ffmpeg v4l2采集摄像头

最新推荐文章于 2024-08-28 16:56:59 发布

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最新推荐文章于 2024-08-28 16:56:59 发布

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/*=============================================================================
#     FileName: read_device.c
#         Desc: use ffmpeg read a frame data from v4l2
#       Author: licaibiao
#   LastChange: 2017-03-15
=============================================================================

最近在学习FFMPEG，发现网上的很多例子都是基于读文件的。直接从摄像头中读取数据的却很少。之前写过通过v4l2采集摄像头数据然后调用x264编码成视频文件的例子。在FFMPEG中，它将很多的V4L2操作函数已经封装好，这里提供一个最简的例程。需要注意的是，我采用的FFMPEG的版本是最新的ffmpeg-3.2.4 版本，不同版本的库，接口函数有有些不一样。

*/
#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 = "test.jpeg";

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\n");
        return;
    }

    if (avformat_open_input ( &fmtCtx, file_name, inputFmt, NULL) < 0){
        printf("can not open_input_file\n");         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\n",packet->size);

    fp = fopen(out_file, "wb");
    if (fp < 0)    {
        printf("open frame data file failed\n");
        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/include/
    INCLUDE = -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/

    FFMPEG_LIBS = -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   = read_device.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 *~ *.jpeg