1 AVFilter ff_vf_blend = {
 2     .name          = "blend",
 3     .description   = NULL_IF_CONFIG_SMALL("Blend two video frames into each other."),
 4     .init          = init,
 5     .uninit        = uninit,
 6     .priv_size     = sizeof(BlendContext),
 7     .query_formats = query_formats,
 8     .inputs        = blend_inputs,
 9     .outputs       = blend_outputs,
10     .priv_class    = &blend_class,
11     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL | AVFILTER_FLAG_SLICE_THREADS,
12 };

  1 #include <stdio.h>
  2  
  3 #define __STDC_CONSTANT_MACROS
  4  
  5 #ifdef _WIN32
  6 #define snprintf _snprintf
  7 //Windows
  8 extern "C"
  9 {
 10 #include "libavfilter/avfiltergraph.h"
 11 #include "libavfilter/buffersink.h"
 12 #include "libavfilter/buffersrc.h"
 13 #include "libavutil/avutil.h"
 14 #include "libavutil/imgutils.h"
 15 #include "libavformat/avformat.h"
 16 };
 17 #else
 18 //Linux...
 19 #ifdef __cplusplus
 20 extern "C"
 21 {
 22 #endif
 23 #include <libavfilter/avfiltergraph.h>
 24 #include <libavfilter/buffersink.h>
 25 #include <libavfilter/buffersrc.h>
 26 #include <libavutil/avutil.h>
 27 #include <libavutil/imgutils.h>
 28 #ifdef __cplusplus
 29 };
 30 #endif
 31 #endif
 32  
 33  
 34 static AVFormatContext *pFormatCtx;
 35 static AVCodecContext *pCodecCtx;
 36 static int video_stream_index = -1;
 37  
 38 AVFilterContext *inputContexts1, *inputContexts2;
 39 AVFilterContext *outputContext;
 40 AVFilterGraph *graph;
 41  
 42 static int init_filter_graph(AVFilterGraph **pGraph, AVFilterContext **pInput1, AVFilterContext **pInput2, AVFilterContext **pOutput)
 43 {
 44     AVFilterGraph* tFilterGraph;
 45     AVFilterContext* tBufferContext1;
 46     AVFilter* tBuffer1;
 47     AVFilterContext* tBufferContext2;
 48     AVFilter* tBuffer2;
 49     AVFilterContext* tOverlayContext;
 50     AVFilter* tOverlay;
 51     AVFilterContext* tBufferSinkContext;
 52     AVFilter* tBufferSink;
 53     AVFilter* tFormat;
 54     AVFilterContext* tFormatContext;
 55  
 56     int tError;
 57  
 58     /* Create a new filtergraph, which will contain all the filters. */
 59     tFilterGraph = avfilter_graph_alloc();
 60     const char *args = "video_size=512x288:pix_fmt=0:time_base=1/30:pixel_aspect=1/1";//这里的参数根据实际视频参数来设置
 61  
 62     if (!tFilterGraph) {
 63         return -1;
 64     }
 65  
 66     { // BUFFER FILTER 1
 67         tBuffer1 = avfilter_get_by_name("buffer");
 68         if (!tBuffer1) {
 69             return -1;
 70         }
 71             int ret = avfilter_graph_create_filter(&tBufferContext1, tBuffer1, "top",
 72                 args, NULL, tFilterGraph);
 73             if (ret < 0) {
 74                 printf("Cannot create buffer source\n");
 75                 return ret;
 76             }
 77     }
 78  
 79     { // BUFFER FILTER 2
 80         tBuffer2 = avfilter_get_by_name("buffer");
 81         if (!tBuffer2) {
 82             return -1;
 83         }
 84         if (1) {
 85  
 86             int ret = avfilter_graph_create_filter(&tBufferContext2, tBuffer2, "bottom",
 87                 args, NULL, tFilterGraph);
 88             if (ret < 0) {
 89                 printf("Cannot create buffer source\n");
 90                 return ret;
 91             }
 92         }
 93     }
 94  
 95     { // BLEND FILTER
 96         tOverlay = avfilter_get_by_name("blend");
 97         if (!tOverlay) {
 98             return -1;
 99         }
100         tOverlayContext = avfilter_graph_alloc_filter(tFilterGraph, tOverlay, "blend");
101         if (!tOverlayContext) {
102             return -1;
103         }
104         AVDictionary *tOptionsDict = NULL;
105         av_dict_set(&tOptionsDict, "all_mode", "normal", 0);
106         av_dict_set(&tOptionsDict, "all_opacity", "1", 0);
107         av_dict_set(&tOptionsDict, "all_expr", "A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))", 0);//详情参见ffmpeg官方文档
108         tError = avfilter_init_dict(tOverlayContext, &tOptionsDict);
109         av_dict_free(&tOptionsDict);
110         if (tError < 0) {
111             return tError;
112         }
113     }
114  
115     { // FORMAT FILTER
116         tFormat = avfilter_get_by_name("format");
117         if (!tFormat) {
118             // Could not find the tFormat filter.
