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avformat/flvenc: implement support for multi-track video

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Based on enhanced-rtmp v2 spec published by Veovera:
https://veovera.github.io/enhanced-rtmp/docs/enhanced/enhanced-rtmp-v2

This implementation maintains some backwards compatibility by only
writing the track information for track indices > 0. This means that
older FFmpeg versions - and possibly other software - can still read the
first video track properly and skip over unsupported packets.

Signed-off-by: Dennis Sädtler <dennis@obsproject.com>
Signed-off-by: Timo Rothenpieler <timo@rothenpieler.org>
This commit is contained in:
Dennis Sädtler 2024-04-01 18:16:49 +02:00 • committed by Timo Rothenpieler
parent cedd9151f8
commit d8d0175d3a
2 changed files with 120 additions and 47 deletions
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7
libavformat/flv.h
View file

@ -125,6 +125,13 @@ enum {
PacketTypeCodedFramesX = 3,
PacketTypeMetadata = 4,
PacketTypeMPEG2TSSequenceStart = 5,
PacketTypeMultitrack = 6,
};
enum {
MultitrackTypeOneTrack = 0x00,
MultitrackTypeManyTracks = 0x10,
MultitrackTypeManyTracksManyCodecs = 0x20,
};
enum {

160
libavformat/flvenc.c
View file

@ -126,8 +126,9 @@ typedef struct FLVContext {
AVCodecParameters *data_par;
int flags;
int64_t last_ts[FLV_STREAM_TYPE_NB];
int metadata_pkt_written;
int64_t *last_ts;
int *metadata_pkt_written;
int *video_track_idx_map;
} FLVContext;
static int get_audio_flags(AVFormatContext *s, AVCodecParameters *par)
@ -485,7 +486,7 @@ static void write_metadata(AVFormatContext *s, unsigned int ts)
avio_wb32(pb, flv->metadata_totalsize + 11);
}
static void flv_write_metadata_packet(AVFormatContext *s, AVCodecParameters *par, unsigned int ts)
static void flv_write_metadata_packet(AVFormatContext *s, AVCodecParameters *par, unsigned int ts, int stream_idx)
{
AVIOContext *pb = s->pb;
FLVContext *flv = s->priv_data;
@ -495,7 +496,9 @@ static void flv_write_metadata_packet(AVFormatContext *s, AVCodecParameters *par
int64_t total_size = 0;
const AVPacketSideData *side_data = NULL;
if (flv->metadata_pkt_written) return;
if (flv->metadata_pkt_written[stream_idx])
return;
if (par->codec_id == AV_CODEC_ID_HEVC || par->codec_id == AV_CODEC_ID_AV1 ||
par->codec_id == AV_CODEC_ID_VP9) {
int flags_size = 5;
@ -617,7 +620,7 @@ static void flv_write_metadata_packet(AVFormatContext *s, AVCodecParameters *par
avio_wb24(pb, total_size);
avio_skip(pb, total_size + 10 - 3);
avio_wb32(pb, total_size + 11); // previous tag size
flv->metadata_pkt_written = 1;
flv->metadata_pkt_written[stream_idx] = 1;
}
}
@ -632,7 +635,7 @@ static int unsupported_codec(AVFormatContext *s,
return AVERROR(ENOSYS);
}
static void flv_write_codec_header(AVFormatContext* s, AVCodecParameters* par, int64_t ts) {
static void flv_write_codec_header(AVFormatContext* s, AVCodecParameters* par, int64_t ts, int stream_index) {
int64_t data_size;
AVIOContext *pb = s->pb;
FLVContext *flv = s->priv_data;
@ -682,12 +685,32 @@ static void flv_write_codec_header(AVFormatContext* s, AVCodecParameters* par, i
}
avio_write(pb, par->extradata, par->extradata_size);
} else {
if (par->codec_id == AV_CODEC_ID_HEVC) {
avio_w8(pb, FLV_IS_EX_HEADER | PacketTypeSequenceStart | FLV_FRAME_KEY); // ExVideoTagHeader mode with PacketTypeSequenceStart
avio_write(pb, "hvc1", 4);
} else if (par->codec_id == AV_CODEC_ID_AV1 || par->codec_id == AV_CODEC_ID_VP9) {
avio_w8(pb, FLV_IS_EX_HEADER | PacketTypeSequenceStart | FLV_FRAME_KEY);
avio_write(pb, par->codec_id == AV_CODEC_ID_AV1 ? "av01" : "vp09", 4);
