[linux-dvb] Re: problems with test_dvr

[Johannes Stezenbach <js@convergence.de>]

Antonio Mosquera Quindimil wrote:
>  
> I have a problem with test_dvr.c.
> If I send a complete transport stream to dvr doing:
> cat file.ts > /dev/dvb/adapter0/dvr0  , and then run test_dvr, the
> programme can't read anything.

Works for me. If the TS includes a valid PAT, PMT and SDT you can
run "apps/scan/scan -c" on it.
test_dvr then can filter out any of the PIDs.
Note: test_dvr uses a buffer of 64K, so if you are trying to filter out
low bandwidth data, test_dvr won't output anything before it got 64K.
You can change BUF_SIZE in test_dvr.c if you want.

BUT: Wrt. performance it does not make any much sense to copy a full TS
into the kernel, then pass it through the software demux in the driver and
copy the filtered TS packets back to userspace. Even if you had demux hardware
that wouldn't make sense. We'd need to have the ability to use DMA to
pass a stream from disk through the demux.
Rigth now it's better to do it all in userspace, maybe the
mpegtools can do it. http://www.metzlerbros.de/mbros/dvb/

> And also, if I run szap -r <channel_name>, and then I run test_dvr, it
> only record the ts-packets with the pids of the audio and video of the
> channel, and I want to record all the pids.  Could anyone give an
> idea, please?

szap -r sets tow filters to record video/audio via the dvr device.
test_dvr then sets additional filters. If you don't want video/audio,
run szap without -r.

Johannes


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