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• Unable to encode single frame h264 (.mp4) video with FFmpeg. No video stream present

  1er avril 2021, par Maxito

  I have achieved this with ffmpeg command line tool using the command. The folder had only one image.

  



  


  ffmpeg -r 24 -i image%03d.bmp -c:v libx264 -pix_fmt yuv420p
 oneframex.mp4

  


  



  I would like to do the same with C++. If I encode a video of three or more frames, video encodes correctly, but the result of encoding a one or two frames video never has a video stream, as reported by ffprobe and some media players.

  



  Comparing with ffprobe, my video (the one with three or more frames) and the one generated by the command tool show almost the same information. Only bitrate and encoder version are different.

  



  I have tried adding force_key_frames to 1, tried with many encoding options and have be unsuccessful.

  



  The application output gives me this information :

  



  


  [libx264 @ 20d1b840] using cpu capabilities : MMX2 SSE2Fast SSSE3
 SSE4.2 AVX

  
 


  [libx264 @ 20d1b840] profile High, level 4.0

  
 


  [libx264 @ 20d1b840] 264 - core 142 r2431 ac76440 - H.264/MPEG-4 AVC
 codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html -
 options : cabac=0 ref=1 deblock=1:0:0 analyse=0x3:0x113 me=dia subme=8
 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=0 trellis=0
 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2
 threads=1 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1
 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0
 keyint=1 keyint_min=1 scenecut=0 intra_refresh=0 rc=crf mbtree=0
 crf=10.0 qcomp=0.60 qpmin=0 qpmax=25 qpstep=4 ip_ratio=1.40 aq=1:1.00

  


  



  These are my main parameters :

  



  pCodecCtx->codec_id = AV_CODEC_ID_H264;
pCodecCtx->pix_fmt= AV_PIX_FMT_YUV420P; 
pCodecCtx->gop_size = 1;
pCodecCtx->bit_rate = 400000;
pCodecCtx->me_range = 16;
pCodecCtx->max_qdiff = 4;
pCodecCtx->qcompress = 0.6;
pCodecCtx->qmin = 0;
pCodecCtx->qmax = 25;
pCodecCtx->time_base.den = 24;
pCodecCtx->time_base.num = 1;

AVDictionary *param = 0;
            av_dict_set(&param, "preset", "slow", 0);
            av_dict_set(&param, "profile", "high", 0);
            av_dict_set(&param, "crf", "10", 0); //this gave me quality
            av_dict_set(&param, "force_key_frames", "1", 0);


  



  In my encoding I just added

  



  ppicture->pts = pCodecCtx->frame_number


  



  to avoid non-strictly-monotonic PTS message. And tried the methods from this question in case it had something to do.

  



  I’m sure I must be missing some important parameter to be able to create such a small video. I will take any suggestion.

  


• Unable to encode single frame h264 (.mp4) video with FFmpeg. No video stream present

  5 mai 2015, par Maxito

  I have achieved this with ffmpeg command line tool using the command. The folder had only one image.

  ffmpeg -r 24 -i image%03d.bmp -c:v libx264 -pix_fmt yuv420p
  oneframex.mp4

  I would like to do the same with C++. If I encode a video of three or more frames, video encodes correctly, but the result of encoding a one or two frames video never has a video stream, as reported by ffprobe and some media players.

  Comparing with ffprobe, my video (the one with three or more frames) and the one generated by the command tool show almost the same information. Only bitrate and encoder version are different.

  I have tried adding force_key_frames to 1, tried with many encoding options and have be unsuccessful.