int track_idx = flv->video_track_idx_map[stream_index];
// If video stream has track_idx > 0 we need to send H.264 as extended video packet
int extended_flv = (par->codec_id == AV_CODEC_ID_H264 && track_idx) ||
par->codec_id == AV_CODEC_ID_HEVC ||
par->codec_id == AV_CODEC_ID_AV1 ||
par->codec_id == AV_CODEC_ID_VP9;
if (extended_flv) {
if (track_idx) {
avio_w8(pb, FLV_IS_EX_HEADER | PacketTypeMultitrack | FLV_FRAME_KEY);
avio_w8(pb, MultitrackTypeOneTrack | PacketTypeSequenceStart);
} else {
avio_w8(pb, FLV_IS_EX_HEADER | PacketTypeSequenceStart | FLV_FRAME_KEY);
}
if (par->codec_id == AV_CODEC_ID_H264)
avio_write(pb, "avc1", 4);
else if (par->codec_id == AV_CODEC_ID_HEVC)
avio_write(pb, "hvc1", 4);
else if (par->codec_id == AV_CODEC_ID_AV1)
avio_write(pb, "av01", 4);
else if (par->codec_id == AV_CODEC_ID_VP9)
avio_write(pb, "vp09", 4);
if (track_idx)
avio_w8(pb, track_idx);
} else {
avio_w8(pb, par->codec_tag | FLV_FRAME_KEY); // flags
avio_w8(pb, 0); // AVC sequence header
@ -770,13 +793,14 @@ static int shift_data(AVFormatContext *s)
static int flv_init(struct AVFormatContext *s)
{
int i;
int video_ctr = 0;
FLVContext *flv = s->priv_data;
if (s->nb_streams > FLV_STREAM_TYPE_NB) {
av_log(s, AV_LOG_ERROR, "invalid number of streams %d\n",
s->nb_streams);
return AVERROR(EINVAL);
}
flv->last_ts = av_calloc(s->nb_streams, sizeof(*flv->last_ts));
flv->metadata_pkt_written = av_calloc(s->nb_streams, sizeof(*flv->metadata_pkt_written));
flv->video_track_idx_map = av_calloc(s->nb_streams, sizeof(*flv->video_track_idx_map));
if (!flv->last_ts || !flv->metadata_pkt_written || !flv->video_track_idx_map)
return AVERROR(ENOMEM);
for (i = 0; i < s->nb_streams; i++) {
AVCodecParameters *par = s->streams[i]->codecpar;
@ -787,12 +811,17 @@ static int flv_init(struct AVFormatContext *s)
s->streams[i]->avg_frame_rate.num) {
flv->framerate = av_q2d(s->streams[i]->avg_frame_rate);
}
if (flv->video_par) {
flv->video_track_idx_map[i] = video_ctr++;
if (flv->video_par && flv->flags & FLV_ADD_KEYFRAME_INDEX) {
av_log(s, AV_LOG_ERROR,
"at most one video stream is supported in flv\n");
"at most one video stream is supported in flv with keyframe index\n");
return AVERROR(EINVAL);
} else if (flv->video_par) {
av_log(s, AV_LOG_WARNING,
"more than one video stream is not supported by most flv demuxers.\n");
}
flv->video_par = par;
if (!flv->video_par)
flv->video_par = par;
if (!ff_codec_get_tag(flv_video_codec_ids, par->codec_id))
return unsupported_codec(s, "Video", par->codec_id);
@ -882,7 +911,7 @@ static int flv_write_header(AVFormatContext *s)
}
for (i = 0; i < s->nb_streams; i++) {
flv_write_codec_header(s, s->streams[i]->codecpar, 0);
flv_write_codec_header(s, s->streams[i]->codecpar, 0, i);
}
flv->datastart_offset = avio_tell(pb);
@ -990,6 +1019,7 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
uint8_t frametype = pkt->flags & AV_PKT_FLAG_KEY ? FLV_FRAME_KEY : FLV_FRAME_INTER;
int flags = -1, flags_size, ret = 0;
int64_t cur_offset = avio_tell(pb);
int track_idx = flv->video_track_idx_map[pkt->stream_index];
if (par->codec_type == AVMEDIA_TYPE_AUDIO && !pkt->size) {
av_log(s, AV_LOG_WARNING, "Empty audio Packet\n");
@ -1006,7 +1036,12 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
else
flags_size = 1;
if (par->codec_id == AV_CODEC_ID_HEVC && pkt->pts != pkt->dts)
if (par->codec_type == AVMEDIA_TYPE_VIDEO && track_idx)
flags_size += 2; // additional header bytes for multi-track video
if ((par->codec_id == AV_CODEC_ID_HEVC ||
(par->codec_id == AV_CODEC_ID_H264 && track_idx))
&& pkt->pts != pkt->dts)
flags_size += 3;
if (par->codec_id == AV_CODEC_ID_AAC || par->codec_id == AV_CODEC_ID_H264
