[mythtv-users] great tip: using PVR-350 TV-out with audio

Luke McKee hojuruku at gmail.com
Tue Jan 30 15:52:17 UTC 2007


HI All,

I'll be posting to the list a lot more in the future now that I'm setting up
a PVR hardware solution based on mythtv for retail in Australia.

Anyone who is using a PVR-350 and wants to use low CPU when playing back
DVDs will find that they don't get the audio channel because most DVDs use
AC3 for the audio track and the firmware can't handle that format.

I get 5% cpu on a AMD 1.8GHZ, and probably most of that is reading from a
software raid5 (doing XOR operations) so the utilization you get should be
lower on equivalent hardware.

Users of mythtv can add the appropriate DVD player command in their sql
database.

mencoder -ovc copy -of mpeg -oac twolame -noskip -mpegopts format=dvd:tsaf
-twolameopts mode=jstereo:br=224   -o /dev/video18 dvd://1

You need a version of mplayer compiled with twolame or toolame libraries
available at compile time.
There are other codecs but they are more cpu intensive.

Add -quiet in production. I didn't test the tsaf option but I guess it
works.

Where can I get information on the full capabilities of the firmware? What
other audio formats does it accept (e.g. pcm?)

To take advantage of this mythv I'd like to see it do a similar kind of
coversion when TV-Output is enabled in configuration, also the ability to
ts->ps stream conversion for those of us who also capture from DVB.
Keeping the CPU down should be a priority for those of use who want to use
cheap hardware in embedded systems.


Cheers,

Luke


P.S. All my problems with the player card freezing the PC are gone! Everyone
should have larger buffer sizes by default!! (module options)
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