text is decoded, when the input of the same letter twice (requesting a letter to be swapped with itself) terminates the program. Step 7: If we have a large enough sample of coded text, we can use knowledge of English to aid in finding the permutation. The first clue is in the frequency of occurrence of each letter. Write a function void LetterFreq(const char[],int,freq[]); which takes the piece of text given as the first two arguments (same as above) and returns in the 26 long array of structs (the third argument), the table of the frequency of the 26 letters. This frequency table should be in decreasing order of popularity. A simple Selection Sort will suffice. (This will be described in lectures.) When printed, this summary would look something like v x r s z j p t n c l h u o i b w d g e a q y k f m 168106 68 66 59 54 48 45 44 35 26 24 22 20 20 20 17 13 12 12 4 4 1 0 0 0 The formatting will require the use of input/output manipulators. See the header file for the definition of the struct called freq. Modify the program so that, before each swap is requested, the current frequency of the letters is printed. This does not require further calls to LetterFreq, however. You may use the traditional order of regular letter frequencies (E T A I O N S H R D L U) as a guide when deciding what characters to exchange. Step 8: The decoding process can be made more difficult if blank is also coded. That is, consider the alphabet to be 27 letters. Rewrite LetterFreq and your main program to handle blank as another character to code. In the above frequency order, space usually comes first.

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Write a C++ program to encrypt and decrypt certain codes.

- by Amber

Step 1: Write a function int GetText(char[],int); which fills a character array from a requested file. That is, the function should prompt the user to input the filename, and then read up to the number of characters given as the second argument, terminating when the number has been reached or when the end of file is encountered. The file should then be closed. The number of characters placed in the array is then returned as the value of the function. Every character in the file should be transferred to the array. Whitespace should not be removed. When testing, assume that no more than 5000 characters will be read. The function should be placed in a file called coding.cpp while the main will be in ass5.cpp. To enable the prototypes to be accessible, the file coding.h contains the prototypes for all the functions that are to be written in coding.cpp for this assignment. (You may write other functions. If they are called from any of the functions in coding.h, they must appear in coding.cpp where their prototypes should also appear. Do not alter coding.h. Any other functions written for this assignment should be placed, along with their prototypes, with the main function.) Step 2: Write a function int SimplifyText(char[],int); which simplifies the text in the first argument, an array containing the number of characters as given in the second argument, by converting all alphabetic characters to lower case, removing all non-alpha characters, and replacing multiple whitespace by one blank. Any leading whitespace at the beginning of the array should be removed completely. The resulting number of characters should be returned as the value of the function. Note that another array cannot appear in the function (as the file does not contain one). For example, if the array contained the 29 characters "The 39 Steps" by John Buchan (with the " appearing in the array), the simplified text would be the steps by john buchan of length 24. The array should not contain a null character at the end. Step 3: Using the file test.txt, test your program so far. You will need to write a function void PrintText(const char[],int,int); that prints out the contents of the array, whose length is the second argument, breaking the lines to exactly the number of characters in the third argument. Be warned that, if the array contains newlines (as it would when read from a file), lines will be broken earlier than the specified length. Step 4: Write a function void Caesar(const char[],int,char[],int); which takes the first argument array, with length given by the second argument and codes it into the third argument array, using the shift given in the fourth argument. The shift must be performed cyclicly and must also be able to handle negative shifts. Shifts exceeding 26 can be reduced by modulo arithmetic. (Is C++'s modulo