Initial commit

examples/demuxing_decoding/main.go

@@ -0,0 +1,140 @@
+package main
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"log"
+	"strings"
+
+	"github.com/asticode/go-astiav"
+)
+
+var (
+	input = flag.String("i", "", "the input path")
+)
+
+type stream struct {
+	decCodec        *astiav.Codec
+	decCodecContext *astiav.CodecContext
+	inputStream     *astiav.Stream
+}
+
+func main() {
+	// Handle ffmpeg logs
+	astiav.SetLogLevel(astiav.LogLevelDebug)
+	astiav.SetLogCallback(func(l astiav.LogLevel, msg, parent string) {
+		log.Printf("ffmpeg log: %s (level: %d)\n", strings.TrimSpace(msg), l)
+	})
+
+	// Parse flags
+	flag.Parse()
+
+	// Usage
+	if *input == "" {
+		log.Println("Usage: <binary path> -i <input path>")
+		return
+	}
+
+	// Alloc packet
+	pkt := astiav.AllocPacket()
+	defer pkt.Free()
+
+	// Alloc frame
+	f := astiav.AllocFrame()
+	defer f.Free()
+
+	// Alloc input format context
+	inputFormatContext := astiav.AllocFormatContext()
+	if inputFormatContext == nil {
+		log.Fatal(errors.New("main: input format context is nil"))
+	}
+	defer inputFormatContext.Free()
+
+	// Open input
+	if err := inputFormatContext.OpenInput(*input, nil, nil); err != nil {
+		log.Fatal(fmt.Errorf("main: opening input failed: %w", err))
+	}
+	defer inputFormatContext.CloseInput()
+
+	// Find stream info
+	if err := inputFormatContext.FindStreamInfo(nil); err != nil {
+		log.Fatal(fmt.Errorf("main: finding stream info failed: %w", err))
+	}
+
+	// Loop through streams
+	streams := make(map[int]*stream) // Indexed by input stream index
+	for _, is := range inputFormatContext.Streams() {
+		// Only process audio or video
+		if is.CodecParameters().MediaType() != astiav.MediaTypeAudio &&
+			is.CodecParameters().MediaType() != astiav.MediaTypeVideo {
+			continue
+		}
+
+		// Create stream
+		s := &stream{inputStream: is}
+
+		// Find decoder
+		if s.decCodec = astiav.FindDecoder(is.CodecParameters().CodecID()); s.decCodec == nil {
+			log.Fatal(errors.New("main: codec is nil"))
+		}
+
+		// Alloc codec context
+		if s.decCodecContext = astiav.AllocCodecContext(s.decCodec); s.decCodecContext == nil {
+			log.Fatal(errors.New("main: codec context is nil"))
+		}
+		defer s.decCodecContext.Free()
+
+		// Update codec context
+		if err := is.CodecParameters().ToCodecContext(s.decCodecContext); err != nil {
+			log.Fatal(fmt.Errorf("main: updating codec context failed: %w", err))
+		}
+
+		// Open codec context
+		if err := s.decCodecContext.Open(s.decCodec, nil); err != nil {
+			log.Fatal(fmt.Errorf("main: opening codec context failed: %w", err))
+		}
+
+		// Add stream
+		streams[is.Index()] = s
+	}
+
+	// Loop through packets
+	for {
+		// Read frame
+		if err := inputFormatContext.ReadFrame(pkt); err != nil {
+			if errors.Is(err, astiav.ErrEof) {
+				break
+			}
+			log.Fatal(fmt.Errorf("main: reading frame failed: %w", err))
+		}
+
+		// Get stream
+		s, ok := streams[pkt.StreamIndex()]
+		if !ok {
+			continue
+		}
+
+		// Send packet
+		if err := s.decCodecContext.SendPacket(pkt); err != nil {
+			log.Fatal(fmt.Errorf("main: sending packet failed: %w", err))
+		}
+
+		// Loop
+		for {
+			// Receive frame
+			if err := s.decCodecContext.ReceiveFrame(f); err != nil {
+				if errors.Is(err, astiav.ErrEof) || errors.Is(err, astiav.ErrEagain) {
+					break
+				}
+				log.Fatal(fmt.Errorf("main: receiving frame failed: %w", err))
+			}
+
+			// Do something with decoded frame
+			log.Printf("new frame: stream %d - pts: %d", pkt.StreamIndex(), f.Pts())
+		}
+	}
+
+	// Success
+	log.Println("success")
+}