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

[James Almer]

On 1/3/2019 10:07 PM, Rostislav Pehlivanov wrote:
> 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.

It was my suggestion, as that's what's done for mastering metadata.

> 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.

You're right, that does sound simpler. Is this SEI valid for every frame
after it shows up? If so, it's definitely a better solution.

> 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.
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