119             return -1;
120         }
121  
122         tFormatContext = avfilter_graph_alloc_filter(tFilterGraph, tFormat, "format");
123         if (!tFormatContext) {
124             // Could not allocate the tFormat instance.
125             return -1;
126         }
127         AVDictionary *tOptionsDict = NULL;
128         av_dict_set(&tOptionsDict, "pix_fmts", "yuv420p", 0);
129         tError = avfilter_init_dict(tFormatContext, &tOptionsDict);
130         av_dict_free(&tOptionsDict);
131         if (tError < 0) {
132             // Could not initialize the tFormat filter.
133             return tError;
134         }
135     }
136  
137     { // BUFFERSINK FILTER
138         tBufferSink = avfilter_get_by_name("buffersink");
139         if (!tBufferSink) {
140             return -1;
141         }
142  
143         tBufferSinkContext = avfilter_graph_alloc_filter(tFilterGraph, tBufferSink, "sink");
144         if (!tBufferSinkContext) {
145             return -1;
146         }
147  
148         tError = avfilter_init_str(tBufferSinkContext, NULL);
149         if (tError < 0) {
150             return tError;
151         }
152     }
153  
154     // Linking graph
155     tError = avfilter_link(tBufferContext1, 0, tOverlayContext, 0);
156     if (tError >= 0)
157     {
158         tError = avfilter_link(tBufferContext2, 0, tOverlayContext, 1);
159     }
160     if (tError >= 0)
161     {
162         tError = avfilter_link(tOverlayContext, 0, tFormatContext, 0);
163     }
164     if (tError >= 0)
165     {
166         tError = avfilter_link(tFormatContext, 0, tBufferSinkContext, 0);
167     }
168     if (tError < 0) { // Error connecting filters.
169         return tError;
170     }
171  
172     tError = avfilter_graph_config(tFilterGraph, NULL);
173     if (tError < 0) {
174         return tError;
175     }
176  
177     *pGraph = tFilterGraph;
178     *pInput1 = tBufferContext1;
179     *pInput2 = tBufferContext2;
180     *pOutput = tBufferSinkContext;
181  
182     return 0;
183 }
184  
185 static int open_input_file(const char *filename)
186 {
187     int ret;
188     AVCodec *dec;
189  
190     if ((ret = avformat_open_input(&pFormatCtx, filename, NULL, NULL)) < 0) {
191         printf("Cannot open input file\n");
192         return ret;
193     }
194  
195     if ((ret = avformat_find_stream_info(pFormatCtx, NULL)) < 0) {
196         printf("Cannot find stream information\n");
197         return ret;
198     }
199  
200     /* select the video stream */
201     ret = av_find_best_stream(pFormatCtx, AVMEDIA_TYPE_VIDEO, -1, -1, &dec, 0);
202     if (ret < 0) {
203         printf("Cannot find a video stream in the input file\n");
204         return ret;
205     }
206     video_stream_index = ret;
207     pCodecCtx = pFormatCtx->streams[video_stream_index]->codec;
208  
209     /* init the video decoder */
210     if ((ret = avcodec_open2(pCodecCtx, dec, NULL)) < 0) {
211         printf("Cannot open video decoder\n");
212         return ret;
213     }
214  
215     return 0;
216 }
217  
218  
219 int main(int argc, char* argv[])
220 {
221     av_register_all();
222     avfilter_register_all();
223  
224     if ((open_input_file("cuc_ieschool.flv")) < 0)
225         return 1;
226  
227     init_filter_graph(&graph,&inputContexts1,&inputContexts2,&outputContext);
228  
229     int ret;
230     AVFrame *frame_in;
231     AVFrame *frame_out;
232     unsigned char *frame_buffer_in;
233     unsigned char *frame_buffer_out;
234      
235     //Input YUV
236     FILE *fp_in=fopen("512x288.yuv","rb+");
237     if(fp_in==NULL){
238         printf("Error open input file.\n");
239         return -1;
240     }
241     //Ouput YUV
242     FILE *fp_yuv = fopen("test.yuv", "wb+");
243     int in_width= 512;
244     int in_height= 288;
245      
246  
