[FFmpeg-devel] [PATCH 1/2] Support HDR dynamic metdata (HDR10+) in HEVC decoder.

[Rostislav Pehlivanov]

On Thu, 3 Jan 2019 at 20:13, Mohammad Izadi <moh.izadi at gmail.com> wrote:

>
>  /**
> @@ -94,6 +95,50 @@ typedef struct HEVCSEIMasteringDisplay {
>      uint32_t min_luminance;
>  } HEVCSEIMasteringDisplay;
>
> +typedef struct HEVCSEIDynamicHDRPlus{
> +    int present;
> +    uint8_t itu_t_t35_country_code;
> +    uint8_t application_version;
> +    uint8_t num_windows;
> +    struct {
> +        AVRational window_upper_left_corner_x;
> +        AVRational window_upper_left_corner_y;
> +        AVRational window_lower_right_corner_x;
> +        AVRational window_lower_right_corner_y;
> +        uint16_t center_of_ellipse_x;
> +        uint16_t center_of_ellipse_y;
> +        uint8_t rotation_angle;
> +        uint16_t semimajor_axis_internal_ellipse;
> +        uint16_t semimajor_axis_external_ellipse;
> +        uint16_t semiminor_axis_external_ellipse;
> +        uint8_t overlap_process_option;
> +        AVRational maxscl[3];
> +        AVRational average_maxrgb;
> +        uint8_t num_distribution_maxrgb_percentiles;
> +        struct {
> +            uint8_t percentage;
> +            AVRational percentile;
> +        } distribution_maxrgb[15];
> +        AVRational fraction_bright_pixels;
> +        uint8_t tone_mapping_flag;
> +        AVRational knee_point_x;
> +        AVRational knee_point_y;
> +        uint8_t num_bezier_curve_anchors;
> +        AVRational bezier_curve_anchors[15];
> +        uint8_t color_saturation_mapping_flag;
> +        AVRational color_saturation_weight;
> +    } params[3];
> +    AVRational targeted_system_display_maximum_luminance;
> +    uint8_t targeted_system_display_actual_peak_luminance_flag;
> +    uint8_t num_rows_targeted_system_display_actual_peak_luminance;
> +    uint8_t num_cols_targeted_system_display_actual_peak_luminance;
> +    AVRational targeted_system_display_actual_peak_luminance[25][25];
> +    uint8_t mastering_display_actual_peak_luminance_flag;
> +    uint8_t num_rows_mastering_display_actual_peak_luminance;
> +    uint8_t num_cols_mastering_display_actual_peak_luminance;
> +    AVRational mastering_display_actual_peak_luminance[25][25];
> +} HEVCSEIDynamicHDRPlus;
> +
>

There's no reason to create a new struct for this if all you're going to do
is to copy it over and over to new frames.
What you can do is this: on every SEI containing this thing just allocate a
AVDynamicHDRPlus struct via av_dynamic_hdr_plus_alloc, wrap it as an
AVBufferRef via av_buffer_create, populate it, put it as a pointer in
HEVCSEIContentLight and then on every frame just add it to the frame via
av_frame_new_side_data_from_buf. If a new SEI is received unref your
pointer in HEVCSEIDynamicHDRPlus and repeat by allocating a new struct,
wrapping it as a buffer, populating it, etc.
I figure the only reason this wasn't done with other metadata was because
they were much smaller and because av_frame_new_side_data_from_buf didn't
exist until recently.


+            av_log(s->avctx, AV_LOG_DEBUG, ")");
> +            if (metadata->params[w].color_saturation_mapping_flag) {
> +                av_log(s->avctx, AV_LOG_DEBUG,
> +                       " color_saturation_weight=%5.4f",
> +
>  av_q2d(metadata->params[w].color_saturation_weight));
> +            }
> +            av_log(s->avctx, AV_LOG_DEBUG, "}\n");
> +        }
> +        av_log(s->avctx, AV_LOG_DEBUG,
> +               "} End of HDR10+ (SMPTE 2094-40)\n");
> +    }
>

Don't spam stuff like than in the debug log, especially not on every single
frame. Tools exist to print side data so just don't.