[Ffmpeg-devel] FW: Bug encountered with ffmpeg.

Steven Dzik sdzik
Wed May 31 20:09:37 CEST 2006


 

ffmpeg bug report:

 

I encountered the following bug when using ffmpeg to convert a wav file

to mp2 format. The resulting file had audio pops. 

Encoded at 320kbits/sec. worked correctly.

The input and output files are attached.

 

Command line:

ffmpeg -i temp2.wav -ab 384 temp2.mp2

 

The resulting mp2 file contained spikes not found in the original wave.

 

However, transcoding to 320kbits/sec worked fine:

ffmpeg -i temp2.wav -ab 320 temp2.mp2

 

Output from command:

 

$ ./ffmpeg -i temp2.wav -ab 384 temp2.mp2

FFmpeg version CVS, Copyright (c) 2000-2004 Fabrice Bellard

  configuration:

  libavutil version: 49.0.0

  libavcodec version: 51.9.0

  libavformat version: 50.4.0

  built on May 26 2006 16:11:36, gcc: 3.3.1 (cygming special)

Input #0, wav, from 'temp2.wav':

  Duration: 00:00:59.9, start: 0.000000, bitrate: 1535 kb/s

  Stream #0.0: Audio: pcm_s16le, 48000 Hz, stereo, 1536 kb/s

Output #0, mp2, to 'temp2.mp2':

  Stream #0.0: Audio: mp2, 48000 Hz, stereo, 384 kb/s

Stream mapping:

  Stream #0.0 -> #0.0

Press [q] to stop encoding

size=    2811kB time=60.0 bitrate= 384.0kbits/s

video:0kB audio:2811kB global headers:0kB muxing overhead 0.000000%

 

 

Result from gdb:

 

$ gdb ffmpeg_g

GNU gdb 2003-09-20-cvs (cygwin-special)

Copyright 2003 Free Software Foundation, Inc.

GDB is free software, covered by the GNU General Public License, and you are

welcome to change it and/or distribute copies of it under certain
conditions.

Type "show copying" to see the conditions.

There is absolutely no warranty for GDB.  Type "show warranty" for details.

This GDB was configured as "i686-pc-cygwin"...

(gdb) run -i temp2.wav -ab 384 test2a.mp2

Starting program: /cygdrive/c/ffmpeg-cvs/ffmpeg_20060519/ffmpeg_g.exe -i
temp0

FFmpeg version CVS, Copyright (c) 2000-2004 Fabrice Bellard

  configuration:

  libavutil version: 49.0.0

  libavcodec version: 51.9.0

  libavformat version: 50.4.0

  built on May 26 2006 16:11:36, gcc: 3.3.1 (cygming special)

Input #0, wav, from 'temp2.wav':

  Duration: 00:00:59.9, start: 0.000000, bitrate: 1535 kb/s

  Stream #0.0: Audio: pcm_s16le, 48000 Hz, stereo, 1536 kb/s

Output #0, mp2, to 'test2a.mp2':

  Stream #0.0: Audio: mp2, 48000 Hz, stereo, 384 kb/s

Stream mapping:

  Stream #0.0 -> #0.0

Press [q] to stop encoding

size=    2811kB time=60.0 bitrate= 384.0kbits/s

video:0kB audio:2811kB global headers:0kB muxing overhead 0.000000%

 

Program exited normally.

(gdb)

 

 

If you have any questions please do not hesitate to contact me.

 

                      Thanks,

 

 

                           Steven Dzik

 

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