No Audio

Chris Worley cworley at symbionsys.com
Tue May 1 06:46:37 CEST 2001


I don't know if this is a problem with videolan/vlc or my PES stream. If
I strip the audio packets from the pes stream, and remove the PES
headers, then the audio plays correctly through mpg123, but the full
audio+video PES stream through vlc only plays the video.  I'm using an
AWE64 with the commercial OSS drivers, that normally work quite well,
under SuSE 7.1 and kernel 2.2.18 (SuSE patched).  No esd.

My command line is:

  vlc -I qt -v  -a mpeg voy_v.mpeg

I can set "-I" to "qt" or "gtk"... no difference.  I can set "-V" to
"x11" or "sdl".  Still, no difference.  

When I do an "fuser" on "/dev/dsp" while vlc is running, it shows all
vlc's threads open on the device.

The only errors I get are:

	module error: failed calling init in builtin module

But, all the modules load successfully (I know: I've seen the errors
when there's a problem with a module).  Every once in a while, I get:

	warning: late picture skipped (0x...)

But, that's to be expected.  After awhile, I get:

	PES trashed - decoder fifo full !

Which is a problem, but I'll look into that once I get the audio
working.

I'm concerned that my hardware's to blame...

My hardware's MPEG2 encoder outputs PES streams.  I've
traced through the audio decode thread, it seems to be walking through
the audio data correctly, but I'm really not sure where to look for
problems.

Maybe someone proficient at MPEG sound headers can scan this for
problems? 
Here's an example chunk, from the beginning, of a 16 byte PES header
plus some of the MPEG audio data following:

> od -A x -t x1 ../test.mpeg | less
000000 00 00 01 c0 1e 6a 8c 80 07 21 00 05 fa 1b ff ff
000010 ff fd a8 00 66 66 44 55 55 33 33 33 33 33 33 25
000020 b4 92 25 22 52 25 22 52 55 55 55 5a aa aa aa 4a
000030 ff ff ff 5f ff ff f0 ff ff ff f3 4d 3c e5 96 5d
000040 76 58 75 d7 1c 76 27 1f 89 b6 dd 89 d8 9d 85 c8
000050 60 8e 08 dd 89 d8 5f 99 e9 9e 99 d9 a1 9a 19 9f
000060 91 f9 21 9a 19 9e 99 e9 a1 a2 1a 20 a1 fa 23 a2
000070 3a 1f 9a c7 e6 b2 2a 22 a2 0a 20 a2 39 a2 9a 0a

Thanks,

Chris




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