[FFmpeg-user] Error converting 4K DCP

[Kieran O Leary]

Hi Carles,

On Fri, Sep 22, 2017 at 3:10 PM, Carles Vila <cvilad at gmail.com> wrote:
>> Seems like your source has four components, maybe an alpha channel? I'd
>> like to see the pix_fmt, but maybe ffmpeg gives the same error.
>>
>> Not sure if using libopenjpeg as decoder would help?
>> Just add
>> -c:v libopenjpeg
>> Before your
>> -i
>>
>
> Hi! I claimed victory too early. Libopenjpeg starts the conversion, but xyz
> color is not convertred automatically to RGB ...
> Any way to force the conversion?

You can take the advice already given: update ffmpeg!! Older versions
of ffmpeg required an rgb2xyz command, but now the transform is done
for you. You also mentioned that libopenjpeg was slower. Again, you
need to update ffmpeg which will also hopefully update libopenjpeg.
>From my experience, libopenjpeg is faster and better than the native
ffmpeg jpeg2000 encoder.

Also you will encounter some colour issues in your output file, mostly
that everything will look too green. A tool like Fraunhofer EasyDCP
PLayer will apply the correct LUT that will fix this but from what I
can see, you can't do this in ffmpeg as of yet. Here's some attempts
of mine to get it working:
https://ffmpeg.org/pipermail/ffmpeg-user/2016-November/034223.html

The issue is described better on page 30/31 of this manual:
https://www.easydcp.com/sync/manuals/easyDCP_Player_User_Manual.pdf

Best,

-Kieran.