[FFmpeg-devel] [PATCH] avformat/hlsenc: support CODECS Attribute in hevc EXT-X-STREAM-INF
Steven Liu
lq at chinaffmpeg.org
Tue Oct 13 04:13:09 EEST 2020
> 2020年10月12日 下午11:43,Guangxin Xu <oddstone at gmail.com> 写道:
>
> On Mon, Oct 12, 2020 at 9:57 PM Steven Liu <lq at chinaffmpeg.org> wrote:
>
>>
>>
>>> 在 2020年10月12日,21:45,Guangxin Xu <oddstone at gmail.com> 写道:
>>>
>>>
>>>
>>> On Mon, Oct 12, 2020 at 5:18 PM Steven Liu <lq at chinaffmpeg.org> wrote:
>>> fix ticket: 8904
>>> parse the SPS from extradata and get profile_tier_level
>>> write the profile_tier_level info into CODECS Attribute
>>>
>>> reference to :
>> https://developer.apple.com/documentation/http_live_streaming/hls_authoring_specification_for_apple_devices/hls_authoring_specification_for_apple_devices_appendixes
>>>
>>> Signed-off-by: Steven Liu <lq at chinaffmpeg.org>
>>> ---
>>> libavformat/hlsenc.c | 41 +++++++++++++++++++++++++++++++++++++++++
>>> 1 file changed, 41 insertions(+)
>>>
>>> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
>>> index cb31d6aed7..574d9f81e9 100644
>>> --- a/libavformat/hlsenc.c
>>> +++ b/libavformat/hlsenc.c
>>> @@ -337,6 +337,43 @@ static void write_codec_attr(AVStream *st,
>> VariantStream *vs)
>>> } else {
>>> goto fail;
>>> }
>>> + } else if (st->codecpar->codec_id == AV_CODEC_ID_HEVC) {
>>> + uint8_t *data = st->codecpar->extradata;
>>> + int i = 0;
>>> + int profile = FF_PROFILE_UNKNOWN;
>>> + int level = FF_LEVEL_UNKNOWN;
>>> +
>>> + if (st->codecpar->profile != FF_PROFILE_UNKNOWN)
>>> + profile = st->codecpar->profile;
>>> + if (st->codecpar->level != FF_LEVEL_UNKNOWN)
>>> + level = st->codecpar->level;
>>> +
>>> + while (data && (data - st->codecpar->extradata) <
>> st->codecpar->extradata_size) {
>>> + /* get HEVC SPS NAL and seek to profile_tier_level */
>>> + if (data && (data[0] | data[1] | data[2]) == 0 && data[3]
>> == 1 && ((data[4] & 0x42) == 0x42)) {
>>> Read beyond the boundary if data + 1 - st->codecpar->extradata >=
>> st->codecpar->extradata_size
>> ok
>>> Is it possible reuese ff_hevc_decode_extradata here?
>> it is in libavcodec, i don’t think depend libavcodec in hlsenc is a good
>> way, so parse sps here.
>>
> Then, we have a lot of hard work:
> 1. remove emulation prevent code.
> 2. get profile/level from vps too.
Do you mean it must or always show in VPS?
I think it should alway in SPS if I’m not misunderstand.
> full details you can check at
> https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/hevc.c#L713
I just want get profile, tier and level in hlsenc,
At first I parse the nalunit as the libavformat/hevc, but I think hlsenc maybe not
need alloc new memory to save the new extract_rbsp, just get the value is ok here.
So I think just check the boundary is ok here, isn’t it?
>
> thanks
>
>
>
>>>
>>> + int rbsp_byte_size;
>>> + data += 7;
>>> + /* process by reference General NAL unit syntax */
>>> + profile = *data & 0x1f;
>>> + rbsp_byte_size = st->codecpar->extradata_size - (data -
>> st->codecpar->extradata);
>>> + for (i = 0; i < rbsp_byte_size; i++, data++) {
>>> + if (data[0] == 0 && data[1] == 0 && data[2] == 3) {
>>> + data += 2;
>>> + i++;
>>> + }
>>> + /* skip 8 + 32 + 4 + 43 + 1 bit */
>>> + if (i == 11)
>>> + level = *data;
>>> + }
>>> + break;
>>> + }
>>> + data++;
>>> + }
>>> + if (st->codecpar->codec_tag == MKTAG('h','v','c','1') &&
>>> + profile != FF_PROFILE_UNKNOWN &&
>>> + level != FF_LEVEL_UNKNOWN) {
>>> + snprintf(attr, sizeof(attr), "%s.%d.4.L%d.B01",
>> av_fourcc2str(st->codecpar->codec_tag), profile, level);
>>> + }
>>> } else if (st->codecpar->codec_id == AV_CODEC_ID_MP2) {
>>> snprintf(attr, sizeof(attr), "mp4a.40.33");
>>> } else if (st->codecpar->codec_id == AV_CODEC_ID_MP3) {
>>> @@ -2247,6 +2284,10 @@ static int hls_write_header(AVFormatContext *s)
>>> continue;
>>> }
>>> avpriv_set_pts_info(outer_st, inner_st->pts_wrap_bits,
>> inner_st->time_base.num, inner_st->time_base.den);
>>> + if (outer_st->codecpar->codec_id == AV_CODEC_ID_HEVC &&
>>> + outer_st->codecpar->codec_tag !=
>> MKTAG('h','v','c','1')) {
>>> + av_log(s, AV_LOG_WARNING, "Stream HEVC is not hvc1, you
>> should use tag:v hvc1 to set it.\n");
>>> + }
>>> write_codec_attr(outer_st, vs);
>>>
>>> }
>>> --
>>> 2.25.0
>>>
>>>
>>>
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>>
>> Thanks
>> Steven
>>
>>
>>
>>
>>
>>
>>
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Thanks
Steven Liu
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