[FFmpeg-devel] Regression (or feature) in .mov creation

[Tim Nicholson]

4778783 introduced a new "feature", in that .mov files created with this
commit, when inspected with ffprobe, report the SAR and DAR twice, but
with different values.

This only seems to happen with .mov files, compare the following snippets:-

>ffprobe DV-good-gdcd207c.mov

[..]

Stream #0:0(eng): Video: dvvideo (dvcp / 0x70637664), yuv420p, 720x576
[SAR 64:45 DAR 16:9], 28800 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc

[..]

=======================================

>ffprobe DV-bad-g4778783.mov

[..]

Stream #0:0(eng): Video: dvvideo (dvcp / 0x70637664), yuv420p, 720x576
[SAR 64:45 DAR 16:9], 28800 kb/s, SAR 118:81 DAR 295:162, 25 fps, 25
tbr, 25 tbn, 25 tbc

[..]

=========================================

>ffprobe DV-bad-g4778783.gxf

[..]

Stream #0:0: Video: dvvideo, yuv420p, 720x576 [SAR 64:45 DAR 16:9], 25
tbr, 50 tbn, 25 tbc

[..]

all files made from the same source, sample command line:-

ffmpeg -i DV.mov -timecode 09:59:30:06 -an -c:v dvvideo -pix_fmt yuv420p
-an -t 1 -y -f mov DV-gdcd207c.mov

All probing done with the same version 'g2a976de'

Furthermore inspecting in QT player 7.6.6 and inspecting the properties
gives the following:-


DV-good-gdcd207c.mov "Normal size 1024x576"
DV-bad-g4778783.mov  "Normal size 1049x576"

It therefore looks like ffmpeg is recognising the fact that in SD TV
terms the 16:9 aspect ratio refers to the display aperture of 702x576,
not the oversized 720x576.

However I am not aware of ffmpeg ever taking this into consideration
before, so is it an undocumented new feature, or a regression that
happens to look right?
-- 
Tim