北京通州网站建设公司,seo数据优化,怎样制作网站站点,今天军事新闻最新消息详细x264_t 结构体维护着CODEC的诸多重要信息 其中成员frames是一个指示和控制帧编码过程的结构。其中current是已经准备就绪可以编码的帧#xff0c;其类型已经确定#xff1b;next是尚未确定类型的帧#xff1b;unused用于回收不使用的frame结构体以备今后再次使用。
struct …x264_t 结构体维护着CODEC的诸多重要信息 其中成员frames是一个指示和控制帧编码过程的结构。其中current是已经准备就绪可以编码的帧其类型已经确定next是尚未确定类型的帧unused用于回收不使用的frame结构体以备今后再次使用。
struct x264_t
{ /* cpu capabilities */ unsigned int cpu; /* bitstream output */ struct { int i_nal; //定义一个网络提取层// x264_nal_t nal[3]; /* for now 3 is enought */ int i_bitstream; /* size of p_bitstream */ uint8_t *p_bitstream; /* will hold data for all nal */ bs_t bs; } out; /* encoder parameters */ x264_param_t param; /* frame number/poc (TODO: rework that for B-frame) */ int i_frame; //一个指示和控制帧编码过程的结构 int i_poc; int i_frame_offset; /* decoding only */ int i_frame_num; /* decoding only*/ int i_poc_msb; /* decoding only */ int i_poc_lsb; /* decoding only */ /* We use only one SPS and one PPS */ x264_sps_t sps_array[32]; x264_sps_t *sps; x264_pps_t pps_array[256]; x264_pps_t *pps; int i_idr_pic_id; /* Slice header */ x264_slice_header_t sh; /*cabac context */ x264_cabac_t cabac; /*current picture being encoded */ x264_picture_t *picture; /*bframe handling (only encoding for now) */ x264_frame_t *bframe_current[X264_BFRAME_MAX]; /* store the sequence of b frame being encoded */ x264_frame_t *frame_next[X264_BFRAME_MAX1]; /* store the next sequence of frames to be encoded */这个是定义下一个帧,但不一定是B帧 x264_frame_t *frame_unused[X264_BFRAME_MAX1]; /* store unused frames */ /*frame being reconstructed */ x264_frame_t *fdec; /*Current MB DCT coeffs */ struct { DECLARE_ALIGNED( int, luma16×16_dc[16], 16 ); DECLARE_ALIGNED( int, chroma_dc[2][4], 16 );//色度 struct { DECLARE_ALIGNED( int, residual_ac[15], 16 ); DECLARE_ALIGNED( int, luma4×4[16], 16 ); } block[168];16*8的宏快的取用情况 } dct;离散余弦变换 /* MBtable and cache for current frame/mb */ struct { /*Strides */ int i_mb_stride; /*Current index */ int i_mb_x; int i_mb_y; int i_mb_xy; unsigned int i_neighbour; /* mb table */ int8_t *type; /*mb type */ int8_t *qp; /* mb qp */ int16_t *cbp; /* mbcbp: 0×0?: luma, 0x?0: chroma, 0×100: luma dc, 0×0200 and 0×0400: chromadc (all set for PCM)*/ int8_t (*intra4×4_pred_mode)[7]; /* intra4×4 predmode. for non I4×4 set to I_PRED_4×4_DC(2) */ uint8_t (*non_zero_count)[1644]; /* nzc. for I_PCMset to 16 */ int8_t *chroma_pred_mode; /*chroma_pred_mode. cabac only. for non intra I_PRED_CHROMA_DC(0) */ int16_t (*mv[2])[2]; /* mb mv. set to 0 for intra mb */ int16_t (*mvd[2])[2]; /* mb mv difference with predict. set to 0 if intra. cabac only */ int8_t *ref[2]; /*mb ref. set to -1 if non used (intra or Lx only */ /*current value */ int i_type; int i_partition; int i_sub_partition[4]; int i_cbp_luma; int i_cbp_chroma; int i_intra16×16_pred_mode; int i_chroma_pred_mode; struct { /*pointer over mb of the frame to be compressed */ uint8_t *p_img[3]; int i_img[3]; /*pointers over mb of references and reconstrucated frame */ uint8_t *p_fdec[3]; uint8_t*p_fref[2][16][3]; int i_fdec[3]; /* same strides for p_fdec/p_fref */ } pic; /*cache */ struct { /*real intra4×4_pred_mode if I_4X4, I_PRED_4×4_DC if mb available, -1 if not */ int intra4×4_pred_mode[X264_SCAN8_SIZE];色度预测模式 /*i_non_zero_count if availble else 0×80 */ int non_zero_count[X264_SCAN8_SIZE]; /*-1 if unused, -2 if unavaible */ int8_t ref[2][X264_SCAN8_SIZE]; /*0 if non avaible */ int16_t mv[2][X264_SCAN8_SIZE][2]; int16_t mvd[2][X264_SCAN8_SIZE][2];运动矢量与真实值之间的差 } cache; /**/ int i_last_qp; /* last qp */ int i_last_dqp; /*last delta qp */ } mb;宏快的预测以及运动补偿和运动估计 /*frames used for reference */ x264_frame_t *freference[161]; /* all references frames plus current */ int i_ref0; 参考帧列表一定义为lsit0意为向前预测编码 x264_frame_t *fref0[16]; /* ref list 0*/ int i_ref1;参考帧列表二定义为lsit1意为向后预测编码 x264_frame_t *fref1[16]; /* ref list 1*/ /*rate