[FFmpeg-devel] [PATCH v4 2/3] avformat/flvenc: support enhanced flv PacketTypeMetadata

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Sat Mar 2 16:59:49 EET 2024


zhupengfei via ffmpeg-devel:
> From: Zhu Pengfei <411294962 at qq.com>
> 
> Signed-off-by: Zhu Pengfei <411294962 at qq.com>
> ---
>  libavformat/flvenc.c | 142 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 142 insertions(+)
> 
> diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
> index f6d10f331c..ae7ea84bad 100644
> --- a/libavformat/flvenc.c
> +++ b/libavformat/flvenc.c
> @@ -24,6 +24,7 @@
>  #include "libavutil/intfloat.h"
>  #include "libavutil/avassert.h"
>  #include "libavutil/mathematics.h"
> +#include "libavutil/mastering_display_metadata.h"
>  #include "libavcodec/codec_desc.h"
>  #include "libavcodec/mpeg4audio.h"
>  #include "avio.h"
> @@ -124,6 +125,7 @@ typedef struct FLVContext {
>  
>      int flags;
>      int64_t last_ts[FLV_STREAM_TYPE_NB];
> +    int write_metadata_pkt;

Should be metadata_pkt_written to be consistent with its semantics.

>  } FLVContext;
>  
>  static int get_audio_flags(AVFormatContext *s, AVCodecParameters *par)
> @@ -478,6 +480,145 @@ 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)
> +{
> +    AVIOContext *pb = s->pb;
> +    FLVContext *flv = s->priv_data;
> +    AVContentLightMetadata *lightMetadata = NULL;
> +    AVMasteringDisplayMetadata *displayMetadata = NULL;

Can be constified.

> +    const int flags_size = 5;
> +    int64_t metadata_size_pos = 0;
> +    int64_t total_size = 0;
> +    const AVPacketSideData *side_data = NULL;
> +
> +    if (par->codec_id == AV_CODEC_ID_HEVC || par->codec_id == AV_CODEC_ID_AV1 ||
> +        par->codec_id == AV_CODEC_ID_VP9) {

You can avoid one level of indentation by returning early here.

