[FFmpeg-devel] [PATCH] avutil: Add basic transfer functions for each AVColorTransferCharacteristic

[Kevin Wheatley]

On Tue, Sep 1, 2015 at 12:33 PM, Ronald S. Bultje <rsbultje at gmail.com> wrote:
> Hi,
>
> On Tue, Sep 1, 2015 at 7:02 AM, Kevin Wheatley <kevin.j.wheatley at gmail.com>
> wrote:
>
>> Following on from my previous email, this adds some functions to
>> actually convert from linear to non-linear encoding. I have another
>> that changes the OpenEXR codec to actually use these.
>
>
> Won't performance be crumblingly slow with this kind of API? It seems to
> make more sense to write a filter that can convert between different TRC
> types, or do it in swscale, and then add some fast implementations
> (LUT-based, or approximation-based) alongside the slow versions.

I'm using the functions to construct a LUT in the OpenEXR reader when
possible, the cleanest design would be to pass floating point into the
swscale engine for sure, but I'm not sure I'd personally want to go
changing that code. I'm happy for some other approach to be put
forward, I have some users who wanted the feature, so I have something
that works for their needs so my urgency is minimal.

I've performed a few more tests and spotted something missing in one
of my earlier changes in the pixel description code, patch to
follow...

Kevin