云南省建设测量员注册网站,淘宝基地网站怎么做,广告法,Wordpress博客欣赏SODB 数据比特串#xff0d;#xff0d;#xff1e;最原始的编码数据
RBSP 原始字节序列载荷#xff0d;#xff0d;#xff1e;在SODB的后面填加了结尾比特#xff08;RBSP trailing bits 一个bit“1”#xff09;若干比特“0”,以便字节对齐。
EBSP 扩展字节序…SODB 数据比特串最原始的编码数据
RBSP 原始字节序列载荷在SODB的后面填加了结尾比特RBSP trailing bits 一个bit“1”若干比特“0”,以便字节对齐。
EBSP 扩展字节序列载荷--在RBSP基础上填加了仿校验字节0X03它的原因是 在NALU加到Annexb上时需要填加每组NALU之前的开始码StartCodePrefix,如果该NALU对应的slice为一帧的开始则用4位字节表示ox00000001,否则用3位字节表示ox000001.为了使NALU主体中不包括与开始码相冲突的在编码时每遇到两个字节连续为0就插入一个字节的0x03。解码时将0x03去掉。也称为脱壳操作。 网上查询的区别
在对整帧图像的数据比特串(SODB)添加原始字节序列载荷(RBSP)结尾比特(RBSP trailing bits,添加一比特的“1”和若干比特“0”,以便字节对齐)后,再检查RBSP 中是否存在连续的三字节“00000000 00000000 000000xx”;若存在这种连续的三字节码,在第三字节前插入一字节的“0×03”,以免与起始码竞争,形成EBSP码流,这需要将近两倍的整帧图像码流大小。为了减小存储器需求,在每个宏块编码结束后即检查该宏块SODB中的起始码竞争问题,并保留SODB最后两字节的零字节个数,以便与下一宏块的SODB的开始字节形成连续的起始码竞争检测;对一帧图像的最后一个宏块,先添加结尾停止比特,再检测起始码竞争。 程序 typedef struct
{
int byte_pos; //! current position in bitstream;
int bits_to_go; //! current bitcounter
byte byte_buf; //! current buffer for last written byte
int stored_byte_pos; //! storage for position in bitstream;
int stored_bits_to_go; //! storage for bitcounter
byte stored_byte_buf; //! storage for buffer of last written byte byte byte_buf_skip; //! current buffer for last written byte
int byte_pos_skip; //! storage for position in bitstream;
int bits_to_go_skip; //! storage for bitcounter byte *streamBuffer; //! actual buffer for written bytes
int write_flag; //! Bitstream contains data and needs to be written } Bitstream; 定义比特流结构 static byte *NAL_Payload_buffer;
void SODBtoRBSP(Bitstream *currStream) { currStream-byte_buf 1; //左移1bit currStream-byte_buf | 1; //在尾部填一个“1”占1bit currStream-bits_to_go--; currStream-byte_buf currStream-bits_to_go; currStream-streamBuffer[currStream-byte_pos] currStream-byte_buf; currStream-bits_to_go 8; currStream-byte_buf 0; } int RBSPtoEBSP(byte *streamBuffer, int begin_bytepos, int end_bytepos, int min_num_bytes) { int i, j, count;
for(i begin_bytepos; i end_bytepos; i) NAL_Payload_buffer[i] streamBuffer[i];
count 0; j begin_bytepos; for(i begin_bytepos; i end_bytepos; i) { if(count ZEROBYTES_SHORTSTARTCODE !(NAL_Payload_buffer[i] 0xFC)) { streamBuffer[j] 0x03; j; count 0; } streamBuffer[j] NAL_Payload_buffer[i]; if(NAL_Payload_buffer[i] 0x00) count; else count 0; j; } while (j begin_byteposmin_num_bytes) { streamBuffer[j] 0x00; // cabac stuffing word streamBuffer[j1] 0x00; streamBuffer[j2] 0x03; j 3; stat-bit_use_stuffingBits[img-type]16; } return j; }
