[FFmpeg-user] converting to non HD avi with ffmpeg

[Lou]

On Tue, 11 Sep 2012 13:25:21 +0300
Kevin Wilson <wkevils at gmail.com> wrote:

> Hi,
> I have downloaded from the web a video file with webm extension:
> ubunutuArm.webm (some lecture in video)
> 
> Now, I converted it to avi thus:
> ffmpeg -i ubunutuArm.webm ubunutuArm.avi
> 
> and put the ubunutuArm.avi on disk On Key.
> When trying to view it on TV with a DVD I see this
> messsage:
> "HD is not supported".
> Indeed, HD is not supported in my DVD and TV.
> Is there a way I can convert this video file with ffmpeg
> to an AVI so the result will be non HD ?

ffmpeg -i input -filter:v scale=640:-1 -q:v 3 output

I added the scale filter which will create an output that is 640 pixels
wide and the height will be automatically calculated to preserve the
aspect ratio. Of course you can change 640 to whatever desired width
you want. You can also switch the position of the -1 and provide a
desired height.

The other addition controls the output quality to something probably
better than the default of "-b:v 200k".

> (Second question: given some avi file, is there a way
> I can know whether it is in HD or not ?)

You can see the size of a video stream with the output of:
ffmpeg -i input