linux 摄像头v4l2 推流 rtmp 服务器 c语言完整代码

以下是一个使用C语言实现在Linux上通过v4l2摄像头推流到RTMP服务器的完整代码示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/videodev2.h>
#include <libavformat/avformat.h>

#define WIDTH 640
#define HEIGHT 480
#define FRAME_RATE 30
#define BIT_RATE 400000

int main(int argc, char* argv[]) {
    int fd;
    struct v4l2_capability cap;
    struct v4l2_format format;
    struct v4l2_requestbuffers reqbuf;
    struct v4l2_buffer buf;
    void* buffer;
    AVFormatContext* avformat_ctx = NULL;
    AVCodecContext* avcodec_ctx = NULL;
    AVStream* stream = NULL;
    AVCodec* codec = NULL;
    AVPacket packet;
    int frame_count = 0;

    // 打开摄像头设备
    fd = open("/dev/video0", O_RDWR);
    if (fd < 0) {
        perror("Failed to open device");
        return -1;
    }

    // 查询摄像头设备能力
    if (ioctl(fd, VIDIOC_QUERYCAP, &cap) < 0) {
        perror("Failed to query device capabilities");
        close(fd);
        return -1;
    }

    // 设置视频格式
    format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    format.fmt.pix.width = WIDTH;
    format.fmt.pix.height = HEIGHT;
    format.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
    format.fmt.pix.field = V4L2_FIELD_NONE;
    if (ioctl(fd, VIDIOC_S_FMT, &format) < 0) {
        perror("Failed to set video format");
        close(fd);
        return -1;
    }

    // 分配并映射内存用于存储视频帧数据
    reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    reqbuf.memory = V4L2_MEMORY_MMAP;
    reqbuf.count = 1;
    if (ioctl(fd, VIDIOC_REQBUFS, &reqbuf) < 0) {
        perror("Failed to request buffers");
        close(fd);
        return -1;
    }

    memset(&buf, 0, sizeof(buf));
    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    buf.memory = V4L2_MEMORY_MMAP;
    buf.index = 0;
    if (ioctl(fd, VIDIOC_QUERYBUF, &buf) < 0) {
        perror("Failed to query buffer");
        close(fd);
        return -1;
    }

    buffer = mmap(NULL, buf.length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, buf.m.offset);
    if (buffer == MAP_FAILED) {
        perror("Failed to map buffer");
        close(fd);
        return -1;
    }

    // 初始化FFmpeg
    av_register_all();
    avformat_network_init();

    // 创建AVFormatContext
    avformat_ctx = avformat_alloc_context();
    if (!avformat_ctx) {
        fprintf(stderr, "Failed to allocate AVFormatContext\n");
        munmap(buffer, buf.length);
        close(fd);
        return -1;
    }

    // 配置输出格式
    avformat_ctx->oformat = av_guess_format("flv", NULL, NULL);
    if (!avformat_ctx->oformat) {
        fprintf(stderr, "Failed to guess output format\n");
        munmap(buffer, buf.length);
        close(fd);
        return -1;
    }

    // 打开输出URL
    if (avio_open2(&avformat_ctx->pb, "rtmp://your-rtmp-server-url", AVIO_FLAG_WRITE, NULL, NULL) < 0) {
        fprintf(stderr, "Failed to open output URL\n");
        munmap(buffer, buf.length);
        close(fd);
        return -1;
    }

    // 创建视频流
    stream = avformat_new_stream(avformat_ctx, codec);
    if (!stream) {
        fprintf(stderr, "Failed to allocate stream\n");
        avio_close(avformat_ctx->pb);
        avformat_free_context(avformat_ctx);
        munmap(buffer, buf.length);
        close(fd);
        return -1;
    }

    avcodec_ctx = stream->codec;
    avcodec_ctx->codec_id = avformat_ctx->oformat->video_codec;
    avcodec_ctx->codec_type = AVMEDIA_TYPE_VIDEO;
    avcodec_ctx->width = WIDTH;
    avcodec_ctx->height = HEIGHT;
    avcodec_ctx->bit_rate = BIT_RATE;
    avcodec_ctx->time_base.num = 1;
    avcodec_ctx->time_base.den = FRAME_RATE;
    avcodec_ctx->gop_size = 10;
    avcodec_ctx->pix_fmt = AV_PIX_FMT_YUV420P;

    // 初始化视频编码器
    if (avcodec_open2(avcodec_ctx, codec, NULL) < 0) {
        fprintf(stderr, "Failed to open video encoder\n");
        avio_close(avformat_ctx->pb);
        avformat_free_context(avformat_ctx);
        munmap(buffer, buf.length);
        close(fd);
        return -1;
    }

    // 写入文件头
    if (avformat_write_header(avformat_ctx, NULL) < 0) {
        fprintf(stderr, "Failed to write header\n");
        avcodec_close(avcodec_ctx);
        avio_close(avformat_ctx->pb);
        avformat_free_context(avformat_ctx);
        munmap(buffer, buf.length);
        close(fd);
        return -1;
    }

