FFmpeg/OpenCV 实现全屏斜体水印

实现思路 ​ 基于，画布的方式，创建画布 -> 水印 -> 旋转 -> 抠图 -> 叠加到图像上基于，旋转图片的方式，填充 -> 水印 -> 顺时针旋转 -> 逆时针旋转 -> 截图基于，创建画布 -> 水印 -> 仿射变换 -> 水平垂直拼接 -> 叠加图片上

经测试比对，实现方式效率是最快的

代码实现

旋转画布方式

旋转图片方式

思路: 基于 实现

	// 填充// [in]scale=原图宽:原图高,pad=填充后宽:填充后高:填充左右大小:填充上下大小:black[out]// 四周填充,  pad 输入尺寸的一半char dtext[512];snprintf(dtext, sizeof(dtext), "[in]scale=%d:%d,pad=%d:%d:%d:%d:black[out]",frameWidth, frameHeight, expandFrameWidth, expandFrameHeight, expandSize, expandSize);// 水印// inxxxx[a];[a]xxx[a];[a]xxx[out]  中间传的文字标签首位对应([a] [a]). 结束没有';'. char dtext[1000];snprintf(dtext, sizeof(dtext), "[in]drawtext=fontfile=%s:text=%s:x=%d:y=%d:fontsize=%d:fontcolor=%s:alpha=%.1f[a];",kFont, txt.c_str(), start_x, start_y, kFontSize, kFontColor, italicTextInfo_.alpha);// 翻转// [in]rotate=PI* angel /180[out] char dtext[512];snprintf(dtext, sizeof(dtext), "[in]rotate=PI* %d /180[out]", angel);// 截取 // [in]crop=原图宽:原图高:截取x:截取y[out]char dtext[512];snprintf(dtext, sizeof(dtext), "[in]crop=%d:%d:%d:%d[out]", frameWidth, frameHeight, startx, starty);

创建

int init_filter_graph(const std::string& filter) {filterGraph_ = avfilter_graph_alloc();const AVFilter* buffersrc = avfilter_get_by_name("buffer");const AVFilter* buffersink = avfilter_get_by_name("buffersink");char args[512];snprintf(args, sizeof(args), "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d", frameWidth_, frameHeight_, frameFormat_, 1, videoFps_, 1, 1);int ret = avfilter_graph_create_filter(&buffersrcCtx_, buffersrc, "in", args, NULL, filterGraph_);if (ret < 0){avfilter_graph_free(&filterGraph_);filterGraph_ = NULL;return -1;}// buffer video sink: to terminate the filter chain.enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_YUV420P, AV_PIX_FMT_NV12, AV_PIX_FMT_NONE };AVBufferSinkParams* buffersink_params = av_buffersink_params_alloc();buffersink_params->pixel_fmts = pix_fmts;ret = avfilter_graph_create_filter(&buffersinkCtx_, buffersink, "out", NULL, buffersink_params, filterGraph_);av_free(buffersink_params);if (ret < 0){avfilter_graph_free(&filterGraph_);filterGraph_ = NULL;return -1;}AVFilterInOut* outputs = avfilter_inout_alloc();/* Endpoints for the filter graph. */outputs->name = av_strdup("in");outputs->filter_ctx = buffersrcCtx_;outputs->pad_idx = 0;outputs->next = NULL;AVFilterInOut* inputs = avfilter_inout_alloc();inputs->name = av_strdup("out");inputs->filter_ctx = buffersinkCtx_;inputs->pad_idx = 0;inputs->next = NULL;if ((ret = avfilter_graph_parse_ptr(filterGraph_, filter.c_str(), &inputs, &outputs, NULL)) < 0)goto end;ret = avfilter_graph_config(filterGraph_, NULL);if (ret < 0)goto end;
end:avfilter_inout_free(&inputs);avfilter_inout_free(&outputs);return ret;
}

向滤波输入帧, 然后从中取出一个

	AVFrame* overlay(AVFrame* in) {if (!isInit_)return nullptr;int ret = av_buffersrc_add_frame(buffersrcCtx_, in);if (ret < 0)return nullptr;ret = av_buffersink_get_frame(buffersinkCtx_, out_);if (ret < 0){av_frame_unref(out_);return nullptr;}return out_;}

生成对应 , 然后 向滤波中输入帧

// 大概流程思路
void xxxxx(){...// 生成对应filterstd::string filter = "对应filter";init_filter_graph(filter);...while (true){ret = av_read_frame(ifmtCtx, pkt);if (ret < 0)goto end;// audioif (pkt->stream_index == aistream) {av_packet_unref(pkt);continue;}// decode encode pktret = avcodec_send_packet(deCodecCtx, pkt);if (ret < 0)goto end;while (ret >= 0) {ret = avcodec_receive_frame(deCodecCtx, frame);if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {break;}else if (ret < 0) {goto end;}// solove [libx264 @ 0x34b88a0] specified frame type (3) at 0 is not compatible with keyframe intervalframe->pict_type = AV_PICTURE_TYPE_NONE;// overlay italic txt infoAVFrame* overlay_frame = overlay(frame);if (overlay_frame == nullptr)goto end;ret = encode_frame_to_write_file(enCodecCtx, overlay_frame, pkt, ifmtCtx->streams[vistream]->time_base, ofmtCtx->streams[vostream]->time_base, ofmtCtx);if (ret < 0) {av_frame_free(&overlay_frame);goto end;}av_packet_unref(pkt);av_frame_unref(frame);av_frame_unref(overlay_frame);}#pragma endregionav_packet_unref(pkt);}...}

