ffmpeg4.4 学习笔记 -（2）读取视频文件并用SDL 显示_商少-CSDN博客

修改saveframe，改用mfc bitmap 显示视频：

void CMFCAudioResampleDlg::OnBnClickedButtonChooseFile()
{CRGB24PlayerDlg dlg;std::thread([&dlg](){dlg.DoModal();}).detach();// TODO: 在此添加控件通知处理程序代码auto target = GetOneFile();m_targetFilePath.SetWindowTextW(target.c_str());UpdateData(TRUE);CString strTargetWindowText;m_targetFilePath.GetWindowTextW(strTargetWindowText);AVFormatContext* avFormatContext = avformat_alloc_context();USES_CONVERSION;if (!PathFileExists(strTargetWindowText.GetBuffer())) {return;}auto result = avformat_open_input(&avFormatContext, W2A((strTargetWindowText.GetBuffer())), nullptr, nullptr);if (result < 0) {assert(false);}result = avformat_find_stream_info(avFormatContext, NULL);if (result < 0){assert(false);}av_dump_format(avFormatContext, 0, NULL, 0);// Find the first video streamint videoStream = -1;for (int i = 0; i < avFormatContext->nb_streams; i++)if (avFormatContext->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {videoStream = i;break;}if (videoStream == -1)return ; // Didn't find a video streamAVCodecContext* avCodecContext = avcodec_alloc_context3(NULL);result = avcodec_parameters_to_context(avCodecContext, avFormatContext->streams[videoStream]->codecpar);if (result < 0){assert(false);}avCodecContext->pkt_timebase = avFormatContext->streams[videoStream]->time_base;AVCodec* codec = avcodec_find_decoder(avCodecContext->codec_id);avCodecContext->codec_id = codec->id;result = avcodec_open2(avCodecContext, codec, nullptr);if (result < 0){msgBoxFFmpegError(result);assert(false);}AVFrame* pFrame = nullptr;pFrame = av_frame_alloc();// 我们最终的目的是将原始视频帧存储为24-bit RGB 视频。AVFrame* pFrameRGB24 = av_frame_alloc();uint8_t* bufferRawRGB24 = nullptr;const int numBytes = av_image_get_buffer_size(AV_PIX_FMT_RGB24, avCodecContext->width, avCodecContext->height, 1);bufferRawRGB24 = (uint8_t*)av_malloc(numBytes * sizeof(uint8_t));av_image_fill_arrays(pFrameRGB24->data, pFrameRGB24->linesize, bufferRawRGB24, AV_PIX_FMT_RGB24, avCodecContext->width, avCodecContext->height, 1);// 读取数据// sws_ctx 定义了从pix_fmt 到 AV_PIX_FMT_RGB24的转换struct SwsContext* sws_ctx = NULL;int frameFinished;// initialize SWS context for software scalingsws_ctx = sws_getContext(avCodecContext->width,avCodecContext->height,avCodecContext->pix_fmt,avCodecContext->width,avCodecContext->height,AV_PIX_FMT_RGB24,SWS_BILINEAR,NULL,NULL,NULL);int i = 0;AVPacket packet;bool bReadEof = false;while (true){Sleep(33);int readResult = -1;if (!bReadEof){readResult = av_read_frame(avFormatContext, &packet);if (readResult < 0) {::MessageBoxA(0, 0, GetFFmpegErorString(readResult).c_str(), 0);bReadEof = true;}else if (readResult == 0) {static int iCnt = 0;if (packet.stream_index == videoStream) {++iCnt;}CString str;str.Format(L"cunt[%d]\r\n", iCnt);OutputDebugStringW(str.GetBuffer());}}if (bReadEof){// 需要给刷空avcodec_send_packet(avCodecContext, NULL);}else{// Is this a packet from the video stream?if (packet.stream_index == videoStream) {// Decode video frameavcodec_send_packet(avCodecContext, &packet);}}int receiveResult = avcodec_receive_frame(avCodecContext, pFrame);// Did we get a video frame?if (receiveResult == 0) {// Convert the image from its native format to RGBsws_scale(sws_ctx, (uint8_t const* const*)pFrame->data,pFrame->linesize, 0, avCodecContext->height,pFrameRGB24->data, pFrameRGB24->linesize);++i;
// 			SaveFrame(pFrameRGB24, avCodecContext->width,
// 				avCodecContext->height, i);dlg.DisplayNewRGB24(pFrameRGB24->data[0], avCodecContext->width, avCodecContext->height);}else if (receiveResult == AVERROR_EOF){::MessageBoxA(0, 0, "read eof", 0);break;}else if(receiveResult == AVERROR(EAGAIN)){if (bReadEof) {break;}else {}}else {msgBoxFFmpegError(receiveResult);}// Free the packet that was allocated by av_read_frameif(readResult == 0)av_packet_unref(&packet);}av_frame_free(&pFrame);av_frame_free(&pFrameRGB24);av_free(bufferRawRGB24);avcodec_close(avCodecContext);avformat_close_input(&avFormatContext);
}

