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nevcairiel · 13th March 2012, 09:28

MPEG-2 video is a bit special because its header information has the information in some odd ways, and ffmpeg has quite a few workarounds to rather match real-world files instead of strict specs. Its possible that libmpeg2 just strictly follows the spec and therefor ends up with a wrong AR.
Unless you can find a file that actually shows wrong behavior, there isn't anything to do for me.

Note that this depends on which codec is used, so H264 and MPEG-2 might be completely different beasts.

Edit:
The second file specifiys a aspect ratio index of "2", which according to the H264 spec is a SAR of 12:11*, which translates to a PAR of 15:11 on your videos resolution. Working as intended.
Like i said, don't take MediaInfo as an authoritative source for everything. It may be interpreting or mis-representing data.

* This particular AR seems to be meant for 4:3 PAL signals with horizontal overscan, at least according to the spec, which would explain why its being stretched to a slightly bit wider then 4:3

13th March 2012, 09:28	#9848 \| Link
nevcairiel Registered Developer Join Date: Mar 2010 Location: Hamburg/Germany Posts: 10,348	MPEG-2 video is a bit special because its header information has the information in some odd ways, and ffmpeg has quite a few workarounds to rather match real-world files instead of strict specs. Its possible that libmpeg2 just strictly follows the spec and therefor ends up with a wrong AR. Unless you can find a file that actually shows wrong behavior, there isn't anything to do for me. Note that this depends on which codec is used, so H264 and MPEG-2 might be completely different beasts. Edit: The second file specifiys a aspect ratio index of "2", which according to the H264 spec is a SAR of 12:11, which translates to a PAR of 15:11 on your videos resolution. Working as intended. Like i said, don't take MediaInfo as an authoritative source for everything. It may be interpreting or mis-representing data. This particular AR seems to be meant for 4:3 PAL signals with horizontal overscan, at least according to the spec, which would explain why its being stretched to a slightly bit wider then 4:3 __________________ LAV Filters - open source ffmpeg based media splitter and decoders Last edited by nevcairiel; 13th March 2012 at 10:36.