search for: uv_stride

hi all, i'm trying to code a tool to get some images from a ogg/theora file .... so basically i need to get a frame and convert to rgb ... and here is my question (sorry, i'm newbe here) ... how to convert a yuv_buffer to a rgb matrix ? i tryied diferent ways but my mistakes are bassically cause i don't understant how yuv_buffer structure works ... anybody can help? thanks a lot.

...me[cc*4+3]=255; //R = Y + 1.371(CR - 128) //G = Y - 0.698(CR - 128) - 0.336(CB - 128) //B = Y + 1.732(CB - 128) //A = 255 } But it seems to me that this code is incorrect, because don't use y_stride, uv_height, uv_width, uv_stride fields. File libtheora-1.0alpha4.pdf doesn't contain enough useful information concerning these fields: y_stride, uv_height, uv_width, uv_stride. Please, write an example-code for needeed YCbCr to RGB convertion or give me link where wrote about that. Thanks! ls, russian enthusiast.

...v_buffer struct and set the widths, heights, and strides correctly. What I've been trying to use is: yuv_buffer yuv; yuv.y_width = Width; yuv.y_height = Height; yuv.y_stride = Width; yuv.uv_width = Width; yuv.uv_height = Height; yuv.uv_stride = Width; yuv.y = YDATA; yuv.u = UDATA; yuv.v = VDATA; There isn't a lot of documentation on how Theora "wants" the pixel data in theora.h, so I really feel like this should be right (since I have a 1:1:1 ratio of RGB data to YUV data)....

...etSize(); long* texMem = (long*) texture->lock(); for (int y=0; y<texDim.Height; ++y) { for (int x=0; x<texDim.Width; ++x) { int Y = yuvBuffer.y [y*yuvBuffer.y_stride + x]; int U = yuvBuffer.u [(y/2)*yuvBuffer.uv_stride + (x/2)]; int V = yuvBuffer.v [(y/2)*yuvBuffer.uv_stride + (x/2)]; int B = (int)(1.164*(Y - 16) + 2.018*(U - 128)); int G = (int)(1.164*(Y - 16) - 0.813*(V - 128) - 0.391*(U - 128)); int R = (int)(1.164*(Y - 16) + 1...

...said plugin to work was basically possible only because I'm good at using emacs copying functions, using your code for clipping+offset. I couldn't really understand why it worked, because there was one relevant concept which I simply can't understand -- stride. There's y_stride and uv_stride. Everything works now, but I'd rather understand _why_ it works, so if someone could explain what stride is (from a little googling it seems to be a concept which exists in most YUV codecs), I'd be very greatful. Other stuff: I was talking to meu on #theora about the aspect values. I wante...

Just trying to debug my theora encoder... just wondering if someone could give me some insight on a few thigns... In the yuv_buffer i'm sending in... i am just setting y_stride = y_width = videoWidth uv_stride = videoWidth/2 y_height = videoHeight uv_height = videoHeight/2 Making the y buffer (width*height) and each of u and v (width*height/4) Am i correct in doing this ? I knwo stride needn't equal width... but from the videos width, can i just make them equal ? Any restrictions ? Also the other...

hi all I guess that *Theora* will convert the input color space (RGB or CMYK or any) into YUV before it process and encode. (that means theora can operate on several color space, but it get convert into YUV before process) Is that true...? I want to get a gray scale, encoded video output from the *Theora* encoder while the input video is getting from a web cam (color input and gray scale

...gned char *yuvframe, ogg_page *op) { while (ogg_stream_pageout(&enc_stream, op) == 0) { yuv_buffer yuv_enc; yuv_enc.y_width=enc_width; yuv_enc.y_height=enc_height; yuv_enc.y_stride=enc_width; yuv_enc.uv_width=enc_width/2; yuv_enc.uv_height=enc_height/2; yuv_enc.uv_stride=enc_width/2; yuv_enc.y=yuvframe; yuv_enc.u=yuvframe+enc_width*enc_height; yuv_enc.v=yuvframe+enc_width*enc_height*5/4; theora_encode_YUVin(&enc_state,&yuv_enc); ogg_packet opacket; theora_encode_packetout(&enc_state,0,&opacket); ogg_stream_packetin(&a...

I posted this the other day... but it didn't get delivered... ------------------------------------------------------------------- I'm getting stuck into a theora decoder for directshow... i was just wondering if someone could give me some info. What output format does theora use ? http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnwmt/html/YUVFormats.asp

Hi there, is there any document giving a high-level overview of how to use "libtheora"? As it stands, I'm scrounging through headers and example code, and doing a whole lot of guessing. In the meantime, could you either confirm or deny the following guesses? 1) Before compressing with Theora, I must unpack my YUY2 data into three separate arrays (Y, U, and V respectively), and

I'd previously been working on the assumption that the frame_height was the height of the inner picture region... and height was the height of the outer frame. Then upon readnig the spec... where it calls the outer part the frame and the inner part the picture region... i assumed i'd made a mistake and that frame_width is actually >= width in the theorainfo structure... ie

...*yuvframe; int fetch_video_page( ogg_page *videopage, ogg_stream_state *to, theora_state *td ) { yuv_buffer yuv; ogg_packet op; yuv.y_width = video_x; yuv.y_height = video_y; yuv.y_stride = video_x; yuv.uv_width = video_x / 2; yuv.uv_height = video_y / 2; yuv.uv_stride = video_x / 2; yuv.y = yuvframe; yuv.u = yuvframe + video_x * video_y; yuv.v = yuvframe + video_x * video_y * 5 / 4; /* is there a video page flushed? If not, work until there is. */ while( 1 ) { frame_counter--; fprintf( stderr, "\r%c", SPIN[frame_c...

...L ) { fprintf( stderr, "### malloc() error \n" ); return -1; } tYUVbuffer.y_width = iVideoX; tYUVbuffer.y_height = iVideoY; tYUVbuffer.y_stride = iVideoX; tYUVbuffer.uv_width = iVideoX / 2; tYUVbuffer.uv_height = iVideoY / 2; tYUVbuffer.uv_stride = iVideoX / 2; tYUVbuffer.y = ucYUVframe; tYUVbuffer.u = ucYUVframe + iVideoX * iVideoY; tYUVbuffer.v = ucYUVframe + iVideoX * iVideoY * 5 / 4; return 0; } int OGG_OpenClip( const char *szFilename ) { int iRet = 0; printf( "+++ OGG_OpenClip() \n" ); theora...