Hi,

I use 'ffmpeg' to convert a .AAC file to MP3 format:
Code:
bash-3.1$ ffmpeg.exe -y -i in.aac out.mp3 && mplayer.exe out.mp3
(see at the end the full output)
The output audio file is playable but too slow.

I've tried to change the '-ar' and '-ab' parameter, but it doesn't seem
to have any effect:
Code:
bash-3.1$ ffmpeg.exe -y -i in.aac out.mp3 -ar 32000 -ab 15 && mplayer.exe out.mp3
(no effect, see below)

How can I change the 'speed' of the music after convertion with ffmpeg?
(and get a playable MP3 file)

Regards,
Petru

1. Simple convertion : output audio file too slow
----------------------------------------------------------------------
----------------------------------------------------------------------
Code:
bash-3.1$ ffmpeg.exe -y -i in.aac out.mp3 && mplayer.exe out.mp3
FFmpeg version SVN-r5804, Copyright (c) 2000-2004 Fabrice Bellard
  configuration:  --enable-mp3lame --enable-faac --enable-faad
--enable-gpl
  libavutil version: 49.0.0
  libavcodec version: 51.10.0
  libavformat version: 50.5.0
  built on Jul 25 2006 07:42:27, gcc: 3.4.4 (cygming special) (gdc
0.12, using dmd 0.125)
Input #0, aac, from 'in.aac':
  Duration: 00:00:03.9, start: 0.000000, bitrate: 15 kb/s
  Stream #0.0: Audio: aac, 8000 Hz, mono, 15 kb/s
Output #0, mp3, to 'out.mp3':
  Stream #0.0: Audio: mp3, 8000 Hz, mono, 64 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
Press [q] to stop encoding
[mp3 @ 0x72e550]lame: output buffer too small (buffer index: 321, free
bytes: 1983)
size=     138kB time=17.7 bitrate=  64.0kbits/s
video:0kB audio:138kB global headers:0kB muxing overhead 0.000000%

MPlayer dev-SVN-r19147-3.4.4 (C) 2000-2006 MPlayer Team
CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ (Family: 15, Model:
35, Stepping: 2)
CPUflags:  MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 1
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx SSE SSE2
Playing out.mp3.
Audio file file format detected.
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
AUDIO: 8000 Hz, 2 ch, s16le, 64.0 kbit/25.00% (ratio: 8000->32000)
Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================
AO: [win32] 8000Hz 2ch s16le (2 bytes per sample)
Video: no video
Starting playback...
A:  15.6 (15.6) of 17.0 (17.0)  0.1%
Exiting... (End of file)
bash-3.1$
2. Changed the '-ar' and '-ab' param - no effect!
-----------------------------------------------------------------
-----------------------------------------------------------------
Code:
bash-3.1$ ffmpeg.exe -y -i in.aac out.mp3 -ar 32000 -ab 15 &&
mplayer.exe out.mp3
FFmpeg version SVN-r5804, Copyright (c) 2000-2004 Fabrice Bellard
  configuration:  --enable-mp3lame --enable-faac --enable-faad
--enable-gpl
  libavutil version: 49.0.0
  libavcodec version: 51.10.0
  libavformat version: 50.5.0
  built on Jul 25 2006 07:42:27, gcc: 3.4.4 (cygming special) (gdc
0.12, using dmd 0.125)
Input #0, aac, from 'in.aac':
  Duration: 00:00:03.9, start: 0.000000, bitrate: 15 kb/s
  Stream #0.0: Audio: aac, 8000 Hz, mono, 15 kb/s
Output #0, mp3, to 'out.mp3':
  Stream #0.0: Audio: mp3, 8000 Hz, mono, 64 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
Press [q] to stop encoding
[mp3 @ 0x72e550]lame: output buffer too small (buffer index: 321, free
bytes: 1983)
size=     138kB time=17.7 bitrate=  64.0kbits/s
video:0kB audio:138kB global headers:0kB muxing overhead 0.000000%
MPlayer dev-SVN-r19147-3.4.4 (C) 2000-2006 MPlayer Team
CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ (Family: 15, Model:
35, Stepping: 2)
CPUflags:  MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 1
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx SSE SSE2

Playing out.mp3.
Audio file file format detected.
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
AUDIO: 8000 Hz, 2 ch, s16le, 64.0 kbit/25.00% (ratio: 8000->32000)
Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================
AO: [win32] 8000Hz 2ch s16le (2 bytes per sample)
Video: no video
Starting playback...
A:  15.6 (15.6) of 17.0 (17.0)  0.0%

Exiting... (End of file)
bash-3.1$
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