6 #include <condition_variable>
13 // An interface for frame allocators; if you do not specify one
14 // (using set_video_frame_allocator), a default one that pre-allocates
15 // a freelist of eight frames using new[] will be used. Specifying
16 // your own can be useful if you have special demands for where you want the
17 // frame to end up and don't want to spend the extra copy to get it there, for
18 // instance GPU memory.
19 class FrameAllocator {
22 uint8_t *data = nullptr;
23 uint8_t *data2 = nullptr; // Only if interleaved == true.
24 size_t len = 0; // Number of bytes we actually have.
25 size_t size = 0; // Number of bytes we have room for.
26 void *userdata = nullptr;
27 FrameAllocator *owner = nullptr;
29 // If set to true, every other byte will go to data and to data2.
30 // If so, <len> and <size> are still about the number of total bytes
31 // so if size == 1024, there's 512 bytes in data and 512 in data2.
32 bool interleaved = false;
35 virtual ~FrameAllocator();
37 // Request a video frame. Note that this is called from the
38 // USB thread, which runs with realtime priority and is
39 // very sensitive to delays. Thus, you should not do anything
40 // here that might sleep, including calling malloc().
41 // (Taking a mutex is borderline.)
43 // The Frame object will be given to the frame callback,
44 // which is responsible for releasing the video frame back
45 // once it is usable for new frames (ie., it will no longer
46 // be read from). You can use the "userdata" pointer for
47 // whatever you want to identify this frame if you need to.
49 // Returning a Frame with data==nullptr is allowed;
50 // if so, the frame in progress will be dropped.
51 virtual Frame alloc_frame() = 0;
53 virtual void release_frame(Frame frame) = 0;
56 typedef std::function<void(uint16_t timecode,
57 FrameAllocator::Frame video_frame, size_t video_offset, uint16_t video_format,
58 FrameAllocator::Frame audio_frame, size_t audio_offset, uint16_t audio_format)>
61 // The actual capturing class, representing capture from a single card.
64 BMUSBCapture(int vid = 0x1edb, int pid = 0xbd3b)
69 // Does not take ownership.
70 void set_video_frame_allocator(FrameAllocator *allocator)
72 video_frame_allocator = allocator;
75 FrameAllocator *get_video_frame_allocator()
77 return video_frame_allocator;
80 // Does not take ownership.
81 void set_audio_frame_allocator(FrameAllocator *allocator)
83 audio_frame_allocator = allocator;
86 FrameAllocator *get_audio_frame_allocator()
88 return audio_frame_allocator;
91 void set_frame_callback(frame_callback_t callback)
93 frame_callback = callback;
96 void configure_card();
97 void start_bm_capture();
99 static void start_bm_thread();
100 static void stop_bm_thread();
106 FrameAllocator::Frame frame;
109 void start_new_audio_block(const uint8_t *start);
110 void start_new_frame(const uint8_t *start);
112 void queue_frame(uint16_t format, uint16_t timecode, FrameAllocator::Frame frame, std::deque<QueuedFrame> *q);
113 void dequeue_thread();
115 static void usb_thread_func();
116 static void cb_xfr(struct libusb_transfer *xfr);
118 FrameAllocator::Frame current_video_frame;
119 FrameAllocator::Frame current_audio_frame;
121 std::mutex queue_lock;
122 std::condition_variable queues_not_empty;
123 std::deque<QueuedFrame> pending_video_frames;
124 std::deque<QueuedFrame> pending_audio_frames;
126 FrameAllocator *video_frame_allocator = nullptr;
127 FrameAllocator *audio_frame_allocator = nullptr;
128 frame_callback_t frame_callback = nullptr;
130 int current_register = 0;
132 static constexpr int NUM_BMUSB_REGISTERS = 60;
133 uint8_t register_file[NUM_BMUSB_REGISTERS];
136 std::vector<libusb_transfer *> iso_xfrs;