On 3/2/2023 3:33 PM, quietvoid wrote:> 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<rzu...@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.
Are you sure about HEVC? I just checked a sample and trace_headers
reported this:
[trace_headers] Prefix Supplemental Enhancement Information
[trace_headers] 0 forbidden_zero_bit 0 = 0
[trace_headers] 1 nal_unit_type 100111 = 39
[trace_headers] 7 nuh_layer_id 000000 = 0
[trace_headers] 13 nuh_temporal_id_plus1 001 = 1
[trace_headers] 16 last_payload_type_byte 00000100 = 4
[trace_headers] 24 last_payload_size_byte 01000000 = 64
[trace_headers] User Data Registered ITU-T T.35
[trace_headers] 32 itu_t_t35_country_code 10110101 = 181
[trace_headers] 40 itu_t_t35_payload_byte[1] 00000000 = 0
[trace_headers] 48 itu_t_t35_payload_byte[2] 00111100 = 60
[trace_headers] 56 itu_t_t35_payload_byte[3] 00000000 = 0
[trace_headers] 64 itu_t_t35_payload_byte[4] 00000001 = 1
[trace_headers] 72 itu_t_t35_payload_byte[5] 00000100 = 4
[trace_headers] 80 itu_t_t35_payload_byte[6] 00000001 = 1
Which is in line with section 8.3.1 of ITU-T Rec. H.274 as well as
section D.2.6 of ITU-T Rec. H.265.
So i think this function should not set the country code at all as part
of the payload, and start with itu_t_t35_terminal_provider_code.
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