Preparar
ffmpeg 4.4
Un video en bruto en YUV420p
proceso de filtrado
1. Cree un AVFilterGraph para administrar todo el proceso de filtrado
2. Cree filtros de búfer y sumidero de búfer, el búfer es la fuente del filtro y el sumidero de búfer es el punto final del filtro
3. Crear los diversos filtros que necesitamos usar
4.avfilter_link conecta el filtro de acuerdo con el flujo de procesamiento, hay dos líneas de procesamiento en la figura, consulte la siguiente figura
5. Use avfilter_graph_config para verificar la configuración del proceso de filtrado
6. Bucle para leer archivos
7.av_buffersrc_add_frame envía un marco al filtro de búfer
8.av_buffersink_get_frame obtiene datos de fotogramas procesados de buffersink
9. Limpieza después de completar la lectura del archivo
código fuente
#include <stdio.h>
extern "C" {
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
//#include <libavfilter/avfiltergraph.h>
#include <libavfilter/avfilter.h>
#include <libavfilter/buffersink.h>
#include <libavfilter/buffersrc.h>
#include <libavutil/opt.h>
#include <libavutil/imgutils.h>
}
int mainfgdgd(int argc, char** argv)
{
int ret = 0;
// input yuv
FILE* inFile = NULL;
const char* inFileName = "D:/测试工程/sound/yuv420p_1280x720.yuv";
fopen_s(&inFile, inFileName, "rb+");
if (!inFile) {
printf("Fail to open file\n");
return -1;
}
int in_width = 1280;
int in_height = 720;
// output yuv
FILE* outFile = NULL;
const char* outFileName = "D:/测试工程/sound/filter.yuv";
fopen_s(&outFile, outFileName, "wb");
if (!outFile) {
printf("Fail to create file for output\n");
return -1;
}
AVFilterGraph* filter_graph = avfilter_graph_alloc();
if (!filter_graph) {
printf("Fail to create filter graph!\n");
return -1;
}
// source filter
char args[512];
sprintf(args,
"video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
in_width, in_height, AV_PIX_FMT_YUV420P, 1, 30, 1, 1);
printf("%s", args);
AVFilter* bufferSrc = (AVFilter *)avfilter_get_by_name("buffer"); // AVFilterGraph的输入源
AVFilterContext* bufferSrc_ctx;
ret = avfilter_graph_create_filter(&bufferSrc_ctx, bufferSrc, "in", args, NULL, filter_graph);
if (ret < 0) {
printf("Fail to create filter bufferSrc\n");
return -1;
}
// sink filter
//AVBufferSinkParams bufferSink_params;
AVFilterContext* bufferSink_ctx;
AVFilter* bufferSink = (AVFilter*)avfilter_get_by_name("buffersink");
enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE };
// bufferSink_params = av_buffersink_params_alloc();
// bufferSink_params.pixel_fmts = pix_fmts;
ret = avfilter_graph_create_filter(&bufferSink_ctx, bufferSink, "out", NULL, nullptr, filter_graph);
if (ret < 0) {
printf("Fail to create filter sink filter\n");
return -1;
}
// split filter
AVFilter* splitFilter = (AVFilter*)avfilter_get_by_name("split");
AVFilterContext* splitFilter_ctx;
ret = avfilter_graph_create_filter(&splitFilter_ctx, splitFilter, "split", "outputs=2",
NULL, filter_graph);
if (ret < 0) {
printf("Fail to create split filter\n");
return -1;
}
// crop filter
AVFilter* cropFilter = (AVFilter*)avfilter_get_by_name("crop");
AVFilterContext* cropFilter_ctx;
ret = avfilter_graph_create_filter(&cropFilter_ctx, cropFilter, "crop",
"out_w=iw:out_h=ih/2:x=0:y=0", NULL, filter_graph);
if (ret < 0) {
printf("Fail to create crop filter\n");
return -1;
}
// vflip filter
AVFilter* vflipFilter = (AVFilter*)avfilter_get_by_name("vflip");
AVFilterContext* vflipFilter_ctx;
ret = avfilter_graph_create_filter(&vflipFilter_ctx, vflipFilter, "vflip", NULL, NULL, filter_graph);
if (ret < 0) {
printf("Fail to create vflip filter\n");
return -1;
}
// overlay filter
AVFilter* overlayFilter = (AVFilter*)avfilter_get_by_name("overlay");
AVFilterContext* overlayFilter_ctx;
