OpenCV进行RTSP推流

发表于 更新于

OpenCV进行RTSP推流

1 概述

将 OpenCV 处理后的图像直接进行 RTSP 推流，支持多种实现方案。

2 测试命令

2.1 推流本地文件

1
gst-launch-1.0 filesrc location=D:\5.mp4 ! decodebin ! videoconvert ! x264enc ! rtspclientsink location=rtsp://127.0.0.1:8554/live

2.2 播放推流内容

1
gst-launch-1.0 rtspsrc location=rtsp://127.0.0.1:8554/live ! rtph264depay ! h264parse ! avdec_h264 ! autovideosink

3 方案一：GStreamer推流

3.1 核心代码

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
#include <gst/gst.h>
#include <gst/app/gstappsrc.h>
#include <opencv2/opencv.hpp>

#define RTSP_SERVER_URL "rtsp://127.0.0.1:8554/live"
#define CAPTURE_WIDTH 640
#define CAPTURE_HEIGHT 480
#define CAPTURE_FPS 30
#define FRAME_INTERVAL_MS (1000 / CAPTURE_FPS)

int main(int argc, char* argv[]) 
{
    // 初始化GStreamer
    gst_init(&argc, &argv);
    std::cout << "3e" << std::endl;
    
    // 创建管道
    GstElement* pipeline = gst_pipeline_new("rtsp-pipeline");
    GstElement* appsrc = gst_element_factory_make("appsrc", "app-source");
    GstElement* videoconvert = gst_element_factory_make("videoconvert", "convert");
    GstElement* x264enc = gst_element_factory_make("x264enc", "encoder");
    GstElement* rtph264pay = gst_element_factory_make("rtph264pay", "payloader");
    GstElement* rtspclientsink = gst_element_factory_make("rtspclientsink", "sink");

    // 配置appsrc
    g_object_set(G_OBJECT(appsrc), "is-live", TRUE, NULL);
    g_object_set(G_OBJECT(appsrc), "format", GST_FORMAT_TIME, NULL);
    g_object_set(G_OBJECT(appsrc), "caps", gst_caps_new_simple("video/x-raw",
        "format", G_TYPE_STRING, "BGR",
        "width", G_TYPE_INT, CAPTURE_WIDTH,
        "height", G_TYPE_INT, CAPTURE_HEIGHT,
        "framerate", GST_TYPE_FRACTION, CAPTURE_FPS, 1,
        NULL), NULL);

    // 添加元素到管道
    gst_bin_add_many(GST_BIN(pipeline), appsrc, videoconvert, x264enc, rtph264pay, rtspclientsink, NULL);

    // 连接元素
    gst_element_link_many(appsrc, videoconvert, x264enc, rtph264pay, rtspclientsink, NULL);

    // 配置RTSP目标地址
    g_object_set(G_OBJECT(rtspclientsink), "location", RTSP_SERVER_URL, NULL);

    // 启动管道
    gst_element_set_state(pipeline, GST_STATE_PLAYING);

    // 打开摄像头
    cv::VideoCapture cap(0);
    if (!cap.isOpened()) {
        std::cerr << "Error: Unable to open camera." << std::endl;
        return -1;
    }

    // 推流循环
    while (true)
    {
        cv::Mat frame;
        cap >> frame;
        if (frame.empty()) {
            std::cerr << "Warning: Empty frame." << std::endl;
            continue;
        }

        // 打印时间戳（精确到毫秒）
        std::chrono::system_clock::time_point now = std::chrono::system_clock::now();
        auto t = std::chrono::system_clock::to_time_t(now);
        auto tp = std::chrono::system_clock::from_time_t(t);
        auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(now - tp).count();
        auto in_time_t = std::chrono::system_clock::to_time_t(now);
        std::cout << std::put_time(std::localtime(&in_time_t), "%Y-%m-%d %X") << "." << ms << std::endl;

        // 创建GStreamer缓冲区
        GstBuffer* buffer = gst_buffer_new_allocate(NULL, frame.total() * frame.elemSize(), NULL);
        GstMapInfo map;
        gst_buffer_map(buffer, &map, GST_MAP_WRITE);
        memcpy(map.data, frame.data, frame.total() * frame.elemSize());
        gst_buffer_unmap(buffer, &map);

        // 推送缓冲区
        GstFlowReturn ret;
        g_signal_emit_by_name(appsrc, "push-buffer", buffer, &ret);
        gst_buffer_unref(buffer);

        // 控制帧率
        g_usleep(FRAME_INTERVAL_MS * 1000);
    }

    // 清理资源
    gst_element_set_state(pipeline, GST_STATE_NULL);
    gst_object_unref(pipeline);

    return 0;
}

3.2 流程说明

步骤 操作
1 初始化 GStreamer
2 创建管道和元素（appsrc → videoconvert → x264enc → rtph264pay → rtspclientsink）
3 配置 appsrc 参数（分辨率、帧率、格式）
4 启动管道
5 循环读取摄像头帧并推送

