Changing aspect radio of a video file that has no aspect info, or has the wrong aspect meta data, without having to re-render it, is simple and can be done keeping the original quality. I use YAMB to create MP4 files and to cut,join or multiplex MP4, M4A and M4V files. It is a GUI to MP4Box, which is a command line MP4 multiplexer. It can import MPEG-4 video, DivX, XviD, 3ivx, h264 etc, audio streams and subtitles into the .mp4 container. The end result is a compliant MP4 stream. Given an mpeg4 h264 file, it changes meta data but doesn’t have to compress or render the video. So it’s completely lossless.
I compiled a video on how to proceed:
So how do we change the aspect of a h.264 mov file.
If you’re on Windows, and the .MOV uses H.264 video, you can do it losslessly:
1. download and start YAMB
2. In Yamb choose “Creation” and click on “Click to create an MP4 filer …” and open your video file.
3. Select the H.264 stream and click the properties button.
4. From the dropdown menu Pixels Aspect Ratio menu select the value that you require.
5. Select the output filename and click “next”. Wait for the program to do its job.