Restructure ffmpeg (#2392)

* Refactor transcode generation
* Move phash generation into separate package
* Refactor image thumbnail generation
* Move JSONTime to separate package
* Ffmpeg refactoring
* Refactor live transcoding
* Refactor scene marker preview generation
* Refactor preview generation
* Refactor screenshot generation
* Refactor sprite generation
* Change ffmpeg.IsStreamable to return error
* Move frame rate calculation into ffmpeg
* Refactor file locking
* Refactor title set during scan
* Add missing lockmanager instance
* Return error instead of logging in MatchContainer

pkg/ffmpeg/transcoder/screenshot.go

@@ -0,0 +1,109 @@
+package transcoder
+
+import "github.com/stashapp/stash/pkg/ffmpeg"
+
+type ScreenshotOptions struct {
+	OutputPath string
+	OutputType ScreenshotOutputType
+
+	// Quality is the quality scale. See https://ffmpeg.org/ffmpeg.html#Main-options
+	Quality int
+
+	Width int
+
+	// Verbosity is the logging verbosity. Defaults to LogLevelError if not set.
+	Verbosity ffmpeg.LogLevel
+
+	UseSelectFilter bool
+}
+
+func (o *ScreenshotOptions) setDefaults() {
+	if o.Verbosity == "" {
+		o.Verbosity = ffmpeg.LogLevelError
+	}
+}
+
+type ScreenshotOutputType struct {
+	codec  ffmpeg.VideoCodec
+	format ffmpeg.Format
+}
+
+func (t ScreenshotOutputType) Args() []string {
+	var ret []string
+	if t.codec != "" {
+		ret = append(ret, t.codec.Args()...)
+	}
+	if t.format != "" {
+		ret = append(ret, t.format.Args()...)
+	}
+
+	return ret
+}
+
+var (
+	ScreenshotOutputTypeImage2 = ScreenshotOutputType{
+		format: "image2",
+	}
+	ScreenshotOutputTypeBMP = ScreenshotOutputType{
+		codec:  ffmpeg.VideoCodecBMP,
+		format: "rawvideo",
+	}
+)
+
+func ScreenshotTime(input string, t float64, options ScreenshotOptions) ffmpeg.Args {
+	options.setDefaults()
+
+	var args ffmpeg.Args
+	args = args.LogLevel(options.Verbosity)
+	args = args.Overwrite()
+	args = args.Seek(t)
+
+	args = args.Input(input)
+	args = args.VideoFrames(1)
+
+	if options.Quality > 0 {
+		args = args.FixedQualityScaleVideo(options.Quality)
+	}
+
+	var vf ffmpeg.VideoFilter
+
+	if options.Width > 0 {
+		vf = vf.ScaleWidth(options.Width)
+		args = args.VideoFilter(vf)
+	}
+
+	args = args.AppendArgs(options.OutputType)
+	args = args.Output(options.OutputPath)
+
+	return args
+}
+
+// ScreenshotFrame uses the select filter to get a single frame from the video.
+// It is very slow and should only be used for files with very small duration in secs / frame count.
+func ScreenshotFrame(input string, frame int, options ScreenshotOptions) ffmpeg.Args {
+	options.setDefaults()
+
+	var args ffmpeg.Args
+	args = args.LogLevel(options.Verbosity)
+	args = args.Overwrite()
+
+	args = args.Input(input)
+	args = args.VideoFrames(1)
+
+	args = args.VSync(ffmpeg.VSyncMethodPassthrough)
+
+	var vf ffmpeg.VideoFilter
+	// keep only frame number options.Frame)
+	vf = vf.Select(frame)
+
+	if options.Width > 0 {
+		vf = vf.ScaleWidth(options.Width)
+	}
+
+	args = args.VideoFilter(vf)
+
+	args = args.AppendArgs(options.OutputType)
+	args = args.Output(options.OutputPath)
+
+	return args
+}