Re: [FFmpeg-devel] [PATCH 2/2] avutil: add HDR10+ dynamic metadata serialization function

[quietvoid <tcchlisop0@gmail.com>]

On 27/02/2023 12.34, Raphaël Zumer wrote:

> Resent due to my mail client incorrectly re-wrapping lines in the version I sent earlier.
> See the previous patch for context.
>
> Signed-off-by: Raphaël Zumer<rzumer@tebako.net>
> ---
>   libavutil/hdr_dynamic_metadata.c | 147 +++++++++++++++++++++++++++++++
>   libavutil/hdr_dynamic_metadata.h |  10 +++
>   libavutil/version.h              |   2 +-
>   3 files changed, 158 insertions(+), 1 deletion(-)
>
> diff --git a/libavutil/hdr_dynamic_metadata.c b/libavutil/hdr_dynamic_metadata.c
> index 98f399b032..72d310e633 100644
> --- a/libavutil/hdr_dynamic_metadata.c
> +++ b/libavutil/hdr_dynamic_metadata.c
> @@ -225,3 +225,150 @@ int av_dynamic_hdr_plus_from_t35(AVDynamicHDRPlus *s, const uint8_t *data,
>   
>       return 0;
>   }
> +
> +AVBufferRef *av_dynamic_hdr_plus_to_t35(AVDynamicHDRPlus *s)
> +{
> +    AVBufferRef *buf;
> +    size_t size_bits, size_bytes;
> +    PutBitContext pbc, *pb = &pbc;
> +
> +    if (!s)
> +        return NULL;
> +
> +    // Buffer size per CTA-861-H p.253-254:
> +    size_bits =
> +    // 56 bits for the header
> +    58 +
> +    // 2 bits for num_windows
> +    2 +
> +    // 937 bits for window geometry for each window above 1
> +    FFMAX((s->num_windows - 1), 0) * 937 +
> +    // 27 bits for targeted_system_display_maximum_luminance
> +    27 +
> +    // 1-3855 bits for targeted system display peak luminance information
> +    1 + (s->targeted_system_display_actual_peak_luminance_flag ? 10 +
> +        s->num_rows_targeted_system_display_actual_peak_luminance *
> +        s->num_cols_targeted_system_display_actual_peak_luminance * 4 : 0) +
> +    // 0-442 bits for intra-window pixel distribution information
> +    s->num_windows * 82;
> +    for (int w = 0; w < s->num_windows; w++) {
> +        size_bits += s->params[w].num_distribution_maxrgb_percentiles * 24;
> +    }
> +    // 1-3855 bits for mastering display peak luminance information
> +    size_bits += 1 + (s->mastering_display_actual_peak_luminance_flag ? 10 +
> +        s->num_rows_mastering_display_actual_peak_luminance *
> +        s->num_cols_mastering_display_actual_peak_luminance * 4 : 0) +
> +    // 0-537 bits for per-window tonemapping information
> +    s->num_windows * 1;
> +    for (int w = 0; w < s->num_windows; w++) {
> +        if (s->params[w].tone_mapping_flag) {
> +            size_bits += 28 + s->params[w].num_bezier_curve_anchors * 10;
> +        }
> +    }
> +    // 0-21 bits for per-window color saturation mapping information
> +    size_bits += s->num_windows * 1;
> +    for (int w = 0; w < s->num_windows; w++) {
> +        if (s->params[w].color_saturation_mapping_flag) {
> +            size_bits += 6;
> +        }
> +    }
> +
> +    size_bytes = (size_bits + 7) / 8;
> +
> +    buf = av_buffer_alloc(size_bytes);
> +    if (!buf) {
> +        return NULL;
> +    }
> +
> +    init_put_bits(pb, buf->data, size_bytes);
> +
> +    // itu_t_t35_country_code shall be 0xB5 (USA)
> +    put_bits(pb, 8, 0xB5);

This patch series mentions that it would be used for AV1, however the AV1
specification is clear that the payload does not contain the country code.
https://aomediacodec.github.io/av1-hdr10plus/#hdr10plus-metadata, Figure 1.

