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• Convert individual pixel values from RGB to YUV420 and save the frame - C++

  24 mars 2014, par learner

  I have been working with RGB->YUV420 conversion for sometime using the FFmpeg library. Already tried the sws_scale functionality but its not working well. Now, I have decided to convert each pixel individually, using colorspace conversion formulae. So, following is the code that gets me few frames and allows me to access individual R,G,B values of each pixel :

  // Read frames and save first five frames to disk
  
      i=0;
  
      while((av_read_frame(pFormatCtx, &packet)>=0) && (i<5)) 
  
      {
  
          // Is this a packet from the video stream?
  
          if(packet.stream_index==videoStreamIdx) 
  
          {   
  
              /// Decode video frame            
  
              avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
  
  
  
              // Did we get a video frame?
  
              if(frameFinished) 
  
              {
  
                  i++;
  
                  sws_scale(img_convert_ctx, (const uint8_t * const *)pFrame->data,
  
                            pFrame->linesize, 0, pCodecCtx->height,
  
                            pFrameRGB->data, pFrameRGB->linesize);
  
  
  
                  int x, y, R, G, B;
  
                  uint8_t *p = pFrameRGB->data[0];
  
                  for(y = 0; y < h; y++)
  
                  {  
  
                      for(x = 0; x < w; x++) 
  
                      {
  
                          R = *p++;
  
                          G = *p++;
  
                          B = *p++;
  
                          printf(" %d-%d-%d ",R,G,B);
  
                      }
  
                  }
  
  
  
                  SaveFrame(pFrameRGB, pCodecCtx->width, pCodecCtx->height, i);
  
              }
  
          }
  
  
  
          // Free the packet that was allocated by av_read_frame
  
          av_free_packet(&packet);
  
      }

  I read online that to convert RGB->YUV420 or vice-versa, one should first convert to YUV444 format. So, its like : RGB->YUV444->YUV420. How do I implement this in C++ ?

  Also, here is the SaveFrame() function used above. I guess this will also have to change a little since YUV420 stores data differently. How to take care of that ?

  void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame)
  
  {
  
      FILE *pFile;
  
      char szFilename[32];
  
      int  y;
  
  
  
      // Open file
  
      sprintf(szFilename, "frame%d.ppm", iFrame);
  
      pFile=fopen(szFilename, "wb");
  
      if(pFile==NULL)
  
          return;
  
  
  
      // Write header
  
      fprintf(pFile, "P6\n%d %d\n255\n", width, height);
  
  
  
      // Write pixel data
  
      for(y=0; ydata[0]+y*pFrame->linesize[0], 1, width*3, pFile);
  
  
  
      // Close file
  
      fclose(pFile);
  
  }

  Can somebody please suggest ? Many thanks !!!

• ffmpeg doesn't recognize Quicktime DV codec

  8 août 2017, par 3pointedit

  I have had success with excellent advice, on a Mac OSX10.5, converting a modified MXF media structure to h264 while retaining multitrack audio. But I cannot get ffmpeg to work in Windows environment.

  See this page.

  Here’s the result of latest failure-

  Microsoft Windows [Version 6.1.7601]
  
  Copyright (c) 2009 Microsoft Corporation.  All rights reserved.
  
  
  
  F:\>h:
  
  
  
  H:\>cd conversion folder
  
  
  
  
  
  H:\Conversion folder>ffmpeg ffmpeg -report -enable_drefs 1 -use_absolute_path 1
  
  -i fdb9_AerialsEagleFarm_0610.mov -map 0:v -map 0:a -write_tmcd 1 fd9_AerialsEag
  
  leFarm_A0609.mp4
  
  ffmpeg started on 2017-08-08 at 15:01:24
  
  Report written to "ffmpeg-20170808-150124.log"
  
  ffmpeg version N-86950-g1bef008 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with gcc 7.1.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --e
  
  nable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --
  
  enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv
  
  --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-li
  
  bfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug -
  
  -enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enabl
  
  e-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-li
  
  bsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolam
  
  e --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx
  
   --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable
  
  -libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
  
    libavutil      55. 70.100 / 55. 70.100
  
    libavcodec     57.102.100 / 57.102.100
  
    libavformat    57. 76.100 / 57. 76.100
  
    libavdevice    57.  7.100 / 57.  7.100
  
    libavfilter     6. 98.100 /  6. 98.100
  
    libswscale      4.  7.102 /  4.  7.102
  
    libswresample   2.  8.100 /  2.  8.100
  
    libpostproc    54.  6.100 / 54.  6.100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000000005c99a0] Opening 'video.vid' for reading
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000000005c99a0] stream 0, error opening alias: path
  
  ='/VibrintAVFiles/Xchange In/fdb9_AerialsEagleFarm_0610.vmf/video.vid', dir='fdb
  
  9_AerialsEagleFarm_0610.vmf', filename='video.vid', volume='default', nlvl_from=
  
  1, nlvl_to=1
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000000005c99a0] Opening 'audio_0.pcm' for reading
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000000005c99a0] stream 1, error opening alias: path
  
  ='/VibrintAVFiles/Xchange In/fdb9_AerialsEagleFarm_0610.vmf/audio_0.pcm', dir='f
  
  db9_AerialsEagleFarm_0610.vmf', filename='audio_0.pcm', volume='default', nlvl_f
  
  rom=1, nlvl_to=1
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000000005c99a0] Opening 'audio_1.pcm' for reading
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000000005c99a0] stream 2, error opening alias: path
  
