[mythtv] Box Processor Limits
bjm at lvcm.com
Tue Jan 21 19:48:08 EST 2003
Doug Wiltanger wrote:
> I'm really looking for a log file that says how many frames are dropped.
>>From what I've gathered I need to capture stdout and errout.
> If visuals are the key, then an Athlon at 1100 Mhz cannot keep up with
> recording at 640X480. Live TV is not really possible here. The decoding
> of the stream doesn't even use 5% CPU at this res. It's all about encoding
> quality vs diskspace.
Exactly. In fact, decoding will be even more efficient in
0.8. Playback is almost free =).
> I find that 512X384 with bit rate at 3300 provides a consistent 85%
> utilization of CPU. I also have audio set to 32000 with quality setting of
> 3. This yields nearly 1GB an hour.
That sounds about right. You may want to try 480x480 just
for comparison sake...
> This is with .7 release. Once .8 is release I'll be transitioning to my
> server machine which then will have a Celeron 1.4Ghz. I'm hoping to be
> able to keep that res.
Should be no problem.
> Question is, how much of an impact does increasing the bit rate have on the
> reduction of CPU utilization...
Bitrate doesn't have nearly as much implicit as resolution.
It may seem logical that a higher bitrate needs to do less
compressing. However, it actually take more cycles to prepare
more bits. I did some quick test to verify this and the lowest
mpeg4 bitrate used the least CPU time. From lowest to highest
bitrate only varied the CPU usage by 10-15%
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