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

Bruce Markey mythtv-dev@snowman.net
Fri, 13 Dec 2002 14:52:42 -0800

Matt Zimmerman wrote:
> On Fri, Dec 13, 2002 at 03:27:34AM -0800, Bruce Markey wrote:
>>Henk Poley wrote:
>>>>Van: Bruce Markey <bjm@lvcm.com>
>>>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.
>>Good point. Bitrate is a factor. Today I did some new tests
>>with the current CVS and found that decoding CPU usage was
>>very low for each of several resolutions. I used scaled bit
>>rate @ 3300 for all of the test recordings.
> Bitrate does not make a significant difference in CPU utilization in my
> experience.  The size of the captured frames is the largest factor by far.

Ya, I agree. It is a factor but not nearly as significant as
as the size. Tweaking bitrate is more significant while trading
quality flaws for disk space.

I regret quoting the 17% earlier. This was a few weeks ago
when I first added a second tuner and was testing to find
a resolution that would accommodate two recordings with one
playback. This was likely a few days before the decoding
improvements were checked in and was while recording two
shows at the same time.

--  bjm