🚧 Trim with ffmpeg

media/ffmpeg.go

@@ -0,0 +1,57 @@
+package media
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+
+	"codeberg.org/danjones000/strip-beats/config"
+	ffmpeg "github.com/u2takey/ffmpeg-go"
+)
+
+func TrimWithFade(in Probe, out string, start, stop, up, down float64) error {
+	// -ss (start) -t (end) -af afade=t=in:st=(start):d=(up),afade=t=out:st=(downstart):d=(down)
+	st := in.GetFirstAcceptableAudio()
+	if st == nil {
+		return errors.New("Can't find an audio stream")
+	}
+	args := ffmpeg.KwArgs{"c:a": "copy"}
+	if start != 0 {
+		args["ss"] = start
+	}
+	if stop != 0 {
+		end := stop - start
+		args["t"] = end
+	} else {
+		stop = st.Duration
+	}
+
+	input := ffmpeg.Input(in.Format.Path).Get(strconv.Itoa(st.Index))
+	if up != 0 {
+		args["c:a"] = config.GetConfig().FfEncoder
+		input = input.Filter("afade", ffmpeg.Args{
+			"t=in",
+			fmt.Sprintf("st=%v", start),
+			fmt.Sprintf("d=%v", up)})
+	}
+
+	if down != 0 {
+		args["c:a"] = config.GetConfig().FfEncoder
+		downstart := stop - down
+		input = input.Filter("afade", ffmpeg.Args{
+			"t=out",
+			fmt.Sprintf("st=%v", downstart),
+			fmt.Sprintf("d=%v", down)})
+	}
+	output := input.Output(out, args).GlobalArgs("-y")
+	// @todo out should be stdout
+	return output.Run()
+}
+
+func Trim(in Probe, out string, start, stop float64) error {
+	return TrimWithFade(in, out, start, stop, 0, 0)
+}
+
+func Fade(in Probe, out string, up, down float64) error {
+	return TrimWithFade(in, out, 0, 0, up, down)
+}