4 方案二：FFmpeg推流

4.1 头文件

1
2
3
#include "rtspencoder.h"
#include <QCoreApplication>
#include <QDebug>

4.2 类定义

1
2
3
4
5
6
7
8
9
10
RTSPEncoder::RTSPEncoder(const char* rtspUrl, int outputWidth, int outputHeight, QObject* parent)
    : QThread(parent), m_rtspUrl(rtspUrl), m_outputWidth(outputWidth), m_outputHeight(outputHeight)
{

}

RTSPEncoder::~RTSPEncoder()
{
    cleanup();
}

4.3 初始化

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
int RTSPEncoder::initialize()
{
    avformat_network_init();

    // 初始化输出上下文
    m_outFormatCtx = nullptr;
    avformat_alloc_output_context2(&m_outFormatCtx, nullptr, "rtsp", m_rtspUrl.c_str());
    if (!m_outFormatCtx) 
    {
        std::cerr << "Error: Failed to allocate output context\n";
        return -1;
    }

    // 查找H264编码器
    m_codec = (AVCodec*)avcodec_find_encoder(AV_CODEC_ID_H264);
    if (!m_codec) {
        std::cerr << "Error: Failed to find H264 encoder\n";
        return -1;
    }

    // 添加视频流
    m_outStream = avformat_new_stream(m_outFormatCtx, m_codec);
    if (!m_outStream) {
        std::cerr << "Error: Failed to create new stream\n";
        return -1;
    }

    // 初始化编码器上下文
    m_codecCtx = avcodec_alloc_context3(m_codec);
    if (!m_codecCtx) {
        std::cerr << "Error: Failed to allocate codec context\n";
        return -1;
    }
    m_codecCtx->codec_id = AV_CODEC_ID_H264;
    m_codecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
    m_codecCtx->pix_fmt = AV_PIX_FMT_YUV420P;
    m_codecCtx->width = m_outputWidth;
    m_codecCtx->height = m_outputHeight;
    m_codecCtx->time_base = { 1, 25 };  // 25fps
    m_codecCtx->bit_rate = 700000;
    m_codecCtx->gop_size = 10;
    m_codecCtx->max_b_frames = 0;
    m_codecCtx->flags = AV_CODEC_FLAG_GLOBAL_HEADER | AV_CODEC_FLAG_LOW_DELAY;

    // 配置编码器选项
    AVDictionary* codecOptions = nullptr;
    av_dict_set(&codecOptions, "preset", "ultrafast", 0);
    av_dict_set(&codecOptions, "tune", "zerolatency", 0);

    // 打开编码器
    if (avcodec_open2(m_codecCtx, m_codec, &codecOptions) < 0) {
        std::cerr << "Error: Failed to open encoder\n";
        return -1;
    }

    // 复制编码器参数到输出流
    avcodec_parameters_from_context(m_outStream->codecpar, m_codecCtx);

    // 写入流头部
    avformat_write_header(m_outFormatCtx, nullptr);

    m_frame.create(m_outputHeight, m_outputWidth, CV_8UC3);
    m_frame.setTo(0);
    m_frameCount = 0;

    m_avFrame = av_frame_alloc();

    return 0;
}

4.4 编码与发送

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
void RTSPEncoder::encodeFrameAndSend()
{
    while (1)
    {
        // 阻塞等待新帧
        {
            std::unique_lock<std::mutex> lock(mtx);

            while (!m_isReady) {
                m_cv.wait(lock);
            }
            m_isReady = false;

            // 转换颜色空间 BGR → I420
            cv::cvtColor(m_frame, m_im420, cv::COLOR_RGB2YUV_I420);

            // 配置AVFrame
            m_avFrame->data[0] = m_im420.data;
            m_avFrame->data[1] = m_avFrame->data[0] + m_codecCtx->width * m_codecCtx->height;
            m_avFrame->data[2] = m_avFrame->data[1] + m_codecCtx->width * m_codecCtx->height / 4;
            m_avFrame->linesize[0] = m_codecCtx->width;
            m_avFrame->linesize[1] = m_codecCtx->width / 2;
            m_avFrame->linesize[2] = m_codecCtx->width / 2;
            m_avFrame->width = m_codecCtx->width;
            m_avFrame->height = m_codecCtx->height;
            m_avFrame->format = AV_PIX_FMT_YUV420P;
            m_avFrame->pts = m_frameCount++;

            // 发送帧到编码器
            auto ret = avcodec_send_frame(m_codecCtx, m_avFrame);
            if (ret < 0)
            {
                std::cerr << "Error: Failed to send frame for encoding\n";
                return;
            }

