feat(log): point to passthrough as a potential issue when unable to generate thumbnails

Re: #3433 and #3431

core/data/config.go

@@ -620,14 +620,14 @@ func VerifySettings() error {
 }
 
 // FindHighestVideoQualityIndex will return the highest quality from a slice of variants.
-func FindHighestVideoQualityIndex(qualities []models.StreamOutputVariant) int {
+func FindHighestVideoQualityIndex(qualities []models.StreamOutputVariant) (int, bool) {
 	type IndexedQuality struct {
 		quality models.StreamOutputVariant
 		index   int
 	}
 
 	if len(qualities) < 2 {
-		return 0
+		return 0, qualities[0].IsVideoPassthrough
 	}
 
 	indexedQualities := make([]IndexedQuality, 0)
@@ -649,7 +649,8 @@ func FindHighestVideoQualityIndex(qualities []models.StreamOutputVariant) int {
 	})
 
 	// nolint:gosec
-	return indexedQualities[0].index
+	selectedQuality := indexedQualities[0]
+	return selectedQuality.index, selectedQuality.quality.IsVideoPassthrough
 }
 
 // GetForbiddenUsernameList will return the blocked usernames as a comma separated string.

core/streamState.go

@@ -69,7 +69,8 @@ func setStreamAsConnected(rtmpOut *io.PipeReader) {
 	}()
 
 	go webhooks.SendStreamStatusEvent(models.StreamStarted)
-	transcoder.StartThumbnailGenerator(segmentPath, data.FindHighestVideoQualityIndex(_currentBroadcast.OutputSettings))
+	selectedThumbnailVideoQualityIndex, isVideoPassthrough := data.FindHighestVideoQualityIndex(_currentBroadcast.OutputSettings)
+	transcoder.StartThumbnailGenerator(segmentPath, selectedThumbnailVideoQualityIndex, isVideoPassthrough)
 
 	_ = chat.SendSystemAction("Stay tuned, the stream is **starting**!", true)
 	chat.SendAllWelcomeMessage()

core/transcoder/thumbnailGenerator.go

@@ -25,7 +25,7 @@ func StopThumbnailGenerator() {
 }
 
 // StartThumbnailGenerator starts generating thumbnails.
-func StartThumbnailGenerator(chunkPath string, variantIndex int) {
+func StartThumbnailGenerator(chunkPath string, variantIndex int, isVideoPassthrough bool) {
 	// Every 20 seconds create a thumbnail from the most
 	// recent video segment.
 	_timer = time.NewTicker(20 * time.Second)
@@ -36,7 +36,11 @@ func StartThumbnailGenerator(chunkPath string, variantIndex int) {
 			select {
 			case <-_timer.C:
 				if err := fireThumbnailGenerator(chunkPath, variantIndex); err != nil {
-					log.Errorln("Unable to generate thumbnail:", err)
+					logMsg := "Unable to generate thumbnail: " + err.Error()
+					if isVideoPassthrough {
+						logMsg += ". Video Passthrough is enabled. You should disable it to fix this, and other, streaming errors. https://owncast.online/troubleshoot"
+					}
+					log.Errorln("Unable to generate thumbnail:", logMsg)
 				}
 			case <-quit:
 				log.Debug("thumbnail generator has stopped")