I have a MKV files (DVB-T recording generated by TVHeadend).
These mkv contain all recorded channel data including commercials.
I would like to re-scale my recordings to be 2x smaller in size (width/height). However I'm unable to do that correctly (tried ffmpeg and mencoder).
The aspect ratio of video image is changing even during playback, since the video is 4:3 for some time, then it switches to 16:9 during commercials, and then again back to 4:3; later it may switch to 16:9 again, all within the one single MKV file.
If I use ffmpeg or mencoder to scale down the video, it makes it indeed smaller, but remembers the aspect ratio used at the beginning of the video and it forces the same aspect during the whole video stream, ignoring the fact that the stream's aspect changes from time to time. So If my recordings start with commercials which are 16:9, and then the programme goes 4:3 (The Simpsons old series, for example), my rescalled video is always 16:9 for the entire duration, which is bad.
Is there any way to rescale the video (for example to a fixed width, variable height) while automatically adjusting the height so that the aspect ratio is always preserved like in the original?
Thank you