libobs: Fix skipped frames reporting

When frames are skipped the skipped frame count would increment, but the
total frame count would not increment, causing the percentage
calculation to fail.

Additionally, the skipped frames log reporting has been moved to
media-io/video-io.c instead of each output.

libobs/media-io/video-io.c

@@ -16,6 +16,7 @@
 ******************************************************************************/
 
 #include <assert.h>
+#include <inttypes.h>
 #include "../util/bmem.h"
 #include "../util/platform.h"
 #include "../util/profiler.h"
@@ -150,6 +151,8 @@ static inline bool video_output_cur_frame(struct video_output *video)
 
 		if (++video->available_frames == video->info.cache_size)
 			video->last_added = video->first_added;
+	} else {
+		++video->skipped_frames;
 	}
 
 	pthread_mutex_unlock(&video->data_mutex);
@@ -333,6 +336,11 @@ bool video_output_connect(video_t *video,
 
 	pthread_mutex_lock(&video->input_mutex);
 
+	if (video->inputs.num == 0) {
+		video->skipped_frames = 0;
+		video->total_frames = 0;
+	}
+
 	if (video_get_input_idx(video, callback, param) == DARRAY_INVALID) {
 		struct video_input input;
 		memset(&input, 0, sizeof(input));
@@ -378,6 +386,20 @@ void video_output_disconnect(video_t *video,
 		da_erase(video->inputs, idx);
 	}
 
+	if (video->inputs.num == 0) {
+		double percentage_skipped = (double)video->skipped_frames /
+			(double)video->total_frames * 100.0;
+
+		if (video->skipped_frames)
+			blog(LOG_INFO, "Video stopped, number of "
+					"skipped frames due "
+					"to encoding lag: "
+					"%"PRIu32"/%"PRIu32" (%0.1f%%)",
+					video->skipped_frames,
+					video->total_frames,
+					percentage_skipped);
+	}
+
 	pthread_mutex_unlock(&video->input_mutex);
 }
 
@@ -403,7 +425,6 @@ bool video_output_lock_frame(video_t *video, struct video_frame *frame,
 	pthread_mutex_lock(&video->data_mutex);
 
 	if (video->available_frames == 0) {
-		video->skipped_frames += count;
 		video->cache[video->last_added].count += count;
 		locked = false;