Merge branch 'ffmpeg61' of github.com:mutablelogic/go-media into ffmpeg61

Author: djthorpe

pkg/ffmpeg/encoder.go

@@ -0,0 +1,245 @@
+package ffmpeg
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"syscall"
+
+	// Packages
+	ff "github.com/mutablelogic/go-media/sys/ffmpeg61"
+
+	// Namespace imports
+	. "github.com/djthorpe/go-errors"
+)
+
+////////////////////////////////////////////////////////////////////////////////
+// TYPES
+
+type Encoder struct {
+	ctx    *ff.AVCodecContext
+	stream *ff.AVStream
+	packet *ff.AVPacket
+
+	// We are flushing the encoder
+	eof bool
+
+	// The next presentation timestamp
+	next_pts int64
+}
+
+// EncoderFrameFn is a function which is called to receive a frame to encode. It should
+// return nil to continue encoding or io.EOF to stop encoding.
+type EncoderFrameFn func(int) (*ff.AVFrame, error)
+
+// EncoderPacketFn is a function which is called for each packet encoded, with
+// the stream timebase.
+type EncoderPacketFn func(*ff.AVPacket, *ff.AVRational) error
+
+////////////////////////////////////////////////////////////////////////////////
+// LIFECYCLE
+
+// Create an encoder with the given parameters
+func NewEncoder(ctx *ff.AVFormatContext, stream int, par *Par) (*Encoder, error) {
+	encoder := new(Encoder)
+
+	// Get codec
+	codec_id := ff.AV_CODEC_ID_NONE
+	switch par.CodecType() {
+	case ff.AVMEDIA_TYPE_AUDIO:
+		codec_id = ctx.Output().AudioCodec()
+	case ff.AVMEDIA_TYPE_VIDEO:
+		codec_id = ctx.Output().VideoCodec()
+	case ff.AVMEDIA_TYPE_SUBTITLE:
+		codec_id = ctx.Output().SubtitleCodec()
+	}
+	if codec_id == ff.AV_CODEC_ID_NONE {
+		return nil, ErrBadParameter.Withf("no codec specified for stream %v", stream)
+	}
+
+	// Allocate codec
+	codec := ff.AVCodec_find_encoder(codec_id)
+	if codec == nil {
+		return nil, ErrBadParameter.Withf("codec %q cannot encode", codec_id)
+	}
+	if codecctx := ff.AVCodec_alloc_context(codec); codecctx == nil {
+		return nil, ErrInternalAppError.With("could not allocate audio codec context")
+	} else {
+		encoder.ctx = codecctx
+	}
+
+	// Check codec against parameters and set defaults as needed, then
+	// copy back to codec
+	if err := par.ValidateFromCodec(encoder.ctx); err != nil {
+		ff.AVCodec_free_context(encoder.ctx)
+		return nil, err
+	} else if err := par.CopyToCodec(encoder.ctx); err != nil {
+		ff.AVCodec_free_context(encoder.ctx)
+		return nil, err
+	}
+
+	// Create the stream
+	if streamctx := ff.AVFormat_new_stream(ctx, nil); streamctx == nil {
+		ff.AVCodec_free_context(encoder.ctx)
+		return nil, ErrInternalAppError.With("could not allocate stream")
+	} else {
+		streamctx.SetId(stream)
+		encoder.stream = streamctx
+	}
+
+	// Some formats want stream headers to be separate.
+	if ctx.Output().Flags().Is(ff.AVFMT_GLOBALHEADER) {
+		encoder.ctx.SetFlags(encoder.ctx.Flags() | ff.AV_CODEC_FLAG_GLOBAL_HEADER)
+	}
+
+	// Open it
+	if err := ff.AVCodec_open(encoder.ctx, codec, nil); err != nil {
+		ff.AVCodec_free_context(encoder.ctx)
+		return nil, ErrInternalAppError.Withf("codec_open: %v", err)
+	}
+
+	// Copy parameters to stream
+	if err := ff.AVCodec_parameters_from_context(encoder.stream.CodecPar(), encoder.ctx); err != nil {
+		ff.AVCodec_free_context(encoder.ctx)
+		return nil, err
+	}
+
+	// Create a packet
+	packet := ff.AVCodec_packet_alloc()
+	if packet == nil {
+		ff.AVCodec_free_context(encoder.ctx)
+		return nil, errors.New("failed to allocate packet")
+	} else {
+		encoder.packet = packet
+	}
+
+	// Return it
+	return encoder, nil
+}
+
+func (encoder *Encoder) Close() error {
+	// Free respurces
+	if encoder.ctx != nil {
+		ff.AVCodec_free_context(encoder.ctx)
+	}
+	if encoder.packet != nil {
+		ff.AVCodec_packet_free(encoder.packet)
+	}
+
+	// Release resources
+	encoder.packet = nil
+	encoder.stream = nil
+	encoder.ctx = nil
+
+	// Return success
