1 // A wrapper around x264, to encode video in higher quality than Quick Sync
2 // can give us. We maintain a queue of uncompressed Y'CbCr frames (of 50 frames,
3 // so a little under 100 MB at 720p), then have a separate thread pull out
4 // those threads as fast as we can to give it to x264 for encoding.
6 // TODO: We use x264's “speedcontrol” patch if available, so that quality is
7 // automatically scaled up or down to content and available CPU time.
9 // The encoding threads are niced down because mixing is more important than
10 // encoding; if we lose frames in mixing, we'll lose frames to disk _and_
11 // to the stream, as where if we lose frames in encoding, we'll lose frames
12 // to the stream only, so the latter is strictly better. More importantly,
13 // this allows speedcontrol (when implemented) to do its thing without
14 // disturbing the mixer.
17 #define _X264ENCODE_H 1
24 #include <condition_variable>
30 #include <unordered_map>
33 #include <libavformat/avformat.h>
36 #include "print_latency.h"
39 class X264SpeedControl;
43 X264Encoder(AVOutputFormat *oformat); // Does not take ownership.
45 // Called after the last frame. Will block; once this returns,
46 // the last data is flushed.
49 // Must be called before first frame. Does not take ownership.
50 void set_mux(Mux *mux) { this->mux = mux; }
52 // <data> is taken to be raw NV12 data of WIDTHxHEIGHT resolution.
54 void add_frame(int64_t pts, int64_t duration, const uint8_t *data, const ReceivedTimestamps &received_ts);
56 std::string get_global_headers() const {
57 while (!x264_init_done) {
60 return global_headers;
63 void change_bitrate(unsigned rate_kbit) {
64 new_bitrate_kbit = rate_kbit;
69 int64_t pts, duration;
71 ReceivedTimestamps received_ts;
73 void encoder_thread_func();
75 void encode_frame(QueuedFrame qf);
77 // One big memory chunk of all 50 (or whatever) frames, allocated in
78 // the constructor. All data functions just use pointers into this
80 std::unique_ptr<uint8_t[]> frame_pool;
83 bool wants_global_headers;
85 std::string global_headers;
86 std::string buffered_sei; // Will be output before first frame, if any.
88 std::thread encoder_thread;
89 std::atomic<bool> x264_init_done{false};
90 std::atomic<bool> should_quit{false};
92 std::unique_ptr<X264SpeedControl> speed_control;
94 std::atomic<unsigned> new_bitrate_kbit{0}; // 0 for no change.
96 // Protects everything below it.
99 // Frames that are not being encoded or waiting to be encoded,
100 // so that add_frame() can use new ones.
101 std::queue<uint8_t *> free_frames;
103 // Frames that are waiting to be encoded (ie., add_frame() has been
104 // called, but they are not picked up for encoding yet).
105 std::queue<QueuedFrame> queued_frames;
107 // Whenever the state of <queued_frames> changes.
108 std::condition_variable queued_frames_nonempty;
110 // Key is the pts of the frame.
111 std::unordered_map<int64_t, ReceivedTimestamps> frames_being_encoded;
114 #endif // !defined(_X264ENCODE_H)