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• Does Buffer Source change the pixel format to `pix_fmt` or does it only read the input as if it was that format ?

  5 décembre 2022, par Wynell

  I am learning libav and related things.
  
I came across this example from the ffmpeg documentation :

  


       /* buffer video source: the decoded frames from the decoder will be inserted here. */
     snprintf(args, sizeof(args),
             "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
             dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt,
             time_base.num, time_base.den,
             dec_ctx->sample_aspect_ratio.num, dec_ctx->sample_aspect_ratio.den);
  
     ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in",
                                        args, NULL, filter_graph);


  


  If I specify a pix_fmt other than dec_ctx->pix_fmt (for example, rgb24), will this buffer source convert the pixel format to rgb24, or will it instead read the source as if it was in rgb24 format, thereby causing incorrect decoding ?

  


  And what happens if I set a different video_size ?

  


• Encoding Android Camera Frames h263/h264 [on hold]

  29 décembre 2015, par Another Guy

  I want to implement a Video Chatting app on Android . I created a SurfaceView , get Camera preview and captured the frame as a byte[ ] using Camera.PreviewCallback.onPreviewFrame( ) method . Now I want to encode that byte[ ] to a h263 frame , pass over the network . Also get similar type of frame over network , decode it to a byte[ ] ( or a displayable format ) , and show it in a View . I want to do it at least 15 FPS rate . I am asking help for the encoding/decoding part .

  For that purpose , which library would be suitable for me ? From where I should start ? Is my starting point wrong ? Is there any support on SDK or would I have to use NDK ? I have heard about FFMpeg/x264 library , but I could not figure out how I can use them in my purpose . It’s highly appreciated If you name any library , any reference , learning path , link or code snippet . Can you help me saying any workflow I should follow ? What if I want to use h264 encoding ? I just want to get it done , GPL/LGPL license of library would not matter a lot .

  I am a beginner in Android development . Any kind of assistance would be highly appreciated . Thanks in advance .

• Encoding Android Camera Frames h263/h264 [closed]

  29 décembre 2015, par Another Guy

  I want to implement a Video Chatting app on Android . I created a SurfaceView , get Camera preview and captured the frame as a byte[ ] using Camera.PreviewCallback.onPreviewFrame( ) method . Now I want to encode that byte[ ] to a h263 frame , pass over the network . Also get similar type of frame over network , decode it to a byte[ ] ( or a displayable format ) , and show it in a View . I want to do it at least 15 FPS rate . I am asking help for the encoding/decoding part .

  For that purpose , which library would be suitable for me ? From where I should start ? Is my starting point wrong ? Is there any support on SDK or would I have to use NDK ? I have heard about FFMpeg/x264 library , but I could not figure out how I can use them in my purpose . It’s highly appreciated If you name any library , any reference , learning path , link or code snippet . Can you help me saying any workflow I should follow ? What if I want to use h264 encoding ? I just want to get it done , GPL/LGPL license of library would not matter a lot .

  I am a beginner in Android development . Any kind of assistance would be highly appreciated . Thanks in advance .