first working version!

video/video.go

@@ -0,0 +1,66 @@
+package video
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path"
+	"strconv"
+
+	"arimelody.space/live-vod-uploader/youtube"
+	ffmpeg "github.com/u2takey/ffmpeg-go"
+)
+
+type (
+	probeFormat struct {
+		Duration string `json:"duration"`
+	}
+	probeData struct {
+		Format probeFormat `json:"format"`
+	}
+)
+
+func ConcatVideo(video *youtube.Video, vodFiles []string) error {
+	fileListPath := path.Join(
+		path.Dir(video.Filename),
+		"files.txt",
+	)
+
+	totalDuration := float64(0.0)
+	fileListString := ""
+	for _, file := range vodFiles {
+		fileListString += fmt.Sprintf("file '%s'\n", file)
+		jsonProbe, err := ffmpeg.Probe(path.Join(path.Dir(video.Filename), file))
+		if err != nil {
+			return fmt.Errorf("failed to probe file `%s`: %v", file, err)
+		}
+		probe := probeData{}
+		json.Unmarshal([]byte(jsonProbe), &probe)
+		duration, err := strconv.ParseFloat(probe.Format.Duration, 64)
+		if err != nil {
+			return fmt.Errorf("failed to parse duration of file `%s`: %v", file, err)
+		}
+		totalDuration += duration
+	}
+	err := os.WriteFile(
+		fileListPath,
+		[]byte(fileListString),
+		0o644,
+	)
+	if err != nil {
+		return fmt.Errorf("failed to write file list: %v", err)
+	}
+
+	err = ffmpeg.Input(fileListPath, ffmpeg.KwArgs{
+		"f": "concat",
+		"safe": "0",
+	}).Output(video.Filename, ffmpeg.KwArgs{
+		"c": "copy",
+	}).OverWriteOutput().ErrorToStdOut().Run()
+
+	if err != nil {
+		return fmt.Errorf("ffmpeg error: %v", err)
+	}
+
+	return nil
+}