[FFmpeg-user] Aspect Ratio information

Mike Scheutzow mike.scheutzow at alcatel-lucent.com
Wed Jun 6 15:18:47 CEST 2012

Tarun singhal wrote:
> Hi all,
> [This one is little urgent -
> Can anybody let me know what does aspect_ratio_idc means?

In h.264, it is a value which specifies the aspect ratio for a single pixel.

> I got to know from here-
> www.atsc.org/cms/standards/a72/a_72_part_1.pdf
> that is stands for Aspect ratio information
> but how it is calculated thats my question.?

The value can not be calculated mathematically. You look up the value in 
Table E-1 in the H.264 standard.

> Is there any way to set this value from ffmpeg?

Check the x264 docs for setting sample aspect ratio (--sar) and the 
ffmpeg docs for -x264opts.

Mike Scheutzow

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