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• Why when converting avi video file to another format the first 2-3 seconds are blurry ?

  13 juin 2016, par Sharon Gabriel

  The source file is avi. The target new file is mp4.
  The first 2-3 seconds are blurry. Then after 2-3 second the whole video until the end is smooth and sharp.

  Another sub question is how come that 2.16 GB avi file after conversion using ffmpeg is only 1.34 MB ? It’s not part of a movie or something it’s collection of screenshots images i did in c# and then used AviFile Lib to create from them a avi video file. and yet from 2.16 GB to 1.34 MB and it keep the quality i think almost the same quality like the original avi file and the same duration 2:20 minutes.

  About the blurry problem this is my code where i set the ffmpeg arguments and set the process :

  private void Convert()
  
          {
  
              try
  
              {
  
                  Control.CheckForIllegalCrossThreadCalls = false;
  
                  if (ComboBox1.SelectedIndex == 3) 
  
                  {
  
                      strFFCMD = " -i " + (char)34 + InputFile + (char)34 + " -c:v libx264 -s 1920x1080 -pix_fmt yuv420p -qp 18 -profile high444 -c:a libvo_aacenc -b:a 128k -ar 44100 -ac 2 -y " + OutputFile;
  
                  }    
  
                  psiProcInfo.FileName = exepath;
  
                  psiProcInfo.Arguments = strFFCMD;        
  
                  psiProcInfo.UseShellExecute = false;      
  
                  psiProcInfo.WindowStyle = ProcessWindowStyle.Hidden;    
  
                  psiProcInfo.RedirectStandardError = true;             
  
                  psiProcInfo.RedirectStandardOutput = true;         
  
                  psiProcInfo.CreateNoWindow = true;                 
  
                  prcFFMPEG.StartInfo = psiProcInfo;           
  
                  prcFFMPEG.Start();
  
                  ffReader = prcFFMPEG.StandardError;
  
  
  
                  do
  
                  {
  
                      if (Bgw1.CancellationPending)
  
                      {
  
                          return;
  
                      }
  
                      Button5.Enabled = true;
  
                      Button3.Enabled = false;
  
                      strFFOUT = ffReader.ReadLine();                    
  
                      RichTextBox1.Text = strFFOUT;
  
                      if (strFFOUT != null)
  
                      {
  
                          if (strFFOUT.Contains("frame="))
  
                          {
  
                              currentFramestr = strFFOUT.Substring(7, 6).Trim();
  
                              Regex rx = new Regex(@"^\d+");
  
                              Match m = rx.Match(currentFramestr);
  
                              if (m.Success)
  
                              {
  
                                  currentFrameInt = System.Convert.ToInt32(m.Value);
  
                              }
  
                          }
  
                      }
  
                      string percentage = ((double)ProgressBar1.Value / (double)ProgressBar1.Maximum * 100.0).ToString();
  
                      textBox3.Text = ProgressBar1.Value.ToString();                    
  
                      ProgressBar1.Maximum = FCount + 1;
  
                      ProgressBar1.Value = (currentFrameInt);
  
                      Label12.Text = "Current Encoded Frame: " + currentFrameInt;
  
                      Label11.Text = percentage;
  
                  } while (!(prcFFMPEG.HasExited || string.IsNullOrEmpty(strFFOUT)));
  
              }
  
              catch(Exception err)
  
              {
  
                  string errors = err.ToString();
  
              }
  
          }

  psiProcInfo is ProcessStartInfo

  prcFFMPEG is Process

  And this is how it looks like when i play the target the new created converted video file the mp4 the first seconds :

  Duration : 00:02:20

  Width : 1920 Height : 1080

  Data Rate and Total Rate both : 80kbps

  Frame rate : 2 frames/second

  

  This is the output of the ffmpeg console while converting the file.

    ffmpeg version 2.8.git Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 5.2.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  
    libavutil      55. 11.100 / 55. 11.100
  
    libavcodec     57. 17.100 / 57. 17.100
  
    libavformat    57. 20.100 / 57. 20.100
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 21.100 /  6. 21.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  [avi @ 00000147a882b660] Stream #0: not enough frames to estimate rate; consider increasing probesize
  
  Input #0, avi, from 'C:\temp\video\new.avi':
  
    Duration: 00:02:20.50, start: 0.000000, bitrate: 132710 kb/s
  
      Stream #0:0: Video: rawvideo, bgra, 1920x1080, 2 fps, 2 tbr, 2 tbn, 2 tbc
  
  Please use -profile:a or -profile:v, -profile is ambiguous
  
  Codec AVOption b (set bitrate (in bits/s)) specified for output file #0 (C:\temp\video\5.mp4) has not been used for any stream. The most likely reason is either wrong type (e.g. a video option with no video streams) or that it is a private option of some encoder which was not actually used for any stream.
  
