[mythtv-users] MythTV performance in a demanding real-life environment

Chris Pinkham cpinkham at bc2va.org
Tue Apr 10 03:19:37 UTC 2007

* On Mon Apr 09, 2007 at 11:24:19AM -0700, Robert Tsai wrote:
> Is this statement for SD or HD (flagging running faster than
> realtime)?


SD can be flagged faster than realtime on low-end hardware
and much faster on high-end hardware.  I've seen the same
triple-digit FPS rates that Yeechang Lee reports.

HD can be flagged faster than realtime on higher-end hardware.
I transcode a lot of HD down to 352x480 .nuv files to make it
playable on my slow frontend and I can transcode almost near
realtime inside my mythjobqueue VM running on a 3.0Ghz P4 so
flagging HD faster than realtime is easily doable on modern

The ClassicCommDetector has some code to try to keep the flag
timing relatively consistent so that a 1920x1080 recording
(2073600 pixels) doesn't take 6 times longer than a 640x480
recording (only 307200 pixels).  The scene change detection
code uses a step size dependent on the size of the video,
so it doesn't sample every pixel at either resolution.  This
means it's not quite as accurate as it could be, but I don't
think that affects it much.


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