[linux-dvb] TTUSB DEC-2000T Driver: tuning problems

Peter Beutner p.beutner at gmx.net
Tue Oct 17 18:18:23 CEST 2006


Mario Rossi schrieb:
>> IIRC DMX_PES_OTHER is the correct pid filter, while DMX_PES_AUDIO and
>> _VIDEO
>> were used only by FF cards
... and all devices driven by the ttusb-dec driver ;)

> 
> This is the same thing I've read.
> The card has a MPEG-decoder but it is not possible to use it from USB
> (it works when connecting the card to television), so I am not sure
> whether it is a FF card or not.
> 
> Reading the source code, in
> linux/drivers/media/dvb/ttusb-dec/ttusb_dec.c I can find a lot of
> support for _PES_AUDIO and _PES_VIDEO while (apparently) nothing for
> _PES_OTHER.
It's not really a FF card as the MPEG-decoder is not used when connected to
a pc, as you said. However the card does the initial processing of the TS stream,
and sends only the extracted MPEG ES stream for video and the MPEG PES stream
for audio(iirc).
It not possible to just get a part of the TS stream by setting an arbitrary PID filter.
It is only possible to tell the device which PIDs belong to the video/audio stream.
So using DMX_PES_OTHER is not possible.

An application can simply try DMX_PES_OTHER first and if -ENOTSUPPORTED is returned,
as it would be the case here, it can fallback to DMX_PES_{AUDIO,VIDEO}.
Mythtv does it this way afaik.



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