using namespace std::chrono;
using namespace bmusb;
+namespace {
+
+steady_clock::time_point compute_frame_start(int64_t frame_pts, int64_t pts_origin, const AVRational &video_timebase, const steady_clock::time_point &origin, double rate)
+{
+ const duration<double> pts((frame_pts - pts_origin) * double(video_timebase.num) / double(video_timebase.den));
+ return origin + duration_cast<steady_clock::duration>(pts / rate);
+}
+
+} // namespace
+
FFmpegCapture::FFmpegCapture(const string &filename, unsigned width, unsigned height)
: filename(filename), width(width), height(height)
{
unique_ptr<AVCodecContext, decltype(avcodec_close)*> codec_ctx_cleanup(
codec_ctx.get(), avcodec_close);
+ int64_t pts_origin = 0, last_pts = 0;
steady_clock::time_point start = steady_clock::now();
+ steady_clock::time_point next_frame_start = start;
+ double rate = 1.0;
unique_ptr<SwsContext, decltype(sws_freeContext)*> sws_ctx(nullptr, sws_freeContext);
int sws_last_width = -1, sws_last_height = -1;
// Main loop.
while (!producer_thread_should_quit) {
+ // Process any queued commands from other threads.
+ vector<QueuedCommand> commands;
+ {
+ lock_guard<mutex> lock(queue_mu);
+ swap(commands, command_queue);
+ }
+ for (const QueuedCommand &cmd : commands) {
+ switch (cmd.command) {
+ case QueuedCommand::REWIND:
+ if (av_seek_frame(format_ctx.get(), /*stream_index=*/-1, /*timestamp=*/0, /*flags=*/0) < 0) {
+ fprintf(stderr, "%s: Rewind failed, stopping play.\n", pathname.c_str());
+ }
+ pts_origin = last_pts = 0;
+ start = next_frame_start = steady_clock::now();
+ break;
+
+ case QueuedCommand::CHANGE_RATE:
+ start = next_frame_start;
+ pts_origin = last_pts;
+ rate = cmd.new_rate;
+ break;
+ }
+ }
+
// Read packets until we have a frame or there are none left.
int frame_finished = 0;
AVFrameWithDeleter frame = av_frame_alloc_unique();
fprintf(stderr, "%s: Rewind failed, not looping.\n", pathname.c_str());
return true;
}
+ pts_origin = last_pts = 0;
start = steady_clock::now();
continue;
}
video_format.has_signal = true;
video_format.is_connected = true;
- const duration<double> pts(frame->pts * double(video_timebase.num) / double(video_timebase.den));
- const steady_clock::time_point frame_start = start + duration_cast<steady_clock::duration>(pts);
+ next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
+ last_pts = frame->pts;
FrameAllocator::Frame video_frame = video_frame_allocator->alloc_frame();
if (video_frame.data != nullptr) {
int linesizes[4] = { int(video_format.stride), 0, 0, 0 };
sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
video_frame.len = video_format.stride * height;
- video_frame.received_timestamp = frame_start;
+ video_frame.received_timestamp = next_frame_start;
}
FrameAllocator::Frame audio_frame;
audio_format.bits_per_sample = 32;
audio_format.num_channels = 8;
- this_thread::sleep_until(frame_start);
+ // TODO: Make it interruptable somehow.
+ this_thread::sleep_until(next_frame_start);
frame_callback(timecode++,
video_frame, 0, video_format,
audio_frame, 0, audio_format);