[FFmpeg-user] HDR 4K support in ffmpeg
rens at offlinemedia.nl
Thu Dec 17 00:27:59 CET 2015
> In order to encode 4K HDR format. Firstly, you need to transform (i.e.,
> tone-mapping) HDR data to 8 or 10 bit video sequence. Later, you can use
> On Wed, Dec 16, 2015 at 10:58 PM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
>> tarun singhal <tsinghal18 <at> gmail.com> writes:
>> > I have been asked to check whether ffmpeg supports
>> > 4K encoding
>> 4k is supported in FFmpeg for (at least) ten years.
>> > with HDR or not
>> I believe that strictly speaking HDR means logarithmic
>> or float colour space support. FFmpeg does not support
>> logarithmic colour space and float support is extremely
>> limited (input only, will be converted to rgb48 / rgb64
>> x264 supports 9 and 10 bit encoding, x265 supports
>> 10 bit encoding, this is all supported by FFmpeg.
HDR or High Dynamic Range is using a different
Optical to Electrical Transfer [OETF] and
Electrical to Optical Transfer [EOTF] then
the standard Gamma curves used in Low Dynamic Range (LDR]
This is just an other curve to fit more of the sensor dynamic
range into 10 Bits and expand on the display side.
Camera Capture formats can have bit depths up 16bit
to capture even more dynamic range.
Currently there is no agreed standard how this
curve should be defined. The NHK/BBC proposal
seems to be the most promising
If the input file already has an OETF applied encoding
with ffmpeg should be straight forward in 10 bit x264
If you need to apply an OETF or EOTF then the 3dlut filter
i.c with the right 3dlut might be the way to go..
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