使用ffmepg实现多路视频流合并 |
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使用ffmepg实现多路视频流合并
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首先说明需要用到的ffmpeg对象，以及一些必要的字段。 ffmpeg版本： version 4.3 所用到的头文件： #include #include #include需要的数据结构如下： 每一条输入流需要如下的字段 typedef struct Stream{ int x; int y; int width; int height; int format;//参考AVPixelFormat AVFilterContext* buffersrc_ctx; AVFilter* buffersrc; AVFilterInOut* output; AVFrame* inputFrame; } Stream;输出流需要如下字段 typedef struct Merge { AVFilterGraph* filter_graph; AVFilterContext* buffersink_ctx; AVFilter* buffersink; AVFilterInOut* input; const char* filters_descr; AVFrame* outputFrame; unsigned char* outputBuffer; int outputWidth; int outputHeight; int outputFormat;//参考AVPixelFormat Stream *streams[128]; int streamCount; } Merge;主要流程如下： 1、构造输出流及输入流 构造输出流，输出流需要设置分辨率以及输出的像素格式 Merge* Merge_Create(int outputWidth, int outputHeight, int outputFormat) { Merge* merge = malloc(sizeof(Merge)); memset(merge, 0, sizeof(Merge)); merge->outputWidth = outputWidth; merge->outputHeight = outputHeight; merge->outputFormat = outputFormat; return merge; }添加输入流，输入流需要设置在输出流中的位置和大小，以及输入流像素格式 Stream* Merge_AddStream(Merge* merge, int x, int y, int width, int height, int format) { Stream* stream = malloc(sizeof(Stream)); memset(merge, 0, sizeof(Stream)); stream->x = x; stream->y = y; stream->width = width; stream->height = height; stream->format = format; merge->streams[merge->streamCount++] = stream; return stream; }本文福利， 免费领取C++音视频学习资料包、技术视频/代码，内容包括（音视频开发，面试题，FFmpeg ，webRTC ，rtmp ，hls ，rtsp ，ffplay ，编解码，推拉流，srs）↓↓↓↓↓↓见下面↓↓文章底部点击免费领取↓↓ 2、初始化滤镜 主要用到的滤镜是filters_descr = "[in0]pad=1280:640:0:0:black[x0];[x0][in1]overlay=640:0[x1];[x1][in2]overlay=600:0[x2];[x2]null[out]"; //初始化Merge int Merge_Init(Merge* merge) { char args[512]; char name[8]; char* filters_descr = NULL; int ret; //avfilter_register_all();//旧版可能用到此行 merge->buffersink = avfilter_get_by_name("buffersink"); av_assert0(merge->buffersink); merge->input = avfilter_inout_alloc(); if (merge->input == NULL) { printf("alloc inout fail\n"); goto fail; } merge->filter_graph = avfilter_graph_alloc(); if (merge->input == NULL) { printf("alloc graph fail\n"); goto fail; } ret = avfilter_graph_create_filter(&merge->buffersink_ctx, merge->buffersink, "out", NULL, NULL, merge->filter_graph); if (ret < 0) { printf("graph create fail\n"); goto fail; } merge->input->name = av_strdup("out"); merge->input->filter_ctx = merge->buffersink_ctx; merge->input->pad_idx = 0; merge->input->next = NULL; merge->outputFrame = av_frame_alloc(); if (merge->outputFrame == NULL) { printf("alloc frame fail\n"); goto fail; } merge->outputBuffer = (unsigned char*)av_malloc(av_image_get_buffer_size(merge->outputFormat, merge->outputWidth, merge->outputHeight, 1)); if (merge->outputBuffer == NULL) { printf("alloc buffer fail\n"); goto fail; } enum AVPixelFormat pix_fmts[2] = { 0, AV_PIX_FMT_NONE }; pix_fmts[0] = merge->outputFormat; ret = av_opt_set_int_list(merge->buffersink_ctx, "pix_fmts", pix_fmts, AV_PIX_FMT_NONE, AV_OPT_SEARCH_CHILDREN); if (ret < 0) { printf("set opt fail\n"); goto fail; } Stream** streams = merge->streams; for (int i = 0; i < merge->streamCount; i++) { streams[i]->buffersrc = avfilter_get_by_name("buffer"); av_assert0(streams[i]->buffersrc); snprintf(args, sizeof(args), "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d", streams[i]->width, streams[i]->height, streams[i]->format, 1, 90000, 1, 1); snprintf(name, sizeof(name), "in%d", i); ret = avfilter_graph_create_filter(&streams[i]->buffersrc_ctx, streams[i]->buffersrc, name, args, NULL, merge->filter_graph); if (ret < 0) { printf("stream graph create fail\n"); goto fail; } streams[i]->output = avfilter_inout_alloc(); streams[i]->output->name = av_strdup(name); streams[i]->output->filter_ctx = streams[i]->buffersrc_ctx; streams[i]->output->pad_idx = 0; streams[i]->output->next = NULL; streams[i]->inputFrame = av_frame_alloc(); if (streams[i]->inputFrame == NULL) { printf("alloc frame fail\n"); goto fail; } streams[i]->inputFrame->format = streams[i]->format; streams[i]->inputFrame->width = streams[i]->width; streams[i]->inputFrame->height = streams[i]->height; if (i > 0) { streams[i - 1]->output->next = streams[i]->output; } } /*filters_descr = "[in0]pad=1280:640:0:0:black[x0];[x0][in1]overlay=640:0[x1];[x1][in2]overlay=600:0[x2];[x2]null[out]";*/ filters_descr = malloc(sizeof(char) * merge->streamCount * 128); if (filters_descr == NULL) { printf("alloc string fail\n"); goto fail; } char sigle_descr[128]; snprintf(sigle_descr, sizeof(sigle_descr), "[in0]pad=%d:%d:%d:%d:black[x0];", merge->outputWidth, merge->outputHeight, streams[0]->x, streams[0]->y); strcpy(filters_descr, sigle_descr); int i = 1; for (; i < merge->streamCount; i++) { snprintf(sigle_descr, sizeof(sigle_descr), "[x%d][in%d]overlay=%d:%d[x%d];", i - 1, i, streams[i]->x, streams[i]->y, i); strcat(filters_descr, sigle_descr); } snprintf(sigle_descr, sizeof(sigle_descr), "[x%d]null[out]", i - 1); strcat(filters_descr, sigle_descr); ret = avfilter_graph_parse_ptr(merge->filter_graph, filters_descr, &merge->input, &streams[0]->output, NULL); if (ret < 0) { printf("graph parse fail\n"); goto fail; } // 过滤配置初始化 ret = avfilter_graph_config(merge->filter_graph, NULL); if (ret < 0) { printf("graph config fail\n"); goto fail; } if (filters_descr != NULL) free(filters_descr); return 0; fail: if (filters_descr != NULL) free(filters_descr); Merge_Deinit(merge); //执行反初始化 return -1; }3、写输入流 void Merge_WriteStream(Merge* merge, Stream* stream, const unsigned char* buffer, int timestamp) { av_image_fill_arrays(stream->inputFrame->data, stream->inputFrame->linesize, buffer, stream->format, stream->width, stream->height, 1); stream->inputFrame->pts = timestamp; if (av_buffersrc_write_frame(stream->buffersrc_ctx, stream->inputFrame) < 0) { printf("Error while add frame.\n"); } }4、合并流 调用下列方法，即可得到合并后的一帧的数据。可以按照一定帧率调用3、4方法。 const unsigned char* Merge_Merge(Merge* merge) { int ret = av_buffersink_get_frame(merge->buffersink_ctx, merge->outputFrame); if (ret < 0) { printf("Error while get frame.\n"); return NULL; } av_image_copy_to_buffer(merge->outputBuffer, av_image_get_buffer_size(merge->outputFormat, merge->outputWidth, merge->outputHeight, 1), merge->outputFrame->data, merge->outputFrame->linesize, merge->outputFrame->format, merge->outputFrame->width, merge->outputFrame->height, 1); av_frame_unref(merge->outputFrame); return merge->outputBuffer; }5、结束，反初始化，销毁对象 static void Merge_Deinit(Merge* merge) { if (merge->input != NULL) avfilter_inout_free(&merge->input); if (merge->filter_graph != NULL) avfilter_graph_free(&merge->filter_graph); if (merge->outputFrame != NULL) av_frame_free(&merge->outputFrame); if (merge->outputBuffer != NULL) av_free(merge->outputBuffer); for (int i = 0; i < merge->streamCount; i++) { Stream* stream = merge->streams[i]; if (stream->inputFrame != NULL) av_frame_free(&stream->inputFrame); free(stream); } merge->streamCount = 0; } void Merge_Destroy(Merge* merge) { Merge_Deinit(merge); free(merge); }调用流程示例： int main() { int flag = 1; Merge* merge = Merge_Create(1920, 1080, 0); Stream* stream1 = Merge_AddStream(merge, 0, 0, 960, 540, 0); Stream* stream2 = Merge_AddStream(merge, 960, 540, 960, 540, 0); Stream* stream3 = Merge_AddStream(merge, 0, 540, 960, 540, 0); if (Merge_Init(merge) != 0) { Merge_Destroy(merge); return -1; } while (flag) { clock_t time = clock(); unsigned char* buffer1; unsigned char* buffer2; unsigned char* buffer3; //获取每路流的数据 ... //获取每路流的数据-end Merge_WriteStream(merge, stream1, buffer1, time); Merge_WriteStream(merge, stream2, buffer2, time); Merge_WriteStream(merge, stream3, buffer3, time); unsigned char* mergedBuffer = Merge_Merge(merge); //显示或编码推流 ... //显示或编码推流-end } Merge_Destroy(merge); }需要注意的是上述方法最好在单线程中使用，多线程使用可能需要另外做修改。 效果如下
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