x264_param_default()原始碼分析;
阿新 • • 發佈:2019-02-15
/****************************************************************************
* x264_param_default:
****************************************************************************/
void x264_param_default( x264_param_t *param )
{
/* */
memset( param, 0, sizeof( x264_param_t ) );
/* CPU autodetect */
param->cpu = x264_cpu_detect();
param->i_threads = X264_THREADS_AUTO;//x264.h 中#define X264_THREADS_AUTO 0 /* Automatically select optimal number of threads */
將其定義為0,在設定之後要修改該引數。
param->i_lookahead_threads = X264_THREADS_AUTO;//較好的值為cpu個數*cpu核數
param->b_deterministic = 1;
param->i_sync_lookahead = X264_SYNC_LOOKAHEAD_AUTO;
/* Video properties */
param->i_csp = X264_CHROMA_FORMAT ? X264_CHROMA_FORMAT : X264_CSP_I420;//#define X264_CHROMA_FORMAT $config_chroma_format
的定義在configure,跟配置x264編譯時相關,但之後的指令碼並未看懂。
param->i_width = 0;//寬,預設0,需要設定。
param->i_height = 0;//長
param->vui.i_sar_width = 0;
param->vui.i_sar_height= 0;
param->vui.i_overscan = 0; /* undef */
param->vui.i_vidformat = 5; /* undef */
param->vui.b_fullrange = -1; /* default depends on input */
param->vui.i_colorprim = 2; /* undef */
param->vui.i_transfer = 2; /* undef */
param->vui.i_colmatrix = -1; /* default depends on input */
param->vui.i_chroma_loc= 0; /* left center */
param->i_fps_num = 25;//預設幀率25,不符合需要修改,否則視訊變慢或者變快。
param->i_fps_den = 1;//幀率分母
param->i_level_idc = -1;
param->i_slice_max_size = 0;
param->i_slice_max_mbs = 0;
param->i_slice_count = 0;
/* Encoder parameters 編碼引數*/
param->i_frame_reference = 3;//參考幀個數
param->i_keyint_max = 250;//最大關鍵幀間隔
param->i_keyint_min = X264_KEYINT_MIN_AUTO;//預設值為0
param->i_bframe = 3;//兩個參考幀之間的b幀數
param->i_scenecut_threshold = 40;
param->i_bframe_adaptive = X264_B_ADAPT_FAST;
param->i_bframe_bias = 0;
param->i_bframe_pyramid = X264_B_PYRAMID_NORMAL;
param->b_interlaced = 0;
param->b_constrained_intra = 0;
param->b_deblocking_filter = 1;
param->i_deblocking_filter_alphac0 = 0;
param->i_deblocking_filter_beta = 0;
param->b_cabac = 1;
param->i_cabac_init_idc = 0;
//位元速率控制模組,參看“”“”“”
param->rc.i_rc_method = X264_RC_CRF;//預設恆定位元速率
param->rc.i_bitrate = 0;//預設位元率,需要修改
param->rc.f_rate_tolerance = 1.0;
param->rc.i_vbv_max_bitrate = 0;
param->rc.i_vbv_buffer_size = 0;
param->rc.f_vbv_buffer_init = 0.9;
param->rc.i_qp_constant = 23 + QP_BD_OFFSET;
param->rc.f_rf_constant = 23; //恆定視訊質量量化因子
param->rc.i_qp_min = 0;//最小量化因子,越小越清晰
param->rc.i_qp_max = QP_MAX;//最大值為51+18+QP_BD_OFFSET QP_BD_OFFSET
為(6*(BIT_DEPTH-8))
param->rc.i_qp_step = 4;//步長
param->rc.f_ip_factor = 1.4;
param->rc.f_pb_factor = 1.3;
param->rc.i_aq_mode = X264_AQ_VARIANCE;
param->rc.f_aq_strength = 1.0;
param->rc.i_lookahead = 40;
param->rc.b_stat_write = 0;
param->rc.psz_stat_out = "x264_2pass.log";
param->rc.b_stat_read = 0;
param->rc.psz_stat_in = "x264_2pass.log";
param->rc.f_qcompress = 0.6;
param->rc.f_qblur = 0.5;
param->rc.f_complexity_blur = 20;
param->rc.i_zones = 0;
param->rc.b_mb_tree = 1;
/* 列印訊息*/
param->pf_log = x264_log_default;
param->p_log_private = NULL;
param->i_log_level = X264_LOG_INFO;
/* 分析預測引數*/
param->analyse.intra = X264_ANALYSE_I4x4 | X264_ANALYSE_I8x8;
param->analyse.inter = X264_ANALYSE_I4x4 | X264_ANALYSE_I8x8
| X264_ANALYSE_PSUB16x16 | X264_ANALYSE_BSUB16x16;
param->analyse.i_direct_mv_pred = X264_DIRECT_PRED_SPATIAL;
param->analyse.i_me_method = X264_ME_HEX;
param->analyse.f_psy_rd = 1.0;
param->analyse.b_psy = 1;
param->analyse.f_psy_trellis = 0;
param->analyse.i_me_range = 16;
param->analyse.i_subpel_refine = 7;
param->analyse.b_mixed_references = 1;
param->analyse.b_chroma_me = 1;
param->analyse.i_mv_range_thread = -1;
param->analyse.i_mv_range = -1; // set from level_idc
param->analyse.i_chroma_qp_offset = 0;
param->analyse.b_fast_pskip = 1;
param->analyse.b_weighted_bipred = 1;
param->analyse.i_weighted_pred = X264_WEIGHTP_SMART;
param->analyse.b_dct_decimate = 1;
param->analyse.b_transform_8x8 = 1;
param->analyse.i_trellis = 1;
param->analyse.i_luma_deadzone[0] = 21;
param->analyse.i_luma_deadzone[1] = 11;
param->analyse.b_psnr = 0;
param->analyse.b_ssim = 0;
//量化引數
param->i_cqm_preset = X264_CQM_FLAT;
memset( param->cqm_4iy, 16, sizeof( param->cqm_4iy ) );
memset( param->cqm_4py, 16, sizeof( param->cqm_4py ) );
memset( param->cqm_4ic, 16, sizeof( param->cqm_4ic ) );
memset( param->cqm_4pc, 16, sizeof( param->cqm_4pc ) );
memset( param->cqm_8iy, 16, sizeof( param->cqm_8iy ) );
memset( param->cqm_8py, 16, sizeof( param->cqm_8py ) );
memset( param->cqm_8ic, 16, sizeof( param->cqm_8ic ) );
memset( param->cqm_8pc, 16, sizeof( param->cqm_8pc ) );
param->b_repeat_headers = 1;
param->b_annexb = 1;
param->b_aud = 0;
param->b_vfr_input = 1;
param->i_nal_hrd = X264_NAL_HRD_NONE;
param->b_tff = 1;
param->b_pic_struct = 0;
param->b_fake_interlaced = 0;
param->i_frame_packing = -1;
param->b_opencl = 0;
param->i_opencl_device = 0;
param->opencl_device_id = NULL;
param->psz_clbin_file = NULL;
}
紅色為應該檢測修改的。量化和分析模組的,自己看不是太懂,學習中。