> +        if (flv->write_metadata_pkt) return;
> +
> +        side_data = av_packet_side_data_get(par->coded_side_data, par->nb_coded_side_data,
> +                                            AV_PKT_DATA_CONTENT_LIGHT_LEVEL);
> +        if (side_data)
> +            lightMetadata = (AVContentLightMetadata *)side_data->data;
> +
> +        side_data = av_packet_side_data_get(par->coded_side_data, par->nb_coded_side_data,
> +                                            AV_PKT_DATA_MASTERING_DISPLAY_METADATA);
> +        if (side_data)
> +            displayMetadata = (AVMasteringDisplayMetadata *)side_data->data;
> +
> +        /*
> +        * Reference Enhancing FLV
> +        * https://github.com/veovera/enhanced-rtmp/blob/main/enhanced-rtmp.pdf
> +        * */
> +        avio_w8(pb, FLV_TAG_TYPE_VIDEO); //write video tag type
> +        metadata_size_pos = avio_tell(pb);
> +        avio_wb24(pb, 0 + flags_size);
> +        put_timestamp(pb, ts); //ts = pkt->dts, gen
> +        avio_wb24(pb, flv->reserved);
> +
> +        if (par->codec_id == AV_CODEC_ID_HEVC) {
> +            avio_w8(pb, FLV_IS_EX_HEADER | PacketTypeMetadata| FLV_FRAME_VIDEO_INFO_CMD); // ExVideoTagHeader mode with PacketTypeMetadata
> +            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 | PacketTypeMetadata| FLV_FRAME_VIDEO_INFO_CMD);
> +            avio_write(pb, par->codec_id == AV_CODEC_ID_AV1 ? "av01" : "vp09", 4);
> +        }
> +
> +        avio_w8(pb, AMF_DATA_TYPE_STRING);
> +        put_amf_string(pb, "colorInfo");
> +
> +        avio_w8(pb, AMF_DATA_TYPE_OBJECT);
> +
> +        put_amf_string(pb, "colorConfig");  // colorConfig
> +
> +        avio_w8(pb, AMF_DATA_TYPE_OBJECT);
> +
> +        if (par->color_trc != AVCOL_TRC_UNSPECIFIED &&
> +            par->color_trc < AVCOL_TRC_NB) {
> +            put_amf_string(pb, "transferCharacteristics");  // color_trc
> +            put_amf_double(pb, par->color_trc);
> +        }
> +
> +        if (par->color_space != AVCOL_SPC_UNSPECIFIED &&
> +            par->color_space < AVCOL_SPC_NB) {
> +            put_amf_string(pb, "matrixCoefficients"); // colorspace
> +            put_amf_double(pb, par->color_space);
> +        }
> +
> +        if (par->color_primaries != AVCOL_PRI_UNSPECIFIED &&
> +            par->color_primaries < AVCOL_PRI_NB) {
> +            put_amf_string(pb, "colorPrimaries"); // color_primaries
> +            put_amf_double(pb, par->color_primaries);
> +        }
> +
> +        put_amf_string(pb, "");
> +        avio_w8(pb, AMF_END_OF_OBJECT);
> +
> +        if (lightMetadata) {
> +            put_amf_string(pb, "hdrCll");
> +            avio_w8(pb, AMF_DATA_TYPE_OBJECT);
> +
> +            put_amf_string(pb, "maxFall");
> +            put_amf_double(pb, lightMetadata->MaxFALL);
> +
> +            put_amf_string(pb, "maxCLL");
> +            put_amf_double(pb, lightMetadata->MaxCLL);
> +
> +            put_amf_string(pb, "");
> +            avio_w8(pb, AMF_END_OF_OBJECT);
> +        }
> +
> +        if (displayMetadata && (displayMetadata->has_primaries || displayMetadata->has_luminance)) {
> +            put_amf_string(pb, "hdrMdcv");
> +            avio_w8(pb, AMF_DATA_TYPE_OBJECT);
> +            if (displayMetadata->has_primaries) {
> +                put_amf_string(pb, "redX");
> +                put_amf_double(pb, av_q2d(displayMetadata->display_primaries[0][0]));
> +
> +                put_amf_string(pb, "redY");
> +                put_amf_double(pb, av_q2d(displayMetadata->display_primaries[0][1]));
> +
> +                put_amf_string(pb, "greenX");
> +                put_amf_double(pb, av_q2d(displayMetadata->display_primaries[1][0]));
> +
> +                put_amf_string(pb, "greenY");
> +                put_amf_double(pb, av_q2d(displayMetadata->display_primaries[1][1]));
> +
> +                put_amf_string(pb, "blueX");
> +                put_amf_double(pb, av_q2d(displayMetadata->display_primaries[2][0]));
> +
> +                put_amf_string(pb, "blueY");
> +                put_amf_double(pb, av_q2d(displayMetadata->display_primaries[2][1]));
> +
> +                put_amf_string(pb, "whitePointX");
> +                put_amf_double(pb, av_q2d(displayMetadata->white_point[0]));
> +
> +                put_amf_string(pb, "whitePointY");
> +                put_amf_double(pb, av_q2d(displayMetadata->white_point[1]));
> +            }
> +            if (displayMetadata->has_luminance) {
> +                put_amf_string(pb, "maxLuminance");
> +                put_amf_double(pb, av_q2d(displayMetadata->max_luminance));
> +
> +                put_amf_string(pb, "minLuminance");
> +                put_amf_double(pb, av_q2d(displayMetadata->min_luminance));
> +            }
> +            put_amf_string(pb, "");
> +            avio_w8(pb, AMF_END_OF_OBJECT);
> +        }
> +        put_amf_string(pb, "");
> +        avio_w8(pb, AMF_END_OF_OBJECT);
> +
> +        total_size = avio_tell(pb) - metadata_size_pos - 10;
> +        avio_seek(pb, metadata_size_pos, SEEK_SET);

I see nothing that guarantees that this seek will succeed. In fact, this
whole muxer seems to presume that the output is seekable, without
checking so. Even worse: flv_write_header() clears the AVIOContext's
seekability field in case the FLV_NO_METADATA flag is set.

> +        avio_wb24(pb, total_size);
> +        avio_tell(pb);
> +        avio_skip(pb, total_size + 10 - 3);
> +        avio_tell(pb);

These two avio_tell() are useless.

> +        avio_wb32(pb, total_size + 11); // previous tag size
> +        flv->write_metadata_pkt = 1;
> +    }
> +}
> +
>  static int unsupported_codec(AVFormatContext *s,
>                               const char* type, int codec_id)
>  {
> @@ -878,6 +1019,7 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
>              memcpy(par->extradata, side, side_size);
>              flv_write_codec_header(s, par, pkt->dts);
>          }
> +        flv_write_metadata_packet(s, par, pkt->dts);
>      }
>  
>      if (flv->delay == AV_NOPTS_VALUE)



More information about the ffmpeg-devel mailing list