Updated examples

Author: djthorpe

cmd/examples/decode/main.go

@@ -1,63 +1,47 @@
 package main
 
 import (
-	"flag"
+	"context"
 	"log"
 	"os"
 
-	// Packages
-	ffmpeg "github.com/mutablelogic/go-media"
-)
-
-var (
-	in           = flag.String("in", "", "input file to decode")
-	audio_stream = flag.Int("audio", -1, "audio stream to decode")
-	video_stream = flag.Int("video", -1, "video stream to decode")
+	media "github.com/mutablelogic/go-media"
 )
 
 func main() {
-	flag.Parse()
-
-	// Check input file - read it
-	if *in == "" {
-		log.Fatal("-in flag must be specified")
-	}
-	r, err := os.Open(*in)
-	if err != nil {
-		log.Fatal(err)
-	}
-	defer r.Close()
+	manager := media.NewManager()
 
-	input, err := ffmpeg.NewReader(r, "")
+	// Open a media file for reading. The format of the file is guessed.
+	// Alteratively, you can pass a format as the second argument. Further optional
+	// arguments can be used to set the format options.
+	file, err := manager.Open(os.Args[1], nil)
 	if err != nil {
 		log.Fatal(err)
 	}
-	defer input.Close()
-
-	// Create a decoder for audio
-	audio, err := input.NewDecoder(ffmpeg.AUDIO, *audio_stream)
+	defer file.Close()
+
+	// Choose which streams to demultiplex - pass the stream parameters
+	// to the decoder. If you don't want to resample or reformat the streams,
+	// then you can pass nil as the function and all streams will be demultiplexed.
+	decoder, err := file.Decoder(func(stream media.Stream) (media.Parameters, error) {
+		// Copy streams, don't resample or resize
+		return stream.Parameters(), nil
+	})
 	if err != nil {
 		log.Fatal(err)
-	} else if err := audio.ResampleS16Mono(22000); err != nil {
-		log.Fatal(err)
 	}
 
-	// Create a decoder for video
-	video, err := input.NewDecoder(ffmpeg.VIDEO, *video_stream)
-	if err != nil {
-		log.Fatal(err)
-	} else if err := video.Rescale(1024, 720); err != nil {
-		log.Fatal(err)
-	}
+	// Demuliplex the stream and receive the frames of audio and video.
+	if err := decoder.Decode(context.Background(), func(frame media.Frame) error {
+		// Each packet is specific to a stream. It can be processed here
+		// to receive audio or video frames, then resize or resample them,
+		// for example. Alternatively, you can pass the packet to an encoder
+		// to remultiplex the streams without processing them.
+		log.Print(frame)
 
-	// Demux and decode the audio and video
-	n := 0
-	if err := input.Demux(input.Decode(func(frame ffmpeg.Frame) error {
-		log.Print("frame: ", n, "=>", frame)
-		n++
+		// Return io.EOF to stop processing, nil to continue
 		return nil
-	})); err != nil {
-
+	}); err != nil {
 		log.Fatal(err)
 	}
 }

cmd/examples/demux/main.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"context"
+	"log"
+	"os"
+
+	media "github.com/mutablelogic/go-media"
+)
+
+func main() {
+	manager := media.NewManager()
+
+	// Open a media file for reading. The format of the file is guessed.
+	// Alteratively, you can pass a format as the second argument. Further optional
+	// arguments can be used to set the format options.
+	file, err := manager.Open(os.Args[1], nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+
+	// Choose which streams to demultiplex - pass the stream parameters
+	// to the decoder. If you don't want to resample or reformat the streams,
+	// then you can pass nil as the function and all streams will be demultiplexed.
+	decoder, err := file.Decoder(func(stream media.Stream) (media.Parameters, error) {
+		return stream.Parameters(), nil
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Demuliplex the stream and receive the packets from the stream
+	if err := decoder.Demux(context.Background(), func(packet media.Packet) error {
+		// Each packet is specific to a stream. It can be processed here
+		// to decode audio or video frames, then resize or resample them,
+		// for example. Alternatively, you can pass the packet to an encoder
+		// to remultiplex the streams without processing them.
+		// You may get 'nil' packets when the stream is flushed.
+		log.Print(packet)
+
+		// Return io.EOF to stop processing, nil to continue
+		return nil
+	}); err != nil {
+		log.Fatal(err)
+	}
+}

decoder.go

@@ -365,13 +365,13 @@ func equalsStream(dest Parameters, src *ff.AVCodecParameters) (bool, error) {
 	switch src.CodecType() {
 	case ff.AVMEDIA_TYPE_AUDIO:
 		if !dest.Type().Is(AUDIO) {
-			return false, fmt.Errorf("source is audio, but destination is %v", dest.Type())
+			return false, fmt.Errorf("source is AUDIO, but destination is %v", dest.Type())
 		} else {
 			return equalsAudioPar(dest, src), nil
 		}
 	case ff.AVMEDIA_TYPE_VIDEO:
 		if !dest.Type().Is(VIDEO) {
-			return false, fmt.Errorf("source is video, but destination are %v", dest.Type())
+			return false, fmt.Errorf("source is VIDEO, but destination is %v", dest.Type())
 		} else {
 			return equalsVideoPar(dest, src), nil
 		}

mediatype.go

@@ -40,7 +40,7 @@ func (v MediaType) MarshalJSON() ([]byte, error) {
 
 func (v MediaType) String() string {
 	if v == NONE {
-		return v.String()
+		return v.FlagString()
 	}
 	str := ""
 	for f := MIN; f <= MAX; f <<= 1 {