So far all the AV1 HDR10+ conformance samples also respect this.
There would probably be a need to specify which behaviour is wanted.
The SEI for HEVC does keep the country code in the payload, but not AV1.

> +    // itu_t_t35_terminal_provider_code shall be 0x003C
> +    put_bits(pb, 16, 0x003C);
> +    // itu_t_t35_terminal_provider_oriented_code is set to ST 2094-40
> +    put_bits(pb, 16, 0x0001);
> +    // application_identifier shall be set to 4
> +    put_bits(pb, 8, 4);
> +    // application_mode is set to Application Version 1
> +    put_bits(pb, 8, 1);
> +
> +    // Payload as per CTA-861-H p.253-254
> +    put_bits(pb, 2, s->num_windows);
> +
> +    for (int w = 1; w < s->num_windows; w++) {
> +        put_bits(pb, 16, s->params[w].window_upper_left_corner_x.num / s->params[w].window_upper_left_corner_x.den);
> +        put_bits(pb, 16, s->params[w].window_upper_left_corner_y.num / s->params[w].window_upper_left_corner_y.den);
> +        put_bits(pb, 16, s->params[w].window_lower_right_corner_x.num / s->params[w].window_lower_right_corner_x.den);
> +        put_bits(pb, 16, s->params[w].window_lower_right_corner_y.num / s->params[w].window_lower_right_corner_y.den);
> +        put_bits(pb, 16, s->params[w].center_of_ellipse_x);
> +        put_bits(pb, 16, s->params[w].center_of_ellipse_y);
> +        put_bits(pb, 8, s->params[w].rotation_angle);
> +        put_bits(pb, 16, s->params[w].semimajor_axis_internal_ellipse);
> +        put_bits(pb, 16, s->params[w].semimajor_axis_external_ellipse);
> +        put_bits(pb, 16, s->params[w].semiminor_axis_external_ellipse);
> +        put_bits(pb, 1, s->params[w].overlap_process_option);
> +    }
> +
> +    put_bits(pb, 27, s->targeted_system_display_maximum_luminance.num * luminance_den /
> +        s->targeted_system_display_maximum_luminance.den);
> +    put_bits(pb, 1, s->targeted_system_display_actual_peak_luminance_flag);
> +    if (s->targeted_system_display_actual_peak_luminance_flag) {
> +        put_bits(pb, 5, s->num_rows_targeted_system_display_actual_peak_luminance);
> +        put_bits(pb, 5, s->num_cols_targeted_system_display_actual_peak_luminance);
> +        for (int i = 0; i < s->num_rows_targeted_system_display_actual_peak_luminance; i++) {
> +            for (int j = 0; j < s->num_cols_targeted_system_display_actual_peak_luminance; j++) {
> +                put_bits(pb, 4, s->targeted_system_display_actual_peak_luminance[i][j].num * peak_luminance_den /
> +                    s->targeted_system_display_actual_peak_luminance[i][j].den);
> +            }
> +        }
> +    }
> +
> +    for (int w = 0; w < s->num_windows; w++) {
> +        for (int i = 0; i < 3; i++) {
> +            put_bits(pb, 17, s->params[w].maxscl[i].num * rgb_den / s->params[w].maxscl[i].den);
> +        }
> +        put_bits(pb, 17, s->params[w].average_maxrgb.num * rgb_den / s->params[w].average_maxrgb.den);
> +        put_bits(pb, 4, s->params[w].num_distribution_maxrgb_percentiles);
> +        for (int i = 0; i < s->params[w].num_distribution_maxrgb_percentiles; i++) {
> +            put_bits(pb, 7, s->params[w].distribution_maxrgb[i].percentage);
> +            put_bits(pb, 17, s->params[w].distribution_maxrgb[i].percentile.num * rgb_den /
> +                s->params[w].distribution_maxrgb[i].percentile.den);
> +        }
> +        put_bits(pb, 10, s->params[w].fraction_bright_pixels.num * fraction_pixel_den /
