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BrainLai
21st March 2006, 09:01
Is there anyone who can ever play alaw audio in mp4 files successfully?

The popular player VLC(0.8.4a on FC4) seems not to support to save alaw in mp4 files since its message dialog says:

mux_mp4 error: unsupported codec alaw in mp4
main error: cannot add this stream

However, VLC can play alaw certainly from an RTSP session. Hence, I apply live555.com's library QuickTimeFileSink to save the alaw stream in an output mp4 file.

Unfortunately, VLC and most other players ( QT7, WMP 10 with Stormcodec 5.07 or ACE proffessional) cannot play the alaw audio in the mp4 file. Only the "mp4player" from the project mpeg4ip can play it. I am wondering what's wrong and how to correct it.

Any suggestion?

Brain Lai

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PS: when playing the mp4 file, the VLC message dialog says:

mp4 debug: find 2 tracks
mp4 warning: elst box found
mp4 debug: - [0] duration=7000ms media time=0ms) rate=1.0
mp4 debug: track[Id 0x1] read 1 chunk
mp4 debug: track[Id 0x1] read 56000 samples length:7s
main debug: selecting program id=0
mp4 debug: adding track[Id 0x1] audio (enable) language undef
mp4 debug: ignoring track[Id 0x2]
main debug: using demux2 module "mp4"
mp4 warning: DEMUX_GET_FPS unimplemented !!
main debug: looking for a subtitle file in /home/BrainLai/media/
main debug: looking for decoder module: 22 candidates
araw error: bad channels count (1-Cool
ffmpeg debug: libavcodec initialized (interface 3277056 )
ffmpeg debug: ffmpeg codec (PCM ALAW) started
main debug: using decoder module "ffmpeg"
main debug: thread 113585072 (decoder) created at priority 0 (src/input/decoder.c:159)
main debug: `/home/BrainLai/media/demo-2006-3-21-14-19-20.mp4' successfully opened
mp4 debug: elst (0) gives 0ms (movie)-> 0ms (track)
mp4 debug: track[Id 0x1] does not provide Sync Sample Box (stss)
mp4 warning: recreate ES for track[Id 0x1]
ffmpeg debug: ffmpeg codec (PCM ALAW) stopped
main debug: unlocking module "ffmpeg"
main debug: thread 113585072 joined (src/input/decoder.c:191)
main debug: killing decoder fourcc `alaw', 1 PES in FIFO
main debug: Program doesn't contain anymore ES
main debug: looking for decoder module: 22 candidates
araw error: bad channels count (1-Cool
ffmpeg debug: libavcodec already initialized
ffmpeg debug: ffmpeg codec (PCM ALAW) started
main debug: using decoder module "ffmpeg"
main debug: thread 113585072 (decoder) created at priority 0 (src/input/decoder.c:159)
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
ffmpeg warning: invalid channels count 27745
main debug: EOF reached
main debug: waiting decoder fifos to empty
ffmpeg warning: invalid channels count 27745
main debug: closing input
mp4 debug: freeing all memory
main debug: unlocking module "mp4"
main debug: unlocking module "access_file"
ffmpeg debug: ffmpeg codec (PCM ALAW) stopped
main debug: unlocking module "ffmpeg"
main debug: thread 113585072 joined (src/input/decoder.c:191)
main debug: killing decoder fourcc `alaw', 0 PES in FIFO
main debug: thread 55204784 joined (src/input/input.c:386)
main warning: Unable to find parent !
main: nothing to play
foxyshadis
21st March 2006, 12:09
What's wrong is alaw is not an mpeg4 format, it should be obvious from all the error messages. You have mkv, mov, avi, and other containers that are more generic than mp4 for storing all those weird and wacky formats, there's no sense in forcing everything into mp4.