详解如何实现C#和Python间实时视频数据交互_C#

我们在做rtsp|rtmp播放的时候，遇到好多开发者，他们的视觉算法大多运行在python下，需要高效率的实现c#和python的视频数据交互，常用的方法如下：

方法一：通过http请求传输视频数据

服务器端（python）

使用flask或django等web框架创建一个http服务器，通过api接口提供视频数据。

from flask import flask, send_file, request, jsonify  
import cv2  
import io  
import base64  
  
app = flask(__name__)  
  
def get_video_frame():  
    # 读取视频帧  
    cap = cv2.videocapture('your_video.mp4')  
    ret, frame = cap.read()  
    cap.release()  
    if not ret:  
        return none, "no more frames"  
  
    # 转换为rgb格式  
    frame_rgb = cv2.cvtcolor(frame, cv2.color_bgr2rgb)  
  
    # 转换为字节流  
    ret, buffer = cv2.imencode('.jpg', frame_rgb)  
    if not ret:  
        return none, "could not encode frame"  
  
    # 将字节流转换为base64字符串  
    img_str = base64.b64encode(buffer).decode('utf-8')  
    return img_str, 200  
  
@app.route('/video_frame', methods=['get'])  
def video_frame():  
    img_str, status_code = get_video_frame()  
    if img_str is none:  
        return jsonify({"error": status_code}), status_code  
    return jsonify({"image": img_str})  
  
if __name__ == '__main__':  
    app.run(debug=true)

客户端（c#）

使用httpclient从python服务器获取视频帧，并将其显示在picturebox中。

using system;  
using system.drawing;  
using system.drawing.imaging;  
using system.io;  
using system.net.http;  
using system.windows.forms;  
  
public class videoform : form  
{  
    private picturebox picturebox;  
    private httpclient httpclient;  
  
    public videoform()  
    {  
        picturebox = new picturebox  
        {  
            dock = dockstyle.fill,  
            sizemode = pictureboxsizemode.stretchimage  
        };  
        this.controls.add(picturebox);  
  
        httpclient = new httpclient();  
        timer timer = new timer();  
        timer.interval = 100; // adjust the interval as needed  
        timer.tick += timer_tick;  
        timer.start();  
    }  
  
    private async void timer_tick(object sender, eventargs e)  
    {  
        try  
        {  
            httpresponsemessage response = await httpclient.getasync("http://localhost:5000/video_frame");  
            response.ensuresuccessstatuscode();  
            string jsonresponse = await response.content.readasstringasync();  
            dynamic jsondata = newtonsoft.json.jsonconvert.deserializeobject(jsonresponse);  
            string base64string = jsondata.image;  
            byte[] imagebytes = convert.frombase64string(base64string);  
            using (memorystream ms = new memorystream(imagebytes))  
            {  
                image image = image.fromstream(ms);  
                picturebox.image = image;  
            }  
        }  
        catch (exception ex)  
        {  
            messagebox.show($"error: {ex.message}");  
        }  
    }  
  
    [stathread]  
    public static void main()  
    {  
        application.enablevisualstyles();  
        application.run(new videoform());  
    }  
}

方法二：通过zeromq传输视频数据

zeromq是一种高性能的异步消息库，适用于需要低延迟和高吞吐量的应用。

服务器端（python）

使用pyzmq库发送视频帧。

import zmq  
import cv2  
import numpy as np  
  
context = zmq.context()  
socket = context.socket(zmq.pub)  
socket.bind("tcp://*:5555")  
  
cap = cv2.videocapture('your_video.mp4')  
  
while true:  
    ret, frame = cap.read()  
    if not ret:  
        break  
    frame_rgb = cv2.cvtcolor(frame, cv2.color_bgr2rgb)  
    frame_bytes = frame_rgb.tobytes()  
    socket.send_string("frame", zmq.sndmore)  
    socket.send(frame_bytes, flags=0, copy=false)

客户端（c#）

使用netmq库接收视频帧。

using system;  
using system.drawing;  
using system.drawing.imaging;  
using system.runtime.interopservices;  
using system.threading.tasks;  
using system.windows.forms;  
using netmq;  
using netmq.sockets;  
  
public class videoform : form  
{  
    private picturebox picturebox;  
    private subscribersocket subscriber;  
  
    public videoform()  
    {  
        picturebox = new picturebox  
        {  
            dock = dockstyle.fill,  
            sizemode = pictureboxsizemode.stretchimage  
        };  
        this.controls.add(picturebox);  
  
        var address = "tcp://localhost:5555";  
        using (var context = netmqcontext.create())  
        {  
            subscriber = context.createsubscribersocket();  
            subscriber.connect(address);  
            subscriber.subscribe("frame");  
  
            task.run(() => receiveframesasync(subscriber));  
        }  
    }  
  
    private async task receiveframesasync(subscribersocket subscriber)  
    {  
        while (true)  
        {  
            var topic = await subscriber.receiveframestringasync();  
            var framebytes = await subscriber.receiveframebytesasync();  
  
            if (topic == "frame")  
            {  
                int width = 640; // adjust based on your video resolution  
                int height = 480; // adjust based on your video resolution  
                int stride = width * 3;  
                bitmap bitmap = new bitmap(width, height, pixelformat.format24bpprgb);  
                bitmapdata bitmapdata = bitmap.lockbits(new rectangle(0, 0, width, height), imagelockmode.writeonly, bitmap.pixelformat);  
                marshal.copy(framebytes, 0, bitmapdata.scan0, framebytes.length);  
                bitmap.unlockbits(bitmapdata);  
  
                picturebox.image = bitmap;  
            }  
        }  
    }  
  
    [stathread]  
    public static void main()  
    {  
        application.enablevisualstyles();  
        application.run(new videoform());  
    }  
}