[Ffmpeg-devel] AMR encoding on Linux

Daniel Kubec niel
Thu May 11 15:34:53 CEST 2006


just encoding to 3gp and audio track in encoded movie plays about 20% faster then it should.
any idea ? bug or wrong parameters ?


ffmpeg -v 10 -t 10 -vd /dev/video -ad /dev/dsp1 -acodec amr_nb -ac 1 -ab 12 -ar 8000 -vcodec h263 -r 10 -b 88 -s qcif ./test.3gp
FFmpeg version CVS, Copyright (c) 2000-2004 Fabrice Bellard
  configuration:  --enable-mp3lame --enable-pp --enable-gpl --enable-a52 --enable-amr_nb --enable-faac --enable-pthreads
  libavutil version: 49.0.0
  libavcodec version: 51.9.0
  libavformat version: 50.4.0
  built on May 10 2006 20:37:20, gcc: 4.1.0 20060304 (Red Hat 4.1.0-3)
File './test.3gp' already exists. Overwrite ? [y/N] y
Input #0, video4linux, from '':
  Duration: N/A, bitrate: N/A
  Stream #0.0, 1/1000000, 10.00 fps(r): Video: rawvideo, yuv420p, 176x144, 1/10, 3041 kb/s
Input #1, audio_device, from '':
  Duration: N/A, bitrate: N/A
  Stream #1.0, 1/1000000: Audio: pcm_s16le, 8000 Hz, mono, 128 kb/s
Output #0, 3gp, to './test.3gp':
  Stream #0.0, 1/90000, 10.00 fps(c): Video: h263, yuv420p, 176x144, 1/10, q=2-31, 88 kb/s
  Stream #0.1, 1/90000: Audio: amr_nb, 8000 Hz, mono, 12 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #1.0 -> #0.1
Press [q] to stop encoding
timestamp discontinuity 1147354362842745, new offset= -1147354362842745
timestamp discontinuity 1147354362849514, new offset= -1147354362849514
frame=  139 q=11.9 Lsize=     245kB time=10.0 bitrate= 200.3kbits/s dup=0 drop=0
video:225kB audio:16kB global headers:0kB muxing overhead 1.718178%

Daniel


" I work on the QuickTime team at Apple and it was brought to my  
" attention that there might be an issue with a bad AMR bit stream  
" generated by FFMPEG on linux. Specifically, the bit stream returns a  
" value of 10 frames per sample when the value should be 1.
" 
" This is causing the file to not playback in QuickTime on Mac OS X or  
" Windows.
" 
" Has anyone else seen this?
" 
" Thanks in advance,
" Stephen Tonna
" QuickTime, Apple Computer
" 
" _______________________________________________
" ffmpeg-devel mailing list
" ffmpeg-devel at mplayerhq.hu
" http://mplayerhq.hu/mailman/listinfo/ffmpeg-devel





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