Pull the Mux class out of HTTPD. (First step towards decoupling file and HTTP muxing.)

[nageru] / mux.cpp

diff --git a/mux.cpp b/mux.cpp
new file mode 100644 (file)
index 0000000..82d42ab
--- /dev/null
+++ b/mux.cpp
@@ -0,0 +1,115 @@
+#include <assert.h>
+
+#include <string>
+#include <vector>
+
+#include "defs.h"
+#include "mux.h"
+#include "timebase.h"
+
+using namespace std;
+
+Mux::Mux(AVFormatContext *avctx, int width, int height, Codec video_codec, int time_base)
+       : avctx(avctx)
+{
+       AVCodec *codec_video = avcodec_find_encoder((video_codec == CODEC_H264) ? AV_CODEC_ID_H264 : AV_CODEC_ID_RAWVIDEO);
+       avstream_video = avformat_new_stream(avctx, codec_video);
+       if (avstream_video == nullptr) {
+               fprintf(stderr, "avformat_new_stream() failed\n");
+               exit(1);
+       }
+       avstream_video->time_base = AVRational{1, time_base};
+       avstream_video->codec->codec_type = AVMEDIA_TYPE_VIDEO;
+       if (video_codec == CODEC_H264) {
+               avstream_video->codec->codec_id = AV_CODEC_ID_H264;
+       } else {
+               assert(video_codec == CODEC_NV12);
+               avstream_video->codec->codec_id = AV_CODEC_ID_RAWVIDEO;
+               avstream_video->codec->codec_tag = avcodec_pix_fmt_to_codec_tag(AV_PIX_FMT_NV12);
+       }
+       avstream_video->codec->width = width;
+       avstream_video->codec->height = height;
+       avstream_video->codec->time_base = AVRational{1, time_base};
+       avstream_video->codec->ticks_per_frame = 1;  // or 2?
+
+       // Colorspace details. Closely correspond to settings in EffectChain_finalize,
+       // as noted in each comment.
+       // Note that the H.264 stream also contains this information and depending on the
+       // mux, this might simply get ignored. See sps_rbsp().
+       avstream_video->codec->color_primaries = AVCOL_PRI_BT709;  // RGB colorspace (inout_format.color_space).
+       avstream_video->codec->color_trc = AVCOL_TRC_UNSPECIFIED;  // Gamma curve (inout_format.gamma_curve).
+       avstream_video->codec->colorspace = AVCOL_SPC_SMPTE170M;  // YUV colorspace (output_ycbcr_format.luma_coefficients).
+       avstream_video->codec->color_range = AVCOL_RANGE_MPEG;  // Full vs. limited range (output_ycbcr_format.full_range).
+       avstream_video->codec->chroma_sample_location = AVCHROMA_LOC_LEFT;  // Chroma sample location. See chroma_offset_0[] in Mixer::subsample_chroma().
+       avstream_video->codec->field_order = AV_FIELD_PROGRESSIVE;
+       if (avctx->oformat->flags & AVFMT_GLOBALHEADER) {
+               avstream_video->codec->flags = AV_CODEC_FLAG_GLOBAL_HEADER;
+       }
+
+       AVCodec *codec_audio = avcodec_find_encoder_by_name(AUDIO_OUTPUT_CODEC_NAME);
+       if (codec_audio == nullptr) {
+               fprintf(stderr, "ERROR: Could not find codec '%s'\n", AUDIO_OUTPUT_CODEC_NAME);
+               exit(1);
+       }
+       avstream_audio = avformat_new_stream(avctx, codec_audio);
+       if (avstream_audio == nullptr) {
+               fprintf(stderr, "avformat_new_stream() failed\n");
+               exit(1);
+       }
+       avstream_audio->time_base = AVRational{1, time_base};
+       avstream_audio->codec->bit_rate = AUDIO_OUTPUT_BIT_RATE;
+       avstream_audio->codec->sample_rate = OUTPUT_FREQUENCY;
+       avstream_audio->codec->channels = 2;
+       avstream_audio->codec->channel_layout = AV_CH_LAYOUT_STEREO;
+       avstream_audio->codec->time_base = AVRational{1, time_base};
+       if (avctx->oformat->flags & AVFMT_GLOBALHEADER) {
+               avstream_audio->codec->flags = AV_CODEC_FLAG_GLOBAL_HEADER;
+       }
+
+       AVDictionary *options = NULL;
+       vector<pair<string, string>> opts = MUX_OPTS;
+       for (pair<string, string> opt : opts) {
+               av_dict_set(&options, opt.first.c_str(), opt.second.c_str(), 0);
+       }
+       if (avformat_write_header(avctx, &options) < 0) {
+               fprintf(stderr, "avformat_write_header() failed\n");
+               exit(1);
+       }
+}
+
+Mux::~Mux()
+{
+       av_write_trailer(avctx);
+       av_free(avctx->pb->buffer);
+       av_free(avctx->pb);
+       avformat_free_context(avctx);
+}
+
+void Mux::add_packet(const AVPacket &pkt, int64_t pts, int64_t dts)
+{
+       if (!seen_keyframe && !(pkt.stream_index == 0 && (pkt.flags & AV_PKT_FLAG_KEY))) {
+               // Wait until we see the first (video) key frame.
+               return;
+       }
+       seen_keyframe = true;
+
+       AVPacket pkt_copy;
+       av_copy_packet(&pkt_copy, &pkt);
+       if (pkt.stream_index == 0) {
+               pkt_copy.pts = av_rescale_q(pts, AVRational{1, TIMEBASE}, avstream_video->time_base);
+               pkt_copy.dts = av_rescale_q(dts, AVRational{1, TIMEBASE}, avstream_video->time_base);
+       } else if (pkt.stream_index == 1) {
+               pkt_copy.pts = av_rescale_q(pts, AVRational{1, TIMEBASE}, avstream_audio->time_base);
+               pkt_copy.dts = av_rescale_q(dts, AVRational{1, TIMEBASE}, avstream_audio->time_base);
+       } else {
+               assert(false);
+       }
+
+       if (av_interleaved_write_frame(avctx, &pkt_copy) < 0) {
+               fprintf(stderr, "av_interleaved_write_frame() failed\n");
+               exit(1);
+       }
+
+       av_packet_unref(&pkt_copy);
+}
+