[mythtv-users] overlay mode available?
Andreas Bohnert
abo at online.de
Tue Nov 4 03:08:22 EST 2003
Joseph A. Caputo wrote:
>The likely reason that you're seeing frame drops has nothing to do with
>'overlay' mode, but is more likely because you're pegging your CPU.
>Xawtv has low resource requirements because it merely overlays/blits
>the live video feed directly from the TV card to the display card. It
>doesn't have to encode or decode anything. MythTV, however, is a true
>PVR with timeshifting capabilities -- meaning when you're watching
>LiveTV, what it's really doing is encoding the TV stream to disk
>(RTjpeg, MPEG-4 or HW MPEG-2), then decoding it and playing the decoded
>stream. The decoded stream must be scaled for playback, i.e., if
>you're recording at 640x480 but your display resolution is 800x600, the
>video must be scaled up to 800x600. This scaling is very CPU
>intensive, but is supposed to be hardware-assisted by the Xv extensions
>to XFree86 that work with your video card.
>
>
ok, I see. thanks for your explanations!
I didn't realize that even when I just watch tv there is a encoding
going on.
So I will have a look at the recording settings.
Your are right, my video card does not support Xv, that's why I will buy
me a new one.
I have a PIII with 350 Mhz. my framegrapper card is a wintv togo.
I hope that with the new video card I'm able to use RTjpeg and get at
least 640x480 without any drops.
I get lots of audio buffer overflows as well. I hope this is because of
the framedrops (and the poor synchronization..) and not because of the
quality of my sound card.
thank you
andreas
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