x264学习笔记1.doc

X264编码流程参数的初始化1.opt，param根据输入的参数和标准的规定，进行初始化设置。Opt的说明如下：Opt-hin用于给出读入的yuv文件的指针地址Opt-hout给出了输出的文件的指针地址Opt-i_seek给出了起始编码帧的帧数，是由编码时的seek命令参数决定的如：X264 -seek 10 -o foreman.cif test.264 352x288i_seek 设为10，表示起始编码的帧为元序列的第十帧Opt-qpfile按照说明，为qp值文件输入进行定义这种方式的接口，可以通过读入标准的文件格式，对编码时的qp值进行定义。Param的说明：typedef struct /* CPU flags */ unsigned int cpu; int i_threads; /* divide each frame into multiple slices, encode in parallel */线程数，用于多线程并行编码 /* Video Properties */ int i_width; 图像的宽度 int i_height; 图像的高度 int i_csp; /* CSP of encoded bitstream, only i420 supported */ 色彩空间的设置 int i_level_idc; level值的设置 int i_frame_total; /* number of frames to encode if known, else 0 */ 总共需要编码的帧数，由-frames设置Vui参数集 struct /* they will be reduced to be 0 x i_fps_num, &p-i_fps_den ) = 2 ) ; else if( sscanf( value, %f, &fps ) ) p-i_fps_num = (int)(fps * 1000 + .5); p-i_fps_den = 1000; else b_error = 1; Value的值就是fps。 /* Bitstream parameters */ int i_frame_reference; /* Maximum number of reference frames */ int i_keyint_max; /* Force an IDR keyframe at this interval */ int i_keyint_min; /* Scenecuts closer together than this are coded as I, not IDR. */ int i_scenecut_threshold; /* how aggressively to insert extra I frames */ int i_bframe; /* how many b-frame between 2 references pictures */ int b_bframe_adaptive; int i_bframe_bias; int b_bframe_pyramid; /* Keep some B-frames as references */去块滤波器需要的参数 int b_deblocking_filter; int i_deblocking_filter_alphac0; /* -6, 6 -6 light filter, 6 strong */ int i_deblocking_filter_beta; /* -6, 6 idem */熵编码 int b_cabac; int i_cabac_init_idc;量化 int i_cqm_preset; char *psz_cqm_file; /* JM format */ uint8_t cqm_4iy16; /* used only if i_cqm_preset = X264_CQM_CUSTOM */ uint8_t cqm_4ic16; uint8_t cqm_4py16; uint8_t cqm_4pc16; uint8_t cqm_8iy64; uint8_t cqm_8py64; /* Log */ void (*pf_log)( void *, int i_level, const char *psz, va_list ); void *p_log_private; int i_log_level; int b_visualize; /* Encoder analyser parameters */ struct unsigned int intra; /* intra partitions */ unsigned int inter; /* inter partitions */ int b_transform_8x8; int b_weighted_bipred; /* implicit weighting for B-frames */ int i_direct_mv_pred; /* spatial vs temporal mv prediction */ int i_chroma_qp_offset; int i_me_method; /* motion estimation algorithm to use (X264_ME_*) */ int i_me_range; /* integer pixel motion estimation search range (from predicted mv) */ int i_mv_range; /* maximum length of a mv (in pixels) */ int i_subpel_refine; /* subpixel motion estimation quality */ int b_bidir_me; /* jointly optimize both MVs in B-frames */ int b_chroma_me; /* chroma ME for subpel and mode decision in P-frames */ int b_bframe_rdo; /* RD based mode decision for B-frames */ int b_mixed_references; /* allow each mb partition in P-frames to have its own reference number */ int i_trellis; /* trellis RD quantization */ int b_fast_pskip; /* early SKIP detection on P-frames */ int b_dct_decimate; /* transform coefficient thresholding on P-frames */ int i_noise_reduction; /* adaptive pseudo-deadzone */ int b_psnr; /* Do we compute PSNR stats (save a few % of cpu) */ analyse; /* Rate control parameters */ struct int i_rc_method; /* X264_RC_* */ int i_qp_constant; /* 0-51 */ int i_qp_min; /* min allowed QP value */ int i_qp_max; /* max allowed QP value */ int i_qp_step; /* max QP step between frames */ int i_bitrate; 比特率 -bitrate控制 int i_rf_constant; /* 1pass VBR, nominal QP */ float f_rate_tolerance; int i_vbv_max_bitrate; int i_vbv_buffer_size; float f_vbv_buffer_init; float f_ip_factor; float f_pb_factor; /* 2pass */ int b_stat_write; /* Enable stat writing in psz_stat_out */ char *psz_stat_out; int b_stat_read; /* Read stat from psz_stat_in and use it */ char *psz_stat_in; /* 2pass params (same as ffmpeg ones) */ char *psz_rc_eq; /* 2 pass rate control equation */ float f_qcompress; /* 0.0 = cbr, 1.0 = constant qp */ float f_qblur; /* temporally blur quants */ float f_complexity_blur; /* temporally blur complexity */ x264_zone_t *zones; /* ratecontrol overrides */ int i_zones; /* sumber of zone_ts */ char *psz_zones; /* alternate method of