+	return nil
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// STRINGIFY
+
+func (e *Encoder) MarshalJSON() ([]byte, error) {
+	type jsonEncoder struct {
+		Codec  *ff.AVCodecContext `json:"codec"`
+		Stream *ff.AVStream       `json:"stream"`
+	}
+	return json.Marshal(&jsonEncoder{
+		Codec:  e.ctx,
+		Stream: e.stream,
+	})
+}
+
+func (e *Encoder) String() string {
+	data, _ := json.MarshalIndent(e, "", "  ")
+	return string(data)
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// PUBLIC METHODS
+
+// Encode a frame and pass packets to the EncoderPacketFn. If the frame is nil, then
+// the encoder will flush any remaining packets. If io.EOF is returned then
+// it indicates that the encoder has ended prematurely.
+func (e *Encoder) Encode(frame *ff.AVFrame, fn EncoderPacketFn) error {
+	if fn == nil {
+		return ErrBadParameter.With("nil fn")
+	}
+	// Encode a frame (or flush the encoder)
+	return e.encode(frame, fn)
+}
+
+// Return the codec parameters
+func (e *Encoder) Par() *Par {
+	par := new(Par)
+	if err := ff.AVCodec_parameters_from_context(&par.AVCodecParameters, e.ctx); err != nil {
+		return nil
+	} else {
+		return par
+	}
+}
+
+// Return the codec type
+func (e *Encoder) nextPts(frame *ff.AVFrame) int64 {
+	next_pts := int64(0)
+	switch e.ctx.Codec().Type() {
+	case ff.AVMEDIA_TYPE_AUDIO:
+		next_pts = ff.AVUtil_rational_rescale_q(int64(frame.NumSamples()), ff.AVUtil_rational(1, frame.SampleRate()), e.stream.TimeBase())
+	case ff.AVMEDIA_TYPE_VIDEO:
+		next_pts = ff.AVUtil_rational_rescale_q(1, ff.AVUtil_rational_invert(e.ctx.Framerate()), e.stream.TimeBase())
+	default:
+		// Dunno what to do with subtitle and data streams yet
+		fmt.Println("TODO: next_pts for subtitle and data streams")
+		return 0
+	}
+	return next_pts
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// PRIVATE METHODS
+
+func (e *Encoder) encode(frame *ff.AVFrame, fn EncoderPacketFn) error {
+	timebase := e.stream.TimeBase()
+
+	// Send the frame to the encoder
+	if err := ff.AVCodec_send_frame(e.ctx, frame); err != nil {
+		return err
+	}
+
+	// Write out the packets
+	var result error
+	for {
+		// Receive the packet
+		if err := ff.AVCodec_receive_packet(e.ctx, e.packet); errors.Is(err, syscall.EAGAIN) || errors.Is(err, io.EOF) {
+			// Finished receiving packet or EOF
+			break
+		} else if err != nil {
+			return err
+		}
+
+		// rescale output packet timestamp values from codec to stream timebase
+		ff.AVCodec_packet_rescale_ts(e.packet, e.ctx.TimeBase(), e.stream.TimeBase())
+		e.packet.SetStreamIndex(e.stream.Index())
+		e.packet.SetTimeBase(e.stream.TimeBase())
+
+		// Pass back to the caller
+		if err := fn(e.packet, &timebase); errors.Is(err, io.EOF) {
+			// End early, return EOF
+			result = io.EOF
+			break
+		} else if err != nil {
+			return err
+		}
+
+		// Re-allocate frames for next iteration
+		ff.AVCodec_packet_unref(e.packet)
+	}
+
+	// Flush
+	if result == nil {
+		result = fn(nil, &timebase)
+	}
+
+	// Return success or EOF
+	return result
+}

pkg/ffmpeg/metadata.go

@@ -0,0 +1,35 @@
+package ffmpeg
+
+import (
+	"encoding/json"
+)
+
+////////////////////////////////////////////////////////////////////////////////
+// TYPES
+
+type Metadata struct {
+	Key   string `json:"key" writer:",width:30"`
+	Value any    `json:"value,omitempty" writer:",wrap,width:50"`
+}
+
+const (
+	MetaArtwork = "artwork" // Metadata key for artwork, set the value as []byte
+)
+
+////////////////////////////////////////////////////////////////////////////////
+// LIFECYCLE
+
+func NewMetadata(key string, value any) *Metadata {
+	return &Metadata{
+		Key:   key,
+		Value: value,
+	}
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// STRINIGY
+
+func (m *Metadata) String() string {
+	data, _ := json.MarshalIndent(m, "", "  ")
+	return string(data)
+}