[FFmpeg-user] display size vs coded size

[Terry Bolands]

________________________________
 From: Carl Eugen Hoyos <cehoyos at ag.or.at>


Terry Bolands <tbolands <at> yahoo.com> writes:

> Is there anyway to specify a display size that differs 
> from the coded size with ffmpeg? So in other words if I
> want to tell a player to only show some of the coded 
> video, but keep that video in the file so it could be
> retrieved later, is there a way to do that?

I am not sure I understand your question:
Are you searching for -vf crop / -vf pad ?
Or do you want to know how to ask libavcodec 
programmatically (from within your video 
player application) to not decode the complete 
frame, but only a part of it (I don't think this 
is generally possible)?




No, I'm looking for this functionality on the encoder side. I was hoping this would be available from the ffmpeg command line but if it is available via the libavcodec API, that'd be good too.

What I want is to have video that is coded with a certain resolution, but to be able to additionally indicate in the container format that there is a different resolution that contains the interesting data. I've worked in closed multi-media systems before where this sort of thing to was used to indicate that even though the video needed to be encoded on a 16 pixel boundary, the actual valid input video might have had some different resolution (e.g. if the input video is 600x480, you might code the video at 608x480 but tell the player to only display 600x480). This obviously also requires you to be able to specify which pixels are the interesting ones.

Thanks,
TB