On Sat, 13 Apr 2024 17:21:08 +0200 Kacper Michajłow <kaspe...@gmail.com> wrote:
> As we can read in ST 2086:
>
> Values outside the specified ranges of luminance and chromaticity values
> are not reserved by SMPTE, and can be used for purposes outside the
> scope of this standard.
>
> This is further acknowledged by ITU-T H.264 and ITU-T H.265. Which says
> that values out of range are unknown or unspecified or specified by
> other means not specified in this Specification.
>
> Signed-off-by: Kacper Michajłow <kaspe...@gmail.com>
> ---
> libavcodec/h2645_sei.c | 55 ++++++++++++++++++++++++++++++------------
> 1 file changed, 39 insertions(+), 16 deletions(-)
>
> diff --git a/libavcodec/h2645_sei.c b/libavcodec/h2645_sei.c
> index 933975f076..96a22e7cf6 100644
> --- a/libavcodec/h2645_sei.c
> +++ b/libavcodec/h2645_sei.c
> @@ -587,38 +587,61 @@ static int h2645_sei_to_side_data(AVCodecContext
> *avctx, H2645SEI *sei,
> return ret;
>
> if (metadata) {
> + metadata->has_luminance = 1;
> + metadata->has_primaries = 1;
> +
> for (i = 0; i < 3; i++) {
> const int j = mapping[i];
> metadata->display_primaries[i][0].num =
> sei->mastering_display.display_primaries[j][0];
> metadata->display_primaries[i][0].den = chroma_den;
> + metadata->has_primaries &=
> sei->mastering_display.display_primaries[j][0] >= 5 &&
> +
> sei->mastering_display.display_primaries[j][0] <= 37000;
> +
> metadata->display_primaries[i][1].num =
> sei->mastering_display.display_primaries[j][1];
> metadata->display_primaries[i][1].den = chroma_den;
> + metadata->has_primaries &=
> sei->mastering_display.display_primaries[j][1] >= 5 &&
> +
> sei->mastering_display.display_primaries[j][1] <= 42000;
> }
> metadata->white_point[0].num =
> sei->mastering_display.white_point[0];
> metadata->white_point[0].den = chroma_den;
> + metadata->has_primaries &= sei->mastering_display.white_point[0]
> >= 5 &&
> + sei->mastering_display.white_point[0]
> <= 37000;
> +
> metadata->white_point[1].num =
> sei->mastering_display.white_point[1];
> metadata->white_point[1].den = chroma_den;
> + metadata->has_primaries &= sei->mastering_display.white_point[1]
> >= 5 &&
> + sei->mastering_display.white_point[1]
> <= 42000;
>
> metadata->max_luminance.num =
> sei->mastering_display.max_luminance;
> metadata->max_luminance.den = luma_den;
> + metadata->has_luminance &= sei->mastering_display.max_luminance
> >= 50000 &&
> + sei->mastering_display.max_luminance
> <= 100000000;
> +
> metadata->min_luminance.num =
> sei->mastering_display.min_luminance;
> metadata->min_luminance.den = luma_den;
> - metadata->has_luminance = 1;
> - metadata->has_primaries = 1;
> -
> - av_log(avctx, AV_LOG_DEBUG, "Mastering Display Metadata:\n");
> - av_log(avctx, AV_LOG_DEBUG,
> - "r(%5.4f,%5.4f) g(%5.4f,%5.4f) b(%5.4f %5.4f) wp(%5.4f,
> %5.4f)\n",
> - av_q2d(metadata->display_primaries[0][0]),
> - av_q2d(metadata->display_primaries[0][1]),
> - av_q2d(metadata->display_primaries[1][0]),
> - av_q2d(metadata->display_primaries[1][1]),
> - av_q2d(metadata->display_primaries[2][0]),
> - av_q2d(metadata->display_primaries[2][1]),
> - av_q2d(metadata->white_point[0]),
> av_q2d(metadata->white_point[1]));
> - av_log(avctx, AV_LOG_DEBUG,
> - "min_luminance=%f, max_luminance=%f\n",
> - av_q2d(metadata->min_luminance),
> av_q2d(metadata->max_luminance));
> + metadata->has_luminance &= sei->mastering_display.min_luminance
> >= 1 &&
> + sei->mastering_display.min_luminance
> <= 50000 &&
> + sei->mastering_display.min_luminance <
> + sei->mastering_display.max_luminance;
> +
> + if (metadata->has_luminance || metadata->has_primaries)
> + av_log(avctx, AV_LOG_DEBUG, "Mastering Display Metadata:\n");
> + if (metadata->has_primaries) {
> + av_log(avctx, AV_LOG_DEBUG,
> + "r(%5.4f,%5.4f) g(%5.4f,%5.4f) b(%5.4f %5.4f)
> wp(%5.4f, %5.4f)\n",
> + av_q2d(metadata->display_primaries[0][0]),
> + av_q2d(metadata->display_primaries[0][1]),
> + av_q2d(metadata->display_primaries[1][0]),
> + av_q2d(metadata->display_primaries[1][1]),
> + av_q2d(metadata->display_primaries[2][0]),
> + av_q2d(metadata->display_primaries[2][1]),
> + av_q2d(metadata->white_point[0]),
> av_q2d(metadata->white_point[1]));
> + }
> + if (metadata->has_luminance) {
> + av_log(avctx, AV_LOG_DEBUG,
> + "min_luminance=%f, max_luminance=%f\n",
> + av_q2d(metadata->min_luminance),
> av_q2d(metadata->max_luminance));
> + }
> }
> }
>
> --
> 2.43.0
>
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LGTM.
As was discussed on IRC, this validation logic strictly follows the
wording of SMPTE ST 2086 and H.264/H.265. While we may wish to handle
invalid metadata in a different layer, there is no similar bitstream
conformance requirements in AV1 etc. (And who's to say what brightness
ranges for the min/max *should* be considered "valid"?)
Merged as 1c45104f74e59beb25ce7451c98527f7a3c518f6
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