Changes to remove framerate

cmd/examples/capture/context.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"context"
+	"os"
+	"os/signal"
+)
+
+///////////////////////////////////////////////////////////////////////////////
+// PUBLIC METHODS
+
+// ContextForSignal returns a context object which is cancelled when a signal
+// is received. It returns nil if no signal parameter is provided
+func ContextForSignal(signals ...os.Signal) context.Context {
+	if len(signals) == 0 {
+		return nil
+	}
+
+	ch := make(chan os.Signal, 1)
+	ctx, cancel := context.WithCancel(context.Background())
+
+	// Send message on channel when signal received
+	signal.Notify(ch, signals...)
+
+	// When any signal received, call cancel
+	go func() {
+		<-ch
+		cancel()
+	}()
+
+	// Return success
+	return ctx
+}

cmd/examples/capture/main.go

@@ -0,0 +1,95 @@
+package main
+
+import (
+	"fmt"
+	"image/jpeg"
+	"log"
+	"os"
+	"regexp"
+	"syscall"
+
+	// Packages
+	media "github.com/mutablelogic/go-media"
+	ffmpeg "github.com/mutablelogic/go-media/pkg/ffmpeg"
+)
+
+var (
+	reDeviceNamePath = regexp.MustCompile(`^([a-z][a-zA-Z0-9]+)\:(.*)$`)
+)
+
+func main() {
+	if len(os.Args) != 2 {
+		log.Fatal("Usage: capture device:path")
+	}
+
+	// Get the format associated with the input file
+	device := reDeviceNamePath.FindStringSubmatch(os.Args[1])
+	if device == nil {
+		log.Fatal("Invalid device name, use device:path")
+	}
+
+	// Create a media manager
+	manager, err := ffmpeg.NewManager(ffmpeg.OptLog(false, nil))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Find device
+	devices := manager.Formats(media.DEVICE, device[1])
+	if len(devices) == 0 {
+		log.Fatalf("No devices found for %v", device[1])
+	}
+	if len(devices) > 1 {
+		log.Fatalf("Multiple devices found: %q", devices)
+	}
+
+	// Open device
+	media, err := manager.Open(device[2], devices[0])
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer media.Close()
+
+	// Tmpdir
+	tmpdir, err := os.MkdirTemp("", "capture")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Frame function
+	frameFunc := func(stream int, frame *ffmpeg.Frame) error {
+		w, err := os.Create(fmt.Sprintf("%v/frame-%v.jpg", tmpdir, frame.Ts()))
+		if err != nil {
+			return err
+		}
+		defer w.Close()
+
+		image, err := frame.Image()
+		if err != nil {
+			return err
+		}
+
+		if err := jpeg.Encode(w, image, nil); err != nil {
+			return err
+		}
+
+		fmt.Println("Written", w.Name())
+
+		return nil
+	}
+
+	// Map function
+	mapFunc := func(_ int, in *ffmpeg.Par) (*ffmpeg.Par, error) {
+		fmt.Println("Input", in)
+		return ffmpeg.VideoPar("yuv420p", in.WidthHeight(), in.FrameRate()), nil
+	}
+
+	// Receive frames
+	if err := media.(*ffmpeg.Reader).Decode(
+		ContextForSignal(os.Interrupt, syscall.SIGQUIT),
+		mapFunc,
+		frameFunc,
+	); err != nil {
+		log.Fatal(err)
+	}
+}

cmd/examples/encode/context.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"context"
+	"os"
+	"os/signal"
+)
+
+///////////////////////////////////////////////////////////////////////////////
+// PUBLIC METHODS
+
+// ContextForSignal returns a context object which is cancelled when a signal
+// is received. It returns nil if no signal parameter is provided
+func ContextForSignal(signals ...os.Signal) context.Context {
+	if len(signals) == 0 {
+		return nil
+	}
+
+	ch := make(chan os.Signal, 1)
+	ctx, cancel := context.WithCancel(context.Background())
+
+	// Send message on channel when signal received
+	signal.Notify(ch, signals...)
+
+	// When any signal received, call cancel
+	go func() {
+		<-ch
+		cancel()
+	}()
+
+	// Return success
+	return ctx
+}

cmd/examples/encode/main.go

@@ -1,10 +1,13 @@
 package main
 
 import (
+	"context"
+	"errors"
 	"fmt"
 	"io"
 	"log"
 	"os"
+	"syscall"
 
 	// Packages
 	ffmpeg "github.com/mutablelogic/go-media/pkg/ffmpeg"
@@ -13,9 +16,14 @@ import (
 
 // This example encodes an audio an video stream to a file
 func main() {
+	// Check we have a filename
+	if len(os.Args) != 2 {
+		log.Fatal("Usage: encode filename")
+	}
+
 	// Create a new file with an audio and video stream
 	file, err := ffmpeg.Create(os.Args[1],
-		ffmpeg.OptStream(1, ffmpeg.VideoPar("yuv420p", "1280x720", 30)),
+		ffmpeg.OptStream(1, ffmpeg.VideoPar("yuv420p", "1280x720", 25, ffmpeg.NewMetadata("crf", 2))),
 		ffmpeg.OptStream(2, ffmpeg.AudioPar("fltp", "mono", 22050)),
 	)
 	if err != nil {
@@ -39,10 +47,13 @@ func main() {
 	}
 	defer audio.Close()
 
