On 24/02/2020 21:28, Vittorio Giovara wrote:
> On Sun, Feb 23, 2020 at 6:41 PM Mark Thompson <s...@jkqxz.net> wrote:
>
>> ---
>> libavcodec/Makefile | 2 +-
>> libavcodec/cbs_h265.c | 99 +++++++++++++++++++++++++++++++++++++++++++
>> libavcodec/cbs_h265.h | 18 ++++++++
>> 3 files changed, 118 insertions(+), 1 deletion(-)
>> create mode 100644 libavcodec/cbs_h265.c
>>
>> ...
>> +void
>> ff_cbs_h265_fill_sei_mastering_display(H265RawSEIMasteringDisplayColourVolume
>> *mdcv,
>> + const
>> AVMasteringDisplayMetadata *mdm)
>> +{
>> + memset(mdcv, 0, sizeof(*mdcv));
>> +
>> + if (mdm->has_primaries) {
>> + // The values in the metadata structure are fractions between 0
>> and 1,
>> + // while the SEI message contains fixed-point values with an
>> increment
>> + // of 0.00002. So, scale up by 50000 to convert between them.
>> +
>> + for (int a = 0; a < 3; a++) {
>> + // The metadata structure stores this in RGB order, but the
>> SEI
>> + // wants it in GBR order.
>> + int b = (a + 1) % 3;
>>
>
> this is a pretty minor comment, but do you think you could use the more
> legible way present in other parts of the codebase?
> const int mapping[3] = {2, 0, 1};
> rather than (a + 1) % 3;
Ok.
Is there a specific reason to make it on the stack rather than static? I see
it's there in hevcdec.
>> + mdcv->display_primaries_x[a] =
>> + rescale_fraction(mdm->display_primaries[b][0], 50000);
>> + mdcv->display_primaries_y[a] =
>> + rescale_fraction(mdm->display_primaries[b][1], 50000);
>> + }
>> +
>> + mdcv->white_point_x = rescale_fraction(mdm->white_point[0],
>> 50000);
>> + mdcv->white_point_y = rescale_fraction(mdm->white_point[1],
>> 50000);
>> + }
>> +
>> + if (mdm->has_luminance) {
>> + // Metadata are rational values in candelas per square metre, SEI
>> + // contains fixed point in units of 0.0001 candelas per square
>> + // metre. So scale up by 10000 to convert between them, and clip
>> to
>> + // ensure that we don't overflow.
>> +
>> + mdcv->max_display_mastering_luminance =
>> + rescale_clip(mdm->max_luminance, 10000, UINT32_MAX);
>> + mdcv->min_display_mastering_luminance =
>> + rescale_clip(mdm->min_luminance, 10000, UINT32_MAX);
>> +
>> + // The spec has a hard requirement that min is less than the max,
>> + // and the SEI-writing code enforces that.
>> + if (!(mdcv->min_display_mastering_luminance <
>> + mdcv->max_display_mastering_luminance)) {
>> + if (mdcv->max_display_mastering_luminance == UINT32_MAX)
>> + mdcv->min_display_mastering_luminance =
>> + mdcv->max_display_mastering_luminance - 1;
>> + else
>> + mdcv->max_display_mastering_luminance =
>> + mdcv->min_display_mastering_luminance + 1;
>> + }
>> + } else {
>> + mdcv->max_display_mastering_luminance = 1;
>> + mdcv->min_display_mastering_luminance = 0;
>> + }
>> +}
>> ...
- Mark
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
