XviD Aspect Ratio in mp4

[Elias]

I'm encoding in XviD now, and the desired container is mp4. So, I've decided to use the Aspect Ratio, but it's supposed to not work that good in avi. What I'm wondering is, if I use the Aspect Ratio stuff, and then direct stream copy the avi into mp4 using say, Mp4Box, will it preserve the Aspect Ratio into the mp4 file?

[stephanV]

its supposed to work just as good in AVI as MP4. The PAR info is stored in the video stream, so you should keep it with remuxing.

[Elias]

Originally posted by stephanV
its supposed to work just as good in AVI as MP4. The PAR info is stored in the video stream, so you should keep it with remuxing. Exactly where in the video stream is the PAR info stored, and will it still be there when remuxed to mp4?

[bond]

the aspect ratio is stored in the video bitstream, it will be there in any container you mux to :)

[Elias]

Originally posted by bond
the aspect ratio is stored in the video bitstream, it will be there in any container you mux to :) Yes I know, this is what the XviD codec says when choosing it. But I meant more in technical details :D

[mediator]

PAR info is stored as part of the VOL header. You will find the VOL header (together with some other not VOP related headers) as part of the DecoderSpecific Config in the 'stsd'-atom of the MPEG-4 container.
'stsd' stands for (as far as i remember) 'sample table sample description'. For even more information I would recommend reading the spec if available (ISO 14496-1 or ISO 14496-12/14) or studying the sourcecode of some open source mpeg-4 decoder / demuxer such as XviD or MPEG4IP.

-mediator

[Elias]

Originally posted by mediator
PAR info is stored as part of the VOL header. You will find the VOL header (together with some other not VOP related headers) as part of the DecoderSpecific Config in the 'stsd'-atom of the MPEG-4 container.
'stsd' stands for (as far as i remember) 'sample table sample description'. For even more information I would recommend reading the spec if available (ISO 14496-1 or ISO 14496-12/14) or studying the sourcecode of some open source mpeg-4 decoder / demuxer such as XviD or MPEG4IP.

-mediator Cool, thanks! You perhaps have any good links? One question though, this anamorphic aspect ratio in xvid, is it similar to the one found in MPEG-2 DVD movies?

[bond]

the easiest way to fread out the vol of .mp4 is propably with the mpeg4vol tool from mpeg4ip :)

[Elias]

Originally posted by bond
the easiest way to fread out the vol of .mp4 is propably with the mpeg4vol tool from mpeg4ip :) Seriously, unless these MPEG4IP tools are packed with a good GUI, I won't have any idea of how to use 'em :)

[bond]

yeah you have to learn how to use commandline ;)

[Elias]

Originally posted by bond
yeah you have to learn how to use commandline ;) Too intricate for me :) GUIs rock!