ret = avfilter_graph_create_filter(&overlayFilter_ctx, overlayFilter, "overlay",
"y=0:H/2", NULL, filter_graph);
if (ret < 0) {
printf("Fail to create overlay filter\n");
return -1;
}
// src filter to split filter
ret = avfilter_link(bufferSrc_ctx, 0, splitFilter_ctx, 0);
if (ret != 0) {
printf("Fail to link src filter and split filter\n");
return -1;
}
// split filter's first pad to overlay filter's main pad
ret = avfilter_link(splitFilter_ctx, 0, overlayFilter_ctx, 0);
if (ret != 0) {
printf("Fail to link split filter and overlay filter main pad\n");
return -1;
}
// split filter's second pad to crop filter
ret = avfilter_link(splitFilter_ctx, 1, cropFilter_ctx, 0);
if (ret != 0) {
printf("Fail to link split filter's second pad and crop filter\n");
return -1;
}
// crop filter to vflip filter
ret = avfilter_link(cropFilter_ctx, 0, vflipFilter_ctx, 0);
if (ret != 0) {
printf("Fail to link crop filter and vflip filter\n");
return -1;
}
// vflip filter to overlay filter's second pad
ret = avfilter_link(vflipFilter_ctx, 0, overlayFilter_ctx, 1);
if (ret != 0) {
printf("Fail to link vflip filter and overlay filter's second pad\n");
return -1;
}
// overlay filter to sink filter
ret = avfilter_link(overlayFilter_ctx, 0, bufferSink_ctx, 0);
if (ret != 0) {
printf("Fail to link overlay filter and sink filter\n");
return -1;
}
// check filter graph
ret = avfilter_graph_config(filter_graph, NULL);
if (ret < 0) {
printf("Fail in filter graph\n");
return -1;
}
char* graph_str = avfilter_graph_dump(filter_graph, NULL);
FILE* graphFile = NULL;
fopen_s(&graphFile, "graphFile.txt", "w"); // 打印filtergraph的具体情况
fprintf(graphFile, "%s", graph_str);
av_free(graph_str);
AVFrame* frame_in = av_frame_alloc();
unsigned char* frame_buffer_in = (unsigned char*)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, in_width, in_height, 1));
av_image_fill_arrays(frame_in->data, frame_in->linesize, frame_buffer_in,
AV_PIX_FMT_YUV420P, in_width, in_height, 1);
AVFrame* frame_out = av_frame_alloc();
unsigned char* frame_buffer_out = (unsigned char*)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, in_width, in_height, 1));
av_image_fill_arrays(frame_out->data, frame_out->linesize, frame_buffer_out,
AV_PIX_FMT_YUV420P, in_width, in_height, 1);
frame_in->width = in_width;
frame_in->height = in_height;
frame_in->format = AV_PIX_FMT_YUV420P;
uint32_t frame_count = 0;
while (1) {
// 读取yuv数据
if (fread(frame_buffer_in, 1, in_width * in_height * 3 / 2, inFile) != in_width * in_height * 3 / 2)
{
break;
}
//input Y,U,V
frame_in->data[0] = frame_buffer_in;
frame_in->data[1] = frame_buffer_in + in_width * in_height;
frame_in->data[2] = frame_buffer_in + in_width * in_height * 5 / 4;
if (av_buffersrc_add_frame(bufferSrc_ctx, frame_in) < 0) {
printf("Error while add frame.\n");
break;
}
// filter内部自己处理
/* pull filtered pictures from the filtergraph */
ret = av_buffersink_get_frame(bufferSink_ctx, frame_out);
if (ret < 0)
break;
//output Y,U,V
if (frame_out->format == AV_PIX_FMT_YUV420P)
{
for (int i = 0; i < frame_out->height; i++)
{
fwrite(frame_out->data[0] + frame_out->linesize[0] * i, 1, frame_out->width, outFile);
}
for (int i = 0; i < frame_out->height / 2; i++)
{
fwrite(frame_out->data[1] + frame_out->linesize[1] * i, 1, frame_out->width / 2, outFile);
}
for (int i = 0; i < frame_out->height / 2; i++)
{
fwrite(frame_out->data[2] + frame_out->linesize[2] * i, 1, frame_out->width / 2, outFile);
}
}
++frame_count;
if (frame_count % 25 == 0)
printf("Process %d frame!\n", frame_count);
av_frame_unref(frame_out);
}
fclose(inFile);
fclose(outFile);
av_frame_free(&frame_in);
av_frame_free(&frame_out);
avfilter_graph_free(&filter_graph); // 内部去释放AVFilterContext产生的内存
return 0;
}