12 Mux::Mux(AVFormatContext *avctx, int width, int height, Codec video_codec, const AVCodec *codec_audio, int time_base, int bit_rate)
15 AVCodec *codec_video = avcodec_find_encoder((video_codec == CODEC_H264) ? AV_CODEC_ID_H264 : AV_CODEC_ID_RAWVIDEO);
16 avstream_video = avformat_new_stream(avctx, codec_video);
17 if (avstream_video == nullptr) {
18 fprintf(stderr, "avformat_new_stream() failed\n");
21 avstream_video->time_base = AVRational{1, time_base};
22 avstream_video->codec->codec_type = AVMEDIA_TYPE_VIDEO;
23 if (video_codec == CODEC_H264) {
24 avstream_video->codec->codec_id = AV_CODEC_ID_H264;
26 assert(video_codec == CODEC_NV12);
27 avstream_video->codec->codec_id = AV_CODEC_ID_RAWVIDEO;
28 avstream_video->codec->codec_tag = avcodec_pix_fmt_to_codec_tag(AV_PIX_FMT_NV12);
30 avstream_video->codec->width = width;
31 avstream_video->codec->height = height;
32 avstream_video->codec->time_base = AVRational{1, time_base};
33 avstream_video->codec->ticks_per_frame = 1; // or 2?
35 // Colorspace details. Closely correspond to settings in EffectChain_finalize,
36 // as noted in each comment.
37 // Note that the H.264 stream also contains this information and depending on the
38 // mux, this might simply get ignored. See sps_rbsp().
39 avstream_video->codec->color_primaries = AVCOL_PRI_BT709; // RGB colorspace (inout_format.color_space).
40 avstream_video->codec->color_trc = AVCOL_TRC_UNSPECIFIED; // Gamma curve (inout_format.gamma_curve).
41 avstream_video->codec->colorspace = AVCOL_SPC_SMPTE170M; // YUV colorspace (output_ycbcr_format.luma_coefficients).
42 avstream_video->codec->color_range = AVCOL_RANGE_MPEG; // Full vs. limited range (output_ycbcr_format.full_range).
43 avstream_video->codec->chroma_sample_location = AVCHROMA_LOC_LEFT; // Chroma sample location. See chroma_offset_0[] in Mixer::subsample_chroma().
44 avstream_video->codec->field_order = AV_FIELD_PROGRESSIVE;
45 if (avctx->oformat->flags & AVFMT_GLOBALHEADER) {
46 avstream_video->codec->flags = AV_CODEC_FLAG_GLOBAL_HEADER;
49 avstream_audio = avformat_new_stream(avctx, codec_audio);
50 if (avstream_audio == nullptr) {
51 fprintf(stderr, "avformat_new_stream() failed\n");
54 avstream_audio->time_base = AVRational{1, time_base};
55 avstream_audio->codec->bit_rate = bit_rate;
56 avstream_audio->codec->sample_rate = OUTPUT_FREQUENCY;
57 avstream_audio->codec->channels = 2;
58 avstream_audio->codec->channel_layout = AV_CH_LAYOUT_STEREO;
59 avstream_audio->codec->time_base = AVRational{1, time_base};
60 if (avctx->oformat->flags & AVFMT_GLOBALHEADER) {
61 avstream_audio->codec->flags = AV_CODEC_FLAG_GLOBAL_HEADER;
64 AVDictionary *options = NULL;
65 vector<pair<string, string>> opts = MUX_OPTS;
66 for (pair<string, string> opt : opts) {
67 av_dict_set(&options, opt.first.c_str(), opt.second.c_str(), 0);
69 if (avformat_write_header(avctx, &options) < 0) {
70 fprintf(stderr, "avformat_write_header() failed\n");
77 av_write_trailer(avctx);
78 av_free(avctx->pb->buffer);
80 avformat_free_context(avctx);
83 void Mux::add_packet(const AVPacket &pkt, int64_t pts, int64_t dts)
85 if (!seen_keyframe && !(pkt.stream_index == 0 && (pkt.flags & AV_PKT_FLAG_KEY))) {
86 // Wait until we see the first (video) key frame.
92 av_copy_packet(&pkt_copy, &pkt);
93 if (pkt.stream_index == 0) {
94 pkt_copy.pts = av_rescale_q(pts, AVRational{1, TIMEBASE}, avstream_video->time_base);
95 pkt_copy.dts = av_rescale_q(dts, AVRational{1, TIMEBASE}, avstream_video->time_base);
96 } else if (pkt.stream_index == 1) {
97 pkt_copy.pts = av_rescale_q(pts, AVRational{1, TIMEBASE}, avstream_audio->time_base);
98 pkt_copy.dts = av_rescale_q(dts, AVRational{1, TIMEBASE}, avstream_audio->time_base);
103 if (av_interleaved_write_frame(avctx, &pkt_copy) < 0) {
104 fprintf(stderr, "av_interleaved_write_frame() failed\n");
108 av_packet_unref(&pkt_copy);