ffmpeg/MediaPlayer: fix seeking in audio with cover art

MediaPlayer is basing its time on both the audio and video frames. This
doesn't go so well when there is a single video frame, resulting in the
whole file being one single "timepoint".

Avoid this problem by having the video decoder set the frame time to
"infinite" when the video stream is finished, which allows for the audio
timings to be used in this case.

Also improve the framerate handling of ffmpeg further, to avoid
MediaPlayer trying to frameskip at 90000fps (it would give up
frameskipping after a few frames and eventually notice that the next
frame was the end of stream, but still, not very clean). Now we report
an FPS of 0 instead, which should make it clear to applications what to
expect from single-frame files.

It seems the cover art is now hidden by a black screen, I'm not sure
why. But I'll leave debugging this for another day.

Fixes #13622.

Change-Id: Ie1dd1358cbb41c11649103dfce52a0e1317b26f8
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2562
Reviewed-by: Adrien Destugues <[email protected]>

src/add-ons/media/plugins/ffmpeg/AVFormatReader.cpp

@@ -396,15 +396,17 @@ StreamBase::FrameRate() const
 			break;
 		case AVMEDIA_TYPE_VIDEO:
 		{
-			AVRational frame_rate = av_guess_frame_rate(NULL, fStream, NULL);
-			if (frame_rate.den != 0 && frame_rate.num != 0)
-				frameRate = av_q2d(frame_rate);
+			AVRational frameRateFrac = av_guess_frame_rate(NULL, fStream, NULL);
+			if (frameRateFrac.den != 0 && frameRateFrac.num != 0)
+				frameRate = av_q2d(frameRateFrac);
 			else if (fStream->time_base.den != 0 && fStream->time_base.num != 0)
 				frameRate = 1 / av_q2d(fStream->time_base);
 
-			// TODO: Fix up interlaced video for real
-			if (frameRate == 50.0f)
-				frameRate = 25.0f;
+			// Catch the obviously wrong default framerate when ffmpeg cannot
+			// guess anything because there are not two frames to compute a
+			// framerate
+			if (fStream->nb_frames < 2 && frameRate == 90000.0f)
+				return 0.0f;
 			break;
 		}
 		default:

src/add-ons/media/plugins/ffmpeg/Utilities.h

@@ -215,8 +215,12 @@ CalculateBytesPerRowWithColorSpaceAndVideoWidth(color_space colorSpace, int vide
 inline void
 ConvertAVCodecContextToVideoFrameRate(AVCodecContext& contextIn, float& frameRateOut)
 {
-	// assert that av_q2d(contextIn.time_base) > 0 and computable
-	assert(contextIn.time_base.num > 0);
+	// A framerate of 0 is allowed for single-frame "video" (cover art, for
+	// example)
+	if (contextIn.time_base.num == 0)
+		frameRateOut = 0.0f;
+
+	// assert that we can compute something
 	assert(contextIn.time_base.den > 0);
 
 	// The following code is based on private get_fps() function of FFmpeg's

src/apps/mediaplayer/media_node_framework/PlaybackManager.cpp

@@ -945,7 +945,7 @@ PlaybackManager::PlaylistTimeForFrame(int64 frame) const
 void
 PlaybackManager::SetCurrentAudioTime(bigtime_t time)
 {
-TRACE("PlaybackManager::SetCurrentAudioTime(%lld)\n", time);
+	TRACE("PlaybackManager::SetCurrentAudioTime(%lld)\n", time);
 	bigtime_t lastFrameTime = _TimeForLastFrame();
 	fCurrentAudioTime = time;
 	bigtime_t newLastFrameTime = _TimeForLastFrame();
@@ -972,7 +972,7 @@ PlaybackManager::SetCurrentVideoFrame(int64 frame)
 void
 PlaybackManager::SetCurrentVideoTime(bigtime_t time)
 {
-TRACE("PlaybackManager::SetCurrentVideoTime(%lld)\n", time);
+	TRACE("PlaybackManager::SetCurrentVideoTime(%lld)\n", time);
 	bigtime_t lastFrameTime = _TimeForLastFrame();
 	fCurrentVideoTime = time;
 	bigtime_t newLastFrameTime = _TimeForLastFrame();
@@ -1546,7 +1546,7 @@ frameCount);
 			frame = startFrame + index;
 			break;
 	}
-TRACE("PlaybackManager::_FrameForRangeFrame() done: %ld\n", frame);
+	TRACE("PlaybackManager::_FrameForRangeFrame() done: %" PRId64 "\n", frame);
 	return frame;
 }
 

src/apps/mediaplayer/media_node_framework/video/VideoProducer.cpp

@@ -775,8 +775,12 @@ VideoProducer::_FrameGeneratorThread()
 						// to color space!
 						memset(buffer->Data(), 0, h->size_used);
 						err = B_OK;
-					} else if (err == B_LAST_BUFFER_ERROR)
+					} else if (err == B_LAST_BUFFER_ERROR) {
+						wasCached = true;
+							// Don't send the buffer: we don't have a buffer
+						err = B_OK;
 						running = false;
+					}
 					// Send the buffer on down to the consumer
 					if (wasCached || ((err = SendBuffer(buffer, fOutput.source,
 							fOutput.destination)) != B_OK)) {
@@ -815,6 +819,7 @@ VideoProducer::_FrameGeneratorThread()
 				break;
 		}
 	}
+	fManager->SetCurrentVideoTime(INT64_MAX);
 	TRACE("_FrameGeneratorThread: frame generator thread done.\n");
 	return B_OK;
 }