[FFmpeg-user] Aspect Ratios: DAR, SAR and Frame Size

Rio Kierkels riokierkels at gmail.com
Mon Jan 13 15:34:46 CET 2014

the DAR and SAR are applied on playback by the player you use. 352x240 are
the actual pixels stored in the file.
By default ffmpeg stretches you image to the dimensions you specify, no
padding or cropping is done.
To do that you can use the video filters pad and crop as per the

Your final question is a bit vague. Maybe give your commandline you tried
and an example of the source and how you want it to look like.

On 13 January 2014 15:28, Adi Shavit <adishavit at gmail.com> wrote:

> Hi,
>   I have a video for which ffmpeg -i prints: Stream #0:0: Video: vp8,
> yuv420p, 352x240, SAR 10:11 DAR 4:3, 15 fps, 15 tbr, 1k tbn, 1k tbc
> (default)
> As can be seen:
>    - The reported frame size is 352x240. This is an aspect ratio (AR) of
>    22:15
>    - SAR = 10:11
>    - DAR = 4:3
> I have a few questions about these AR values:
>    1. Obviously, the frame size is the decoded size of the frame.
>    However, what do DAR and SAR mean in this context when they are both not
>    1:1?
>    2. How many pixels are *actually* stored in each frame before any
>    stretching and/or padding occurs?
>    3. Does ffmpeg only stretch or does it also pad the frame to fit the
>    output?
>    4. My usage does not care about the displayed video aspect-ratio, but I
>    would *really *like to avoid any padding and also reduce any unnecessary
>    processing (like stretching/scaling).
>    Is it possible to tell ffmpeg to do decode the frames/pixels while
>    keeping their internal AR and avoiding any padding and/or stretching?
> Thank you and warm regards,
> Adi
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