Avidemux aspect ratio question [from newbie to Avidemux]

[ANOther1676]

I've got Avidemux and it's pretty much suited to my needs; I've converted a few old AVIs to MPEG-2 and TS files easily.

However, one thing I'm trying to learn is editing the aspect ratio of certain frames - I've got a programme taped from DVB,
but the adverts are 16:9, the programme is 4:3, how would I edit a frame to a certain aspect ratio?
I can cut out commercials fairly easily, may as well learn another new skill as I learn this program!

Yes, I know it's painstaking work, but I'm doing this so I can learn... aspect ratio editing isn't a common thing is it?

Basically what I'm trying to do... edit aspect ratios in Avidemux, which I haven't found a feature in my version (version 2.5).

Any advice is appreciated, thanks.

[jagabo]

The aspect ratio is set in the compression codec's settings. I don't think AviDemux will allow you to set different aspect ratios for different parts of the video. You may have to break it up into sections and join them later.

Note that with some codecs you flag the display aspect ratio (shape of the displayed frame), some you flag the pixel aspect ratio (aka sample aspect ratio), the shape of individual pixels. The general equation:

DAR = SAR * PAR

DAR = display aspect ratio
SAR = frame size
PAR = pixel aspect ratio

For example:

DAR = SAR * PAR
DAR = 720:480 * 8:9
DAR = 720/480 * 8/9
DAR = 720 * 8 / 480 / 9
DAR = 1.333... = 4:3