[linux-dvb] Re: Streaming from hard disk

["Gert-Jan van Dijk" <aka_mr_zapper@hotmail.com>]

> Holger Waechtler wrote:
> > Gert-Jan van Dijk wrote:
> > >
> > >4) Did NOT look at th driver code.
>
> It is not clear to me whether you talk about your drivers one from
> linuxtv.org.

I mean the DVB API 3 sources.

> We used a modified PCI DVB card for this purpose - one where the
> frontend was replaced by a ribbon cable which is used to feed a TTL
> MPEG2 transport stream transparently into the card.

Yep, that's the route we took in previous projects, but then we were also
"in control" of the HW. That's currently not the case and that's why I
prefer the soft solution.

> > But you can do this in software, too - in this case you need to
> > implemend a dummy driver that implements a pseudo frontend (see e.g.
> >
http://linuxtv.org/cgi-bin/cvsweb.cgi/dvb-kernel/linux/drivers/media/dvb/frontends/dvb_dummy_fe.c?rev=1.5&content-type=text/x-cvsweb-markup
> > - you would use this to switch between different streams from your disk
or
> > to switch between different streams from network streaming servers) and
> > some code that registers a software demux and calls the
dvb_dmx_swfilter()
> > callback with the data read from disk or a network connection. Since
> > multiple people asked for a solution like this we highly welcome patches
> > implementing such a debugging driver.

That's a good idea. I just took a glance at the dummy code, and I'll start
from there. Thanks, and rest asure that I'll share the stuff I make when I
get it to work, no worries.

>
> The tricky part is the timing of the TS playback. For the
> av7110 driver the dvr device slurps data as fast as the
> disk can deliver it, unless you set a video and/or audio PID
> with DMX_OUT_DECODER in which case the MPEG decoder controls
> the timing.

That seems logical, so we need to control the speed by also giving it a
symbolrate. That's also what you do on most of the streamers (some determine
this by parsing the tables, others don't). So have to look into the decoder
to see how it controls timing, and then make it configurable via symbolrate.
Thanks, this is grand....

cheers G-J


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