25.05.11 11:21, Tomas Härdin написав(ла):
Maksym Veremeyenko skrev 2011-05-25 07:06:
hi,
years ago there was a patch
http://git.libav.org/?p=libav.git;a=commitdiff;h=6aafe463e5d1483b95ad259334c45d2741c92fb2
that splits aspect ratio detection for SMPTE 314M and IEC 61834.
i have a bunch of files that properly displayed by quicktime, but ffmpeg
(dv decoder) report 16:9 aspect ratio for them.
files originally are IEC 68134[apt == 0] and apt=0, vsc_pack[2]=CF so
they detected as 16:9, albeit Quicktime display it as 4:3.
What does ffprobe say about the container's aspect ratio? I'm inclined
to believe that the container claims 4:3 while the essence is 16:9 (I've
seen this more than once).
In that case QuickTime displays it at 4:3 because it trusts the
container over the essence.
i tested against raw dv files.
moreover then Quicktime generate raw dv files it sets aspect ratio
according to 314m.
if somebody has IEC 61834 pdf's could he confirm that
(vsc_pack[2] & 0x07) == 0x07)
really defines 16:9?
I don't have it, but I trust Michael read the spec.
However: since the value 7 is reserved in S314m, is there really any
harm in just taking it to mean 16:9 regardless of apt? We probably don't
need to though.
similar code present in libdv and dvplay, but seems nobody remember
origin issue...
at least
http://msdn.microsoft.com/en-us/library/dd407313%28v=vs.85%29.aspx did
not mention differences in aspect ration detection and meaning of filed
*DISP*
Uhm, it seems to define DISP to match S314m. Near the bottom:
"DISP: Display select mode. 000 = 4:3 aspect ratio, full format; 010 =
16:9 aspect ratio."
exactly, and no mention about differences and value 111 for 16:9 ...
--
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Maksym Veremeyenko
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