Windows上VS2017单步调试FFmpeg源码的方法
之前在https://blog.csdn.net/fengbingchun/article/details/90114411 介紹過如何在Windows7/10上通過MinGW方式編譯FFmpeg 4.1.3源碼生成庫的步驟,那時只能生成最終的庫,卻不能產生vs工程,無法進行單步調試。GitHub上有個項目ShiftMediaProject/FFmpeg提供了vs工程,下面對編譯過程進行說明:
1. 從https://github.com/ShiftMediaProject/FFmpeg clone到E:\GitCode\FFmpeg_VS2013\ShiftMediaProject目錄下,最新commit id為3371d97d5951e882b3a57c323b3e1f21cfabe900,提交日期為2019.12.14;
2. 按照SMP/readme.txt的說明,要求vs版本需為2013及以上,初始打算使用vs2013,不過提示需要下載最新的Service Pack,因此改為使用vs2017;
3. 下載依賴項,執行FFmpeg/SMP/project_get_dependencies.bat,執行結果如下,可能需要等待較長時間,而且可能需要執行多次,直到所有的依賴項全部clone下來,個別項目(如我多次嘗試下載gnulib始終失敗)可能會需要自己手動clone:git clone https://gitlab.com/libidn/gnulib-mirror.git ??,然后將其拷貝到ShiftMediaProject/gnutls/gnulib目錄下;
4. 按照SMP/readme.txt中的說明,下載額外依賴文件,手動創建新目錄E:\GitCode\FFmpeg_VS2013\msvc,下載完后的內容如下:
(1). 從https://www.khronos.org/registry/OpenGL/index_gl.php ?下載glext.h和wglext.h,將其保存到新創建的目錄msvc/include/gl下;
(2). 從https://www.khronos.org/registry/OpenGL/index_gl.php 下載khrplatform.h,將其保存到新創建的目錄msvc/include/KHR下;
(3). 從https://github.com/FFmpeg/nv-codec-headers 下載include/ffnvcodec,將ffnvcodec整個目錄拷貝到目錄msvc/include下;
(4). 從https://github.com/GPUOpen-LibrariesAndSDKs/AMF 下載amf/public/include,將include下的內容保存到新創建的目錄msvc/include/AMF下;
5. 有些項目有匯編代碼需要ASM編譯,如libavutil需要NASM,依賴項libvpx需要YASM:
(1). 從https://github.com/ShiftMediaProject/VSNASM 下載VSNASM,以管理員身份運行install_script.bat,可多執行幾次,如下圖所示:vs2017安裝成功,vs2013安裝失敗,因為使用vs2017編譯先不管vs2013;如果install_script.bat不能成功安裝,可參照VSNASM下的README.md進行安裝:
(2). 從https://github.com/ShiftMediaProject/VSYASM 下載VSYASM,以管理員身份運行install_script.bat,可多執行幾次,如下圖所示 :vs2017安裝成功,vs2013安裝失敗,因為使用vs2017編譯先不管vs2013;如果install_script.bat不能成功安裝,可參照VSYASM下的README.md進行安裝:
6. 使用vs2017打開FFmpeg/SMP/ffmpeg_deps.sln,發現有些項目不可用,如libass,如下圖所示,點擊安裝并關閉ffmpeg_deps.sln:
7. 再次打開ffmpeg_deps.sln,47個項目均加載成功,如下圖所示:
8. 可選擇編譯靜態庫/動態庫,Debug/Release,x86/x64,這里選擇x64 靜態庫 Debug,選中解決方案”ffmpeg_deps”,點擊重新生成解決方案,第一次可能會產生一些error,可再次點擊生成解決方案,執行結果如下圖所示:
(1). 在E:\GitCode\FFmpeg_VS2013\msvc\bin\x64目錄下會存放可執行文件,包括:ffmpegd.exe、ffplayd.exe、ffprobed.exe;
(2). 在E:\GitCode\FFmpeg_VS2013\msvc\lib\x64目錄下會存放所有的靜態庫文件包括ffmpeg自身的和依賴項的;
(3). 在E:\GitCode\FFmpeg_VS2013\msvc\include目錄下會存放所需要的頭文件;
(4). 驗證ffmpegd.exe的正確性:獲取視頻設備名,執行如下命令,執行結果如下圖所示:顯示ffmpeg版本為4.2,檢測到的視頻設備名為” Integrated Webcam”
ffmpegd.exe -list_devices true -f dshow -i dummy
(5). 驗證ffplayed.exe的正確性:播放一個編碼格式為rawvideo,像素格式為bgr24,幀大小為1280*720的文件,執行如下命令,執行結果如下圖所示:可正常播放
ffplayd.exe -i bgr.bin -f rawvideo -pixel_format bgr -video_size 1280x720
(6). 驗證ffprobed.exe的正確性:查看1.mp4視頻文件信息,執行如下命令,執行結果如下圖所示:可正常顯示視頻文件信息
ffprobed.exe 1.mp4
9. 新建一個test項目,測試代碼test.cpp如下,執行結果如下:可正常打開視頻設備并顯示
#include <stdio.h>
#include <string.h>
#include <iostream>
#include <memory>
#include <fstream>
#include <thread>#ifdef __cplusplus
extern "C" {
#endif#include <libavdevice/avdevice.h>
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libswscale/swscale.h>
#include <libavutil/mem.h>
#include <libavutil/imgutils.h>#ifdef __cplusplus
}
#endif#include <opencv2/opencv.hpp>int main()
{avdevice_register_all();AVCodecID id = AV_CODEC_ID_MJPEG;AVCodec* encoder_id = avcodec_find_encoder(id);AVCodec* decoder_id = avcodec_find_decoder(id);if (!encoder_id || !decoder_id) {fprintf(stderr, "codec not found: %d\n", id);return -1;}AVFormatContext* format_context = avformat_alloc_context();format_context->video_codec_id = id; // 指定編解碼格式AVInputFormat* input_format = av_find_input_format("dshow");AVDictionary* dict = nullptr;//if (av_dict_set(&dict, "vcodec"/*"input_format"*/, "mjpeg", 0) < 0) fprintf(stderr, "fail to av_dict_set: line: %d\n", __LINE__); // 通過av_dict_set設置編解碼格式好像不起作用if (av_dict_set(&dict, "video_size", "960x540", 0) < 0) fprintf(stderr, "fail to av_dict_set: line: %d\n", __LINE__);//if (av_dict_set(&dict, "r", "25", 0) < 