[mythtv-users] Playing back PVR500 recordings on PVR350 decoder

Nick Rosier nick.rosier at gmail.com
Tue Jan 10 18:17:13 UTC 2006


On 1/10/06, Ole Andre Schistad <oschista at chello.no> wrote:
> I recently added a PVR500 to my existing mythtv box, and am hoping there
> is a way to play back all recordings using the hardware decoder chip on
> the 350. My primary reason for this is simply that mpeg2 looks much
> better when output through the HW decoder than when played back in
> software, although I am also experiencing some problems getting sound
> when using software playback (complains about my alsa settings).

My experience is that the TV-out of the 350 is just really, really
good, wether it plays throug the HW-decoder or YUV. So if you are
using ivtv 0.4.x with the latest X-driver, you can just let the
internal player play through the 350 even without HW-decoding enabled.
If your CPU has enough power, you can switch of the decoder and just
use the 350 as a framebuffer. This has, IMHO, several advantages:
- very good quality TV-out
- possibility to do time stretching (playing at x1.2 without the
"chipmunk" voices)
- no lockups from the HW-decoder (usually during FFWD,REW)

> Since the encoder on the PVR500 should produce an identical mpeg2 stream
> to that on the PVR350, there should be no reason why it can't be done -
> only that mythtv may not be coded to actually do things this way out of
> the box.

Played 150 recordings through the 350 HW-decoder without problems so
don't see where it wouldn't work. You just need to make sure that your
500 is configured as a PVR-250/350 card in mythtv-setup, not as e.g. a
v4l-card.

> I expect that there is a flag somewhere in the database which myth uses
> to determine wether to dump a given file to the PVR350s decoder chip or
> to software decode it to the framebuffer? If so, then one way of
> achieving what I want would be to run a periodic equivalent to UPDATE
> tablename SET flagname='recorded_by_350' where
> flagname='not_recorded_by_350' or similar .. but maybe there is a more
> elegant way ? Or am I not supposed to have this particular problem to
> begin with? :)

In the settings you can switch on the 350 decoder; afaik this will
play all mpeg-2 (and maybe 1) through the decoder. All others (divx,
xvid etc...) are through XV.

> Anyway, appreciate any help from you guys.

HTH,
N.


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