  [libx264 @ 00000147a882c820] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2
  
  [libx264 @ 00000147a882c820] profile High, level 4.0
  
  [libx264 @ 00000147a882c820] 264 - core 148 r2638 7599210 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=2 scenecut=40 intra_refresh=0 rc=cqp mbtree=0 qp=18 ip_ratio=1.40 pb_ratio=1.30 aq=0
  
  Output #0, mp4, to 'C:\temp\video\5.mp4':
  
    Metadata:
  
      encoder         : Lavf57.20.100
  
      Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1920x1080, q=-1--1, 2 fps, 16384 tbn, 2 tbc
  
      Metadata:
  
        encoder         : Lavc57.17.100 libx264
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  
  Press [q] to stop, [?] for help
  
  frame=    8 fps=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
  
  frame=   15 fps= 14 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
  
  frame=   21 fps= 13 q=18.0 size=      92kB time=00:00:00.00 bitrate=N/A speed=   0x    
  
  frame=   30 fps= 14 q=18.0 size=     141kB time=00:00:04.50 bitrate= 257.3kbits/s speed=2.03x    
  
  frame=   37 fps= 13 q=20.0 size=     164kB time=00:00:08.00 bitrate= 167.6kbits/s speed=2.82x    
  
  frame=   46 fps= 14 q=18.0 size=     185kB time=00:00:12.50 bitrate= 121.0kbits/s speed= 3.7x    
  
  frame=   51 fps= 13 q=19.0 size=     194kB time=00:00:15.00 bitrate= 106.1kbits/s speed=3.87x    
  
  frame=   58 fps= 13 q=18.0 size=     210kB time=00:00:18.50 bitrate=  93.2kbits/s speed=4.19x    
  
  frame=   65 fps= 13 q=20.0 size=     224kB time=00:00:22.00 bitrate=  83.6kbits/s speed=4.46x    
  
  frame=   71 fps= 13 q=19.0 size=     238kB time=00:00:25.00 bitrate=  78.1kbits/s speed=4.56x    
  
  frame=   78 fps= 13 q=18.0 size=     253kB time=00:00:28.50 bitrate=  72.6kbits/s speed=4.75x    
  
  frame=   83 fps= 13 q=19.0 size=     265kB time=00:00:31.00 bitrate=  70.0kbits/s speed= 4.7x    
  
  frame=   89 fps= 12 q=20.0 size=     280kB time=00:00:34.00 bitrate=  67.4kbits/s speed=4.73x    
  
  frame=   95 fps= 12 q=19.0 size=     291kB time=00:00:37.00 bitrate=  64.5kbits/s speed=4.73x    
  
  frame=  102 fps= 12 q=18.0 size=     308kB time=00:00:40.50 bitrate=  62.3kbits/s speed=4.84x    
  
  frame=  107 fps= 12 q=19.0 size=     317kB time=00:00:43.00 bitrate=  60.4kbits/s speed=4.82x    
  
  frame=  115 fps= 12 q=19.0 size=     336kB time=00:00:47.00 bitrate=  58.6kbits/s speed=4.96x    
  
  frame=  123 fps= 12 q=20.0 size=     354kB time=00:00:51.00 bitrate=  56.8kbits/s speed=5.09x    
  
  frame=  132 fps= 12 q=20.0 size=     371kB time=00:00:55.50 bitrate=  54.8kbits/s speed=5.25x    
  
  frame=  139 fps= 13 q=20.0 size=     392kB time=00:00:59.00 bitrate=  54.5kbits/s speed=5.32x    
  
  frame=  146 fps= 13 q=19.0 size=     408kB time=00:01:02.50 bitrate=  53.5kbits/s speed=5.37x    
  
