Attempt to fix video/audio desync when video pts gets desynced with clock

README.md

@@ -28,6 +28,8 @@ Recording monitors requires a gpu with NvFBC support (note: this is not required
 Run `interactive.sh` or run gpu-screen-recorder directly, for example: `gpu-screen-recorder -w $(xdotool selectwindow) -c mp4 -f 60 -a "$(pactl get-default-sink).monitor" -o test_video.mp4`\
 Then stop the screen recorder with Ctrl+C, which will also save the recording.\
 Send signal SIGUSR1 (`killall -SIGUSR1 gpu-screen-recorder`) to gpu-screen-recorder when in replay mode to save the replay. The paths to the saved files is output to stdout after the recording is saved.\
+You can find the default output audio device (headset, speakers) with the command `pactl get-default-sink`. Add `monitor` to the end of that to use that as an audio input in gpu-screen-recorder.\
+You can find the default input audio device (microphone) with the command `pactl get-default-source`.\
 There is also a gui for the gpu-screen-recorder called [gpu-screen-recorder-gtk](https://git.dec05eba.com/gpu-screen-recorder-gtk/).
 
 # Demo

src/main.cpp

@@ -1582,9 +1582,11 @@ int main(int argc, char **argv) {
                 // res = cuCtxPopCurrent(&old_ctx);
             }
 
-            // TODO: Check if duplicate frame can be saved just by writing it with a different pts instead of sending it again
             const double this_video_frame_time = clock_get_monotonic_seconds();
-            const int num_frames = std::max(1.0, std::round((this_video_frame_time - prev_video_frame_time) / target_fps));
+            const int64_t expected_frames = (this_video_frame_time - start_time_pts) / target_fps;
+
+            const int num_frames = std::max(0L, expected_frames - video_pts_counter);
+            // TODO: Check if duplicate frame can be saved just by writing it with a different pts instead of sending it again
             for(int i = 0; i < num_frames; ++i) {
                 frame->pts = video_pts_counter + i;
                 if (avcodec_send_frame(video_codec_context, frame) >= 0) {