[MPlayer-users] Encoding optimisation that uses the least processing power

[Rich Felker]

On Thu, Dec 15, 2005 at 10:42:17PM +0500, Mustafa Abbasi wrote:
> i am trying to record tv using mencoder and v4l2. i can happily get
> both sound and video now but i am having real problems with the amount
> of processing power that mencoder uses this is the command i use
> 
> nice -n19 /home/mustafa/source_compile/mplayer_1.0/bin/mencoder tv://
> -tv device=/dev/video0:driver=v4l2:freq=312.25:saturation=100:volume=100
> -oac mp3lame -lameopts cbr:br=64  -ofps 23 -ovc lavc -lavcopts 
> vcodec=mpeg4:vbitrate=600 -o /store/match3.avi

1. Don't encode audio with lame. It's incredibly slow. Either leave it
   as raw pcm (if you have enough disk space) or encode to mp2 with
   lavc (which is very fast). You can always quickly reencode the
   audio later and use -ovc copy for the video.

2. Unrelated to slowness, but 23 IS NOT A VALID FRAMERATE FOR TV
   CAPTURE. The only valid framerate is the framerate of the TV
   standard you're capturing from, wither 30000/1001 (NTSC) or 25
   (PAL). Anything else will horribly destroy the field structure of
   the video.

3. Use keyint=0 or a different codec (e.g. mjpeg) to capture then
   reencode to mpeg4 later.

4. I can't even tell what resolution you're capturing because you
   don't have w/h specified in the -tv options. Height MUST be either
   480 or 240 for NTSC and either 576 or 288 for PAL. Width can be
   anything you want. If you need more speed, you can either drop to
   the lower (single-field) height or decrease width. If you use
   two-field height then you MUST either deinterlace or use special
   -lavcopts for interlaced content.

Isn't all of this in the manual?? Did you even read it??

> i am using a
> amd sempron 2400+
> MSI KM3M-V mainboard
> 256 mb ram

This should be a plenty fast to capture at any res....

Rich