使用ffmpeg 的 filter 给图片添加水印。
main.c

#include <stdio.h>#include <libavfilter/avfilter.h>
#include <libavfilter/buffersrc.h>
#include <libavfilter/buffersink.h>
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>AVFilterContext* mainsrc_ctx = NULL;
AVFilterContext* logosrc_ctx = NULL;
AVFilterContext* resultsink_ctx = NULL;
AVFilterGraph* filter_graph = NULL;//初始化过滤器处理
static int init_filters(const AVFrame* main_frame, const AVFrame* logo_frame, int x, int y)
{int ret = 0;AVFilterInOut* inputs = NULL;AVFilterInOut* outputs = NULL;char filter_args[1024] = {0};//初始化用于整个过滤处理的封装filter_graph = avfilter_graph_alloc();if(!filter_graph){printf("%d : avfilter_graph_alloc() failed!\n", __LINE__);return -1;}//所有使用到过滤器处理的命令snprintf(filter_args, sizeof(filter_args),"buffer=video_size=%dx%d:pix_fmt=%d:time_base=1/25:pixel_aspect=%d/%d[main];" // Parsed_buffer_0"buffer=video_size=%dx%d:pix_fmt=%d:time_base=1/25:pixel_aspect=%d/%d[logo];" // Parsed_bufer_1"[main][logo]overlay=%d:%d[result];" // Parsed_overlay_2"[result]buffersink", // Parsed_buffer_sink_3main_frame->width, main_frame->height, main_frame->format, main_frame->sample_aspect_ratio.num, main_frame->sample_aspect_ratio.den,logo_frame->width, logo_frame->height, logo_frame->format, logo_frame->sample_aspect_ratio.num, logo_frame->sample_aspect_ratio.den,x, y);//添加过滤器处理到AVFilterGraphret = avfilter_graph_parse2(filter_graph, filter_args, &inputs, &outputs);if(ret < 0){printf("%d : avfilter_graph_parse2() failed!\n", __LINE__);return ret;}//配置AVFilterGraph的过滤器处理ret = avfilter_graph_config(filter_graph, NULL);if(ret < 0){printf("%d : avfilter_graph_config() failed!\n", __LINE__);return ret;}//获取AVFilterGraph内的过滤器mainsrc_ctx = avfilter_graph_get_filter(filter_graph, "Parsed_buffer_0");logosrc_ctx = avfilter_graph_get_filter(filter_graph, "Parsed_buffer_1");resultsink_ctx = avfilter_graph_get_filter(filter_graph, "Parsed_buffersink_3");avfilter_inout_free(&inputs);avfilter_inout_free(&outputs);return 0;
}//添加水印
static int main_mix_logo(AVFrame* main_frame, AVFrame* logo_frame, AVFrame *result_frame)
{int ret = 0;//添加主图ret = av_buffersrc_add_frame(mainsrc_ctx, main_frame);if(ret < 0)return ret;//添加logoret = av_buffersrc_add_frame(logosrc_ctx, logo_frame);if(ret < 0)return ret;//获取合成图ret = av_buffersink_get_frame(resultsink_ctx, result_frame);return ret;}static AVFrame* get_jpeg(const char* filename)
{int ret = 0;AVFormatContext* format_ctx = NULL;//打开文件if((ret = avformat_open_input(&format_ctx, filename, NULL, NULL)) != 0){printf("%d : avformat_open_input() failed!