[mythtv] Frame Drops

Ray mythtv-dev@snowman.net
Mon, 11 Nov 2002 19:12:15 -0700

On Mon, Nov 11, 2002 at 05:27:32PM -0500, Oatz wrote:

>     My Nuppelvideo to transcode setup, produces 2 gig files every 15
>     minutes (640x480) which take nearly an hour to encode to divx5 or
>     mpeg2 on a 935mhz P3. How does mythtv offer the same functions in
>     realtime?

It mainly uses rtjpeg which is designed for real time compression (similar
to mjpeg?)  If your machine isn't pretty darn fast though you'll probably
have to drop the capture resolution a bit.

> Even with a quad Xeon 2ghz box, you couldnt transcode from
>     nuv to mpeg/divx5 at 640x480 @ 23fps in realtime.

I don't know if it's comparable but I can transcode (using mencoder) from
mjpeg to mpeg4 at around 20fps.  This is on a dual 500Mhz Celeron system so
I guess a dual 1GHz P3 should handle this in real time.  Going to a quad box
wouldn't speed it up much but would allow denoising (sp) or other effects in
real time as well.  On my box converting to mpeg1 or mpeg 2 took a lot
longer (like 4-8x longer) but that was using a different encoder too.  BTW
there isn't currently any way to convert from MythTVs modivied nupplevideo
to anything else but I'm sure someone will get to that eventually.