本文通过OpenCV库采集摄像头视频，随后通过libx264库把帧转化成264格式的码流。
头文件：
#ifndef _X264_ENCODER_H #define _X264_ENCODER_H #include <stdint.h> #include "x264.h" #include "opencv/cv.h" #include "opencv/highgui.h" struct x264_encoder{ x264_param_t param; char preset[20]; char tune[20]; char profile[20]; x264_t* h; x264_picture_t pic_in; x264_picture_t pic_out; long colorspace; x264_nal_t* nal; int iframe; int iframe_size; int inal; }; class x264Encoder { public: x264Encoder(); x264Encoder(int videoWidth, int videoHeight, int channel, int fps); ~x264Encoder(); /** 创建X264编码器 * @param[in] videoWidth 视频宽度 * @param[in] videoHeight 视频高度 * @param[in] fps 帧率 * @return 成功返回true, 失败返回false. */ bool Create(int videoWidth, int videoHeight, int channel = 3, int fps = 30); /** 编码一帧 * @param[in] frame 输入的一帧图像 * @return 返回编码后数据尺寸, 0表示编码失败 */ int EncodeOneFrame(const cv::Mat& frame); /** 获取编码后的帧数据 * 说明: EncodeOneFrame 后调用 * @return 返回裸x264数据 */ uchar* GetEncodedFrame() const; /** 销毁X264编码器 */ void Destory(); // 编码器是否可用 bool IsValid() const; private: void Init(); public: int m_width; int m_height; int m_channel; int m_fps; protected: int m_widthstep; int m_lumaSize; int m_chromaSize; x264_encoder* m_encoder; }; #endif
源文件：
#include "x264_encoder.h" #include <stdio.h> #include <fcntl.h> #include <stdlib.h> #include <string.h> #include "opencv2/imgproc.hpp" #define ENCODER_TUNE "zerolatency" #define ENCODER_PROFILE "baseline" #define ENCODER_PRESET "veryfast" #define ENCODER_COLORSPACE X264_CSP_I420 #define CLEAR(x) (memset((&x),0,sizeof(x))) x264Encoder::x264Encoder() { Init(); } x264Encoder::x264Encoder(int videoWidth, int videoHeight, int channel, int fps) { Init(); Create(videoWidth, videoHeight, channel, fps); } x264Encoder::~x264Encoder() { Destory(); } void x264Encoder::Init() { m_width = 0; m_height = 0; m_channel = 0; m_widthstep = 0; m_fps = 30; m_lumaSize = 0; m_chromaSize = 0; m_encoder = NULL; } bool x264Encoder::Create(int videoWidth, int videoHeight, int channel, int fps) { int ret; int imgSize; if (videoWidth <= 0 || videoHeight <= 0 || channel < 0 || fps <= 0){ printf("wrong input param "); return false; } m_width = videoWidth; m_height = videoHeight; m_channel = channel; m_fps = fps; m_widthstep = videoWidth * channel; m_lumaSize = m_width * m_height; m_chromaSize = m_lumaSize / 4; imgSize = m_lumaSize * channel; m_encoder = (x264_encoder *)malloc(sizeof(x264_encoder)); if (!m_encoder){ printf("cannot malloc x264_encoder ! "); return false; } CLEAR(*m_encoder); m_encoder->iframe = 0; m_encoder->iframe_size = 0; strcpy(m_encoder->preset, ENCODER_PRESET); strcpy(m_encoder->tune, ENCODER_TUNE); /*初始化编码器*/ CLEAR(m_encoder->param); x264_param_default(&m_encoder->param); ret = x264_param_default_preset(&m_encoder->param, m_encoder->preset, m_encoder->tune); if (ret < 0){ printf("x264_param_default_preset error! "); return false; } /*cpuFlags 去空缓冲区继续使用不死锁保证*/ m_encoder->param.i_threads = X264_SYNC_LOOKAHEAD_AUTO; /*视频选项*/ m_encoder->param.i_csp = X264_CSP_I420; m_encoder->param.i_width = m_width; // 要编码的图像的宽度 m_encoder->param.i_height = m_height; // 要编码的图像的高度 m_encoder->param.i_frame_total = 0; // 要编码的总帧数，不知道用0 m_encoder->param.i_keyint_max = 10*fps;// 关键帧间隔 /*流参数*/ m_encoder->param.i_bframe = 5; m_encoder->param.b_open_gop = 0; m_encoder->param.i_bframe_pyramid = 0; m_encoder->param.i_bframe_adaptive = X264_B_ADAPT_TRELLIS; /*log参数，不需要打印编码信息时直接注释掉*/ m_encoder->param.i_log_level = X264_LOG_NONE; m_encoder->param.i_fps_num = fps;//码率分子 m_encoder->param.i_fps_den = 1; //码率分母 m_encoder->param.b_intra_refresh = 1; m_encoder->param.b_annexb = 1; m_encoder->param.rc.f_rf_constant = 24; m_encoder->param.rc.i_rc_method = X264_RC_CRF; ///////////////////////////////////////////////////////////////////////////////////////////////////// strcpy(m_encoder->profile, ENCODER_PROFILE); ret = x264_param_apply_profile(&m_encoder->param, m_encoder->profile); if (ret < 0){ printf("x264_param_apply_profile error! "); return false; } /*打开编码器*/ m_encoder->h = x264_encoder_open(&m_encoder->param); m_encoder->colorspace = ENCODER_COLORSPACE; /*初始化pic*/ ret = x264_picture_alloc(&m_encoder->pic_in, m_encoder->colorspace, m_width, m_height); if ( ret < 0 ){ printf("x264_picture_alloc error! ret=%d ", ret); return false; } m_encoder->pic_in.img.i_csp = m_encoder->colorspace; m_encoder->pic_in.img.i_plane = 3; m_encoder->pic_in.i_type = X264_TYPE_AUTO; m_encoder->inal = 0; m_encoder->nal = (x264_nal_t *)calloc(2, sizeof(x264_nal_t)); if (!m_encoder->nal){ printf("malloc x264_nal_t error! "); return false; } CLEAR(*(m_encoder->nal)); return true; } int x264Encoder::EncodeOneFrame(const cv::Mat& frame) { if (frame.empty()){ return 0; } cv::Mat bgr(frame), yuv; if(1 == frame.channels()){ cv::cvtColor(frame, bgr, CV_GRAY2BGR); } cv::cvtColor(bgr, yuv, CV_BGR2YUV_I420); memcpy(m_encoder->pic_in.img.plane[0], yuv.data, m_lumaSize); memcpy(m_encoder->pic_in.img.plane[1], yuv.data + m_lumaSize, m_chromaSize); memcpy(m_encoder->pic_in.img.plane[2], yuv.data + m_lumaSize + m_chromaSize, m_chromaSize); m_encoder->pic_in.i_pts = m_encoder->iframe ++; m_encoder->iframe_size = x264_encoder_encode(m_encoder->h, &m_encoder->nal, &m_encoder->inal, &m_encoder->pic_in, &m_encoder->pic_out); return m_encoder->iframe_size; } uchar* x264Encoder::GetEncodedFrame() const { return m_encoder->nal->p_payload; } void x264Encoder::Destory() { if (m_encoder){ if (m_encoder->h){ x264_encoder_close(m_encoder->h); m_encoder->h = NULL; } free(m_encoder); m_encoder = NULL; } } bool x264Encoder::IsValid() const { return ((m_encoder != NULL) && (m_encoder->h != NULL)); }