[FFmpeg-devel] [PATCH] Google WebP support

Pascal Massimino pascal.massimino
Wed Oct 13 03:41:04 CEST 2010


Michael,

On Tue, Oct 12, 2010 at 6:13 PM, Pascal Massimino <
pascal.massimino at gmail.com> wrote:

> Michael,
>
> On Tue, Oct 12, 2010 at 2:45 PM, Michael Niedermayer <michaelni at gmx.at>wrote:
>
>> On Tue, Oct 12, 2010 at 11:39:26PM +0200, Michael Niedermayer wrote:
>> > On Mon, Oct 11, 2010 at 11:27:08PM -0700, Pascal Massimino wrote:
>> > > Michael,
>> > >
>> > > On Mon, Oct 11, 2010 at 4:59 AM, Michael Niedermayer <
>> michaelni at gmx.at>wrote:
>> > >
>> [...]
>> > > > there may be other ways to do it but this one seems simplest, other
>> > > > suggestions
>> > > > are welcome but numbered image support, per image metadata and alpha
>> > > > obviously
>> > > > should be possible in the design.
>> > > >
>> > >
>> > > really, i don't see what img2.c is bringing as value. Since i still
>> will
>> > > have to do the code
>> > > for RIFF / metadata handling (somewhere else. Possibly multiple
>> times.). And
>> > > the
>> >
>> > > use-case assumed isn't there. I don't want ./ffmpeg -i *.webp -y
>> toto.avi to
>> > > work
>> >
>> > thats ok, but i want numbered images to work. And if your implementation
>> cannot
>> > handle that or more correctly noone knows how to even add it on top of
>> that
>> > implementation while a img2 based one could handle it, then there is a
>> problem
>> > in your implementation.
>>
>> And note here iam not opposed to your implementation if you can explain
>> how
>> the img2 feature set could be implemented on top of it. But i feel uneasy
>> without knowing if we are moving toward a dead end here
>>
>> $attached would work, except for the discussed caveat:
>  * metadata are not handled (would just require some extra if's i guess)
>  * it hardcodes WEBP==VP8 which may not hold for long
>  * hardcoding the RIFF header writing is bweuuurk
>  * i can't force gop_size to 1 at line 245. I guess it's because
> av_codec_open()
>    occurs later
>

scratch that. Code was at the wrong location.
Attached, a what-should-be-correct version. But gop_size=1 still doesn't
work.
Added support for encoding too:
  ./ffmpeg -i splouch%03d.webp -y OMG_so_much_splouch.avi
but that's a lot of extra if's. And ugly.
Could it be that image2 should map to muxers in addition to codec?

skal



> Still, with that patch, it seems:
>      ./ffmpeg -i holiday_at_molokai_beach_OMG_so_much_fun.avi -g 1 -f
> image2 -y splouch%03d.webp
> works.
>
> skal
>
>
>>
>> [...]
>> --
>>
>> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>>
>> Its not that you shouldnt use gotos but rather that you should write
>> readable code and code with gotos often but not always is less readable
>>
>> -----BEGIN PGP SIGNATURE-----
>> Version: GnuPG v1.4.10 (GNU/Linux)
>>
>> iEYEARECAAYFAky01xEACgkQYR7HhwQLD6srPwCfY+l+p4rBRDegMHV8GgEBpPwR
>> i3wAnRsRhhSDpCWJZo2lnejDeu/NvZCC
>> =scCg
>>
>> -----END PGP SIGNATURE-----
>>
>> _______________________________________________
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>>
>
>
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