feat: add MP4 metadata extraction and integrate gomedia for video handling

storage/telegram/telegram.go

@@ -147,6 +147,17 @@ func (t *Telegram) Save(ctx context.Context, r io.Reader, storagePath string) er
 	switch mtypeStr := mtype.String(); {
 	case strings.HasPrefix(mtypeStr, "video/"):
 		media = docb.Video().SupportsStreaming()
+		rs.Seek(0, io.SeekStart)
+		switch mtypeStr {
+		case "video/mp4":
+			info, err := getMP4Info(rs)
+			if err == nil {
+				media = docb.Video().
+					Duration(time.Duration(info.Duration)*time.Second).
+					Resolution(info.Width, info.Height).
+					SupportsStreaming()
+			}
+		}
 	case strings.HasPrefix(mtypeStr, "audio/"):
 		media = docb.Audio().Title(filename)
 	case strings.HasPrefix(mtypeStr, "image/") && !strings.HasSuffix(mtypeStr, "webp"):

storage/telegram/util.go

@@ -0,0 +1,36 @@
+package telegram
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/yapingcat/gomedia/go-mp4"
+)
+
+type MP4Info struct {
+	Duration int
+	Width    int
+	Height   int
+}
+
+func getMP4Info(r io.ReadSeeker) (*MP4Info, error) {
+	d := mp4.CreateMp4Demuxer(r)
+
+	tracks, err := d.ReadHead()
+	if err != nil {
+		return nil, err
+	}
+
+	for _, track := range tracks {
+		if track.Cid == mp4.MP4_CODEC_H264 {
+			info := d.GetMp4Info()
+			return &MP4Info{
+				Duration: int(info.Duration / info.Timescale),
+				Width:    int(track.Width),
+				Height:   int(track.Height),
+			}, nil
+		}
+	}
+
+	return nil, fmt.Errorf("no h264 track found")
+}