FFMPEG打开摄像头
程序员文章站
2022-07-01 10:55:01
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1.由于现使用的DirctShow技术很难用切问题很多，需要了解FFMPEG技术来控制摄像头，在翻阅了雷神（雷霄骅-搞视频音频的别说你不知道哦，他是一代英才！给FFMPEG技术贡献巨大！）的笔记后汇总了一篇基于雷神原型下的重新启动摄像头显示功能；
2.由于本文章为了方便以后在工作中个人使用，所以很多配置细节没有详细说明，如需下载请联系本人；
3.直接贴源码；
#include "stdafx.h"
#include <stdio.h>
#include "libavutil/pixfmt.h"
//#include "libavdevice/avdevice.h"
#define __STDC_CONSTANT_MACROS
#ifdef _WIN32
//Windows
extern "C"
{
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libswscale/swscale.h"
#include "libavdevice/avdevice.h"
#include "SDL/SDL.h"
};
#else
//Linux...
#ifdef __cplusplus
extern "C"
{
#endif
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavdevice/avdevice.h>
#include <SDL/SDL.h>
#ifdef __cplusplus
};
#endif
#endif
//Output YUV420P
#define OUTPUT_YUV420P 0
//'1' Use Dshow
//'0' Use VFW
#define USE_DSHOW 0
//Refresh Event
#define SFM_REFRESH_EVENT (SDL_USEREVENT + 1)
#define SFM_BREAK_EVENT (SDL_USEREVENT + 2)
#define av_frame_alloc avcodec_alloc_frame
int thread_exit=0;
int sfp_refresh_thread(void *opaque)
{
thread_exit=0;
while (!thread_exit) {
SDL_Event event;
event.type = SFM_REFRESH_EVENT;
SDL_PushEvent(&event);
SDL_Delay(40);
}
thread_exit=0;
//Break
SDL_Event event;
event.type = SFM_BREAK_EVENT;
SDL_PushEvent(&event);
return 0;
}
//Show Dshow Device
void show_dshow_device(){
AVFormatContext *pFormatCtx = avformat_alloc_context();
AVDictionary* options = NULL;
av_dict_set(&options,"list_devices","true",0);
AVInputFormat *iformat = av_find_input_format("dshow");
printf("========Device Info=============\n");
avformat_open_input(&pFormatCtx,"video=dummy",iformat,&options);
printf("================================\n");
}
//Show Dshow Device Option
void show_dshow_device_option(){
AVFormatContext *pFormatCtx = avformat_alloc_context();
AVDictionary* options = NULL;
av_dict_set(&options,"list_options","true",0);
AVInputFormat *iformat = av_find_input_format("dshow");
printf("========Device Option Info======\n");
avformat_open_input(&pFormatCtx,"video=Integrated Camera",iformat,&options);
printf("================================\n");
}
//Show VFW Device
void show_vfw_device(){
AVFormatContext *pFormatCtx = avformat_alloc_context();
AVInputFormat *iformat = av_find_input_format("vfwcap");
printf("========VFW Device Info======\n");
avformat_open_input(&pFormatCtx,"list",iformat,NULL);
printf("=============================\n");
}
//Show AVFoundation Device
void show_avfoundation_device(){
AVFormatContext *pFormatCtx = avformat_alloc_context();
AVDictionary* options = NULL;
av_dict_set(&options,"list_devices","true",0);
AVInputFormat *iformat = av_find_input_format("avfoundation");
printf("==AVFoundation Device Info===\n");
avformat_open_input(&pFormatCtx,"",iformat,&options);
printf("=============================\n");
}
int _tmain(int argc, _TCHAR* argv[])
{
AVFormatContext *pFormatCtx;
int i, videoindex;
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
av_register_all();
avformat_network_init();
pFormatCtx = avformat_alloc_context();
//Open File
//char filepath[]="src01_480x272_22.h265";
//avformat_open_input(&pFormatCtx,filepath,NULL,NULL)
//Register Device
avdevice_register_all();
//Windows
#ifdef _WIN32
//Show Dshow Device
show_dshow_device();
//Show Device Options
show_dshow_device_option();
//Show VFW Options
show_vfw_device();
#if USE_DSHOW
AVInputFormat *ifmt=av_find_input_format("dshow");
//Set own video device's name
if(avformat_open_input(&pFormatCtx,"video=Integrated Camera",ifmt,NULL)!=0){
printf("Couldn't open input stream.\n");
return -1;
}
#else
AVInputFormat *ifmt=av_find_input_format("vfwcap");
if(avformat_open_input(&pFormatCtx,"0",ifmt,NULL)!=0){
printf("Couldn't open input stream.\n");
return -1;
}
#endif
#elif defined linux
//Linux
AVInputFormat *ifmt=av_find_input_format("video4linux2");
if(avformat_open_input(&pFormatCtx,"/dev/video0",ifmt,NULL)!=0){
