Rework FFmpeg hardware support

pkg/ffmpeg/ffmpeg.go

@@ -0,0 +1,80 @@
+package ffmpeg
+
+import (
+	"bytes"
+	"strconv"
+	"strings"
+)
+
+type Args struct {
+	Bin     string   // ffmpeg
+	Global  string   // -hide_banner -v error
+	Input   string   // -re -stream_loop -1 -i /media/bunny.mp4
+	Codecs  []string // -c:v libx264 -g:v 30 -preset:v ultrafast -tune:v zerolatency
+	Filters []string // scale=1920:1080
+	Output  string   // -f rtsp {output}
+
+	Video, Audio int // count of Video and Audio params
+}
+
+func (a *Args) AddCodec(codec string) {
+	a.Codecs = append(a.Codecs, codec)
+}
+
+func (a *Args) AddFilter(filter string) {
+	a.Filters = append(a.Filters, filter)
+}
+
+func (a *Args) InsertFilter(filter string) {
+	a.Filters = append([]string{filter}, a.Filters...)
+}
+
+func (a *Args) String() string {
+	b := bytes.NewBuffer(make([]byte, 0, 512))
+
+	b.WriteString(a.Bin)
+
+	if a.Global != "" {
+		b.WriteByte(' ')
+		b.WriteString(a.Global)
+	}
+
+	b.WriteByte(' ')
+	b.WriteString(a.Input)
+
+	multimode := a.Video > 1 || a.Audio > 1
+	var iv, ia int
+
+	for _, codec := range a.Codecs {
+		// support multiple video and/or audio codecs
+		if multimode && len(codec) >= 5 {
+			switch codec[:5] {
+			case "-c:v ":
+				codec = "-map 0:v:0? " + strings.ReplaceAll(codec, ":v ", ":v:"+strconv.Itoa(iv)+" ")
+				iv++
+			case "-c:a ":
+				codec = "-map 0:a:0? " + strings.ReplaceAll(codec, ":a ", ":a:"+strconv.Itoa(ia)+" ")
+				ia++
+			}
+		}
+
+		b.WriteByte(' ')
+		b.WriteString(codec)
+	}
+
+	if a.Filters != nil {
+		for i, filter := range a.Filters {
+			if i == 0 {
+				b.WriteString(" -vf ")
+			} else {
+				b.WriteByte(',')
+			}
+			b.WriteString(filter)
+		}
+	}
+
+	b.WriteByte(' ')
+	b.WriteString(a.Output)
+
+	return b.String()
+}