  frame=  150 fps= 12 q=20.0 size=     417kB time=00:01:04.50 bitrate=  52.9kbits/s speed=5.28x    
  
  frame=  155 fps= 12 q=18.0 size=     428kB time=00:01:07.00 bitrate=  52.4kbits/s speed=5.25x    
  
  frame=  161 fps= 12 q=20.0 size=     441kB time=00:01:10.00 bitrate=  51.6kbits/s speed=5.26x    
  
  frame=  167 fps= 12 q=19.0 size=     462kB time=00:01:13.00 bitrate=  51.9kbits/s speed=5.29x    
  
  frame=  174 fps= 12 q=20.0 size=     483kB time=00:01:16.50 bitrate=  51.7kbits/s speed=5.33x    
  
  frame=  181 fps= 12 q=18.0 size=     614kB time=00:01:20.00 bitrate=  62.8kbits/s speed=5.36x    
  
  frame=  187 fps= 12 q=20.0 size=     763kB time=00:01:23.00 bitrate=  75.3kbits/s speed=5.35x    
  
  frame=  193 fps= 12 q=19.0 size=     852kB time=00:01:26.00 bitrate=  81.2kbits/s speed=5.36x    
  
  frame=  199 fps= 12 q=18.0 size=     865kB time=00:01:29.00 bitrate=  79.6kbits/s speed=5.37x    
  
  frame=  206 fps= 12 q=20.0 size=     932kB time=00:01:32.50 bitrate=  82.6kbits/s speed=5.39x    
  
  frame=  211 fps= 12 q=20.0 size=     943kB time=00:01:35.00 bitrate=  81.3kbits/s speed=5.38x    
  
  frame=  217 fps= 12 q=18.0 size=    1007kB time=00:01:38.00 bitrate=  84.1kbits/s speed=5.38x    
  
  frame=  223 fps= 12 q=20.0 size=    1175kB time=00:01:41.00 bitrate=  95.3kbits/s speed=5.38x    
  
  frame=  230 fps= 12 q=20.0 size=    1195kB time=00:01:44.50 bitrate=  93.7kbits/s speed=5.42x    
  
  frame=  235 fps= 12 q=18.0 size=    1205kB time=00:01:47.00 bitrate=  92.3kbits/s speed= 5.4x    
  
  frame=  241 fps= 12 q=20.0 size=    1222kB time=00:01:50.00 bitrate=  91.0kbits/s speed= 5.4x    
  
  frame=  247 fps= 12 q=19.0 size=    1232kB time=00:01:53.00 bitrate=  89.3kbits/s speed=5.39x    
  
  frame=  255 fps= 12 q=19.0 size=    1252kB time=00:01:57.00 bitrate=  87.7kbits/s speed=5.45x    
  
  frame=  260 fps= 12 q=20.0 size=    1274kB time=00:01:59.50 bitrate=  87.3kbits/s speed=5.44x    
  
  frame=  267 fps= 12 q=20.0 size=    1287kB time=00:02:03.00 bitrate=  85.7kbits/s speed=5.45x    
  
  frame=  272 fps= 12 q=18.0 size=    1304kB time=00:02:05.50 bitrate=  85.1kbits/s speed=5.43x    
  
  frame=  278 fps= 12 q=20.0 size=    1314kB time=00:02:08.50 bitrate=  83.8kbits/s speed=5.41x    
  
  frame=  281 fps= 12 q=-1.0 Lsize=    1376kB time=00:02:19.50 bitrate=  80.8kbits/s speed=5.76x    
  
  video:1372kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.299861%
  
  [libx264 @ 00000147a882c820] frame I:2     Avg QP:15.00  size: 98930
  
  [libx264 @ 00000147a882c820] frame P:80    Avg QP:18.00  size:  7068

• ffplay : ensure that we buffer at least 1 second of content

  11 juin 2016, par Marton Balint

  ffplay : ensure that we buffer at least 1 second of content
  In order to do that, we keep track of the total duration of packets in a packet
  
  queue.
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] ffplay.c

• What's wrong with my use of timestamps/timebases for frame seeking/reading using libav (ffmpeg) ?

  17 septembre 2013, par mtree

  So I want to grab a frame from a video at a specific time using libav for the use as a thumbnail.

  What I'm using is the following code. It compiles and works fine (in regards to retrieving a picture at all), yet I'm having a hard time getting it to retrieve the right picture.