    // 开始视频采集
    if (ioctl(fd, VIDIOC_STREAMON, &buf.type) < 0) {
        perror("Failed to start capture");
        avcodec_close(avcodec_ctx);
        avio_close(avformat_ctx->pb);
        avformat_free_context(avformat_ctx);
        munmap(buffer, buf.length);
        close(fd);
        return -1;
    }

    while (frame_count < 100) {  // 采集100帧
        // 将视频帧数据读取到缓冲区
        memset(&buf, 0, sizeof(buf));
        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf.memory = V4L2_MEMORY_MMAP;
        buf.index = 0;
        if (ioctl(fd, VIDIOC_QBUF, &buf) < 0) {
            perror("Failed to enqueue buffer");
            avcodec_close(avcodec_ctx);
            avio_close(avformat_ctx->pb);
            avformat_free_context(avformat_ctx);
            munmap(buffer, buf.length);
            close(fd);
            return -1;
        }

        if (ioctl(fd, VIDIOC_DQBUF, &buf) < 0) {
            perror("Failed to dequeue buffer");
            avcodec_close(avcodec_ctx);
            avio_close(avformat_ctx->pb);
            avformat_free_context(avformat_ctx);
            munmap(buffer, buf.length);
            close(fd);
            return -1;
        }

        // 将YUYV格式的视频帧转换为YUV420P格式
        uint8_t* yuyv = (uint8_t*)buffer;
        uint8_t* yuv420p = (uint8_t*)av_malloc(WIDTH * HEIGHT * 3 / 2);
        for (int i = 0; i < WIDTH * HEIGHT; i++) {
            int y = yuyv[i * 2];
            int u = yuyv[i * 2 + 1];
            int v = yuyv[i * 2 + 3];
            int r = y + (int)1.402 * (v - 128);
            int g = y - (int)0.344136 * (u - 128) - (int)0.714136 * (v - 128);
            int b = y + (int)1.772 * (u - 128);
            yuv420p[i] = r > 255 ? 255 : (r < 0 ? 0 : r);
            yuv420p[i + WIDTH * HEIGHT] = g > 255 ? 255 : (g < 0 ? 0 : g);
            yuv420p[i + WIDTH * HEIGHT + WIDTH * HEIGHT / 4] = b > 255 ? 255 : (b < 0 ? 0 : b);
        }

        // 编码并写入视频帧
        av_init_packet(&packet);
        packet.data = NULL;
        packet.size = 0;

        AVFrame* frame = av_frame_alloc();
        frame->format = avcodec_ctx->pix_fmt;
        frame->width = avcodec_ctx->width;
        frame->height = avcodec_ctx->height;
        av_frame_get_buffer(frame, 0);
        av_image_fill_arrays(frame->data, frame->linesize, yuv420p,
                             avcodec_ctx->pix_fmt, avcodec_ctx->width, avcodec_ctx->height, 1);

        if (avcodec_encode_video2(avcodec_ctx, &packet, frame, NULL) < 0) {
            fprintf(stderr, "Failed to encode video frame\n");
            av_frame_free(&frame);
            av_free(yuv420p);
            avcodec_close(avcodec_ctx);
            avio_close(avformat_ctx->pb);
            avformat_free_context(avformat_ctx);
            munmap(buffer, buf.length);
            close(fd);
            return -1;
        }

        av_frame_free(&frame);
        av_free(yuv420p);

        packet.stream_index = stream->index;
        packet.pts = packet.dts = frame_count * (avcodec_ctx->time_base.den) / ((avcodec_ctx->time_base.num) * FRAME_RATE);
        packet.duration = (avcodec_ctx->time_base.den) / ((avcodec_ctx->time_base.num) * FRAME_RATE);

        if (av_interleaved_write_frame(avformat_ctx, &packet) < 0) {
            fprintf(stderr, "Failed to write video frame\n");
            av_packet_unref(&packet);
            avcodec_close(avcodec_ctx);
            avio_close(avformat_ctx->pb);
            avformat_free_context(avformat_ctx);
            munmap(buffer, buf.length);
            close(fd);
            return -1;
        }

        av_packet_unref(&packet);

        frame_count++;
    }

    // 结束视频采集
    if (ioctl(fd, VIDIOC_STREAMOFF, &buf.type) < 0) {
        perror("Failed to stop capture");
        avcodec_close(avcodec_ctx);
        avio_close(avformat_ctx->pb);
        avformat_free_context(avformat_ctx);
        munmap(buffer, buf.length);
        close(fd);
        return -1;
    }

    // 写入文件尾
    if (av_write_trailer(avformat_ctx) < 0) {
        fprintf(stderr, "Failed to write trailer\n");
        avcodec_close(avcodec_ctx);
        avio_close(avformat_ctx->pb);
        avformat_free_context(avformat_ctx);
        munmap(buffer, buf.length);
        close(fd);
        return -1;
    }

    // 释放资源
    munmap(buffer, buf.length);
    close(fd);

    avcodec_close(avcodec_ctx);
    avio_close(avformat_ctx->pb);
    avformat_free_context(avformat_ctx);

    return 0;
}

请注意，上述代码只是一个示例，并且可能需要根据您的需求进行适当的修改和调整。您需要将`"rtmp://your-rtmp-server-url"`替换为实际的RTMP服务器URL。此外，还需要确保已经安装了libavformat和libavcodec库，并将编译命令中添加相应的链接选项。

编译和运行此代码可能需要一些额外的设置和依赖项，因此请根据您的环境和需求进行适当的调整。