Can now encode both mp4 and vp9 with most of the options I need.

.gitignore

@@ -29,3 +29,4 @@ coverage/*
 public
 *.mp4
 ffmpeg*
+renders

config.json

@@ -1,7 +1,6 @@
 [
   {
   "Format": "mp4",
-  "Scale": "1280:720",
   "VideoBitrate": 900,
   "AudioBitrate": 192,
   "Speed": "veryfast",
@@ -9,22 +8,29 @@
   "CRF": 20,
   "FPS": 30,
   "Tune": "animation",
-  "Input": "test*.mp4",
+  "Input": "*.mp4",
   "OutDir": "renders",
-  "Passes": 3
+  "Passes": 3,
+  "Extras": [
+      "-movflags", "faststart",
+      "-tune", "animation"
+    ]
   },
   {
-  "Format": "mp4",
-  "Scale": "1920:1080",
-  "VideoBitrate": 1200,
+  "Format": "webm",
+  "VideoBitrate": 600,
+  "VideoCodec": "libvpx-vp9",
   "AudioBitrate": 192,
+  "AudioCodec": "libopus",
   "Speed": "veryfast",
   "CleanFilename": false,
   "CRF": 20,
   "FPS": 30,
   "Tune": "animation",
-  "Input": "test*.mp4",
+  "Input": "*.mp4",
   "OutDir": "renders",
-  "Passes": 2
+  "Passes": 2,
+  "Extras": [
+   ]
   }
 ]

config/settings.go

@@ -8,9 +8,12 @@ import (
 )
 
 type VideoOpts struct {
+  Format string
   Scale string
   VideoBitrate int
+  VideoCodec string
   AudioBitrate int
+  AudioCodec string
   Speed string
   CleanFilename bool
   CRF int
@@ -21,6 +24,7 @@ type VideoOpts struct {
   Test int
   TestStart int
   Passes int
+  Extras []string
 }
 
 type Settings struct {

main.go

@@ -12,7 +12,7 @@ import (
   "github.com/modfy/fluent-ffmpeg"
 )
 
-func ModFile(fname string, scale string) string {
+func ModFile(fname string, encoding config.VideoOpts) string {
   cleaned := filepath.Clean(fname)
   dir, file := filepath.Split(cleaned)
   ext := filepath.Ext(file)
@@ -20,8 +20,8 @@ func ModFile(fname string, scale string) string {
   base, found := strings.CutSuffix(file, ext)
   if !found { panic("no extension found?!") }
 
-  dim := strings.Replace(scale, ":", ".", 1)
-  renamed := fmt.Sprint(base, ".", dim, ext)
+  dim := strings.Replace(encoding.Scale, ":", ".", 1)
+  renamed := fmt.Sprint(base, ".", dim, ".", encoding.Format)
   return filepath.Join(dir, renamed)
 }
 
@@ -29,40 +29,43 @@ func ModFile(fname string, scale string) string {
 func Run(encoding config.VideoOpts, pass int, pid int, input string, output string) {
   encode := fluentffmpeg.NewCommand("")
 
-  mp4_encoding := []string{
-    "-vf", fmt.Sprintf("scale=%s:flags=lanczos", encoding.Scale),
-    "-aspect", encoding.Scale,
+  extras := []string{
     "-pix_fmt", "yuv420p",
-    "-tune", encoding.Tune,
-    "-movflags", "faststart",
     "-pass", fmt.Sprint(pass),
     "-passlogfile", fmt.Sprintf("ffmpeg2pass-%x.log", pid),
     "-preset", encoding.Speed,
   }
 
+  if encoding.Scale != "" {
+    "-vf", fmt.Sprintf("scale=%s:flags=lanczos", encoding.Scale),
+    "-aspect", encoding.Scale,
+  }
+
+  extras = append(extras, encoding.Extras...)
+
   if pass != encoding.Passes {
-    mp4_encoding = append(mp4_encoding, "-an")
+    extras = append(extras, "-an")
   } else {
-    encode.AudioCodec("aac")
-    mp4_encoding = append(mp4_encoding,
+    encode.AudioCodec(encoding.AudioCodec)
+    extras = append(extras,
       "-b:a", fmt.Sprint(encoding.AudioBitrate * 1024))
   }
 
   if encoding.Test > 0 {
     encode.InputOptions(
       "-ss", fmt.Sprintf("00:%d", encoding.TestStart))
-    mp4_encoding = append(mp4_encoding, "-t", fmt.Sprint(encoding.Test))
+    extras = append(extras, "-t", fmt.Sprint(encoding.Test))
   }
 
-  encode.VideoCodec("libx264").
+  encode.VideoCodec(encoding.VideoCodec).
     VideoBitRate(encoding.VideoBitrate * 1024).
     FrameRate(encoding.FPS).
     ConstantRateFactor(encoding.CRF)
 
-  encode.OutputOptions(mp4_encoding...)
+  encode.OutputOptions(extras...)
 
   cmd := encode.InputPath(input).
-    OutputFormat("mp4").
+    OutputFormat(encoding.Format).
     OutputPath(output).
     Build()
 
@@ -95,7 +98,7 @@ func RenderToDir(encoding config.VideoOpts) {
   for _, path := range matches {
     base := filepath.Base(path)
     target := filepath.Join(encoding.OutDir, base)
-    target = ModFile(target, encoding.Scale)
+    target = ModFile(target, encoding)
 
     _, err := os.Stat(target)