思路 代码 创建斜体水印

int init_water_mark(const std::string& txt, cv::Mat& water) {// 原图宽高int imageW = italicTextInfo_.frameWidth / italicTextInfo_.col;int imageH = italicTextInfo_.frameHeight / italicTextInfo_.row;cv::Mat canvasMat = cv::Mat::zeros(cv::Size(imageW, imageH), CV_8UC3);// 水印，使用 Times New Roman 字体VTText::putTextHuskyC(canvasMat, txt.c_str(), cv::Scalar(255, 255, 255), kFontSize, "Times New Roman", false, false);// 实际显示的水印行列数int w_count = italicTextInfo_.col * 2 - 1;int h_count = italicTextInfo_.row * 2;// 垂直拼接水印std::vector<cv::Mat> vImgs;cv::Mat vResult;for (int vi = 0; vi < h_count; vi++)vImgs.push_back(canvasMat);vconcat(vImgs, vResult);// 水平拼接水印std::vector<cv::Mat> hImgs;cv::Mat hResult;for (int hi = 0; hi < w_count; hi++)hImgs.push_back(vResult);hconcat(hImgs, hResult);cv::Point2f center(hResult.cols / 2.0, hResult.rows / 2.0);// 通过仿射变换将水印旋转45度,实现全屏斜体效果cv::Mat rotation_matix = getRotationMatrix2D(center, italicTextInfo_.italicAngel, 1.0);cv::Mat rotated_image;warpAffine(hResult, rotated_image, rotation_matix, hResult.size());// 然后将水印图裁剪成原图大小，用于后续叠加到原图上.water = rotated_image(cv::Rect((hResult.cols - italicTextInfo_.frameWidth) / 2, (hResult.rows - italicTextInfo_.frameHeight) / 2, italicTextInfo_.frameWidth, italicTextInfo_.frameHeight));return 0;}// 将水印图叠加到原图上// frame: 解码帧 avframe AVFrame* overlayItalicTextInfoCVCanvas(AVFrame* frame) {//cv::Mat src_mat;//frame_to_mat(frame, src_mat);int pktSize;uint8_t* buffer_rgb = convertRgb(frame, frame->width, frame->height, AV_PIX_FMT_YUV420P, frame->width, frame->height, AV_PIX_FMT_BGR24, pktSize);cv::Mat src_mat = cv::Mat(frame->height, frame->width, CV_8UC3, buffer_rgb);cv::Mat roi;roi = src_mat(cv::Rect(0, 0, watermark_.cols, watermark_.rows));cv::addWeighted(roi, 1.0, watermark_, italicTextInfo_.alpha, 0, roi);AVFrame* dst = mat_to_frame(src_mat, src_mat.cols, src_mat.rows, AV_PIX_FMT_YUV420P);if (buffer_rgb != nullptr)av_free(buffer_rgb);return  dst;}

大概流程

void xxxxx(){...// 先创建个带有斜体水印的matcv::Mat water;const std::string txt = "12321321";init_water_mark(txt, water)...while (true){ret = av_read_frame(ifmtCtx, pkt);if (ret < 0)goto end;// audioif (pkt->stream_index == aistream) {av_packet_unref(pkt);continue;}// decode encode pktret = avcodec_send_packet(deCodecCtx, pkt);if (ret < 0)goto end;while (ret >= 0) {ret = avcodec_receive_frame(deCodecCtx, frame);if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {break;}else if (ret < 0) {goto end;}// solove [libx264 @ 0x34b88a0] specified frame type (3) at 0 is not compatible with keyframe intervalframe->pict_type = AV_PICTURE_TYPE_NONE;// overlay italic txt infoAVFrame* overlay_frame = overlayItalicTextInfo(frame);if (overlay_frame == nullptr)goto end;ret = encode_frame_to_write_file(enCodecCtx, overlay_frame, pkt, ifmtCtx->streams[vistream]->time_base, ofmtCtx->streams[vostream]->time_base, ofmtCtx);if (ret < 0) {av_frame_free(&overlay_frame);goto end;}av_packet_unref(pkt);av_frame_unref(frame);av_frame_unref(overlay_frame);}#pragma endregionav_packet_unref(pkt);}...}

整理个demo，基于实现的。demo中 需依赖 ，自己搭建个环境即可运行。 demo: 参考文章 ✨​ 总结 ​ 经测试，基于方式，相比较 ，效率至少能提升2倍。(1920 * 1080 i7 6代u) 基于 , 我感觉应该是可以提升效率的，我的想法先创建出来水印，然后重复叠加到每一张frame上就行，但效率总是提升不了，希望哪位大佬有时间能帮忙试试，或者有什么别的好的方式，抱拳了。以上就是我分享的全部内容了，有不对的地方好，欢迎留言指正。有需要的小伙伴，可以参考参考。

最后来个三连，今年就属你最牛逼了 ​