415 lines
8.4 KiB
Go
415 lines
8.4 KiB
Go
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package atom
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import (
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"io"
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"fmt"
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"bytes"
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)
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type GolombBitReader struct {
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R io.Reader
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buf [1]byte
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left byte
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}
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func (self *GolombBitReader) ReadBit() (res uint, err error) {
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if self.left == 0 {
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if _, err = self.R.Read(self.buf[:]); err != nil {
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return
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}
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self.left = 8
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}
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self.left--
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res = uint(self.buf[0]>>self.left)&1
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return
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}
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func (self *GolombBitReader) ReadBits(n int) (res uint, err error) {
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for i := 0; i < n; i++ {
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var bit uint
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if bit, err = self.ReadBit(); err != nil {
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return
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}
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res |= bit<<uint(n-i-1)
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}
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return
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}
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func (self *GolombBitReader) ReadExponentialGolombCode() (res uint, err error) {
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i := 0
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for {
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var bit uint
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if bit, err = self.ReadBit(); err != nil {
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return
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}
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if !(bit == 0 && i < 32) {
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break
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}
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i++
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}
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if res, err = self.ReadBits(i); err != nil {
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return
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}
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res += (1<<uint(i)) - 1
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return
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}
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func (self *GolombBitReader) ReadSE() (res uint, err error) {
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if res, err = self.ReadExponentialGolombCode(); err != nil {
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return
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}
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if res & 0x01 != 0 {
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res = (res+1)/2
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} else {
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res = -res/2
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}
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return
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}
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type H264SPSInfo struct {
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ProfileIdc uint
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LevelIdc uint
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MbWidth uint
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MbHeight uint
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CropLeft uint
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CropRight uint
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CropTop uint
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CropBottom uint
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Width uint
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Height uint
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}
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func ParseH264SPS(data []byte) (res *H264SPSInfo, err error) {
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r := &GolombBitReader{
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R: bytes.NewReader(data),
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}
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self := &H264SPSInfo{}
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if self.ProfileIdc, err = r.ReadBits(8); err != nil {
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return
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}
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// constraint_set0_flag-constraint_set6_flag,reserved_zero_2bits
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if _, err = r.ReadBits(8); err != nil {
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return
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}
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// level_idc
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if self.LevelIdc, err = r.ReadBits(8); err != nil {
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return
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}
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// seq_parameter_set_id
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if _, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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if self.ProfileIdc == 100 || self.ProfileIdc == 110 ||
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self.ProfileIdc == 122 || self.ProfileIdc == 244 ||
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self.ProfileIdc == 44 || self.ProfileIdc == 83 ||
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self.ProfileIdc == 86 || self.ProfileIdc == 118 {
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var chroma_format_idc uint
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if chroma_format_idc, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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if chroma_format_idc == 3 {
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// residual_colour_transform_flag
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if _, err = r.ReadBit(); err != nil {
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return
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}
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}
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// bit_depth_luma_minus8
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if _, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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// bit_depth_chroma_minus8
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if _, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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// qpprime_y_zero_transform_bypass_flag
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if _, err = r.ReadBit(); err != nil {
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return
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}
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var seq_scaling_matrix_present_flag uint
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if seq_scaling_matrix_present_flag, err = r.ReadBit(); err != nil {
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return
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}
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if seq_scaling_matrix_present_flag != 0 {
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for i := 0; i < 8; i++ {
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var seq_scaling_list_present_flag uint
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if seq_scaling_list_present_flag, err = r.ReadBit(); err != nil {
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return
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}
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if seq_scaling_list_present_flag != 0 {
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var sizeOfScalingList uint
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if i < 6 {
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sizeOfScalingList = 16
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} else {
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sizeOfScalingList = 64
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}
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lastScale := uint(8)
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nextScale := uint(8)
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for j := uint(0); j < sizeOfScalingList; j++ {
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if nextScale != 0 {
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var delta_scale uint
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if delta_scale, err = r.ReadSE(); err != nil {
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return
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}
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nextScale = (lastScale + delta_scale + 256) % 256
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}
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if nextScale != 0 {
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lastScale = nextScale
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}
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}
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}
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}
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}
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}
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// log2_max_frame_num_minus4
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if _, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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var pic_order_cnt_type uint
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if pic_order_cnt_type, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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if pic_order_cnt_type == 0 {
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// log2_max_pic_order_cnt_lsb_minus4
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if _, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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} else if pic_order_cnt_type == 1 {
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// delta_pic_order_always_zero_flag
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if _, err = r.ReadBit(); err != nil {
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return
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}
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// offset_for_non_ref_pic
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if _, err = r.ReadSE(); err != nil {
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return
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}
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// offset_for_top_to_bottom_field
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if _, err = r.ReadSE(); err != nil {
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return
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}
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var num_ref_frames_in_pic_order_cnt_cycle uint
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if num_ref_frames_in_pic_order_cnt_cycle, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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for i := uint(0); i < num_ref_frames_in_pic_order_cnt_cycle; i++ {
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if _, err = r.ReadSE(); err != nil {
