implement libav in some methods

util/av/remux.go

@@ -2,31 +2,117 @@ package av
 
 import (
 	"fmt"
-	"os"
+	"path/filepath"
+	"strings"
 
-	ffmpeg "github.com/u2takey/ffmpeg-go"
+	"github.com/asticode/go-astiav"
 )
 
-func RemuxFile(
-	inputFile string,
-) error {
-	tempFileName := inputFile + ".temp"
-	outputFile := inputFile
-	err := os.Rename(inputFile, tempFileName)
-	if err != nil {
-		return fmt.Errorf("failed to rename file: %w", err)
+func RemuxFile(inputFile string) error {
+	ext := strings.ToLower(filepath.Ext(inputFile))
+	var muxerName string
+	switch ext {
+	case ".mp4":
+		muxerName = "mp4"
+	case ".mkv":
+		muxerName = "matroska"
+	case ".mov":
+		muxerName = "mov"
+	case ".avi":
+		muxerName = "avi"
+	default:
+		return fmt.Errorf("unsupported output container for extension: %s", ext)
 	}
-	defer os.Remove(tempFileName)
-	err = ffmpeg.
-		Input(tempFileName).
-		Output(outputFile, ffmpeg.KwArgs{
-			"c": "copy",
-		}).
-		Silent(true).
-		OverWriteOutput().
-		Run()
+	outputFile := strings.TrimSuffix(inputFile, ext) + ".remuxed" + ext
+
+	inputCtx := astiav.AllocFormatContext()
+	if inputCtx == nil {
+		return fmt.Errorf("failed to alloc input format context")
+	}
+	defer inputCtx.Free()
+
+	if err := inputCtx.OpenInput(inputFile, nil, nil); err != nil {
+		return fmt.Errorf("failed to open input: %w", err)
+	}
+	defer inputCtx.CloseInput()
+
+	if err := inputCtx.FindStreamInfo(nil); err != nil {
+		return fmt.Errorf("failed to find stream info: %w", err)
+	}
+
+	outCtx, err := astiav.AllocOutputFormatContext(nil, muxerName, outputFile)
 	if err != nil {
-		return fmt.Errorf("failed to remux file: %w", err)
+		return fmt.Errorf("failed to alloc output format context: %w", err)
+	}
+	defer outCtx.Free()
+
+	inToOutIdx := make(map[int]int)
+	for inIdx, inStream := range inputCtx.Streams() {
+		inCP := inStream.CodecParameters()
+		if inCP.CodecID() == astiav.CodecIDNone {
+			continue
+		}
+		if mt := inCP.MediaType(); mt != astiav.MediaTypeVideo && mt != astiav.MediaTypeAudio && mt != astiav.MediaTypeSubtitle {
+			continue
+		}
+		outStream := outCtx.NewStream(nil)
+		if outStream == nil {
+			return fmt.Errorf("failed to create new stream in output context")
+		}
+		if err := inCP.Copy(outStream.CodecParameters()); err != nil {
+			return fmt.Errorf("failed to copy codec parameters: %w", err)
+		}
+		outStream.CodecParameters().SetCodecTag(0)
+		outStream.SetTimeBase(inStream.TimeBase())
+		inToOutIdx[inIdx] = len(inToOutIdx)
+	}
+	if len(inToOutIdx) == 0 {
+		return fmt.Errorf("no supported streams to remux")
+	}
+
+	if !outCtx.OutputFormat().Flags().Has(astiav.IOFormatFlagNofile) {
+		ioCtx, err := astiav.OpenIOContext(outputFile, astiav.NewIOContextFlags(astiav.IOContextFlagWrite), nil, nil)
+		if err != nil {
+			return fmt.Errorf("failed to open output IO context: %w", err)
+		}
+		defer ioCtx.Close()
+		outCtx.SetPb(ioCtx)
+	}
+
+	if err := outCtx.WriteHeader(nil); err != nil {
+		return fmt.Errorf("failed to write output header: %w", err)
+	}
+
+	packet := astiav.AllocPacket()
+	defer packet.Free()
+	for {
+		if err := inputCtx.ReadFrame(packet); err != nil {
+			if err == astiav.ErrEof {
+				break
+			}
+			return fmt.Errorf("error reading frame: %w", err)
+		}
+		outIdx, ok := inToOutIdx[packet.StreamIndex()]
+		if !ok {
+			packet.Unref()
+			continue
+		}
+		inStream := inputCtx.Streams()[packet.StreamIndex()]
+		outStream := outCtx.Streams()[outIdx]
+		packet.SetPts(astiav.RescaleQRnd(packet.Pts(), inStream.TimeBase(), outStream.TimeBase(), astiav.RoundingNearInf))
+		packet.SetDts(astiav.RescaleQRnd(packet.Dts(), inStream.TimeBase(), outStream.TimeBase(), astiav.RoundingNearInf))
+		packet.SetDuration(astiav.RescaleQ(packet.Duration(), inStream.TimeBase(), outStream.TimeBase()))
+		packet.SetStreamIndex(outIdx)
+		packet.SetPos(-1)
+		if err := outCtx.WriteInterleavedFrame(packet); err != nil {
+			packet.Unref()
+			return fmt.Errorf("error writing frame: %w", err)
+		}
+		packet.Unref()
+	}
+
+	if err := outCtx.WriteTrailer(); err != nil {
+		return fmt.Errorf("failed to write trailer: %w", err)
 	}
 	return nil
 }