> On Dec 14, 2024, at 23:20, James Almer <jamr...@gmail.com> wrote:
>
> On 12/11/2024 1:23 AM, Zhao Zhili wrote:
>> From: Zhao Zhili <zhiliz...@tencent.com>
>> ---
>> libavcodec/hevc/sei.c | 30 ++++++++++++++++++++++++++++++
>> libavcodec/hevc/sei.h | 14 ++++++++++++++
>> 2 files changed, 44 insertions(+)
>> diff --git a/libavcodec/hevc/sei.c b/libavcodec/hevc/sei.c
>> index e11a33773c..56983fe96e 100644
>> --- a/libavcodec/hevc/sei.c
>> +++ b/libavcodec/hevc/sei.c
>> @@ -150,6 +150,34 @@ static int decode_nal_sei_timecode(HEVCSEITimeCode *s,
>> GetBitContext *gb)
>> return 0;
>> }
>> +static int decode_nal_sei_alpha_info(HEVCSEIAlphaChannelInfo *s,
>> GetBitContext *gb)
>> +{
>> + int length;
>> +
>> + s->has_alpha_channel_info = true;
>> +
>> + s->alpha_channel_cancel_flag = get_bits1(gb);
>> + if (!s->alpha_channel_cancel_flag) {
>
> This should trigger when alpha_channel_cancel_flag is 1.
I made a mistake.
>
>> + s->alpha_channel_use_idc = 2;
>> + s->alpha_channel_incr_flag = 0;
>> + s->alpha_channel_clip_flag = 0;
>> +
>> + return 0;
>> + }
>> +
>> + s->alpha_channel_use_idc = get_bits(gb, 3);
>> + s->alpha_channel_bit_depth_minus8 = get_bits(gb, 3);
>> + length = s->alpha_channel_bit_depth_minus8 + 9;
>> + s->alpha_transparent_value = get_bits(gb, length);
>> + s->alpha_opaque_value = get_bits(gb, length);
>> + s->alpha_channel_incr_flag = get_bits1(gb);
>> + s->alpha_channel_clip_flag = get_bits1(gb);
>> + if (s->alpha_channel_clip_flag)
>> + s->alpha_channel_clip_type_flag = get_bits1(gb);
>> +
>> + return 0;
>> +}
>> +
>> static int decode_nal_sei_3d_reference_displays_info(HEVCSEITDRDI *s,
>> GetBitContext *gb)
>> {
>> s->prec_ref_display_width = get_ue_golomb(gb);
>> @@ -216,6 +244,8 @@ static int decode_nal_sei_prefix(GetBitContext *gb,
>> GetByteContext *gbyte,
>> return decode_nal_sei_active_parameter_sets(s, gb, logctx);
>> case SEI_TYPE_TIME_CODE:
>> return decode_nal_sei_timecode(&s->timecode, gb);
>> + case SEI_TYPE_ALPHA_CHANNEL_INFO:
>> + return decode_nal_sei_alpha_info(&s->alpha, gb);
>> case SEI_TYPE_THREE_DIMENSIONAL_REFERENCE_DISPLAYS_INFO:
>> return decode_nal_sei_3d_reference_displays_info(&s->tdrdi, gb);
>> default: {
>> diff --git a/libavcodec/hevc/sei.h b/libavcodec/hevc/sei.h
>> index ee640003bc..54122c27df 100644
>> --- a/libavcodec/hevc/sei.h
>> +++ b/libavcodec/hevc/sei.h
>> @@ -21,6 +21,7 @@
>> #ifndef AVCODEC_HEVC_SEI_H
>> #define AVCODEC_HEVC_SEI_H
>> +#include <stdbool.h>
>
> Are we using bool anywhere else? Afaik, we just use uint8_t everywhere since
> it's going to be a whole byte anyway.
Patchset v2 dropped this patch.
For something with only true/false state and has no other defect, I prefer to
use bool for clarity.
Maybe we can list cases what’s forbidden or inappropriate to use bool, so bool
can be used in
other cases.
>
>> #include <stdint.h>
>> #include "libavutil/buffer.h"
>> @@ -95,6 +96,18 @@ typedef struct HEVCSEITDRDI {
>> uint8_t three_dimensional_reference_displays_extension_flag;
>> } HEVCSEITDRDI;
>> +typedef struct HEVCSEIAlphaChannelInfo {
>> + bool has_alpha_channel_info;
>> + uint8_t alpha_channel_cancel_flag;
>> + uint8_t alpha_channel_use_idc;
>> + uint8_t alpha_channel_bit_depth_minus8;
>> + uint16_t alpha_transparent_value;
>> + uint16_t alpha_opaque_value;
>> + uint8_t alpha_channel_incr_flag;
>> + uint8_t alpha_channel_clip_flag;
>> + uint8_t alpha_channel_clip_type_flag;
>> +} HEVCSEIAlphaChannelInfo;
>> +
>> typedef struct HEVCSEI {
>> H2645SEI common;
>> HEVCSEIPictureHash picture_hash;
>> @@ -102,6 +115,7 @@ typedef struct HEVCSEI {
>> int active_seq_parameter_set_id;
>> HEVCSEITimeCode timecode;
>> HEVCSEITDRDI tdrdi;
>> + HEVCSEIAlphaChannelInfo alpha;
>> } HEVCSEI;
>> struct HEVCParamSets;
>
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