[FFmpeg-user] ffv1 version 3 read_quant_table error

Carl Eugen Hoyos cehoyos at ag.or.at
Wed Feb 13 02:04:49 CET 2013

Dave Rice <dave <at> dericed.com> writes:

> > (and verify that the files are 
> > different: one should contain a fiel atom, one not).
> This is true. I can find the fiel atom in with_patch.mov 
> but not in without_patch.mov, but I am only discovering 
> this with a hexdump of each file. Dumpster doesn't reveal 
> the fiel atom, nor does mediainfo
> --inform='Details;1'. Is there another atom parser to use?

You can remove the comment ("//") in front of #define DEBUG 
on top of libavformat/mov.c and use -loglevel something 
but I prefer hexdump -C
(I thought ticket #1881 was from you, but I was wrong: 
It shows that at least Dumpster isn't always useful.)

> > The question is if both can be decoded with QuickTime.
> Both appear to operate appropriately and identically 
> within QuickTime 7.6 and QuickTime X.

If you could do one more test, search for a svq3 file - 
Vertical400kbit.sorenson3.mov - remux it with unpatched 
FFmpeg and verify that video still plays with QuickTime, 
then use my patch and replace movenc.c line 1135 
("if (track->enc->field_order != AV_FIELD_UNKNOWN)") 
with something like "track->enc->field_order = AV_FIELD_BB" 
and remux again.
If the file changed but still decodes, the patch should 
really be sufficiently tested;-)

Thank you, Carl Eugen

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