[Ffmpeg-devel] HDTV h264 autodetection

Måns Rullgård mru
Sat Nov 4 20:27:46 CET 2006


matthieu castet <castet.matthieu at free.fr> writes:

> M?ns Rullg?rd wrote:
>> matthieu castet <castet.matthieu at free.fr> writes:
>> This has nothing to do with HD or not.  A transport stream without
>> PMT
>> is *invalid*, and anything that creates such things is broken.  The
>> tools in question were always broken, but it has become more apparent
>> with HDTV as H.264 is commonly used there.
>>
> For the record, mplayer is one of them : it only open the dvb device
> for video pids,audio pids and PAT (pid 0). Not for PMT pids.
>
> The problem I see is that this break some layer separation : dvb
> stream code need to know the pids to open on the device, but these
> pids are know in a upper layer that does the PAT/PMT parsing : the ts
> demuxer.

The PMT PID is specified in the PAT.  A properly written app would
begin with requesting the PAT only, parse that and request the PMT PID
from the DVB device, and finally request the audio/video PIDs listed
in the PMT.  There is of course nothing wrong with caching the PIDs to
save some time.

-- 
M?ns Rullg?rd
mru at inprovide.com




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