  I simply can't get my head around the all but clear logic behind libav's apparent use of multiple time-bases per video. Specifically figuring out which functions expect/return which type of time-base.

  The docs were of basically no help whatsoever, unfortunately. SO to the rescue ?

  #define ABORT(x) do {fprintf(stderr, x); exit(1);} while(0)
  
  
  
  av_register_all();
  
  
  
  AVFormatContext *format_context = ...;
  
  AVCodec *codec = ...;
  
  AVStream *stream = ...;
  
  AVCodecContext *codec_context = ...;
  
  int stream_index = ...;
  
  
  
  // open codec_context, etc.
  
  
  
  AVRational stream_time_base = stream->time_base;
  
  AVRational codec_time_base = codec_context->time_base;
  
  
  
  printf("stream_time_base: %d / %d = %.5f\n", stream_time_base.num, stream_time_base.den, av_q2d(stream_time_base));
  
  printf("codec_time_base: %d / %d = %.5f\n\n", codec_time_base.num, codec_time_base.den, av_q2d(codec_time_base));
  
  
  
  AVFrame *frame = avcodec_alloc_frame();
  
  
  
  printf("duration: %lld @ %d/sec (%.2f sec)\n", format_context->duration, AV_TIME_BASE, (double)format_context->duration / AV_TIME_BASE);
  
  printf("duration: %lld @ %d/sec (stream time base)\n\n", format_context->duration / AV_TIME_BASE * stream_time_base.den, stream_time_base.den);
  
  printf("duration: %lld @ %d/sec (codec time base)\n", format_context->duration / AV_TIME_BASE * codec_time_base.den, codec_time_base.den);
  
  
  
  double request_time = 10.0; // 10 seconds. Video's total duration is ~20sec
  
  int64_t request_timestamp = request_time / av_q2d(stream_time_base);
  
  printf("requested: %.2f (sec)\t-> %2lld (pts)\n", request_time, request_timestamp);
  
  
  
  av_seek_frame(format_context, stream_index, request_timestamp, 0);
  
  
  
  AVPacket packet;
  
  int frame_finished;
  
  do {
  
      if (av_read_frame(format_context, &packet) < 0) {
  
          break;
  
      } else if (packet.stream_index != stream_index) {
  
          av_free_packet(&packet);
  
          continue;
  
      }
  
      avcodec_decode_video2(codec_context, frame, &frame_finished, &packet);
  
  } while (!frame_finished);
  
  
  
  // do something with frame
  
  
  
  int64_t received_timestamp = frame->pkt_pts;
  
  double received_time = received_timestamp * av_q2d(stream_time_base);
  
  printf("received:  %.2f (sec)\t-> %2lld (pts)\n\n", received_time, received_timestamp);

  Running this with a test movie file I get this output :

      stream_time_base: 1 / 30000 = 0.00003
  
      codec_time_base: 50 / 2997 = 0.01668
  
  
  
      duration: 20062041 @ 1000000/sec (20.06 sec)
  
      duration: 600000 @ 30000/sec (stream time base)
  
      duration: 59940 @ 2997/sec (codec time base)
  
  
  
      requested: 10.00 (sec)  -> 300000 (pts)
  
      received:  0.07 (sec)   -> 2002 (pts)

  The times don't match. What's going on here ? What am I doing wrong ?

  ---

  While searching for clues I stumbled upon this this statement from the libav-users mailing list…

  [...] packet PTS/DTS are in units of the format context's time_base,
  where the AVFrame->pts value is in units of the codec context's time_base.

  In other words, the container can have (and usually does) a different
  time_base than the codec. Most libav players don't bother using the
  codec's time_base or pts since not all codecs have one, but most
  containers do. (This is why the dranger tutorial says to ignore AVFrame->pts)

  …which confused me even more, given that I couldn't find any such mention in the official docs.

  Anyway, I replaced…

  double received_time = received_timestamp * av_q2d(stream_time_base);

  …with…

  double received_time = received_timestamp * av_q2d(codec_time_base);

  …and the output changed to this…

  ...
  
  
  
  requested: 10.00 (sec)  -> 300000 (pts)
  
  received:  33.40 (sec)  -> 2002 (pts)

  Still no match. What's wrong ?