ffmpeg tips

delite · 01-11-2009, 03:58 AM

Hi,

I'm no expert when it comes to AV stuff. Anyway I wanted to do a quick tutorial for my little nephew, so i've developed this using ffmpeg:

Code:

ffmpeg  -ar 48000 -vol 512 -f oss -i /dev/audio -t 10 -s 1280x800 -sameq -f x11grab -r 30 -i :0.0 movie.mpg

Now the size, is the size of my screen, however can I change this or will I just do it by re-encoding later?

Also, padtop adds black to the top, but still starts at 0. On trying croptop it errored out. I was wanting to just grab a section of the screen, say a rect ((100,100)(640,480)), at a higher res, any ideas?

I banged in '-sameq' and the quality of the text improved greatly, but does that override any other settings, if so what?

Any other tips and tricks?

Cheers...

H_TeXMeX_H · 01-11-2009, 04:39 AM

Quote:

Originally Posted by delite

Code:

ffmpeg  -ar 48000 -vol 512 -f oss -i /dev/audio -t 10 -s 1280x800 -sameq -f x11grab -r 30 -i :0.0 movie.mpg

Also, padtop adds black to the top, but still starts at 0. On trying croptop it errored out. I was wanting to just grab a section of the screen, say a rect ((100,100)(640,480)), at a higher res, any ideas?

If you want that section why not do:

Code:

ffmpeg  -ar 48000 -vol 512 -f oss -i /dev/audio -t 10 -s 640x480 -sameq -f x11grab -r 30 -i :0.0+100,100 movie.mpg

See here for a decent tutorial:
http://polishlinux.org/linux/ubuntu/...ubuntu-part-2/

Using a different video codec such as mpeg4 or x264 will improve quality to size ratio.

delite · 01-11-2009, 05:34 AM

I like the offset trick, very good!
I'm off to read tut now... (after Click anyway!)