[MEncoder-users] aspect ratio (one more time

[Raimund Berger]

Philippe MONROUX <phi2-monroux at wanadoo.fr> writes:

> Hi,
>
> I'm encoding in h.264 and I want to keep original size.
>
>
> command :
> mencoder crop=704:544:8:16,hqdn3d=2:1:2,harddup -ovc x264 -x264encopts
> bitrate=..... -o video.avi
>
> but when I have a film which is 16/9 letterbox, the result (video.avi)
> don't have the good aspect ratio. Of course I can put
> "-force-avi-aspect 1.78" at the output level but it is not good if I
> take an other output. 
>
> So is there another way (at the encoding level for example) to keep
> both original zize and aspect ratio with letterboxed film ?
>
> thanks

In my recollection, if your video source is standard PAL DVD, either of
"-aspect 4:3" or "-aspect 16:9" should work, no matter if letterboxed
and how much you crop.

This should result in mencoder output of the form
 x264 [info]: using SAR=16/15
resp.
 x264 [info]: using SAR=64/45
as long as you don't scale.

The same should work for NTSC DVD as well, just with different SAR
output values.

In case your source is not DVD, please check the output of 
 mplayer -vo null -ao null -frames 1 -identify input.mpg
and if you have ffmpeg installed also of
 ffmpeg -i input.mpg
to see if your source specifies a proper AR or PAR, where "input.mpg" is
(a placeholder for) your source video.