The existing av_csp_trc_func_from_id() mostly implements the OETF, except for
PQ. As such, we are currently missing a precise definition of an ITU-R EOTF.
Introduce the new functions av_csp_itu_eotf() and av_csp_itu_eotf_inv(), to fill
this void. Note that this is not possible in all cases, e.g. AVCOL_TRC_LOG which
has no corresponding EOTF definition in any ITU-R standard.
Note that we cannot implement the proper HLG and SMPTE 428 OOTFs without access
to all three color channels, because they are not independent per channel. As a
result, we need to define them on double[3] instead of double (*func)(double).
This explanation was inaccurate and highly misleading. The new wording is taken
more or less directly from ITU-T H.273, and also matches my understanding of
these functions.
libavutil/color_utils contains some avpriv_ symbols that map
enum AVTransferCharacteristic values to gamma-curve approximations and
to the actual transfer functions to invert them (i.e. -> linear).
There's two issues with this:
(1) avpriv is evil and should be avoided whenever possible
(2) libavutil/csp.h exposes a public API for handling color that
already handles primaries and matricies
I don't see any reason this API has to be private, so this commit takes
the functionality from avutil/color_utils and merges it into avutil/csp
with an exposed av_ API rather than the previous avpriv_ API.
Every reference to the previous API has been updated to point to the
new one. color_utils.h has been deleted as well. This should not break
any applications as it only contained avpriv_ symbols in the first
place, so nothing in that header could be referenced by other
applications.
Signed-off-by: Leo Izen <leo.izen@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Separate the blocks to make the grouping easier to grasp,
add the file properly to the group and fix the file description
incorrectly used as filename, fixing the following doxy warning:
warning: the name 'Colorspace' supplied as the argument in
the \file statement is not an input file
This commit moves some of the functionality from avfilter/colorspace
into avutil/csp and exposes it as a public API so it can be used by
libavcodec and/or libavformat. It also converts those structs from
double values to AVRational to make regression testing easier and
more consistent.
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
