test hls ll

format/fmp4/esio/decoderconf.go

@@ -0,0 +1,95 @@
+package esio
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/deepch/vdk/av"
+	"github.com/deepch/vdk/codec/aacparser"
+	"github.com/deepch/vdk/utils/bits/pio"
+)
+
+type DecoderConfigDescriptor struct {
+	ObjectType ObjectType
+	StreamType StreamType
+	BufferSize uint32
+	MaxBitrate uint32
+	AvgBitrate uint32
+
+	AudioSpecific []byte
+}
+
+type ObjectType uint8
+
+// ISO/IEC 14496-1 7.2.6.6.2 Table 5
+const ObjectTypeAudio = ObjectType(0x40)
+
+type StreamType uint8
+
+// ISO/IEC 14496-1 7.2.6.6.2 Table 6
+const StreamTypeAudioStream = StreamType(0x05)
+
+func parseDecoderConfig(d []byte) (*DecoderConfigDescriptor, error) {
+	if len(d) < 13 {
+		return nil, errors.New("DecoderConfigDescriptor short")
+	}
+	conf := &DecoderConfigDescriptor{
+		ObjectType: ObjectType(d[0]),
+		StreamType: StreamType(d[1] >> 2),
+		BufferSize: pio.U24BE(d[2:]),
+		MaxBitrate: pio.U32BE(d[5:]),
+		AvgBitrate: pio.U32BE(d[9:]),
+	}
+	d = d[13:]
+	for len(d) > 0 {
+		tag, contents, remainder, err := parseHeader(d)
+		if err != nil {
+			return nil, fmt.Errorf("DecoderConfigDescriptor: %w", err)
+		}
+		d = remainder
+		switch tag {
+		case TagDecoderSpecificInfo:
+			switch conf.ObjectType {
+			case ObjectTypeAudio:
+				conf.AudioSpecific = contents
+			}
+		}
+	}
+	return conf, nil
+}
+
+func (c *DecoderConfigDescriptor) appendTo(b *builder) error {
+	if c == nil {
+		return nil
+	}
+	cursor := b.Descriptor(TagDecoderConfigDescriptor)
+	defer cursor.DescriptorDone(-1)
+	b.WriteByte(byte(c.ObjectType))
+	b.WriteByte(byte(c.StreamType<<2) | 1)
+	b.WriteU24(c.BufferSize)
+	b.WriteU32(c.MaxBitrate)
+	b.WriteU32(c.AvgBitrate)
+	switch {
+	case c.AudioSpecific != nil:
+		// ISO/IEC 14496-3
+		// 1.6.2.1 - base AudioSpecificConfig
+		// 4.4.1 - GASpecificConfig
+		// but we don't actually need to inspect this right now so just preserve the bytes
+		c2 := b.Descriptor(TagDecoderSpecificInfo)
+		b.Write(c.AudioSpecific)
+		c2.DescriptorDone(-1)
+	}
+	return nil
+}
+
+func DecoderConfigFromCodecData(stream av.CodecData) (*DecoderConfigDescriptor, error) {
+	switch cd := stream.(type) {
+	case aacparser.CodecData:
+		return &DecoderConfigDescriptor{
+			ObjectType:    ObjectTypeAudio,
+			StreamType:    StreamTypeAudioStream,
+			AudioSpecific: cd.MPEG4AudioConfigBytes(),
+		}, nil
+	}
+	return nil, fmt.Errorf("can't marshal %T to DecoderConfigDescriptor", stream)
+}