其中CRGB24PlayerDlg 是一个用于显示rgb24图片的对话框：

void CRGB24PlayerDlg::OnPaint()
{CPaintDC dc(this); // device context for painting// TODO: 在此处添加消息处理程序代码// 不为绘图消息调用 CDialogEx::OnPaint()if (m_update && m_memDC){::BitBlt(dc.m_hDC, 0, 0, m_currentSize.Width(), m_currentSize.Height(), m_memDC, 0, 0, SRCCOPY);m_update = false;}
}void CRGB24PlayerDlg::DisplayNewRGB24(void* data, int width, int height)
{std::lock_guard<std::mutex> lock(m_lock);if (m_currentSize.Width() != width || m_currentSize.Height() != height) {m_currentSize.left = 0;m_currentSize.top = 0;m_currentSize.right = width;m_currentSize.bottom = height;RECT rect = {};rect.left = 0;rect.top = 0;rect.right = width;rect.bottom = height;MoveWindow(&rect, true);}if (m_memDC != NULL){if(m_hPreBitmap)SelectObject(m_memDC, m_hPreBitmap);DeleteDC(m_memDC);m_memDC = NULL;}//https://docs.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-bitmapinfoheaderBITMAPINFO bi = { 0 };BITMAPINFOHEADER* bih = &bi.bmiHeader;bih->biSize = sizeof(BITMAPINFOHEADER);bih->biBitCount = 24;bih->biWidth = width;bih->biHeight = -height;bih->biPlanes = 1;bih->biCompression = BI_RGB;m_memDC = CreateCompatibleDC(this->GetDC()->m_hDC);void* dibData = nullptr;HBITMAP hBitmap = CreateDIBSection(m_memDC, &bi, DIB_RGB_COLORS, (void**)&dibData, NULL, 0);for (int i = 0; i < height; i++) {const int lineAlign = ((((width * 24) + 31) & ~31) >> 3);for (int j = 0; j < width; j++) {//RGB to BGR*((uint8_t*)dibData + i * lineAlign + j * 3 + 0) = *((uint8_t*)data + i * width * 3 + j * 3 + 2);*((uint8_t*)dibData + i * lineAlign + j * 3 + 1) = *((uint8_t*)data + i * width * 3 + j * 3 + 1);*((uint8_t*)dibData + i * lineAlign + j * 3 + 2) = *((uint8_t*)data + i * width * 3 + j * 3 + 0);}}m_hPreBitmap = (HBITMAP)SelectObject(m_memDC, hBitmap);m_update = true;this->Invalidate(true);
}

其中核心逻辑是rgb24 到bitmap 24 的格式转换以及memdc 的处理

完整项目ffmpeg4.4playerwithrgb24bitmap-互联网文档类资源-CSDN下载