control encoding only */ x264_ratecontrol_t *rc; /*stats */ struct { /*per slice info */ int i_slice_count[5]; int i_slice_size[5]; float f_psnr_y[5]; float f_psnr_u[5]; float f_psnr_v[5]; int i_mb_count[5][18]; } stat;声明每一片的参数变量 /* CPU functions dependants */ x264_predict_t predict_16×16[43]; x264_predict_t predict_8×8[43]; x264_predict_t predict_4×4[93]; x264_pixel_function_t pixf; x264_mc_function_t mc[2]; x264_dct_function_t dctf; /* vlc table for decoding purpose only */ x264_vlc_table_t *x264_coeff_token_lookup[5]; x264_vlc_table_t *x264_level_prefix_lookup; x264_vlc_table_t *x264_total_zeros_lookup[15]; x264_vlc_table_t *x264_total_zeros_dc_lookup[3]; x264_vlc_table_t *x264_run_before_lookup[7];
};
#endif
给出编码过程中的各个参数的初始化
x264_param_t
typedef struct
{ /* CPU flags */ unsigned int cpu; /* Video Properties */ int i_width; int i_height; struct { /*they will be reduced to be 0 x 65535 and prime */ int i_sar_height; int i_sar_width; } vui; float f_fps; /* Used for rate control only */ /*Bitstream parameters */ int i_frame_reference; /* Maximum number of reference frames */ int i_idrframe; /*every i_idrframe I frame are marked as IDR */ int i_iframe; /* every i_iframe are intra */ int i_bframe; /* how many b-frame between 2 references pictures */ int b_deblocking_filter; int b_cabac; int i_cabac_init_idc;给出熵编码初始化时表格的选择 int i_qp_constant; /* 1-51 */ int i_bitrate; /* not working yet */ /* Encoder analyser parameters */ struct { unsigned int intra; /* intra flags */ unsigned int inter; /* inter flags */ } analyse; }x264_param_t给出编码过程中的各个参数的初始化 sps序列参数集
typedef struct
{ int i_id; int i_profile_idc;指明所用profile int i_level_idc; 指明所用level int b_constraint_set0; int b_constraint_set1; int b_constraint_set2; 当他们值等于1时表示必须遵守某些制约条件 int i_log2_max_frame_num;表示图像解码顺序的最大取值 int i_poc_type; /* poc 0 */ int i_log2_max_poc_lsb; /* poc 1 */ int b_delta_pic_order_always_zero;其值等于一时句法元素delta_pic_order_cnt[0]和 delta_pic_order_cnt[1]不再片头出现且他们的默认值都为0。为0时上述则出现。 int i_offset_for_non_ref_pic;用来计算非参考帧或场的picture order count ,其值应在[-2e31,2e31-1] int i_offset_for_top_to_bottom_field; 用来计算帧的底场的picture order count 其值应在[-2e31,2e31-1] int i_num_ref_frames_in_poc_cycle;用来解码picture order count 取值应在[0255]之间 int i_offset_for_ref_frame[256]; 当picture order count type1时用来解码poc这句语法对循环num_ref_frames_in_poc_cycle中的每一个元素指定了一个偏移 int i_num_ref_frames;指定参考帧队列的最大长度 h264规定最多可为16个参考帧 int b_gaps_in_frame_num_value_allowed;值为1时表示允许句法frame_num可以不连续 int i_mb_width; int i_mb_height; int b_frame_mbs_only; int b_mb_adaptive_frame_field; int b_direct8×8_inference;指明b片的直接和skip模式下运动矢量的预测方法 int b_crop; struct { int i_left; int i_right; int i_top; int i_bottom; } crop;图像剪彩后输出的参数 int b_vui; struct { int i_sar_width; int i_sar_height; /* FIXME to complete */ } vui; }x264_sps_t定义序列参考队列的参数以及初始化 pps图像参数集
typedef struct
{ int i_id; int i_sps_id; int b_cabac; int b_pic_order; int i_num_slice_groups; 加一表示图像中片组的个数 int i_slice_group_map_type;片组分割类型 /*i_slice_group_map_type 0 */ int i_run_length[256]; 指明片组类型为2时每个片组连续的map_units的个数 /* FIXME */ /*i_slice_group_map_type 2 */ int i_top_left[256]; /* FIXME */ int i_bottom_right[256]; /* FIXME */ /*i_slice_group_map_type 3, 4, 5 */ int b_slice_group_change_direction; 当类型为345时与下句语法一起指明片组分割方法 int i_slice_group_change_rate; /*i_slice_group_map_type 6 */ int i_pic_size_in_map_units;类型为6时指明图像以map_units为单位的大小 int i_slice_group_id[256]; /* FIXME */指明map_units属于哪个片组 int i_num_ref_idx_l0_active;加1为参考帧队列的长度 此为list0 int i_num_ref_idx_l1_active;此为list1 int b_weighted_pred;用以指明是否允许P和SP片的加权预测 int b_weighted_bipred; 用以指明是否允许B片的加权预测 int i_pic_init_qp;加26后用以指明亮度分量的量化参数的初始值 int i_pic_init_qs;同上只是用于SP和SI int i_chroma_qp_index_offset;指明计算使用时用到的参数 int b_deblocking_filter_control; int b_constrained_intra_pred;控制PB帧的帧内编码 int b_redundant_pic_cnt;是否出现redundant_pic_cnt句法元素
} x264_pps_t