> +            s->params[w].fraction_bright_pixels.den);
> +    }
> +
> +    put_bits(pb, 1, s->mastering_display_actual_peak_luminance_flag);
> +    if (s->mastering_display_actual_peak_luminance_flag) {
> +        put_bits(pb, 5, s->num_rows_mastering_display_actual_peak_luminance);
> +        put_bits(pb, 5, s->num_cols_mastering_display_actual_peak_luminance);
> +        for (int i = 0; i < s->num_rows_mastering_display_actual_peak_luminance; i++) {
> +            for (int j = 0; j < s->num_cols_mastering_display_actual_peak_luminance; j++) {
> +                put_bits(pb, 4, s->mastering_display_actual_peak_luminance[i][j].num * peak_luminance_den /
> +                    s->mastering_display_actual_peak_luminance[i][j].den);
> +            }
> +        }
> +    }
> +
> +    for (int w = 0; w < s->num_windows; w++) {
> +        put_bits(pb, 1, s->params[w].tone_mapping_flag);
> +        if (s->params[w].tone_mapping_flag) {
> +            put_bits(pb, 12, s->params[w].knee_point_x.num * knee_point_den / s->params[w].knee_point_x.den);
> +            put_bits(pb, 12, s->params[w].knee_point_y.num * knee_point_den / s->params[w].knee_point_y.den);
> +            put_bits(pb, 4, s->params[w].num_bezier_curve_anchors);
> +            for (int i = 0; i < s->params[w].num_bezier_curve_anchors; i++) {
> +                put_bits(pb, 10, s->params[w].bezier_curve_anchors[i].num * bezier_anchor_den /
> +                    s->params[w].bezier_curve_anchors[i].den);
> +            }
> +            put_bits(pb, 1, s->params[w].color_saturation_mapping_flag);
> +            if (s->params[w].color_saturation_mapping_flag) {
> +                put_bits(pb, 6, s->params[w].color_saturation_weight.num * saturation_weight_den /
> +                    s->params[w].color_saturation_weight.den);
> +            }
> +        }
> +    }
> +
> +    flush_put_bits(pb);
> +    return buf;
> +}
> diff --git a/libavutil/hdr_dynamic_metadata.h b/libavutil/hdr_dynamic_metadata.h
> index 1f953ef1f5..f75d3e0739 100644
> --- a/libavutil/hdr_dynamic_metadata.h
> +++ b/libavutil/hdr_dynamic_metadata.h
> @@ -21,6 +21,7 @@
>   #ifndef AVUTIL_HDR_DYNAMIC_METADATA_H
>   #define AVUTIL_HDR_DYNAMIC_METADATA_H
>   
> +#include "buffer.h"
>   #include "frame.h"
>   #include "rational.h"
>   
> @@ -351,4 +352,13 @@ AVDynamicHDRPlus *av_dynamic_hdr_plus_create_side_data(AVFrame *frame);
>   int av_dynamic_hdr_plus_from_t35(AVDynamicHDRPlus *s, const uint8_t *data,
>                                    int size);
>   
> +/**
> + * Serialize dynamic HDR10+ metadata to a user data registered ITU-T T.35 buffer.
> + * @param s A pointer containing the decoded AVDynamicHDRPlus structure.
> + *
> + * @return Pointer to an AVBufferRef containing the raw ITU-T T.35 representation
> + *         of the HDR10+ metadata if succeed, or NULL if buffer allocation fails.
> + */
> +AVBufferRef *av_dynamic_hdr_plus_to_t35(AVDynamicHDRPlus *s);
> +
>   #endif /* AVUTIL_HDR_DYNAMIC_METADATA_H */
> diff --git a/libavutil/version.h b/libavutil/version.h
> index 900b798971..7635672985 100644
> --- a/libavutil/version.h
> +++ b/libavutil/version.h
> @@ -79,7 +79,7 @@
>    */
>   
>   #define LIBAVUTIL_VERSION_MAJOR  58
> -#define LIBAVUTIL_VERSION_MINOR   3
> +#define LIBAVUTIL_VERSION_MINOR   4
>   #define LIBAVUTIL_VERSION_MICRO 100
>   
>   #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
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