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• How to stop perl buffering ffmpeg output

  4 février 2017, par Sebastian King

  I am trying to have a Perl program process the output of an ffmpeg encode, however my test program only seems to receive the output of ffmpeg in periodic chunks, thus I am assuming there is some sort of buffering going on. How can I make it process it in real-time ?

  My test program (the tr command is there because I thought maybe ffmpeg’s carriage returns were causing perl to see one big long line or something) :

  #!/usr/bin/perl
  
  
  
  $i = "test.mkv"; # big file, long encode time
  
  $o = "test.mp4";
  
  
  
  open(F, "-|", "ffmpeg -y -i '$i' '$o' 2>&1 | tr '\r' '\n'")
  
          or die "oh no";
  
  
  
  while(<f>) {
  
          print "A12345: $_"; # some random text so i know the output was processed in perl
  
  }
  
  </f>

  Everything works fine when I replace the ffmpeg command with this script :

  #!/bin/bash
  
  
  
  echo "hello";
  
  
  
  for i in `seq 1 10`; do
  
          sleep 1;
  
          echo "hello $i";
  
  done
  
  
  
  echo "bye";

  When using the above script I see the output each second as it happens. With ffmpeg it is some 5-10 seconds or so until it outputs and will output sometimes 100 lines each output.

  I have tried using the program unbuffer ahead of ffmpeg in the command call but it seems to have no effect. Is it perhaps the 2>&1 that might be buffering ?
  Any help is much appreciated.

  If you are unfamiliar with ffmpeg’s output, it outputs a bunch of file information and stuff to STDOUT and then during encoding it outputs lines like

  frame=  332 fps= 93 q=28.0 size=     528kB time=00:00:13.33 bitrate= 324.2kbits/s speed=3.75x

  which begin with carriage returns instead of new lines (hence tr) on STDERR (hence 2>&1).

• FFMPEG Incompatible sprop-parameter-sets with libstagefright on Android 4.0 for H264

  7 août 2012, par user1582384

  I am having an issue with the RTSP SDP generated by FFMPEG in Android.
  I have the FFMPEG 0.11.1 compiled with NDK and running on Android. I use the FFSERVER to stream an mp4 file locally to the MediaPlayer.

  Here is the generated SDP description :

  08-07 14:04:04.034 : V/rtsp_server(20161) : o=- 0 0 IN IP4 127.0.0.1

  08-07 14:04:04.034 : V/rtsp_server(20161) : s=No Title

  08-07 14:04:04.034 : V/rtsp_server(20161) : c=IN IP4 0.0.0.0

  08-07 14:04:04.034 : V/rtsp_server(20161) : t=0 0

  08-07 14:04:04.034 : V/rtsp_server(20161) : a=tool:libavformat 54.6.100

  08-07 14:04:04.034 : V/rtsp_server(20161) : m=video 0 RTP/AVP 96

  08-07 14:04:04.034 : V/rtsp_server(20161) : b=AS:312

  08-07 14:04:04.034 : V/rtsp_server(20161) : a=x-dimensions:512,384

  08-07 14:04:04.034 : V/rtsp_server(20161) : a=rtpmap:96 H264/90000

  08-07 14:04:04.034 : V/rtsp_server(20161) : a=fmtp:96
  packetization-mode=0 ;profile-level-id=640015 ;sprop-parameter-sets=J2QAH62ECSZuIzSQgSTNxGaSECSZuIzSQgSTNxGaSECSZuIzSQgSTNxGaSEFWuvX1+T+vyfXrrVQgq116+vyf1+T69daq0BAGMg=,KO48sA==

  08-07 14:04:04.034 : V/rtsp_server(20161) : a=control:streamid=0

  08-07 14:04:04.034 : V/rtsp_server(20161) : m=audio 0 RTP/AVP 97

  08-07 14:04:04.034 : V/rtsp_server(20161) : b=AS:29

  08-07 14:04:04.034 : V/rtsp_server(20161) : a=rtpmap:97
  MPEG4-GENERIC/44100/1

  08-07 14:04:04.034 : V/rtsp_server(20161) : a=fmtp:97
  profile-level-id=1 ;mode=AAC-hbr ;sizelength=13 ;indexlength=3 ;indexdeltalength=3 ;
  config=1208

  08-07 14:04:04.034 : V/rtsp_server(20161) : a=control:streamid=1

  Running the same application on Galaxy S2 works since it uses libopencore. But on newer devices it crashes while trying to extract the width and height from the extradata.

  So the problem is with the sprop-parameter-sets.

  My question is why does libstagefright parse the sprop-parameter-sets differently and how could the existing string be converted for compatibility ?

• FFMPEG “buffer queue overflow, dropping.” while filter_complex concating

  8 août 2019, par March3April4

  I’m using the below command to concat several videos to a single video.

  ffmpeg -i /storage/emulated/0/Cache/1565235095822.mp4
  
  -i /storage/emulated/0/Cache/1565235097989.mp4
  
  -i /storage/emulated/0/Cache/1565235099167.mp4 
  
  -i /storage/emulated/0/Cache/1565235100276.mp4
  
  -i /storage/emulated/0/Cache/1565235096982.mp4
  
  -filter_complex [0:v:0] [0:a:0] [1:v:0] [1:a:0] [2:v:0] [2:a:0] [3:v:0] [3:a:0] [4:v:0] [4:a:0] concat=n=5:v=1:a=1 [v] [a]
  
  -map [v]
  
  -map [a]
  
  -max_muxing_queue_size 9999
  
  -preset ultrafast
  
  /storage/emulated/0/Cache/1565235101418.mp4

  The input videos are also made by ffmpeg, and are about 1 megabyte big. (Each consists of a single picture and an audio)

  The above command line works well for mainstream devices such as galaxy s10 series, but for models like Lg K10, the below line appears.

  [Parsed_concat_0 @ 0xb9ab05a0] Buffer queue overflow, dropping.

  The encoding does not stop even though the above line shows up, but the result video contains some time skips and missing audio.

  I assumed that this has to do with performance of the device itself, so, I tried to do the job without encoding. I’ve tried the concat demuxer with no luck.

  What else can I try to make this to work ? Any help will be thankful.

  ------------------Edit-------------------------

  The ffmpeg videos are create by the following command.

          String[] array = {
  
                   "-framerate", "1",
  
                  "-i", "targetVideo.png",
  
                  "-i", "targetAudio.mp3",
  
                  "-r", "14",
  
                  "-c:v", "libx264",
  
                  "-c:a", "aac",
  
                  "-pix_fmt", "yuv420p",
  
                  "-video_track_timescale", "90000",
  
                  "-c:a", "copy",
  
                  outputPath.mp4};