[FFmpeg-devel] [PATCH] libvpx: Enable vp9 alpha encoding

[Vignesh Venkatasubramanian]

On Fri, Jul 1, 2016 at 12:48 PM, Ronald S. Bultje <rsbultje at gmail.com> wrote:
> Hi,
>
> On Fri, Jul 1, 2016 at 3:29 PM, Ronald S. Bultje <rsbultje at gmail.com> wrote:
>
>> Hi,
>>
>> On Fri, Jul 1, 2016 at 3:12 PM, Vignesh Venkatasubramanian <
>> vigneshv-at-google.com at ffmpeg.org> wrote:
>>
>>> On Fri, Jul 1, 2016 at 11:06 AM, James Almer <jamrial at gmail.com> wrote:
>>> > On 7/1/2016 2:53 PM, Ronald S. Bultje wrote:
>>> >> Hi,
>>> >>
>>> >> On Fri, Jul 1, 2016 at 1:40 PM, James Zern <
>>> jzern-at-google.com at ffmpeg.org>
>>> >> wrote:
>>> >>
>>> >>> On Fri, Jul 1, 2016 at 10:07 AM, Carl Eugen Hoyos <cehoyos at ag.or.at>
>>> >>> wrote:
>>> >>>>> Do we have decoder support (for either vp8 or vp9) for these files?
>>> >>>>
>>> >>>> No, only encoding and muxing.
>>> >>>
>>> >>> Seems like a feature request, but no reason to block this one if the
>>> >>> vp8 one is here.
>>> >>
>>> >>
>>> >> I'm not sure I have an opinion on this... But it feels strange to allow
>>> >> encoding of content we cannot decode. Being ffmpeg, how do we recommend
>>> >> people handle the files created with this feature, if not by using
>>> ffmpeg
>>> >> itself?
>>>
>>> One plausible reason is that Chrome can decode this. So it will be
>>> useful for people who already have ffmpeg in their pipelines and want
>>> to create such files. And like James Almer mentioned, this isn't a
>>> first. VP8 Alpha has been this way too.
>>
>>
>> The fact that something is the way it is, does not prove that it is
>> therefore right, or that we should therefore continue doing it that way in
>> other cases.
>>
>> So you're suggesting that it is perfectly fine for people to use Chrome as
>> decoder if FFmpeg is the encoder. What if people don't have Chrome
>> installed? Or what if they want a way of UI-less batch-processing such
>> files, e.g. what if a service like Youtube/Vimeo wants to allow upload of
>> vp8a/vp9a files without invoking Chrome for decoding?
>>
>
> Additional evidence in [1], [2].
>
> There absolutely seems to be interest in support for vp8a/vp9a decoding
> outside Chrome. I'm not saying you should implement it in all multimedia
> frameworks ever created in human history, but doing it in one of them (e.g.
> ffmpeg, since it already supports encoding) certainly sounds helpful?
>

I'm not saying alpha decoder shouldn't ever be implemented in ffmpeg.
I'm just saying that it shouldn't be a reason to block this patch. :)
Sorry if i wasn't clear before.

> Ronald
>
> [1] https://bugzilla.gnome.org/show_bug.cgi?id=735450
> [2]
> http://lists.mplayerhq.hu/pipermail/ffmpeg-user/2014-September/023436.html
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-- 
Vignesh