            // 接收编码后的数据包
            AVPacket pkt;
            av_init_packet(&pkt);
            while (ret >= 0)
            {
                ret = avcodec_receive_packet(m_codecCtx, &pkt);
                if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
                {
                    break;
                }
                else if (ret < 0)
                {
                    std::cout << "Error: Failed to receive encoded packet\n";
                    continue;
                }
                pkt.stream_index = m_outStream->index;
                av_packet_rescale_ts(&pkt, m_codecCtx->time_base, m_outStream->time_base);
                ret = av_interleaved_write_frame(m_outFormatCtx, &pkt);
                av_packet_unref(&pkt);

                if (ret < 0)
                {
                    std::cout << "Error: Failed to write packet to output stream\n";
                    continue;
                }
            }
        }
    }
}

4.5 添加帧

1
2
3
4
5
6
7
8
9
10
11
12
13
14
void RTSPEncoder::AddFrame(cv::Mat& imGBR, int nFrame)
{
    if (imGBR.cols != m_outputWidth || imGBR.rows != m_outputHeight)
        return;

    // 阻塞等待编码
    {
        std::lock_guard<std::mutex> lock(mtx);
        memcpy(m_frame.data, imGBR.data, imGBR.cols * imGBR.rows * 3);
        m_frameCount = nFrame;
        m_isReady = true;
    }
    m_cv.notify_one();
}

4.6 资源清理

1
2
3
4
5
6
7
8
9
10
11
12
13
void RTSPEncoder::cleanup()
{
    // 写入尾部
    av_write_trailer(m_outFormatCtx);

    // 释放资源
    if(m_codecCtx)
        avcodec_free_context(&m_codecCtx);
    if(m_avFrame)
        av_frame_free(&m_avFrame);
    if(m_outFormatCtx)
        avformat_free_context(m_outFormatCtx);
}

5 方案三：OpenCV GStreamer后端

5.1 推流代码

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
void push()
{
    int codec = cv::VideoWriter::fourcc('H', 'E', 'V', 'C');
    m_writer.open(push_str, codec, fps, cv::Size(width, height));

    cv::Mat tmp;
    while (true)
    {
        {
            std::unique_lock<std::mutex> lk(proc2push_mtx);
            proc2push_cv.wait(lk);
            tmp = img_push.clone();
        }

        if (!m_writer.isOpened())
        {
            int codec = cv::VideoWriter::fourcc('H', 'E', 'V', 'C');
            m_writer.open(push_str, codec, fps, cv::Size(width, height));
        }

        m_writer.write(tmp);
    }
}

5.2 优缺点

方案 优点 缺点
GStreamer 灵活性高，延迟低 代码复杂
FFmpeg 功能强大，兼容性好 学习成本高
OpenCV GStreamer 实现简单 延迟较高

6 测试代码

6.1 视频源测试

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
int main1()  
{  
    // USB摄像头（GStreamer格式）
    std::string pipeline = "v4l2src device=/dev/video0 ! image/jpeg,width=1920,height=1080,framerate=30/1 ! nvv4l2decoder mjpeg=1 ! nvvidconv ! appsink";
    cv::VideoCapture capture(pipeline, cv::CAP_GSTREAMER);

    if (!capture.isOpened()) 
    {  
        std::cout << "Read video Failed !" << std::endl;  
        return -1;  
    }  

    cv::Mat frame;  
    cv::namedWindow("video test");  

    int frame_num = capture.get(cv::CAP_PROP_FRAME_COUNT);  
    std::cout << "total frame number is: " << frame_num << std::endl;  

    while(1)
    {  
        capture >> frame;  
        imshow("video test", frame);  
        if (cv::waitKey(30) == 'q')  
        {  
            break;  
        }  
    }  

    cv::destroyWindow("video test");  
    capture.release();  
    return 0;  
}

6.2 GStreamer命令

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
# 文件推流
gst-launch-1.0 -v filesrc location=D:/1.mp4 ! decodebin ! x264enc ! rtph264pay ! udpsink host=127.0.0.1 port=8554

# RTSP播放
gst-launch-1.0 -v rtspsrc location=rtsp://127.0.0.1:10054/live/Fs4FsmKSR ! rtph264depay ! h264parse ! avdec_h264 ! videoconvert ! autovideosink

# 测试源
gst-launch-1.0 -v videotestsrc ! video/x-raw, format=BGRx ! autovideosink

# AppSource推流
gst-launch-1.0 -v appsrc name=mysource is-live=true block=true format=GST_FORMAT_TIME \
    ! videoconvert \
    ! video/x-raw,format=NV12 \
    ! nvv4l2h264enc \
    ! video/x-h264,stream-format=byte-stream \
    ! h264parse \
    ! rtspclientsink location=rtsp://localhost:8554/mystream

7 总结

方案 适用场景
GStreamer 低延迟、高性能推流
FFmpeg 复杂编码需求、跨平台
OpenCV GStreamer 简单场景、快速实现