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return
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}
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}
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}
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// max_num_ref_frames
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if _, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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// gaps_in_frame_num_value_allowed_flag
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if _, err = r.ReadBit(); err != nil {
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return
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}
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if self.MbWidth, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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self.MbWidth++
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if self.MbHeight, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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self.MbHeight++
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var frame_mbs_only_flag uint
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if frame_mbs_only_flag, err = r.ReadBit(); err != nil {
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return
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}
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if frame_mbs_only_flag == 0 {
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// mb_adaptive_frame_field_flag
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if _, err = r.ReadBit(); err != nil {
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return
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}
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}
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// direct_8x8_inference_flag
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if _, err = r.ReadBit(); err != nil {
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return
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}
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var frame_cropping_flag uint
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if frame_cropping_flag, err = r.ReadBit(); err != nil {
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return
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}
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if frame_cropping_flag != 0 {
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if self.CropLeft, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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if self.CropRight, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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if self.CropTop, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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if self.CropBottom, err = r.ReadExponentialGolombCode(); err != nil {
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return
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}
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}
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self.Width = (self.MbWidth*16) - self.CropLeft*2 - self.CropRight*2
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self.Height = ((2-frame_mbs_only_flag)*self.MbHeight*16) - self.CropTop*2 - self.CropBottom*2
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res = self
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return
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}
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type AVCDecoderConfRecord struct {
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AVCProfileIndication int
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ProfileCompatibility int
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AVCLevelIndication int
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LengthSizeMinusOne int
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SPS [][]byte
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PPS [][]byte
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}
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func WriteSampleByNALU(w io.Writer, nalu []byte) (size int, err error) {
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if err = WriteInt(w, len(nalu), 4); err != nil {
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return
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}
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size += 4
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if _, err = w.Write(nalu); err != nil {
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return
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}
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size += len(nalu)
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return
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}
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func CreateAVCDecoderConfRecord(
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SPS []byte,
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PPS []byte,
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) (self AVCDecoderConfRecord, err error) {
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if len(SPS) < 4 {
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err = fmt.Errorf("invalid SPS data")
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return
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}
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self.AVCProfileIndication = int(SPS[1])
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self.ProfileCompatibility = int(SPS[2])
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self.AVCLevelIndication = int(SPS[3])
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self.SPS = [][]byte{SPS}
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self.PPS = [][]byte{PPS}
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self.LengthSizeMinusOne = 3
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return
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}
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func WriteAVCDecoderConfRecord(w io.Writer, self AVCDecoderConfRecord) (err error) {
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if err = WriteInt(w, 1, 1); err != nil {
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return
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}
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if err = WriteInt(w, self.AVCProfileIndication, 1); err != nil {
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return
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}
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if err = WriteInt(w, self.ProfileCompatibility, 1); err != nil {
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return
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}
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if err = WriteInt(w, self.AVCLevelIndication, 1); err != nil {
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return
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}
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if err = WriteInt(w, self.LengthSizeMinusOne | 0xfc, 1); err != nil {
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return
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}
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if err = WriteInt(w, len(self.SPS) | 0xe0, 1); err != nil {
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return
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}
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for _, data := range self.SPS {
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if err = WriteInt(w, len(data), 2); err != nil {
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return
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}
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if err = WriteBytes(w, data, len(data)); err != nil {
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return
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}
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}
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if err = WriteInt(w, len(self.PPS), 1); err != nil {
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return
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}
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for _, data := range self.PPS {
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if err = WriteInt(w, len(data), 2); err != nil {
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return
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}
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if err = WriteBytes(w, data, len(data)); err != nil {
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return
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}
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}
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return
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}
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func WalkAVCDecoderConfRecord(w Walker, self AVCDecoderConfRecord) {
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}
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func ReadAVCDecoderConfRecord(r *io.LimitedReader) (self AVCDecoderConfRecord, err error) {
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if _, err = ReadDummy(r, 1); err != nil {
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return
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}
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if self.AVCProfileIndication, err = ReadInt(r, 1); err != nil {
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return
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}
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if self.ProfileCompatibility, err = ReadInt(r, 1); err != nil {
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return
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}
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if self.AVCLevelIndication, err = ReadInt(r, 1); err != nil {
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return
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}
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if self.LengthSizeMinusOne, err = ReadInt(r, 1); err != nil {
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return
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}
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self.LengthSizeMinusOne &= 0x03
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var n, length int
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var data []byte
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if n, err = ReadInt(r, 1); err != nil {
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return
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}
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n &= 0x1f
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for i := 0; i < n; i++ {
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if length, err = ReadInt(r, 2); err != nil {
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return
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}
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if data, err = ReadBytes(r, length); err != nil {
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return
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}
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self.SPS = append(self.SPS, data)
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}
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if n, err = ReadInt(r, 1); err != nil {
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return
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}
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for i := 0; i < n; i++ {
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if length, err = ReadInt(r, 2); err != nil {
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return
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}
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if data, err = ReadBytes(r, length); err != nil {
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return
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}
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self.PPS = append(self.PPS, data)
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}
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return
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}
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