usb摄像头视频采集及格式转换yuv420

#include "stdafx.h" #include "videocapture.h" #ifdef __cplusplus extern "C" { #endif #include "libavformat/avformat.h" #include "libavcodec/avcodec.h" #include "libswscale/swscale.h" #include "libavutil/avutil.h" #include "libavutil/audio_fifo.h" #include "libavutil/mathematics.h" #include "libswresample/swresample.h" #include "libavutil/imgutils.h" #include "libavutil/opt.h" #include "libavutil/time.h" #include "libavdevice/avdevice.h" #include "inttypes.h" #include "dshow.h" #ifdef __cplusplus }; #endif CVideoCapture::CVideoCapture() { m_pFormatCtx = NULL; m_pCodecCtx = NULL; m_cbYuv = NULL; m_yuvBuffer = NULL; m_strDeviceName = ""; m_nStreamIndex = -1; m_isNeedFormatConversion = false; } CVideoCapture::~CVideoCapture() { } int CVideoCapture::StartCapture(std::string deviceName, int nFrameRate, ZG_Rect rect, YuvCallBackType cbYuv, void *pContext) { m_cbYuv = cbYuv; m_pContext = pContext; m_nDstFrameRate = nFrameRate; m_nDstRect.x = rect.x; m_nDstRect.y = rect.y; m_nDstRect.width = rect.width; m_nDstRect.height = rect.height; m_yuvBuffer = new char[rect.width*rect.height*3/2]; if(!m_yuvBuffer) { goto err; } if(initCapture(deviceName, nFrameRate, rect) != 0) { goto err; } if(startCaptureThread() != 0) { goto err; } return 0; err: StopCapture(); return -1; } int CVideoCapture::StopCapture() { stopCaptureThread(); unInitCapture(); if(m_yuvBuffer) { delete m_yuvBuffer; m_yuvBuffer = NULL; } return 0; } int CVideoCapture::initCapture(std::string deviceName, int nFrameRate, ZG_Rect rect) { m_strDeviceName = deviceName; AVInputFormat *pInputFmt = av_find_input_format("dshow"); if(pInputFmt == NULL) { return -1; } //分配上下文对象 m_pFormatCtx = avformat_alloc_context(); if(m_pFormatCtx == NULL) { return -1; } AVDictionary *optionDic = NULL; char szVideoSize[256] = {0}; sprintf(szVideoSize, "%dx%d", rect.width, rect.height); //设置期望获取到的视频参数 av_dict_set_int(&optionDic, "offset_x", rect.x, 0); av_dict_set_int(&optionDic, "offset_y", rect.y, 0); av_dict_set(&optionDic, "video_size", szVideoSize, 0); av_dict_set_int(&optionDic, "framerate", nFrameRate, 0); av_dict_set_int(&optionDic, "pix_fmt", AV_PIX_FMT_YUV420P, 0); //打开流 int nRet = avformat_open_input(&m_pFormatCtx, m_strDeviceName.c_str(), pInputFmt, &optionDic); if(nRet != 0) { goto err; } //查找流信息 if (avformat_find_stream_info(m_pFormatCtx, NULL) < 0) { goto err; } if(m_pFormatCtx->streams == NULL) { goto err; } //找视频流信息索引 for (int i = 0; i < m_pFormatCtx->nb_streams; i++) { if (m_pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) { m_nStreamIndex = i; break; } } if(m_nStreamIndex < 0) { goto err; } m_pCodecCtx = m_pFormatCtx->streams[m_nStreamIndex]->codec; if(m_pCodecCtx == NULL) { goto err; } m_pCodecCtx->time_base.den = nFrameRate; m_pCodecCtx->time_base.num = 1; //如果格式不是yuv420 则需要进行图像格式转换 即需要创建SwsContext对象 if(m_pCodecCtx->pix_fmt != AV_PIX_FMT_YUV420P) { m_isNeedFormatConversion = true; } if(m_isNeedFormatConversion) { bool bRet = m_videoConvert.InitConvert(m_pCodecCtx->width, m_pCodecCtx->height, m_pCodecCtx->pix_fmt, rect.width, rect.height, AV_PIX_FMT_YUV420P); if(!bRet) { goto err; } } AVCodec *pCodec = avcodec_find_decoder(m_pCodecCtx->codec_id); if(pCodec == NULL) { goto err; } if (avcodec_open2(m_pCodecCtx, pCodec, NULL)<0) { goto err; } return 0; err: unInitCapture(); return -1; } int CVideoCapture::unInitCapture() { if(m_pFormatCtx) { avformat_close_input(&m_pFormatCtx); avformat_free_context(m_pFormatCtx); } m_videoConvert.UnInitConvert(); return 0; } void *CVideoCapture::cbCaptureThreadCallBack(void *param) { CVideoCapture *pThis = (CVideoCapture *)param; return pThis->captureThreadCallBack(); } void *CVideoCapture::captureThreadCallBack() { AVFrame *avFrame = av_frame_alloc(); if(avFrame == NULL) { return 0; } while(m_bRunCapture) { AVPacket pkt = {0}; int nRet = av_read_frame(m_pFormatCtx, &pkt); if(nRet == 0) { int gotFrame = 0; int nRet = avcodec_decode_video2(m_pCodecCtx, avFrame, &gotFrame, &pkt); if(nRet < 0) { char szBuffer[256] = { 0 }; av_make_error_string(szBuffer, 256, nRet); av_free_packet(&pkt); break; } if(gotFrame) { if(m_isNeedFormatConversion) { if (m_videoConvert.DoConvert(avFrame, m_yuvBuffer)) { int width = avFrame->width; int height = avFrame->height; if(m_cbYuv) { m_cbYuv(m_pContext, m_yuvBuffer, width, height); } } } else { } } } else { int i = 0; int err = ::GetLastError(); int aa = 0; } av_free_packet(&pkt); } av_frame_free(&avFrame); return 0; } int CVideoCapture::startCaptureThread() { m_bRunCapture = true; int nRet = pthread_create(&m_captureThreadId, NULL, cbCaptureThreadCallBack, this); if(nRet != 0) { return -1; } return 0; } int CVideoCapture::stopCaptureThread() { m_bRunCapture = false; pthread_join(m_captureThreadId, NULL); return 0; }