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/ffmpeg.go

@@ -0,0 +1,17 @@
+// Package ffmpeg provides a wrapper around the ffmpeg and ffprobe executables.
+package ffmpeg
+
+import (
+	"context"
+	"os/exec"
+
+	stashExec "github.com/stashapp/stash/pkg/exec"
+)
+
+// FFMpeg provides an interface to ffmpeg.
+type FFMpeg string
+
+// Returns an exec.Cmd that can be used to run ffmpeg using args.
+func (f *FFMpeg) Command(ctx context.Context, args []string) *exec.Cmd {
+	return stashExec.CommandContext(ctx, string(*f), args...)
+}