/
picture_header.go
95 lines (76 loc) · 1.99 KB
/
picture_header.go
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package video
import "github.com/32bitkid/bitreader"
import "fmt"
type PictureHeader struct {
temporal_reference uint32 // 10 uimsbf
picture_coding_type PictureCodingType // 3 uimsbf
vbv_delay uint32 // 16 uimsbf
full_pel_forward_vector uint32 // 1 bslbf
forward_f_code uint32 // 3 bslbf
full_pel_backward_vector uint32 // 1 bslbf
backward_f_code uint32 // 3 bslbf
extra_information []byte
}
func (ph PictureHeader) String() string {
return fmt.Sprintf("[%s%d]", ph.picture_coding_type, ph.temporal_reference)
}
func picture_header(br bitreader.BitReader) (*PictureHeader, error) {
err := PictureStartCode.Assert(br)
if err != nil {
return nil, err
}
ph := PictureHeader{}
ph.temporal_reference, err = br.Read32(10)
if err != nil {
return nil, err
}
picture_coding_type, err := br.Read32(3)
if err != nil {
return nil, err
}
ph.picture_coding_type = PictureCodingType(picture_coding_type)
ph.vbv_delay, err = br.Read32(16)
if err != nil {
return nil, err
}
if ph.picture_coding_type == PFrame || ph.picture_coding_type == BFrame {
ph.full_pel_forward_vector, err = br.Read32(1)
if err != nil {
return nil, err
}
ph.forward_f_code, err = br.Read32(3)
if err != nil {
return nil, err
}
}
if ph.picture_coding_type == BFrame {
ph.full_pel_backward_vector, err = br.Read32(1)
if err != nil {
return nil, err
}
ph.backward_f_code, err = br.Read32(3)
if err != nil {
return nil, err
}
}
for {
if extraBit, err := br.Peek1(); err != nil {
return nil, err
} else if extraBit == false {
break
}
if err := br.Skip(1); err != nil {
return nil, err
}
// extra_information_picture
if data, err := br.Read32(8); err != nil {
return nil, err
} else {
ph.extra_information = append(ph.extra_information, byte(data))
}
}
if err := br.Skip(1); err != nil {
return nil, err
}
return &ph, next_start_code(br)
}