247     frame_in=av_frame_alloc();
248     frame_buffer_in=(unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, in_width,in_height,1));
249     av_image_fill_arrays(frame_in->data, frame_in->linesize,frame_buffer_in,
250         AV_PIX_FMT_YUV420P,in_width, in_height,1);
251  
252     frame_in->width=in_width;
253     frame_in->height=in_height;
254     frame_in->format=AV_PIX_FMT_YUV420P;
255  
256     AVPacket packet;
257     AVFrame *pFrame = av_frame_alloc();
258     AVFrame *pFrame_out = av_frame_alloc();
259     int count = 5;//保存的yuv数
260     int readonce = 10;//便于观察，取yuv文件第10副来混合，如果你想混合2个视频，可自行修改，另外注意，blend需要2个Frame意味着如果你需要混合请确保输入满足此要求
261     if (readonce-- > 0) {
262         //get one buffer from yuv.
263         if (fread(frame_buffer_in, 1, in_width*in_height * 3 / 2, fp_in) != in_width*in_height * 3 / 2) {
264             return 1;
265         }
266         //input Y,U,V
267         frame_in->data[0] = frame_buffer_in;
268         frame_in->data[1] = frame_buffer_in + in_width*in_height;
269         frame_in->data[2] = frame_buffer_in + in_width*in_height * 5 / 4;
270     }
271  
272     while (1) {
273         //read one packet.
274         ret = av_read_frame(pFormatCtx, &packet);
275         if (ret< 0)
276             break;
277         if (packet.stream_index == 0) {
278             int got_frame = 0;
279             //decode
280             ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_frame, &packet);
281             if (ret < 0) {
282                 printf("Error decoding video\n");
283                 break;
284             }
285             //success
286             if (got_frame) {
287                 pFrame->pts = av_frame_get_best_effort_timestamp(pFrame);
288                 /* push the decoded frame into the filtergraph */
289                 if (av_buffersrc_add_frame(inputContexts1, pFrame) < 0) {
290                     printf("Error while feeding the filtergraph\n");
291                     break;
292                 }
293                  
294                 frame_in->pts = pFrame->pts;
295                 if (av_buffersrc_add_frame(inputContexts2, frame_in) < 0) {
296                     printf("Error while add frame.\n");
297                     break;
298                 }
299                 /* pull filtered pictures from the filtergraph */
300                 while (1) {
301                     ret = av_buffersink_get_frame(outputContext, pFrame_out);
302                     if (ret < 0)
303                         break;
304                     if (pFrame_out->format == AV_PIX_FMT_YUV420P && count-- > 0) {
305                         //Y, U, V
306                         for (int i = 0; i < pFrame_out->height; i++) {
307                             fwrite(pFrame_out->data[0] + pFrame_out->linesize[0] * i, 1, pFrame_out->width, fp_yuv);
308                         }
309                         for (int i = 0; i < pFrame_out->height / 2; i++) {
310                             fwrite(pFrame_out->data[1] + pFrame_out->linesize[1] * i, 1, pFrame_out->width / 2, fp_yuv);
311                         }
312                         for (int i = 0; i < pFrame_out->height / 2; i++) {
313                             fwrite(pFrame_out->data[2] + pFrame_out->linesize[2] * i, 1, pFrame_out->width / 2, fp_yuv);
314                         }
315                         printf("Process 1 frame!\n");
316                     }
317                     av_frame_unref(pFrame_out);
318                 }
319             }
320             av_frame_unref(pFrame);
321         }
322         av_free_packet(&packet);
323     }
324  
325     fclose(fp_in);
326     fclose(fp_yuv);
327  
328     av_frame_free(&pFrame);
329     av_frame_free(&pFrame_out);
330     av_frame_free(&frame_in);
331     avfilter_graph_free(&graph);
332  
333     return 0;
334 }