0. 进行本代码实验的前提
确保已经在ubuntu内正确安装了ffmpeg
手把手安装教程可以参考我的另一篇博文《音视频入门-4-ffmpeg命令快速体验音视频开发/ ffmpeg编译过程经历的99八十一难》
https://www.cnblogs.com/happybirthdaytoyou/p/14256260.html
1. 直接上代码
readdevice.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include "avformat.h"
#include "avcodec.h"
#include "avdevice.h"
char* input_name = "video4linux2";
char* file_name = "/dev/video0";
char* out_file = "picture";
void captureOneFrame(void){
AVFormatContext *fmtCtx = NULL;
AVPacket *packet;
AVInputFormat *inputFmt;
FILE *fp;
int ret;
inputFmt = av_find_input_format(input_name);
if (inputFmt == NULL) {
printf("can not find_input_format
");
return;
}
if (avformat_open_input( &fmtCtx, file_name, inputFmt, NULL) < 0){
printf("can not open_input_file
"); return;
}
/* print device information*/
av_dump_format(fmtCtx, 0, file_name, 0);
packet = (AVPacket *)av_malloc(sizeof(AVPacket));
av_read_frame(fmtCtx, packet);
printf("data length = %d
",packet->size);
fp = fopen(out_file, "wb");
if (fp < 0) {
printf("open frame data file failed
");
return ;
}
fwrite(packet->data, 1, packet->size, fp);
fclose(fp);
av_free_packet(packet);
avformat_close_input(&fmtCtx);
}
int main(void){
avcodec_register_all();
avdevice_register_all();
captureOneFrame();
return 0;
}
makefile:
OUT_APP = test
INCLUDE_PATH = /usr/local/ffmpeg/include/
INCLUDE = -I$(INCLUDE_PATH) -I$(INCLUDE_PATH)libavutil/ -I$(INCLUDE_PATH)libavdevice/
-I$(INCLUDE_PATH)libavcodec/ -I$(INCLUDE_PATH)libswresample
-I$(INCLUDE_PATH)libavfilter/ -I$(INCLUDE_PATH)libavformat
-I$(INCLUDE_PATH)libswscale/
LIB_PATH = /usr/local/ffmpeg/lib/
FFMPEG_LIBS = -L$(LIB_PATH) -lavformat -lavutil -lavdevice -lavcodec -lswresample -lavfilter -lswscale
SDL_LIBS =
LIBS = $(FFMPEG_LIBS)$(SDL_LIBS)
COMPILE_OPTS = $(INCLUDE)
C = c
OBJ = o
C_COMPILER = cc
C_FLAGS = $(COMPILE_OPTS) $(CPPFLAGS) $(CFLAGS)
LINK = cc -o
LINK_OPTS = -lz -lm -lpthread
LINK_OBJ = readdevice.o
.$(C).$(OBJ):
$(C_COMPILER) -c -g $(C_FLAGS) $<
$(OUT_APP): $(LINK_OBJ)
$(LINK)$@ $(LINK_OBJ) $(LIBS) $(LINK_OPTS)
clean:
-rm -rf *.$(OBJ) $(OUT_APP) core *.core *~ picture
2.
输出的图片格式是依你使用的电脑摄像头硬件决定的,每个人可能都不一样。
.