[FFmpeg-devel] [PATCH 3/3] avformat/mxfdec: Read Apple private Content Light Level from MXF

[Harry Mallon]

> On 7 Sep 2020, at 10:46, Tomas Härdin <tjoppen at acc.umu.se> wrote:
> 
> mån 2020-08-31 klockan 20:07 +0100 skrev Harry Mallon:
>> * As embedded by Apple Compressor
> 
> This needs a sample since it isn't part of any official spec, so that
> we can have a test for this.

I am attaching 3 files from Apple Compressor. They are all HDR10 (BT2020/PQ/metadata) files. I have tried to make them as small as possible but Compressor prefers them to be >=720 width for MXFs. They were all generated from the Netflix open content film Meridian, under creative commons.

Meridian-Apple_ProResProxy-HDR10.mxf - MXF ProRes 422 Proxy, SMPTE mastering display metadata, Apple Content Light Level data
Meridian-Apple_ProResProxy-HDR10.mov - Same as above but in a MOV wrapper, HDR10 metadata in MOV boxes
Meridian-Apple-HEVC-HDR10.mov - Same sequence but HEVC 10bit in a MOV wrapper

There are currently no fate tests that read HDR metadata so I figured these three would be a reasonable start. I had to make the Content Light Level data up as I do not have access to a program to calculate it (it's possible X265 can do it but I couldn't work it out).

> 
>> +        if (IS_KLV_KEY(uid, mxf_coll_apple_max_cll)) {
>> +            if (!descriptor->coll) {
>> +                descriptor->coll = av_content_light_metadata_alloc(&descriptor->coll_size);
>> +                if (!descriptor->coll)
>> +                    return AVERROR(ENOMEM);
>> +            }
> 
> Duplicated allocation here as well. See my comment on PATCH 1/3.
> 

I will approach the rest of the comments in a separate email.

Best,
Harry


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