[mythtv] hardware needed to smoothly record a show while watchinganother

Henk Poley mythtv-dev@snowman.net
Fri, 13 Dec 2002 11:39:28 +0100

> Van: Bruce Markey <bjm@lvcm.com>
> The resolution and bit rate affect how much CPU is needed.
> The example in the docs is based on 640x480 at 3300bps.
> I have a test machine with a 1.2GHz AMD, GForrce4 440MX,

In Russia GeForrce4 renders you!  ;-)

> and two WinTV cards. With this setup, I can record two
> shows while watching a recording without pegging the CPU by
> using a resolution of 352x480. By using a lower horizontal
> resolution, the picture is a little blurrier (but not twice
> as bad ;-). Each encoding takes about 35%-45% CPU. Decoding
> at this resolution takes (surprisingly) less than 2%. At
> the MythTV default setting of 480x480 decoding takes ~17%
> CPU. I'm guessing the hardware scaling is optimized for
> 352 which matches a standard. Again, clarifications welcome.

My guess is that you kept the encode-bitrate at the same setting. So the
compressor has less work to do in comparison to squeezing 480x480 in the
same space (?). Idem with decompression.

	Henk Poley <><