hevc: Add support for alternative transfer characterics SEI

The use of this SEI is for backward compatibility in HLG HDR systems:
older devices that cannot interpret the "arib-std-b67" transfer will
get the compatible transfer (usually bt709 or bt2020) from the VUI,
while newer devices that can interpret HDR will read the SEI and use
its value instead.

Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
This commit is contained in:
Vittorio Giovara 2017-06-09 17:35:22 -04:00
parent 850c6db97d
commit 3426832ac3
3 changed files with 22 additions and 0 deletions

View File

@ -265,6 +265,13 @@ static int decode_nal_sei_active_parameter_sets(HEVCSEIContext *s, GetBitContext
return 0;
}
static int decode_nal_sei_alternative_transfer(HEVCSEIAlternativeTransfer *s, GetBitContext *gb)
{
s->present = 1;
s->preferred_transfer_characteristics = get_bits(gb, 8);
return 0;
}
static int decode_nal_sei_prefix(GetBitContext *gb, HEVCSEIContext *s, const HEVCParamSets *ps,
int type, int size, void *logctx)
{
@ -285,6 +292,8 @@ static int decode_nal_sei_prefix(GetBitContext *gb, HEVCSEIContext *s, const HEV
return decode_nal_sei_active_parameter_sets(s, gb, logctx);
case HEVC_SEI_TYPE_USER_DATA_REGISTERED_ITU_T_T35:
return decode_nal_sei_user_data_registered_itu_t_t35(s, gb, size);
case HEVC_SEI_TYPE_ALTERNATIVE_TRANSFER_CHARACTERISTICS:
return decode_nal_sei_alternative_transfer(&s->alternative_transfer, gb);
default:
av_log(logctx, AV_LOG_DEBUG, "Skipped PREFIX SEI %d\n", type);
skip_bits_long(gb, 8 * size);

View File

@ -56,6 +56,7 @@ typedef enum {
HEVC_SEI_TYPE_REGION_REFRESH_INFO = 134,
HEVC_SEI_TYPE_MASTERING_DISPLAY_INFO = 137,
HEVC_SEI_TYPE_CONTENT_LIGHT_LEVEL_INFO = 144,
HEVC_SEI_TYPE_ALTERNATIVE_TRANSFER_CHARACTERISTICS = 147,
} HEVC_SEI_Type;
typedef struct HEVCSEIPictureHash {
@ -100,6 +101,11 @@ typedef struct HEVCSEIContentLight {
uint16_t max_pic_average_light_level;
} HEVCSEIContentLight;
typedef struct HEVCSEIAlternativeTransfer {
int present;
int preferred_transfer_characteristics;
} HEVCSEIAlternativeTransfer;
typedef struct HEVCSEIContext {
HEVCSEIPictureHash picture_hash;
HEVCSEIFramePacking frame_packing;
@ -109,6 +115,7 @@ typedef struct HEVCSEIContext {
HEVCSEIMasteringDisplay mastering_display;
HEVCSEIContentLight content_light;
int active_seq_parameter_set_id;
HEVCSEIAlternativeTransfer alternative_transfer;
} HEVCSEIContext;
struct HEVCParamSets;

View File

@ -2725,6 +2725,12 @@ static int set_side_data(HEVCContext *s)
s->avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;
}
if (s->sei.alternative_transfer.present &&
av_color_transfer_name(s->sei.alternative_transfer.preferred_transfer_characteristics) &&
s->sei.alternative_transfer.preferred_transfer_characteristics != AVCOL_TRC_UNSPECIFIED) {
s->avctx->color_trc = s->sei.alternative_transfer.preferred_transfer_characteristics;
}
return 0;
}