@ -1019,9 +1054,9 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
if (ret < 0)
return ret;
memcpy(par->extradata, side, side_size);
flv_write_codec_header(s, par, pkt->dts);
flv_write_codec_header(s, par, pkt->dts, pkt->stream_index);
}
flv_write_metadata_packet(s, par, pkt->dts);
flv_write_metadata_packet(s, par, pkt->dts, pkt->stream_index);
}
if (flv->delay == AV_NOPTS_VALUE)
@ -1143,32 +1178,59 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
avio_seek(pb, data_size + 10 - 3, SEEK_CUR);
avio_wb32(pb, data_size + 11);
} else {
av_assert1(flags>=0);
if (par->codec_id == AV_CODEC_ID_HEVC) {
int pkttype = (pkt->pts != pkt->dts) ? PacketTypeCodedFrames : PacketTypeCodedFramesX;
avio_w8(pb, FLV_IS_EX_HEADER | pkttype | frametype); // ExVideoTagHeader mode with PacketTypeCodedFrames(X)
avio_write(pb, "hvc1", 4);
if (pkttype == PacketTypeCodedFrames)
int extended_flv = (par->codec_id == AV_CODEC_ID_H264 && track_idx) ||
par->codec_id == AV_CODEC_ID_HEVC ||
par->codec_id == AV_CODEC_ID_AV1 ||
par->codec_id == AV_CODEC_ID_VP9;
if (extended_flv) {
int h2645 = par->codec_id == AV_CODEC_ID_H264 ||
par->codec_id == AV_CODEC_ID_HEVC;
int pkttype = PacketTypeCodedFrames;
// Optimisation for HEVC/H264: Do not send composition time if DTS == PTS
if (h2645 && pkt->pts == pkt->dts)
pkttype = PacketTypeCodedFramesX;
if (track_idx) {
avio_w8(pb, FLV_IS_EX_HEADER | PacketTypeMultitrack | frametype);
avio_w8(pb, MultitrackTypeOneTrack | pkttype);
} else {
avio_w8(pb, FLV_IS_EX_HEADER | pkttype | frametype);
}
if (par->codec_id == AV_CODEC_ID_H264)
avio_write(pb, "avc1", 4);
else if (par->codec_id == AV_CODEC_ID_HEVC)
avio_write(pb, "hvc1", 4);
else if (par->codec_id == AV_CODEC_ID_AV1)
avio_write(pb, "av01", 4);
else if (par->codec_id == AV_CODEC_ID_VP9)
avio_write(pb, "vp09", 4);
if (track_idx)
avio_w8(pb, track_idx);
if (h2645 && pkttype == PacketTypeCodedFrames)
avio_wb24(pb, pkt->pts - pkt->dts);
} else if (par->codec_id == AV_CODEC_ID_AV1 || par->codec_id == AV_CODEC_ID_VP9) {
avio_w8(pb, FLV_IS_EX_HEADER | PacketTypeCodedFrames | frametype);
avio_write(pb, par->codec_id == AV_CODEC_ID_AV1 ? "av01" : "vp09", 4);
} else {
av_assert1(flags >= 0);
avio_w8(pb, flags);
}
if (par->codec_id == AV_CODEC_ID_VP6)
avio_w8(pb,0);
if (par->codec_id == AV_CODEC_ID_VP6F || par->codec_id == AV_CODEC_ID_VP6A) {
if (par->extradata_size)
avio_w8(pb, par->extradata[0]);
else
avio_w8(pb, ((FFALIGN(par->width, 16) - par->width) << 4) |
(FFALIGN(par->height, 16) - par->height));
} else if (par->codec_id == AV_CODEC_ID_AAC)
avio_w8(pb, 1); // AAC raw
else if (par->codec_id == AV_CODEC_ID_H264 || par->codec_id == AV_CODEC_ID_MPEG4) {
avio_w8(pb, 1); // AVC NALU
avio_wb24(pb, pkt->pts - pkt->dts);
if (par->codec_id == AV_CODEC_ID_VP6) {
avio_w8(pb,0);
} else if (par->codec_id == AV_CODEC_ID_VP6F ||
par->codec_id == AV_CODEC_ID_VP6A) {
if (par->extradata_size)
avio_w8(pb, par->extradata[0]);
else
avio_w8(pb, ((FFALIGN(par->width, 16) - par->width) << 4) |
(FFALIGN(par->height, 16) - par->height));
} else if (par->codec_id == AV_CODEC_ID_AAC) {
avio_w8(pb, 1); // AAC raw
} else if (par->codec_id == AV_CODEC_ID_H264 ||
par->codec_id == AV_CODEC_ID_MPEG4) {
avio_w8(pb, 1); // AVC NALU
avio_wb24(pb, pkt->pts - pkt->dts);
}
}
avio_write(pb, data ? data : pkt->data, size);
@ -1235,6 +1297,10 @@ static void flv_deinit(AVFormatContext *s)
}
flv->filepositions = flv->head_filepositions = NULL;
flv->filepositions_count = 0;
av_freep(&flv->last_ts);
av_freep(&flv->metadata_pkt_written);
av_freep(&flv->video_track_idx_map);
}
static const AVOption options[] = {