[linux-dvb] DVB vs ATSC transport stream formatting

[Marcus Metzler <mocm@metzlerbros.de>]

Greg Herlein writes:
 > It's come to light in my work on transport streams this week that
 > DVB-formatted streams (prevalent in Europe and on many satellites
 > here in the US) have subtle differences from ATSC-formatted
 > streams (prevalent here in the US for digital broadcasting,
 > especially the free to air terrestial).
 > 
 > Specifically, the mapping of AC3 audio is done in 'PES private
 > streams' in DVB where it's has a mandated stream type of 0x06.
 > In ATSC it has to be set to a stream type of 0x81 and is a normal
 > audio PES stream.
 > 

AFAIK and have seen in some ATSC samples the PES for DVB and ATSC are
the same. They may have different entries in the PMT, but the PES
structure is PRIVATE STREAM 1. Compared to a DVD stream the TS AC3 PES
don't have the extra 4 byte header in the payload (not inside PES
header) which defines the audio channel for DVD playback (i.e. 0x80
... 0x8F) and the pointer to the first audio frame. This causes some
complications with a conversion to program streams. But i you have a
pid filter and filter for the audio and video PIDs you get the same
for DVB and ATSC (e.g. if you use ts2ps or replex). Only the
evaluation of the PMT may be different, but I haven't looked at that
yet.

Marcus

-- 
/--------------------------------------------------------------------\
| Dr. Marcus O.C. Metzler        |                                   |
| mocm@metzlerbros.de            | http://www.metzlerbros.de/        |
\--------------------------------------------------------------------/
 |>>>        I like GNU, but I couldn't eat a whole one          <<<|


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