[FFmpeg-user] Quicktime reports diiferent width than ffmpeg

HallMarc Websites marc at hallmarcwebsites.com
Fri Nov 11 18:48:59 CET 2011

> So your DAR (display aspect ratio) is 14395:8192. Take that with your
> and you get:
> (14395 / 8192) * 486 = 854.000244....
> So, it's working exactly as expected, with QT doing exactly what's asked
of it -
> to take 648x486 video and display using the DAR defined in the wrapper,
> giving you 854x486.
> Basically, video is stored in square pixels - in your case 648x486 - so
> pixels per frame. Pixels can have DAR applied and it's down to display
> to STRETCH the original video WIDTH at the DAR ratio to give the final
> In European TV land, all [digital] video of Standard Definition is
> down video pipes that are 720x576 in size. Further, there is padding
> which actually means the "active picture" is contained in 702x576 pixels,
> 9px padding on left/right. When WIDESCREEN was introduced, none of the
> physical equipment changed. Simplistically, all that occurred was flagging
> video with a 16:9 flag. It meant that when a camera captured video, it
took in
> a "viewport" that was 16:9 aspect ratio and scaled/squashed the horizontal
> pixels seen into the 702x576 box. Then the video travelled around all it's
> pipes, vision mixers etc, eventually to TV transmitters into your house
> into your TV, all squashed into the 702x576 box. A side-band flag tells
your TV
> to stretch the video picture back to be shown to you as widescreen. That
> "display" 4:3, 16:9 button on your TV remote is simply overriding the
> from the TV station saying the picture should be shown in widescreen, vs
> old 4:3 aspect ratio.
> Many people thought that the introduction of 16:9 meant better pixels, but
> in fact it means less quality, because the width of what you see is being
> stretched more, rather than less.
> In HD, things are different of course - the signal [usually] transported
to your
> TV is 1920x1080, though it can be 1440x1080, 1280x720, or even 960x720.
> --Dave.
Leave it to an actual Englishman to speak English. Thank you for that! So I
guess my question now is thus; why is ffmpeg not applying this when getting
the video dimensions needed for playback? Why is it giving me dimensions
that squish the video if I were to use them?

And yes I will write the PHP code to check and correct. Thank you for the

More information about the ffmpeg-user mailing list