extern "C" {
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
-#include <libavformat/avio.h>
}
-class PacketDestination {
-public:
- virtual ~PacketDestination() {}
- virtual void add_packet(const AVPacket &pkt, int64_t pts, int64_t dts) = 0;
+#include <sys/types.h>
+#include <atomic>
+#include <condition_variable>
+#include <functional>
+#include <mutex>
+#include <string>
+#include <utility>
+#include <thread>
+#include <vector>
+
+#include "timebase.h"
+
+struct MuxMetrics {
+ // “written” will usually be equal video + audio + mux overhead,
+ // except that there could be buffered packets that count in audio or video
+ // but not yet in written.
+ std::atomic<int64_t> metric_video_bytes{0}, metric_audio_bytes{0}, metric_written_bytes{0};
+
+ // Registers in global_metrics.
+ void init(const std::vector<std::pair<std::string, std::string>> &labels);
+
+ void reset()
+ {
+ metric_video_bytes = 0;
+ metric_audio_bytes = 0;
+ metric_written_bytes = 0;
+ }
};
-class Mux : public PacketDestination {
+class Mux {
public:
enum Codec {
CODEC_H264,
CODEC_NV12, // Uncompressed 4:2:0.
};
+ enum WriteStrategy {
+ // add_packet() will write the packet immediately, unless plugged.
+ WRITE_FOREGROUND,
- // Takes ownership of avctx.
- Mux(AVFormatContext *avctx, int width, int height, Codec video_codec, int time_base, int bit_rate);
+ // All writes will happen on a separate thread, so add_packet()
+ // won't block. Use this if writing to a file and you might be
+ // holding a mutex (because blocking I/O with a mutex held is
+ // not good). Note that this will clone every packet, so it has
+ // higher overhead.
+ WRITE_BACKGROUND,
+ };
+
+ // Takes ownership of avctx. <write_callback> will be called every time
+ // a write has been made to the video stream (id 0), with the pts of
+ // the just-written frame. (write_callback can be nullptr.)
+ // Does not take ownership of <metrics>; elements in there, if any,
+ // will be added to.
+ Mux(AVFormatContext *avctx, int width, int height, Codec video_codec, const std::string &video_extradata, const AVCodecParameters *audio_codecpar, int time_base, std::function<void(int64_t)> write_callback, WriteStrategy write_strategy, const std::vector<MuxMetrics *> &metrics);
~Mux();
- void add_packet(const AVPacket &pkt, int64_t pts, int64_t dts) override;
+ void add_packet(const AVPacket &pkt, int64_t pts, int64_t dts, AVRational timebase = { 1, TIMEBASE });
+
+ // As long as the mux is plugged, it will not actually write anything to disk,
+ // just queue the packets. Once it is unplugged, the packets are reordered by pts
+ // and written. This is primarily useful if you might have two different encoders
+ // writing to the mux at the same time (because one is shutting down), so that
+ // pts might otherwise come out-of-order.
+ //
+ // You can plug and unplug multiple times; only when the plug count reaches zero,
+ // something will actually happen.
+ void plug();
+ void unplug();
private:
- bool seen_keyframe = false;
- AVFormatContext *avctx;
+ // If write_strategy == WRITE_FOREGORUND, Must be called with <mu> held.
+ void write_packet_or_die(const AVPacket &pkt, int64_t unscaled_pts);
+ void thread_func();
+
+ WriteStrategy write_strategy;
+
+ std::mutex mu;
+
+ // These are only in use if write_strategy == WRITE_BACKGROUND.
+ std::atomic<bool> writer_thread_should_quit{false};
+ std::thread writer_thread;
+
+ AVFormatContext *avctx; // Protected by <mu>, iff write_strategy == WRITE_BACKGROUND.
+ int plug_count = 0; // Protected by <mu>.
+
+ // Protected by <mu>. If write_strategy == WRITE_FOREGROUND,
+ // this is only in use when plugging.
+ struct QueuedPacket {
+ AVPacket *pkt;
+ int64_t unscaled_pts;
+ };
+ std::vector<QueuedPacket> packet_queue;
+ std::condition_variable packet_queue_ready;
+
AVStream *avstream_video, *avstream_audio;
+
+ std::function<void(int64_t)> write_callback;
+ std::vector<MuxMetrics *> metrics;
+
+ friend struct PacketBefore;
};
#endif // !defined(_MUX_H)
projects / nageru / blobdiff