operations on negative numbers a problem here?) Demonstrate that the test file, as simplified, can be coded and decoded using a given shift by listing the original input text, the simplified text (indicating the new length), the coded text and finally the decoded text. Step 5: The permutation cypher does not limit the character substitution to just a shift. In fact, each of the 26 characters is coded to one of the others in an arbitrary way. So, for example, a might become f, b become q, c become d, but a letter never remains the same. How the letters are rearranged can be specified using a seed to the random number generator. The code can then be decoded, if the decoder has the same random number generator and knows the seed. Write the function void Permute(const char[],int,char[],unsigned long); with the same first three arguments as Caesar above, with the fourth argument being the seed. The function will have to make up a permutation table as follows: To find what a is coded as, generate a random number from 1 to 25. Add that to a to get the coded letter. Mark that letter as used. For b, generate 1 to 24, then step that many letters after b, ignoring the used letter if encountered. For c, generate 1 to 23, ignoring a or b's codes if encountered. Wrap around at z. Here's an example, for only the 6 letters a, b, c, d, e, f. For the letter a, generate, from 1-5, a 2. Then a - c. c is marked as used. For the letter b, generate, from 1-4, a 3. So count 3 from b, skipping c (since it is marked as used) yielding the coding of b - f. Mark f as used. For c, generate, from 1-3, a 3. So count 3 from c, skipping f, giving a. Note the wrap at the last letter back to the first. And so on, yielding a - c b - f c - a d - b (it got a 2) e - d f - e Thus, for a given seed, a translation table is required. To decode a piece of text, we need the table generated to be re-arranged so that the right hand column is in order. In fact you can just store the table in the reverse way (e.g., if a gets encoded to c, put a opposite c is the table). Write a function called void DePermute(const char[],int,char[], unsigned long); to reverse the permutation cypher. Again, test your functions using the test file. At this point, any main program used to test these functions will not be required as part of the assignment. The remainder of the assignment uses some of these functions, and needs its own main function. When submitted, all the above functions will be tested by the marker's own main function. Step 6: If the seed number is unknown, decoding is difficult. Write a main program which: (i) reads in a piece of text using GetText; (ii) simplifies the text using SimplifyText; (iii) prints the text using PrintText; (iv) requests two letters to swap. If we think 'a' in the text should be 'q' we would type aq as input. The text would be modified by swapping the a's and q's, and the text reprinted. Repeat this last step until the user considers the text is decoded, when the input of the same letter twice (requesting a letter to be swapped with itself) terminates the program. Step 7: If we have a large enough sample of coded text, we can use knowledge of English to aid in finding the permutation. The first clue is in the frequency of occurrence of each letter. Write a function void LetterFreq(const char[],int,freq[]); which takes the piece of text given as the first two arguments (same as above) and returns in the 26 long array of structs (the third argument), the table of the frequency of the 26 letters. This frequency table should be in decreasing order of popularity. A simple Selection Sort will suffice. (This will be described in lectures.) When printed, this summary would look something like v x r s z j p t n c l h u o i b w d g e a q y k f m 168106 68 66 59 54 48 45 44 35 26 24 22 20 20 20 17 13 12 12 4 4 1 0 0 0 The formatting will require the use of input/output manipulators. See the header file for the definition of the struct called freq. Modify the program so that, before each swap is requested, the current frequency of the letters is printed. This does not require further calls to LetterFreq, however. You may use the traditional order of regular letter frequencies (E T A I O N S H R D L U) as a guide when deciding what characters to exchange. Step 8: The decoding process can be made more difficult if blank is also coded. That is, consider the alphabet to be 27 letters. Rewrite LetterFreq and your main program to handle blank as another character to code. In the above frequency order, space usually comes first.