  The application output gives me this information :

  [libx264 @ 20d1b840] using cpu capabilities : MMX2 SSE2Fast SSSE3
  SSE4.2 AVX

  [libx264 @ 20d1b840] profile High, level 4.0

  [libx264 @ 20d1b840] 264 - core 142 r2431 ac76440 - H.264/MPEG-4 AVC
  codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html -
  options : cabac=0 ref=1 deblock=1:0:0 analyse=0x3:0x113 me=dia subme=8
  psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=0 trellis=0
  8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2
  threads=1 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1
  interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0
  keyint=1 keyint_min=1 scenecut=0 intra_refresh=0 rc=crf mbtree=0
  crf=10.0 qcomp=0.60 qpmin=0 qpmax=25 qpstep=4 ip_ratio=1.40 aq=1:1.00

  These are my main parameters :

  pCodecCtx->codec_id = AV_CODEC_ID_H264;
  
  pCodecCtx->pix_fmt= AV_PIX_FMT_YUV420P; 
  
  pCodecCtx->gop_size = 1;
  
  pCodecCtx->bit_rate = 400000;
  
  pCodecCtx->me_range = 16;
  
  pCodecCtx->max_qdiff = 4;
  
  pCodecCtx->qcompress = 0.6;
  
  pCodecCtx->qmin = 0;
  
  pCodecCtx->qmax = 25;
  
  pCodecCtx->time_base.den = 24;
  
  pCodecCtx->time_base.num = 1;
  
  
  
  AVDictionary *param = 0;
  
              av_dict_set(&param, "preset", "slow", 0);
  
              av_dict_set(&param, "profile", "high", 0);
  
              av_dict_set(&param, "crf", "10", 0); //this gave me quality
  
              av_dict_set(&param, "force_key_frames", "1", 0);

  In my encoding I just added

  ppicture->pts = pCodecCtx->frame_number

  to avoid non-strictly-monotonic PTS message. And tried the methods from this question in case it had something to do.

  I’m sure I must be missing some important parameter to be able to create such a small video. I will take any suggestion.

• Problem with ffplay from webcam stream using complex filters

  29 mai 2022, par efelbar

  I'm trying to stream video from a webcam (at /dev/video2) through ffplay to scale and recolor it, add some text, and then reduce the number of colors with palettes. I don't get any errors, but running the ffplay command :

  


  ffplay -i /dev/video2 -vf "hflip,\
  colorbalance=\
    rs=0.4:\
    bs=-0.4\
  ,\
  scale=\
    trunc(iw/8):\
    trunc(ih/8)\
  ,\
  drawtext=\
    text=\
      'efelbar':\
      fontcolor=white:\
      fontsize=10:\
      box=1:\
      boxcolor=black:\
      boxborderw=5:\
      x=(w-text_w)/2:\
      y=(h-text_h)/2\
  ,\
  split[s0][s1];\
  [s0]palettegen=\
    max_colors=16\
  [p];\
  [s1][p]paletteuse"


  


  seems to stall, and fails to produce video output.

  


  Running the simpler command ffplay -i /dev/video2 -vf "split[s0][s1];[s0]palettegen=max_colors=16[p];[s1][p]paletteuse", which takes a stream from a webcam and (should) reduce the number of colors, results in it just sitting there without showing the actual output stream. This might just be a performance issue because I'm on older hardware, but it doesn't give output relfective of that.

  


  The output of that command is as follows :

  


  ffplay version n5.0 Copyright (c) 2003-2022 the FFmpeg developers
  built with gcc 11.2.0 (GCC)
  configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-amf --enable-avisynth --enable-cuda-llvm --enable-lto --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmfx --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librav1e --enable-librsvg --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-libzimg --enable-nvdec --enable-nvenc --enable-shared --enable-version3
  libavutil      57. 17.100 / 57. 17.100
  libavcodec     59. 18.100 / 59. 18.100
  libavformat    59. 16.100 / 59. 16.100
  libavdevice    59.  4.100 / 59.  4.100
  libavfilter     8. 24.100 /  8. 24.100
  libswscale      6.  4.100 /  6.  4.100
  libswresample   4.  3.100 /  4.  3.100
  libpostproc    56.  3.100 / 56.  3.100
Input #0, video4linux2,v4l2, from '/dev/video2':B sq=    0B f=0/0   
  Duration: N/A, start: 254970.739108, bitrate: 147456 kb/s
  Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 640x480, 147456 kb/s, 30 fps, 30 tbr, 1000k tbn


  


  I'm running this on a thinkpad t420s, so I definitely wouldn't be surprised if my laptop just can't process video that quickly. If that is the case, suggestions for optimizations would be great !