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