feat: 修改视频流后端服务，使其适配jpeg格式

server/src/Peripherals/HdmiInClient.cs

@@ -100,6 +100,51 @@ class HdmiIn
         return result.Value;
     }
 
+    public async ValueTask<(byte[] header, byte[] data, byte[] footer)?> GetMJpegFrame()
+    {
+        // 从HDMI读取RGB24数据
+        var readStartTime = DateTime.UtcNow;
+        var frameResult = await ReadFrame();
+        var readEndTime = DateTime.UtcNow;
+        var readTime = (readEndTime - readStartTime).TotalMilliseconds;
+
+        if (!frameResult.IsSuccessful || frameResult.Value == null)
+        {
+            logger.Warn("HDMI帧读取失败或为空");
+            return null;
+        }
+
+        var rgb24Data = frameResult.Value;
+
+        // 验证数据长度是否正确 (RGB24为每像素2字节)
+        var expectedLength = _currentWidth * _currentHeight * 2;
+        if (rgb24Data.Length != expectedLength)
+        {
+            logger.Warn("HDMI数据长度不匹配，期望: {Expected}, 实际: {Actual}",
+                expectedLength, rgb24Data.Length);
+        }
+
+        // 将RGB24转换为JPEG（参考Camera版本的处理）
+        var jpegStartTime = DateTime.UtcNow;
+        var jpegResult = Common.Image.ConvertRGB24ToJpeg(rgb24Data, _currentWidth, _currentHeight, 80);
+        var jpegEndTime = DateTime.UtcNow;
+        var jpegTime = (jpegEndTime - jpegStartTime).TotalMilliseconds;
+
+        if (!jpegResult.IsSuccessful)
+        {
+            logger.Error("HDMI RGB24转JPEG失败: {Error}", jpegResult.Error);
+            return null;
+        }
+
+        var jpegData = jpegResult.Value;
+
+        // 发送MJPEG帧（使用Camera版本的格式）
+        var mjpegFrameHeader = Common.Image.CreateMjpegFrameHeader(jpegData.Length);
+        var mjpegFrameFooter = Common.Image.CreateMjpegFrameFooter();
+
+        return (mjpegFrameHeader, jpegData, mjpegFrameFooter);
+    }
+
     /// <summary>
     /// 获取当前分辨率
     /// </summary>