0) fprintf(stderr, "fail to av_dict_set: line: %d\n", __LINE__); // 通過av_dict_set設置幀率好像不起作用int ret = avformat_open_input(&format_context, "video=Integrated Webcam", input_format, &dict);if (ret != 0) {fprintf(stderr, "fail to avformat_open_input: %d\n", ret);return -1;}ret = avformat_find_stream_info(format_context, nullptr);if (ret < 0) {fprintf(stderr, "fail to get stream information: %d\n", ret);return -1;}int video_stream_index = -1;for (unsigned int i = 0; i < format_context->nb_streams; ++i) {const AVStream* stream = format_context->streams[i];if (stream->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {video_stream_index = i;fprintf(stdout, "type of the encoded data: %d, dimensions of the video frame in pixels: width: %d, height: %d, pixel format: %d\n",stream->codecpar->codec_id, stream->codecpar->width, stream->codecpar->height, stream->codecpar->format);}}if (video_stream_index == -1) {fprintf(stderr, "no video stream\n");return -1;}fprintf(stdout, "frame rate: %f\n", av_q2d(format_context->streams[video_stream_index]->r_frame_rate));AVCodecParameters* codecpar = format_context->streams[video_stream_index]->codecpar;const AVCodec* codec = avcodec_find_decoder(codecpar->codec_id);if (!codec) {fprintf(stderr, "fail to avcodec_find_decoder\n");return -1;}if (codecpar->codec_id != id) {fprintf(stderr, "this test code only support mjpeg encode: %d\n", codecpar->codec_id);return -1;}AVCodecContext* codec_context = avcodec_alloc_context3(codec);if (!codec_context) {fprintf(stderr, "fail to avcodec_alloc_context3\n");return -1;}codec_context->pix_fmt = AVPixelFormat(codecpar->format);codec_context->height = codecpar->height;codec_context->width = codecpar->width;codec_context->thread_count = 16;ret = avcodec_open2(codec_context, codec, nullptr);if (ret != 0) {fprintf(stderr, "fail to avcodec_open2: %d\n", ret);return -1;}AVPixelFormat dst_pixel_format = AV_PIX_FMT_BGR24;AVFrame* frame = av_frame_alloc();AVPacket* packet = (AVPacket*)av_malloc(sizeof(AVPacket));SwsContext* sws_context = sws_getContext(codec_context->width, codec_context->height, codec_context->pix_fmt, codec_context->width, codec_context->height, dst_pixel_format, 0, nullptr, nullptr, nullptr);if (!frame || !packet || !sws_context) {fprintf(stderr, "fail to alloc\n");return -1;}uint8_t *bgr_data[4];int bgr_linesize[4];av_image_alloc(bgr_data, bgr_linesize, codec_context->width, codec_context->height, dst_pixel_format, 1);cv::Mat mat(codec_context->height, codec_context->width, CV_8UC3);const char* winname = "dshow mjpeg video";cv::namedWindow(winname);while (1) {ret = av_read_frame(format_context, packet);if (ret >= 0 && packet->stream_index == video_stream_index && packet->size > 0) {ret = avcodec_send_packet(codec_context, packet);if (ret < 0) {fprintf(stderr, "##### fail to avcodec_send_packet: %d\n", ret);av_packet_unref(packet);continue;}ret = avcodec_receive_frame(codec_context, frame);if (ret < 0) {fprintf(stderr, "##### fail to avcodec_receive_frame: %d\n", ret);av_packet_unref(packet);continue;}sws_scale(sws_context, frame->data, frame->linesize, 0, codec_context->height, bgr_data, bgr_linesize);mat.data = bgr_data[0];cv::imshow(winname, mat);}else if (ret < 0 || packet->size <= 0) {fprintf(stderr, "##### fail to av_read_frame: %d, packet size: %d\n", ret, packet->size);continue;}av_packet_unref(packet);int key = cv::waitKey(30);if (key == 27) break;}cv::destroyWindow(winname);sws_freeContext(sws_context);av_frame_free(&frame);av_freep(packet);av_freep(&bgr_data[0]);avformat_close_input(&format_context);av_dict_free(&dict);fprintf(stdout, "test finish\n");return 0;
}
在av_read_frame處設置斷點,單步調試,可進入av_read_frame函數內部,如下圖所示:
GitHub:https://github.com//fengbingchun/OpenCV_Test
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