\n");return NULL;}//获取媒体文件信息avformat_find_stream_info(format_ctx, NULL);AVCodec* codec = NULL;AVCodecContext* codec_ctx = NULL;int video_stream_index = -1;//获取流video_stream_index = av_find_best_stream(format_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &codec, 0);if(video_stream_index < 0)goto cleanup;codec_ctx = avcodec_alloc_context3(codec);//关联解码器上下文ret = avcodec_open2(codec_ctx, codec, NULL);if(ret < 0)goto cleanup;AVPacket pkt;av_init_packet(&pkt);pkt.data = NULL;pkt.size = 0;//从文件中读一帧ret = av_read_frame(format_ctx, &pkt);if(ret < 0)goto cleanup;//进行解码ret = avcodec_send_packet(codec_ctx, &pkt);if(ret < 0)goto cleanup;//AVFrame* frame = av_frame_alloc();ret = avcodec_receive_frame(codec_ctx, frame);if(ret < 0)av_frame_free(&frame);cleanup:if(format_ctx)avformat_close_input(&format_ctx);if(codec_ctx)avcodec_free_context(&codec_ctx);return frame;
}static int savejpeg(const char* filename, const AVFrame* frame)
{//查找相应编码器AVCodec* jpeg_codec = avcodec_find_encoder(AV_CODEC_ID_MJPEG);if(!jpeg_codec)return -1;AVCodecContext* jpeg_codec_ctx = avcodec_alloc_context3(jpeg_codec);if(!jpeg_codec_ctx)return -2;//设置jpeg相关参数jpeg_codec_ctx->pix_fmt = AV_PIX_FMT_YUVJ420P;jpeg_codec_ctx->width = frame->width;jpeg_codec_ctx->height = frame->height;jpeg_codec_ctx->time_base.num = 1;jpeg_codec_ctx->time_base.den = 25;jpeg_codec_ctx->framerate.num = 25;jpeg_codec_ctx->framerate.den = 1;AVDictionary* encoder_opts = NULL;//encoder_opts 为空就会分配内存的av_dict_set(&encoder_opts, "flags", "+qscale", 0);av_dict_set(&encoder_opts, "qmax", "2", 0);av_dict_set(&encoder_opts, "qmin", "2", 0);int ret = avcodec_open2(jpeg_codec_ctx, jpeg_codec, &encoder_opts);if(ret < 0){avcodec_free_context(&jpeg_codec_ctx);printf("%d : avcodec_open2() failed!\n");return -3;}av_dict_free(&encoder_opts);AVPacket pkt;av_init_packet(&pkt);pkt.data = NULL;pkt.size = 0;//编码ret = avcodec_send_frame(jpeg_codec_ctx, frame);if(ret < 0){avcodec_free_context(&jpeg_codec_ctx);printf("%d : avcodec_send_frame() failed!\n");return -4;}ret = 0;while(ret >= 0){//得到编码数据ret = avcodec_receive_packet(jpeg_codec_ctx, &pkt);if(ret == AVERROR(EAGAIN))continue;if(ret == AVERROR_EOF){ret = 0;break;}FILE* outfile = fopen(filename, "wb");if(!outfile){printf("%d : fopen() failed!\n");ret = -1;break;}//写入文件if(fwrite((char*)pkt.data, 1, pkt.size, outfile) == pkt.size){ret = 0;}else{printf("%d : fwrite failed!\n");ret = -1;}fclose(outfile);ret = 0;break;}avcodec_free_context(&jpeg_codec_ctx);return ret;
}int main()
{printf("Hello watermarkmix!\n");AVFrame *main_frame = get_jpeg("main.jpg");AVFrame *logo_frame = get_jpeg("logo.jpg");AVFrame* result_frame = av_frame_alloc();int ret = 0;if(ret = init_filters(main_frame, logo_frame, 100, 200) < 0) {printf("%d : init_filters failed\n", __LINE__);goto end;}if(main_mix_logo(main_frame, logo_frame, result_frame) < 0) {printf("%d : main_picture_mix_logo failed\n", __LINE__);goto end;}savejpeg("output.jpg", result_frame);
end:if(main_frame)av_frame_free(&main_frame);if(logo_frame)av_frame_free(&logo_frame);if(result_frame)av_frame_free(&result_frame);if(filter_graph)avfilter_graph_free(&filter_graph);printf("finish\n");printf("End watermarkmix!\n");return 0;
}