[FFmpeg-user] Question about handling / unwanted changes of SAR in ffmpeg

Carl Eugen Hoyos ceffmpeg at gmail.com
Wed Dec 26 03:00:30 EET 2018

Von meinem iPhone gesendet

> Am 25.12.2018 um 20:54 schrieb Uwe Freese <uwe.freese at gmx.de>:

> I'm confused about how ffmpeg handles the SAR (sample aspect ratio) and changes it. Maybe someone can explain why this happens:
> I've a video from TV with original size 720x576 pixels (PAL), which shall be shown as 16:9 aspect ratio.
> The SAR of the input video is correctly shown as 64:45 (resulting in 720*64 / 576*45 = 46080 / 25920 = 16 / 9 display aspect ratio).
> When I crop black borders

SAR is expected to change if you crop.
Rounding can be different for different codecs and containers.

Merry Christmas, Carl Eugen

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