  ='/VibrintAVFiles/Xchange In/fdb9_AerialsEagleFarm_0610.vmf/audio_1.pcm', dir='f
  
  db9_AerialsEagleFarm_0610.vmf', filename='audio_1.pcm', volume='default', nlvl_f
  
  rom=1, nlvl_to=1
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000000005c99a0] Opening 'audio_2.pcm' for reading
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000000005c99a0] stream 3, error opening alias: path
  
  ='/VibrintAVFiles/Xchange In/fdb9_AerialsEagleFarm_0610.vmf/audio_2.pcm', dir='f
  
  db9_AerialsEagleFarm_0610.vmf', filename='audio_2.pcm', volume='default', nlvl_f
  
  rom=1, nlvl_to=1
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000000005c99a0] Opening 'audio_3.pcm' for reading
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000000005c99a0] stream 4, error opening alias: path
  
  ='/VibrintAVFiles/Xchange In/fdb9_AerialsEagleFarm_0610.vmf/audio_3.pcm', dir='f
  
  db9_AerialsEagleFarm_0610.vmf', filename='audio_3.pcm', volume='default', nlvl_f
  
  rom=1, nlvl_to=1
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000000005c99a0] Could not find codec parameters for
  
   stream 0 (Video: dvvideo (dvpp / 0x70707664), none, 720x576, 28800 kb/s): unspe
  
  cified pixel format
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  Guessed Channel Layout for Input Stream #0.1 : mono
  
  Guessed Channel Layout for Input Stream #0.2 : mono
  
  Guessed Channel Layout for Input Stream #0.3 : mono
  
  Guessed Channel Layout for Input Stream #0.4 : mono
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'fdb9_AerialsEagleFarm_0610.mov':
  
    Metadata:
  
      creation_time   : 2016-10-06T07:01:58.000000Z
  
    Duration: 00:12:43.90, start: 0.000000, bitrate: 1 kb/s
  
      Stream #0:0(eng): Video: dvvideo (dvpp / 0x70707664), none, 720x576, 28800 k
  
  b/s, SAR 118:81 DAR 295:162, 25 fps, 25 tbr, 2500 tbn, 2500 tbc (default)
  
      Metadata:
  
        creation_time   : 2016-10-06T07:01:58.000000Z
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 01:17:27:12
  
      Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16,
  
   768 kb/s (default)
  
      Metadata:
  
        creation_time   : 2016-10-06T07:01:58.000000Z
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:2(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16,
  
   768 kb/s (default)
  
      Metadata:
  
        creation_time   : 2016-10-06T07:01:58.000000Z
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:3(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16,
  
   768 kb/s (default)
  
      Metadata:
  
        creation_time   : 2016-10-06T07:01:58.000000Z
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:4(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, mono, s16,
  
   768 kb/s (default)
  
      Metadata:
  
        creation_time   : 2016-10-06T07:01:58.000000Z
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:5(eng): Data: none (tmcd / 0x64636D74) (default)
  
      Metadata:
  
        creation_time   : 2016-10-06T07:01:58.000000Z
  
        handler_name    : Apple Handle Data Handler
  
        timecode        : 01:17:27:12
  
  [NULL @ 00000000005cad20] Unable to find a suitable output format for 'ffmpeg'
  
  ffmpeg: Invalid argument

  And a screen grab of file structure (although I’m using an alias for target)

  

• FFmpeg concat produces bad Video

  6 mars 2019, par Amorphis

  I have installed ffmpeg on a microsoft/dotnet:2.2-aspnetcore-runtime docker container using
  1.apt-get update
  2.apt-get install ffmpeg.

  seems to be installed fine, but when I try and use it as such
  ffmpeg -f concat -i /data/mylist.txt -c : copy /data/output.mp4

  the output is that the first video part is ok, but the second colors are all messy (hard to explain) and when I change the order of the videos in the list still the first in the list is ok and the second is messed up.

  p.s same settings on a different machine works (ffmpeg for ubuntu)

  bad

  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x55ccbcce90c0] Auto-inserting h264_mp4toannexb bitstream filter
  
  Input #0, concat, from '/data/mylist.txt':
  
    Duration: N/A, start: 0.000000, bitrate: 14915 kb/s
  
      Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 14915 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc
  
      Metadata:
  
        creation_time   : 2014-10-17T04:06:30.000000Z
  
        handler_name    : GPAC ISO Video Handler
  
  Output #0, mp4, to '/data/output.mp4':
  
    Metadata:
  
      encoder         : Lavf57.56.101
  
      Stream #0:0(und): Video: h264 (Constrained Baseline) ([33][0][0][0] / 0x0021), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 14915 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 30k tbc
  
      Metadata:
  
        creation_time   : 2014-10-17T04:06:30.000000Z
  
        handler_name    : GPAC ISO Video Handler
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)

  good

  Input #0, concat, from '/data/mylist.txt':
  
    Duration: N/A, start: 0.000000, bitrate: 14915 kb/s
  
      Stream #0:0(und): Video: h264 (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 14915 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc
  
      Metadata:
  
        creation_time   : 2014-10-17T04:06:30.000000Z
  
        handler_name    : GPAC ISO Video Handler
  
  Output #0, mp4, to '/data/outGood1.mp4':
  
    Metadata:
  
      encoder         : Lavf58.20.100
  
      Stream #0:0(und): Video: h264 (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 14915 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 30k tbc
  
      Metadata:
  
        creation_time   : 2014-10-17T04:06:30.000000Z
  
        handler_name    : GPAC ISO Video Handler
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)