+	// Bail out when we receive a signal
+	ctx := ContextForSignal(os.Interrupt, syscall.SIGQUIT)
+
 	// Write 90 seconds, passing video and audio frames to the encoder
 	// and returning io.EOF when the duration is reached
 	duration := float64(90)
-	err = file.Encode(func(stream int) (*ffmpeg.Frame, error) {
+	err = file.Encode(ctx, func(stream int) (*ffmpeg.Frame, error) {
 		var frame *ffmpeg.Frame
 		switch stream {
 		case 1:
@@ -51,12 +62,12 @@ func main() {
 			frame = audio.Frame()
 		}
 		if frame != nil && frame.Ts() < duration {
-			fmt.Print(".")
+			fmt.Println(stream, frame.Ts())
 			return frame, nil
 		}
 		return nil, io.EOF
 	}, nil)
-	if err != nil {
+	if err != nil && !errors.Is(err, context.Canceled) {
 		log.Fatal(err)
 	}
 	fmt.Print("\n")

go.mod

@@ -1,8 +1,6 @@
 module github.com/mutablelogic/go-media
 
-go 1.22
-
-toolchain go1.22.4
+go 1.20
 
 require (
 	github.com/alecthomas/kong v0.9.0

manager.go

@@ -5,6 +5,8 @@ functions to determine capabilities and manage media files and devices.
 */
 package media
 
+import "io"
+
 // Manager represents a manager for media formats and devices.
 // Create a new manager object using the NewManager function.
 //
@@ -26,7 +28,7 @@ type Manager interface {
 	// Open a media file or device for reading, from a path or url.
 	// If a format is specified, then the format will be used to open
 	// the file. Close the media object when done.
-	//Open(string, Format, ...string) (Media, error)
+	Open(string, Format, ...string) (Media, error)
 
 	// Open a media stream for reading.  If a format is
 	// specified, then the format will be used to open the file. Close the
@@ -47,11 +49,6 @@ type Manager interface {
 	// of the caller to also close the writer when done.
 	//Write(io.Writer, Format, []Metadata, ...Parameters) (Media, error)
 
-	// Return supported devices for a given format.
-	// Not all devices may be supported on all platforms or listed
-	// if the device does not support enumeration.
-	//Devices(Format) []Device
-
 	// Return audio parameters for encoding
 	// ChannelLayout, SampleFormat, Samplerate
 	//AudioParameters(string, string, int) (Parameters, error)
@@ -68,15 +65,11 @@ type Manager interface {
 	// Codec name, Profile name, Framerate (fps) and VideoParameters
 	//VideoCodecParameters(string, string, float64, VideoParameters) (Parameters, error)
 
-	// Return supported input formats which match any filter, which can be
-	// a name, extension (with preceeding period) or mimetype. The MediaType
-	// can be NONE (for any) or combinations of DEVICE and STREAM.
-	//InputFormats(Type, ...string) []Format
-
-	// Return supported output formats which match any filter, which can be
-	// a name, extension (with preceeding period) or mimetype. The MediaType
-	// can be NONE (for any) or combinations of DEVICE and STREAM.
-	//OutputFormats(Type, ...string) []Format
+	// Return supported input and output container formats which match any filter,
+	// which can be a name, extension (with preceeding period) or mimetype. The Type
+	// can be a combination of DEVICE, INPUT, OUTPUT or ANY to select the right kind of
+	// format
+	Formats(Type, ...string) []Format
 
 	// Return all supported sample formats
 	SampleFormats() []Metadata
@@ -107,3 +100,26 @@ type Manager interface {
 	// Log info messages  with arguments
 	Infof(string, ...any)
 }
+
+// A container format for a media file or stream
+type Format interface {
+	// The type of the format, which can be combinations of
+	// INPUT, OUTPUT, DEVICE, AUDIO, VIDEO and SUBTITLE
+	Type() Type
+
+	// The unique name that the format can be referenced as
+	Name() string
+
+	// Description of the format
+	Description() string
+}
+
+// A container format for a media file, reader, device or
+// network stream
+type Media interface {
+	io.Closer
+
+	// The type of the format, which can be combinations of
+	// INPUT, OUTPUT, DEVICE
+	Type() Type
+}

pkg/ffmpeg/decoder.go

@@ -8,6 +8,9 @@ import (
 
 	// Packages
 	ff "github.com/mutablelogic/go-media/sys/ffmpeg61"
+
+	// Namespace imports
+	. "github.com/djthorpe/go-errors"
 )
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -35,7 +38,7 @@ func NewDecoder(stream *ff.AVStream, dest *Par, force bool) (*Decoder, error) {
 	// Create a frame for decoder output - before resize/resample
 	frame := ff.AVUtil_frame_alloc()
 	if frame == nil {
-		return nil, errors.New("failed to allocate frame")
+		return nil, ErrInternalAppError.With("failed to allocate frame")
 	}
 
 	// Create a codec context for the decoder
@@ -114,12 +117,12 @@ func (d *Decoder) Close() error {
 // correct timebase, etc set
 func (d *Decoder) decode(packet *ff.AVPacket, fn DecoderFrameFn) error {
 	if fn == nil {
-		return errors.New("DecoderFrameFn is nil")
+		return ErrBadParameter.With("DecoderFrameFn is nil")
 	}
 
 	// Submit the packet to the decoder (nil packet will flush the decoder)
 	if err := ff.AVCodec_send_packet(d.codec, packet); err != nil {
-		return err
+		return ErrInternalAppError.With("AVCodec_send_packet:", err)
 	}
 
 	// get all the available frames from the decoder
@@ -136,7 +139,7 @@ func (d *Decoder) decode(packet *ff.AVPacket, fn DecoderFrameFn) error {
 			// Finished decoding packet or EOF
 			break
 		} else if err != nil {
-			return err
+			return ErrInternalAppError.With("AVCodec_receive_frame:", err)
 		}
 
 		// Obtain the output frame. If a new frame is returned, it is