printf("Couldn't open input stream.\n");
return -1;
}
#else
show_avfoundation_device();
//Mac
AVInputFormat *ifmt=av_find_input_format("avfoundation");
//Avfoundation
//[video]:[audio]
if(avformat_open_input(&pFormatCtx,"0",ifmt,NULL)!=0){
printf("Couldn't open input stream.\n");
return -1;
}
#endif
if(avformat_find_stream_info(pFormatCtx,NULL)<0)
{
printf("Couldn't find stream information.\n");
return -1;
}
videoindex=-1;
for(i=0; i<pFormatCtx->nb_streams; i++)
if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO)
{
videoindex=i;
break;
}
if(videoindex==-1)
{
printf("Couldn't find a video stream.\n");
return -1;
}
pCodecCtx=pFormatCtx->streams[videoindex]->codec;
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
if(pCodec==NULL)
{
printf("Codec not found.\n");
return -1;
}
if(avcodec_open2(pCodecCtx, pCodec,NULL)<0)
{
printf("Could not open codec.\n");
return -1;
}
AVFrame *pFrame,*pFrameYUV;
pFrame=av_frame_alloc();
pFrameYUV=av_frame_alloc();
//unsigned char *out_buffer=(unsigned char *)av_malloc(avpicture_get_size(AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height));
//avpicture_fill((AVPicture *)pFrameYUV, out_buffer, AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height);
//SDL----------------------------
if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
printf( "Could not initialize SDL - %s\n", SDL_GetError());
return -1;
}
int screen_w=0,screen_h=0;
SDL_Surface *screen;
screen_w = pCodecCtx->width;
screen_h = pCodecCtx->height;
screen = SDL_SetVideoMode(screen_w, screen_h, 0,0); //show Video
if(!screen) {
printf("SDL: could not set video mode - exiting:%s\n",SDL_GetError());
return -1;
}
SDL_Overlay *bmp;
bmp = SDL_CreateYUVOverlay(pCodecCtx->width, pCodecCtx->height,SDL_YV12_OVERLAY, screen);
SDL_Rect rect;
rect.x = 0;
rect.y = 0;
rect.w = screen_w;
rect.h = screen_h;
//SDL End------------------------
int ret, got_picture;
AVPacket *packet=(AVPacket *)av_malloc(sizeof(AVPacket));
#if OUTPUT_YUV420P
FILE *fp_yuv=fopen("output.yuv","wb+");
#endif
struct SwsContext *img_convert_ctx;
img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height,PIX_FMT_YUV420P,SWS_BICUBIC, NULL, NULL, NULL);
//------------------------------
SDL_Thread *video_tid = SDL_CreateThread(sfp_refresh_thread,NULL);
//
SDL_WM_SetCaption("Simplest FFmpeg Read Camera",NULL);
//Event Loop
SDL_Event event;
for (;;) {
//Wait
SDL_WaitEvent(&event);
if(event.type==SFM_REFRESH_EVENT){
//------------------------------
if(av_read_frame(pFormatCtx, packet)>=0){
if(packet->stream_index==videoindex){
ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
if(ret < 0){
printf("Decode Error.\n");
return -1;
}
if(got_picture){
SDL_LockYUVOverlay(bmp);
pFrameYUV->data[0]=bmp->pixels[0];
pFrameYUV->data[1]=bmp->pixels[2];
pFrameYUV->data[2]=bmp->pixels[1];
pFrameYUV->linesize[0]=bmp->pitches[0];
pFrameYUV->linesize[1]=bmp->pitches[2];
pFrameYUV->linesize[2]=bmp->pitches[1];
sws_scale(img_convert_ctx, (const unsigned char* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameYUV->data, pFrameYUV->linesize);
#if OUTPUT_YUV420P
int y_size=pCodecCtx->width*pCodecCtx->height;
fwrite(pFrameYUV->data[0],1,y_size,fp_yuv); //Y
fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv); //U
fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv); //V
#endif
SDL_UnlockYUVOverlay(bmp);
SDL_DisplayYUVOverlay(bmp, &rect);
}
}
av_free_packet(packet);
}else{
//Exit Thread
thread_exit=1;
}
}else if(event.type==SDL_QUIT){
thread_exit=1;
}else if(event.type==SFM_BREAK_EVENT){
break;
}
}
sws_freeContext(img_convert_ctx);
#if OUTPUT_YUV420P
fclose(fp_yuv);
#endif
SDL_Quit();
//av_free(out_buffer);
av_free(pFrameYUV);
avcodec_close(pCodecCtx);
avformat_close_input(&pFormatCtx);
return 0;
}
注：本人采用罗技摄像头，效果不错；但是鉴于工作中自己开发的305摄像头采集设备还需要再做调整，最终目的废弃DirctShow控制摄像头技术（是在是项目中带来的困扰太多）；
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