[linux-dvb] Audio encoders buggy ?

[Nic Roets <nic@sig.co.za>]

I have written a Linux driver for a DVB card. The Windows drivers only
supports IP over DVB, but I conviced the card to give me audio data as
well. The packets aren't at the transport stream level, because they
don't contain the PIDs, and they can be up to 3000 or 4000 bytes each.

I can cat the data to mpg123 and hear the radio station, but there are
way too many glitches. There are basically 3 kinds of packets :
0 0 0 0 5 x x x x x FF FC A4 ... (Typically 448 bytes long)
0 0 x x x ... (Any length)
x x x x ... (Any length)
Within some of the longer packets, I can see 2 MPEG audio headers (FF FC
A4 XX ) or more in some cases. However, it frequently happens (1 in 5
times) that the two headers are less than 576 bytes apart (e.g. 503
bytes). So the decoder (e.g. mpg123) moans because it expects the next
frame after 576 bytes.

Is the encoders used to generate the stream buggy, or is it my receiver
card ?

I've checked the CRCs (with maplay) on some of the frames, but they are
ussually OK, I suppose because they only cover the first part of the
frame.

I've tried 0 padding the shorter frames and althu the sound is quite
understandable, it is still not what you'd expect from digital.

Any hints on how to put the stream together, or hack the decoder ?

Actually any info on how these packets are built from TS packets will be
usefull !



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