When switching output cards, do it from the mixer thread.

[nageru] / mixer.cpp

diff --git a/mixer.cpp b/mixer.cpp
index e00fff89bd37ce3dd1f565f3eafbabb2ad9da4f0..a83d66ef7194a9ff21b01dbe4843c73bc1d852b9 100644 (file)
--- a/mixer.cpp
+++ b/mixer.cpp
@@ -10,6 +10,7 @@
 #include <movit/image_format.h>
 #include <movit/init.h>
 #include <movit/resource_pool.h>
+#include <pthread.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -202,7 +203,7 @@ Mixer::Mixer(const QSurfaceFormat &format, unsigned num_cards)
                alsa.reset(new ALSAOutput(OUTPUT_FREQUENCY, /*num_channels=*/2));
        }
        if (global_flags.output_card != -1) {
-               set_output_card(global_flags.output_card);
+               set_output_card_internal(global_flags.output_card);
        }
 }
 
@@ -259,31 +260,44 @@ void Mixer::configure_card(unsigned card_index, CaptureInterface *capture, bool
        audio_mixer.trigger_state_changed_callback();
 }
 
-void Mixer::set_output_card(int card_index)
+void Mixer::set_output_card_internal(int card_index)
 {
-       if (card_index == output_card_index) {
-               return;
-       }
+       // We don't really need to take card_mutex, since we're in the mixer
+       // thread and don't mess with any queues (which is the only thing that happens
+       // from other threads), but it's probably the safest in the long run.
        unique_lock<mutex> lock(card_mutex);
        if (output_card_index != -1) {
                // Switch the old card from output to input.
                CaptureCard *old_card = &cards[output_card_index];
                old_card->output->end_output();
 
-               old_card->capture->stop_dequeue_thread();
+               // Stop the fake card that we put into place.
+               // This needs to _not_ happen under the mutex, to avoid deadlock
+               // (delivering the last frame needs to take the mutex).
+               bmusb::CaptureInterface *fake_capture = old_card->capture.get();
+               lock.unlock();
+               fake_capture->stop_dequeue_thread();
+               lock.lock();
                old_card->capture = move(old_card->parked_capture);
                old_card->is_fake_capture = false;
                old_card->capture->start_bm_capture();
        }
-
-       CaptureCard *card = &cards[card_index];
-       card->capture->stop_dequeue_thread();
-       card->parked_capture = move(card->capture);
-       FakeCapture *capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
-       configure_card(card_index, capture, /*is_fake_capture=*/true, card->output.release());
-       card->queue_length_policy.reset(card_index);
-       card->capture->start_bm_capture();
-       card->output->start_output(bmdModeHD720p5994, pts_int);  // FIXME
+       if (card_index != -1) {
+               CaptureCard *card = &cards[card_index];
+               bmusb::CaptureInterface *capture = card->capture.get();
+               // TODO: DeckLinkCapture::stop_dequeue_thread can actually take
+               // several seconds to complete (blocking on DisableVideoInput);
+               // see if we can maybe do it asynchronously.
+               lock.unlock();
+               capture->stop_dequeue_thread();
+               lock.lock();
+               card->parked_capture = move(card->capture);
+               bmusb::CaptureInterface *fake_capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
+               configure_card(card_index, fake_capture, /*is_fake_capture=*/true, card->output.release());
+               card->queue_length_policy.reset(card_index);
+               card->capture->start_bm_capture();
+               card->output->start_output(bmdModeHD720p5994, pts_int);  // FIXME
+       }
        output_card_index = card_index;
 }
 
@@ -555,6 +569,8 @@ void Mixer::bm_hotplug_remove(unsigned card_index)
 
 void Mixer::thread_func()
 {
+       pthread_setname_np(pthread_self(), "Mixer_OpenGL");
+
        eglBindAPI(EGL_OPENGL_API);
        QOpenGLContext *context = create_context(mixer_surface);
        if (!make_current(context, mixer_surface)) {
@@ -577,6 +593,10 @@ void Mixer::thread_func()
        int stats_dropped_frames = 0;
 
        while (!should_quit) {
+               if (desired_output_card_index != output_card_index) {
+                       set_output_card_internal(desired_output_card_index);
+               }
+
                CaptureCard::NewFrame new_frames[MAX_VIDEO_CARDS];
                bool has_new_frame[MAX_VIDEO_CARDS] = { false };
 
@@ -922,6 +942,8 @@ void Mixer::render_one_frame(int64_t duration)
 
 void Mixer::audio_thread_func()
 {
+       pthread_setname_np(pthread_self(), "Mixer_Audio");
+
        while (!should_quit) {
                AudioTask task;