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Steganography Experiment - Trouble hiding message bits in DCT coefficients

- by JohnHankinson

I have an application requiring me to be able to embed loss-less data into an image. As such I've been experimenting with steganography, specifically via modification of DCT coefficients as the method I select, apart from being loss-less must also be relatively resilient against format conversion, scaling/DSP etc. From the research I've done thus far this method seems to be the best candidate. I've seen a number of papers on the subject which all seem to neglect specific details (some neglect to mention modification of 0 coefficients, or modification of AC coefficient etc). After combining the findings and making a few modifications of my own which include: 1) Using a more quantized version of the DCT matrix to ensure we only modify coefficients that would still be present should the image be JPEG'ed further or processed (I'm using this in place of simply following a zig-zag pattern). 2) I'm modifying bit 4 instead of the LSB and then based on what the original bit value was adjusting the lower bits to minimize the difference. 3) I'm only modifying the blue channel as it should be the least visible. This process must modify the actual image and not the DCT values stored in file (like jsteg) as there is no guarantee the file will be a JPEG, it may also be opened and re-saved at a later stage in a different format. For added robustness I've included the message multiple times and use the bits that occur most often, I had considered using a QR code as the message data or simply applying the reed-solomon error correction, but for this simple application and given that the "message" in question is usually going to be between 10-32 bytes I have plenty of room to repeat it which should provide sufficient redundancy to recover the true bits. No matter what I do I don't seem to be able to recover the bits at the decode stage. I've tried including / excluding various checks (even if it degrades image quality for the time being). I've tried using fixed point vs. double arithmetic, moving the bit to encode, I suspect that the message bits are being lost during the IDCT back to image. Any thoughts or suggestions on how to get this working would be hugely appreciated. (PS I am aware that the actual DCT/IDCT could be optimized from it's naive On4 operation using row column algorithm, or an FDCT like AAN, but for now it just needs to work :) ) Reference Papers: http://www.lokminglui.com/dct.pdf http://arxiv.org/ftp/arxiv/papers/1006/1006.1186.pdf Code for the Encode/Decode process in C# below: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Drawing.Imaging; using System.Drawing; namespace ImageKey { public class Encoder { public const int HIDE_BIT_POS = 3; // use bit position 4 (1 << 3). public const int HIDE_COUNT = 16; // Number of times to repeat the message to avoid error. // JPEG Standard Quantization Matrix. // (to get higher quality multiply by (100-quality)/50 .. // for lower than 50 multiply by 50/quality. Then round to integers and clip to ensure only positive integers. public static double[] Q = {16,11,10,16,24,40,51,61, 12,12,14,19,26,58,60,55, 14,13,16,24,40,57,69,56, 14,17,22,29,51,87,80,62, 18,22,37,56,68,109,103,77, 24,35,55,64,81,104,113,92, 49,64,78,87,103,121,120,101, 72,92,95,98,112,100,103,99}; // Maximum qauality quantization matrix (if all 1's doesn't modify coefficients at all). public static double[] Q2 = {1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1}; public static Bitmap Encode(Bitmap b, string key) { Bitmap response = new Bitmap(b.Width, b.Height, PixelFormat.Format32bppArgb); uint imgWidth = ((uint)b.Width) & ~((uint)7); // Maximum usable X resolution (divisible by 8). uint imgHeight = ((uint)b.Height) & ~((uint)7); // Maximum usable Y resolution (divisible by 8). // Start be transferring the unmodified image portions. // As we'll be using slightly less width/height for the encoding process we'll need the edges to be populated. for (int y = 0; y < b.Height; y++) for (int x = 0; x < b.Width; x++) { if( (x >= imgWidth && x < b.Width) || (y>=imgHeight && y < b.Height)) response.SetPixel(x, y, b.GetPixel(x, y)); } // Setup the counters and byte data for the message to encode. StringBuilder sb = new StringBuilder(); for(int i=0;i<HIDE_COUNT;i++) sb.Append(key); byte[] codeBytes = System.Text.Encoding.ASCII.GetBytes(sb.ToString()); int bitofs = 0; // Current bit position we've encoded too. int totalBits = (codeBytes.Length * 8); // Total number of bits to encode. for (int y = 0; y < imgHeight; y += 8) { for (int x = 0; x < imgWidth; x += 8) { int[] redData = GetRedChannelData(b, x, y); int[] greenData = GetGreenChannelData(b, x, y); int[] blueData = GetBlueChannelData(b, x, y); int[] newRedData; int[] newGreenData; int[] newBlueData; if (bitofs < totalBits) { double[] redDCT = DCT(ref redData); double[] greenDCT = DCT(ref greenData); double[] blueDCT = DCT(ref blueData); int[] redDCTI = Quantize(ref redDCT, ref Q2); int[] greenDCTI = Quantize(ref greenDCT, ref Q2); int[] blueDCTI = Quantize(ref blueDCT, ref Q2); int[] blueDCTC = Quantize(ref blueDCT, ref Q); HideBits(ref blueDCTI, ref blueDCTC, ref bitofs, ref totalBits, ref codeBytes); double[] redDCT2 = DeQuantize(ref redDCTI, ref Q2); double[] greenDCT2 = DeQuantize(ref greenDCTI, ref Q2); double[] blueDCT2 = DeQuantize(ref blueDCTI, ref Q2); newRedData = IDCT(ref redDCT2); newGreenData = IDCT(ref greenDCT2); newBlueData = IDCT(ref blueDCT2); } else { newRedData = redData; newGreenData = greenData; newBlueData = blueData; } MapToRGBRange(ref newRedData); MapToRGBRange(ref newGreenData); MapToRGBRange(ref newBlueData); for(int dy=0;dy<8;dy++) { for(int dx=0;dx<8;dx++) { int col = (0xff<<24) + (newRedData[dx+(dy*8)]<<16) + (newGreenData[dx+(dy*8)]<<8) + (newBlueData[dx+(dy*8)]); response.SetPixel(x+dx,y+dy,Color.FromArgb(col)); } } } } if (bitofs < totalBits) throw new Exception("Failed to encode data - insufficient cover image coefficients"); return (response); } public static void HideBits(ref int[] DCTMatrix, ref int[] CMatrix, ref int bitofs, ref int totalBits, ref byte[] codeBytes) { int tempValue = 0; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { if ( (u != 0 || v != 0) && CMatrix[v+(u*8)] != 0 && DCTMatrix[v+(u*8)] != 0) { if (bitofs < totalBits) { tempValue = DCTMatrix[v + (u * 8)]; int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); byte value = (byte)((codeBytes[bytePos] & mask) >> bitPos); // 0 or 1. if (value == 0) { int a = DCTMatrix[v + (u * 8)] & (1 << HIDE_BIT_POS); if (a != 0) DCTMatrix[v + (u * 8)] |= (1 << HIDE_BIT_POS) - 1; DCTMatrix[v + (u * 8)] &= ~(1 << HIDE_BIT_POS); } else if (value == 1) { int a = DCTMatrix[v + (u * 8)] & (1 << HIDE_BIT_POS); if (a == 0) DCTMatrix[v + (u * 8)] &= ~((1 << HIDE_BIT_POS) - 1); DCTMatrix[v + (u * 8)] |= (1 << HIDE_BIT_POS); } if (DCTMatrix[v + (u * 8)] != 0) bitofs++; else DCTMatrix[v + (u * 8)] = tempValue; } } } } } public static void MapToRGBRange(ref int[] data) { for(int i=0;i<data.Length;i++) { data[i] += 128; if(data[i] < 0) data[i] = 0; else if(data[i] > 255) data[i] = 255; } } public static int[] GetRedChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x,y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 16) & 0xff) - 128; } } return (data); } public static int[] GetGreenChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x, y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 8) & 0xff) - 128; } } return (data); } public static int[] GetBlueChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x, y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 0) & 0xff) - 128; } } return (data); } public static int[] Quantize(ref double[] DCTMatrix, ref double[] Q) { int[] DCTMatrixOut = new int[8*8]; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { DCTMatrixOut[v + (u * 8)] = (int)Math.Round(DCTMatrix[v + (u * 8)] / Q[v + (u * 8)]); } } return(DCTMatrixOut); } public static double[] DeQuantize(ref int[] DCTMatrix, ref double[] Q) { double[] DCTMatrixOut = new double[8*8]; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { DCTMatrixOut[v + (u * 8)] = (double)DCTMatrix[v + (u * 8)] * Q[v + (u * 8)]; } } return(DCTMatrixOut); } public static double[] DCT(ref int[] data) { double[] DCTMatrix = new double[8 * 8]; for (int v = 0; v < 8; v++) { for (int u = 0; u < 8; u++) { double cu = 1; if (u == 0) cu = (1.0 / Math.Sqrt(2.0)); double cv = 1; if (v == 0) cv = (1.0 / Math.Sqrt(2.0)); double sum = 0.0; for (int y = 0; y < 8; y++) { for (int x = 0; x < 8; x++) { double s = data[x + (y * 8)]; double dctVal = Math.Cos((2 * y + 1) * v * Math.PI / 16) * Math.Cos((2 * x + 1) * u * Math.PI / 16); sum += s * dctVal; } } DCTMatrix[u + (v * 8)] = (0.25 * cu * cv * sum); } } return (DCTMatrix); } public static int[] IDCT(ref double[] DCTMatrix) { int[] Matrix = new int[8 * 8]; for (int y = 0; y < 8; y++) { for (int x = 0; x < 8; x++) { double sum = 0; for (int v = 0; v < 8; v++) { for (int u = 0; u < 8; u++) { double cu = 1; if (u == 0) cu = (1.0 / Math.Sqrt(2.0)); double cv = 1; if (v == 0) cv = (1.0 / Math.Sqrt(2.0)); double idctVal = (cu * cv) / 4.0 * Math.Cos((2 * y + 1) * v * Math.PI / 16) * Math.Cos((2 * x + 1) * u * Math.PI / 16); sum += (DCTMatrix[u + (v * 8)] * idctVal); } } Matrix[x + (y * 8)] = (int)Math.Round(sum); } } return (Matrix); } } public class Decoder { public static string Decode(Bitmap b, int expectedLength) { expectedLength *= Encoder.HIDE_COUNT; uint imgWidth = ((uint)b.Width) & ~((uint)7); // Maximum usable X resolution (divisible by 8). uint imgHeight = ((uint)b.Height) & ~((uint)7); // Maximum usable Y resolution (divisible by 8). // Setup the counters and byte data for the message to decode. byte[] codeBytes = new byte[expectedLength]; byte[] outBytes = new byte[expectedLength / Encoder.HIDE_COUNT]; int bitofs = 0; // Current bit position we've decoded too. int totalBits = (codeBytes.Length * 8); // Total number of bits to decode. for (int y = 0; y < imgHeight; y += 8) { for (int x = 0; x < imgWidth; x += 8) { int[] blueData = ImageKey.Encoder.GetBlueChannelData(b, x, y); double[] blueDCT = ImageKey.Encoder.DCT(ref blueData); int[] blueDCTI = ImageKey.Encoder.Quantize(ref blueDCT, ref Encoder.Q2); int[] blueDCTC = ImageKey.Encoder.Quantize(ref blueDCT, ref Encoder.Q); if (bitofs < totalBits) GetBits(ref blueDCTI, ref blueDCTC, ref bitofs, ref totalBits, ref codeBytes); } } bitofs = 0; for (int i = 0; i < (expectedLength / Encoder.HIDE_COUNT) * 8; i++) { int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); List<int> values = new List<int>(); int zeroCount = 0; int oneCount = 0; for (int j = 0; j < Encoder.HIDE_COUNT; j++) { int val = (codeBytes[bytePos + ((expectedLength / Encoder.HIDE_COUNT) * j)] & mask) >> bitPos; values.Add(val); if (val == 0) zeroCount++; else oneCount++; } if (oneCount >= zeroCount) outBytes[bytePos] |= mask; bitofs++; values.Clear(); } return (System.Text.Encoding.ASCII.GetString(outBytes)); } public static void GetBits(ref int[] DCTMatrix, ref int[] CMatrix, ref int bitofs, ref int totalBits, ref byte[] codeBytes) { for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { if ((u != 0 || v != 0) && CMatrix[v + (u * 8)] != 0 && DCTMatrix[v + (u * 8)] != 0) { if (bitofs < totalBits) { int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); int value = DCTMatrix[v + (u * 8)] & (1 << Encoder.HIDE_BIT_POS); if (value != 0) codeBytes[bytePos] |= mask; bitofs++; } } } } } } } UPDATE: By switching to using a QR Code as the source message and swapping a pair of coefficients in each block instead of bit manipulation I've been able to get the message to survive the transform. However to get the message to come through without corruption I have to adjust both coefficients as well as swap them. For example swapping (3,4) and (4,3) in the DCT matrix and then respectively adding 8 and subtracting 8 as an arbitrary constant seems to work. This survives a re-JPEG'ing of 96 but any form of scaling/cropping destroys the message again. I was hoping that by operating on mid to low frequency values that the message would be preserved even under some light image manipulation.

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