[vdr] softdevice audio problem. audio repacker issue?

Reinhard Nissl rnissl at gmx.de
Sat Mar 17 20:57:12 CET 2007


Hi,

Stefan Lucke wrote:

> Dumping the first 16 bytes of audio packets we get, shows the following:
> ff fc a4 0d b6 64 88 55 33 65 56 54 44 21 33 33
> ff fc a4 0d 54 6a 88 65 33 44 56 54 33 33 33 33
> ff fc a4 0d 02 a4 88 55 33 54 66 44 43 33 33 33
> 99 77 1b e6 34 b2 5f 41 e8 5b 90 a9 d2 04 24 5e
> ff fc c4 04 7c c4 dd 44 44 66 57 55 55 55 33 33
> ff fc c4 04 1d 61 dd 46 44 66 55 55 55 55 33 33
> 68 6a 60 18 d8 52 92 4f 54 98 0b 93 27 22 4e 74
> ff fc c4 04 94 01 dd 44 56 66 55 55 55 55 33 33
> 
> Is audio repacker active even for old recording ?
> When I deactivate audio repacker, sound is garbled allways.

cAudioRepacker was introduced after VDR-1.3.26 and it is only active in
transfer mode or while recording. It is not active while replaying a
recording, so it has no influence on recordings taken with VDR-1.2.1.

But when cAudioRepacker was not active, an audio PES packet may contain,
 multiple audio frames and/or just a fragment of an audio frame at the
beginning or at the end of the PES packet.

So if ffmpeg can only work on single and/or complete audio frames,
you'll have to break the PES packet apart and assemble the fragments at
the end and the beginning of the next PES packet. cAudioRepacker can do
this for you. Just feed it PES packets via it's Repack() method and the
given ResultBuffer will contain a PES packet per audio frame.

Bye.
-- 
Dipl.-Inform. (FH) Reinhard Nissl
mailto:rnissl at gmx.de



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