[FFmpeg-devel] [PATCH] avformat/hlsenc: fix CODECS Attribute hard code in hevc EXT-X-STREAM-INF
Steven Liu
lingjiujianke at gmail.com
Tue Mar 11 03:42:09 EET 2025
Jack Lau via ffmpeg-devel <ffmpeg-devel at ffmpeg.org> 于2025年3月3日周一 09:38写道:
>
> fix ticket: 10786
> parse the SPS from extradata and get profile_compatibility, tier, constraints which was been hard code before.
>
> HEVC CODECS Attribute reference to: ISO/IEC14496-15
> Signed-off-by: Jack Lau <jacklau1222 at qq.com>
> ---
> libavformat/hlsenc.c | 38 +++++++++++++++++++++++++++++++++++---
> 1 file changed, 35 insertions(+), 3 deletions(-)
>
> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> index 6148685f40..c6ffdb99e5 100644
> --- a/libavformat/hlsenc.c
> +++ b/libavformat/hlsenc.c
> @@ -379,7 +379,10 @@ static void write_codec_attr(AVStream *st, VariantStream *vs)
> } else if (st->codecpar->codec_id == AV_CODEC_ID_HEVC) {
> uint8_t *data = st->codecpar->extradata;
> int profile = AV_PROFILE_UNKNOWN;
> + uint32_t profile_compatibility = AV_PROFILE_UNKNOWN;
> + char tier = 0;
> int level = AV_LEVEL_UNKNOWN;
> + char constraints[8] = "";
>
> if (st->codecpar->profile != AV_PROFILE_UNKNOWN)
> profile = st->codecpar->profile;
> @@ -393,6 +396,8 @@ static void write_codec_attr(AVStream *st, VariantStream *vs)
> uint8_t *rbsp_buf;
> int remain_size = 0;
> int rbsp_size = 0;
> + uint32_t profile_compatibility_flags = 0;
> + uint8_t high_nibble = 0;
> /* skip start code + nalu header */
> data += 6;
> /* process by reference General NAL unit syntax */
> @@ -406,8 +411,32 @@ static void write_codec_attr(AVStream *st, VariantStream *vs)
> }
> /* skip sps_video_parameter_set_id u(4),
> * sps_max_sub_layers_minus1 u(3),
> - * and sps_temporal_id_nesting_flag u(1) */
> + * and sps_temporal_id_nesting_flag u(1)
> + *
> + * TIER represents the general_tier_flag, with 'L' indicating the flag is 0,
> + * and 'H' indicating the flag is 1
> + */
> + tier = (rbsp_buf[1] & 0x20) == 0 ? 'L' : 'H';
> profile = rbsp_buf[1] & 0x1f;
> + /* PROFILE_COMPATIBILITY is general_profile_compatibility_flags, but in reverse bit order,
> + * in a hexadecimal representation (leading zeroes may be omitted).
> + */
> + profile_compatibility_flags = AV_RB32(rbsp_buf + 2);
> + /* revise these bits to get the profile compatibility value */
> + profile_compatibility_flags = ((profile_compatibility_flags & 0x55555555U) << 1) | ((profile_compatibility_flags >> 1) & 0x55555555U);
> + profile_compatibility_flags = ((profile_compatibility_flags & 0x33333333U) << 2) | ((profile_compatibility_flags >> 2) & 0x33333333U);
> + profile_compatibility_flags = ((profile_compatibility_flags & 0x0F0F0F0FU) << 4) | ((profile_compatibility_flags >> 4) & 0x0F0F0F0FU);
> + profile_compatibility_flags = ((profile_compatibility_flags & 0x00FF00FFU) << 8) | ((profile_compatibility_flags >> 8) & 0x00FF00FFU);
> + profile_compatibility = (profile_compatibility_flags << 16) | (profile_compatibility_flags >> 16);
> + /* skip 8 + 8 + 32
> + * CONSTRAINTS is a hexadecimal representation of the general_constraint_indicator_flags.
> + * each byte is separated by a '.', and trailing zero bytes may be omitted.
> + * drop the trailing zero bytes refer to ISO/IEC14496-15.
> + */
> + high_nibble = rbsp_buf[7] >> 4;
> + snprintf(constraints, sizeof(constraints),
> + high_nibble ? "%02x.%x" : "%02x",
> + rbsp_buf[6], high_nibble);
> /* skip 8 + 8 + 32 + 4 + 43 + 1 bit */
> level = rbsp_buf[12];
> av_freep(&rbsp_buf);
> @@ -417,8 +446,11 @@ static void write_codec_attr(AVStream *st, VariantStream *vs)
> }
> if (st->codecpar->codec_tag == MKTAG('h','v','c','1') &&
> profile != AV_PROFILE_UNKNOWN &&
> - level != AV_LEVEL_UNKNOWN) {
> - snprintf(attr, sizeof(attr), "%s.%d.4.L%d.B01", av_fourcc2str(st->codecpar->codec_tag), profile, level);
> + profile_compatibility != AV_PROFILE_UNKNOWN &&
> + tier != 0 &&
> + level != AV_LEVEL_UNKNOWN &&
> + constraints[0] != '\0') {
> + snprintf(attr, sizeof(attr), "%s.%d.%x.%c%d.%s", av_fourcc2str(st->codecpar->codec_tag), profile, profile_compatibility, tier, level, constraints);
> } else
> goto fail;
> } else if (st->codecpar->codec_id == AV_CODEC_ID_MP2) {
> --
> 2.47.1
>
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LGTM
Thanks
Steven
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