test hls ll

format/fmp4/esio/esio.go

@@ -0,0 +1,162 @@
+package esio
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/deepch/vdk/utils/bits/pio"
+)
+
+type StreamDescriptor struct {
+	ESID      uint16
+	DependsOn *uint16
+	URL       *string
+	OCR       *uint16
+
+	DecoderConfig *DecoderConfigDescriptor
+	SLConfig      *SLConfigDescriptor
+}
+
+// Tag identifies element stream descriptor types
+type Tag uint8
+
+// ISO/IEC 14496-1:2004 7.2.2 Table 1
+const (
+	TagForbidden = Tag(iota)
+	TagObjectDescriptor
+	TagInitialObjectDescriptor
+	TagESDescriptor
+	TagDecoderConfigDescriptor
+	TagDecoderSpecificInfo
+	TagSLConfigDescriptor
+)
+
+const (
+	esFlagStreamDependence = 0x80
+	esFlagURL              = 0x40
+	esFlagOCR              = 0x20
+)
+
+func ParseStreamDescriptor(start []byte) (desc *StreamDescriptor, remainder []byte, err error) {
+	// ISO/IEC 14496-1:2004 7.2.6.5.1
+	tag, d, remainder, err := parseHeader(start)
+	if err != nil {
+		err = fmt.Errorf("ES_Descriptor: %w", err)
+		return
+	} else if tag != TagESDescriptor {
+		err = fmt.Errorf("expected ES_Descriptor but got tag %02X", tag)
+		return
+	}
+	desc = &StreamDescriptor{ESID: pio.U16BE(d)}
+	flags := d[2]
+	d = d[3:]
+	if flags&esFlagStreamDependence != 0 {
+		v := pio.U16BE(d)
+		desc.DependsOn = &v
+		d = d[2:]
+	}
+	if flags&esFlagURL != 0 {
+		urlLength := d[0]
+		v := string(d[1 : 1+urlLength])
+		desc.URL = &v
+		d = d[1+urlLength:]
+	}
+	if flags&esFlagOCR != 0 {
+		v := pio.U16BE(d)
+		desc.OCR = &v
+		d = d[2:]
+	}
+	for len(d) > 0 {
+		var child []byte
+		tag, child, d, err = parseHeader(d)
+		if err != nil {
+			err = fmt.Errorf("ES_Descriptor: %w", err)
+			return
+		}
+		switch tag {
+		case TagDecoderConfigDescriptor:
+			desc.DecoderConfig, err = parseDecoderConfig(child)
+		case TagSLConfigDescriptor:
+			desc.SLConfig, err = parseSLConfig(child)
+		}
+		if err != nil {
+			return
+		}
+	}
+	remainder = d
+	return
+}
+
+func (s *StreamDescriptor) Marshal() ([]byte, error) {
+	var b builder
+	cursor := b.Descriptor(TagESDescriptor)
+	b.WriteU16(s.ESID)
+	var flags uint8
+	if s.DependsOn != nil {
+		flags |= esFlagStreamDependence
+	}
+	if s.URL != nil {
+		flags |= esFlagURL
+	}
+	if s.OCR != nil {
+		flags |= esFlagOCR
+	}
+	b.WriteByte(flags)
+	if s.DependsOn != nil {
+		b.WriteU16(*s.DependsOn)
+	}
+	if s.URL != nil {
+		b.WriteByte(byte(len(*s.URL)))
+		b.Write([]byte(*s.URL))
+	}
+	if s.OCR != nil {
+		b.WriteU16(*s.OCR)
+	}
+	if err := s.DecoderConfig.appendTo(&b); err != nil {
+		return nil, err
+	}
+	if err := s.SLConfig.appendTo(&b); err != nil {
+		return nil, err
+	}
+	cursor.DescriptorDone(-1)
+	return b.Bytes(), nil
+}
+
+func parseLength(start []byte) (length int, d []byte, err error) {
+	// ISO/IEC 14496-1:2004 8.3.3
+	d = start
+	for i := 0; i < 4; i++ {
+		if len(d) == 0 {
+			err = errors.New("short tag")
+			return
+		}
+		v := d[0]
+		d = d[1:]
+		length <<= 7
+		length |= int(v & 0x7f)
+		if v&0x80 == 0 {
+			break
+		}
+	}
+	return
+}
+
+func parseHeader(start []byte) (tag Tag, contents, d []byte, err error) {
+	d = start
+	if len(d) < 2 {
+		err = errors.New("short tag")
+		return
+	}
+	tag = Tag(d[0])
+	length, d, err := parseLength(d[1:])
+	if err != nil {
+		return
+	}
+	if length > len(d) {
+		err = fmt.Errorf("short tag: %02x: expected %d bytes but only got %d", tag, length, len(d))
+		return
+	}
+	contents = d[:length]
+	d = d[length:]
+	return
+}