用python 海康网络相机 YUV 转为为 opencv

可以使用 `openh264` 库和 `python-opencv` 库将海康网络相机的 YUV 格式图像转换为 OpenCV 支持的图像格式。

首先需要安装 `openh264` 库，可以通过以下命令安装：

sudo apt-get install libopenh264-dev

然后可以使用以下代码将海康网络相机的 YUV 格式图像转换为 OpenCV 支持的图像格式：

import cv2
import numpy as np
from ctypes import *
from ctypes.util import find_library

# 定义海康网络相机的参数
CAMERA_IP = "192.168.1.64"
CAMERA_PORT = 8000
CAMERA_USER_NAME = "admin"
CAMERA_PASSWORD = "12345"

# 定义海康网络相机的图像参数
IMAGE_WIDTH = 1920
IMAGE_HEIGHT = 1080
IMAGE_FPS = 30

# 加载openh264库
openh264 = CDLL(find_library("openh264"))

# 获取openh264库中的函数
openh264_encoder_create = openh264.WelsCreateSVCEncoder
openh264_encoder_create.restype = c_void_p

openh264_encoder_initialize = openh264.WelsInitializeSVCEncoder
openh264_encoder_initialize.argtypes = [c_void_p, c_void_p]
openh264_encoder_initialize.restype = c_int

openh264_encoder_encode = openh264.WelsEncodeSVCEncoder
openh264_encoder_encode.argtypes = [c_void_p, c_void_p, c_void_p, c_void_p, c_void_p]
openh264_encoder_encode.restype = c_int

openh264_encoder_destroy = openh264.WelsDestroySVCEncoder
openh264_encoder_destroy.argtypes = [c_void_p]

# 创建openh264编码器
openh264_encoder = openh264_encoder_create(None)
if not openh264_encoder:
    raise Exception("Failed to create openh264 encoder")

# 初始化openh264编码器
openh264_param = c_void_p()
openh264_encoder_initialize(openh264_encoder, openh264_param)

# 创建海康网络相机的缓存
yuv_buffer = np.empty((int(IMAGE_HEIGHT * 1.5), IMAGE_WIDTH), dtype=np.uint8)

# 连接海康网络相机
cap = cv2.VideoCapture("rtsp://%s:%s@%s:%d/h264/ch1/main/av_stream" % (CAMERA_USER_NAME, CAMERA_PASSWORD, CAMERA_IP, CAMERA_PORT))

# 读取海康网络相机的 YUV 格式图像并转换为 BGR 格式图像
while True:
    ret, yuv_frame = cap.read()
    if not ret:
        break

    # 将 YUV 格式图像保存到缓存
    yuv_buffer[:IMAGE_HEIGHT, :IMAGE_WIDTH] = yuv_frame.reshape((IMAGE_HEIGHT, IMAGE_WIDTH))

    # 编码 YUV 格式图像为 H264 格式
    h264_buffer = np.empty(IMAGE_WIDTH * IMAGE_HEIGHT * 3 // 2, dtype=np.uint8)
    h264_length = c_uint32(0)
    h264_buffer_pointer = cast(h264_buffer.ctypes.data, POINTER(c_uint8))
    yuv_buffer_pointer = cast(yuv_buffer.ctypes.data, POINTER(c_uint8))
    openh264_encoder_encode(openh264_encoder, yuv_buffer_pointer, IMAGE_WIDTH, yuv_buffer_pointer + IMAGE_WIDTH * IMAGE_HEIGHT, IMAGE_WIDTH // 2, yuv_buffer_pointer + IMAGE_WIDTH * IMAGE_HEIGHT // 4 * 5, IMAGE_WIDTH // 2, h264_buffer_pointer, byref(h264_length), None)

    # 解码 H264 格式图像为 BGR 格式图像
    bgr_frame = cv2.imdecode(np.frombuffer(h264_buffer[:h264_length.value], dtype=np.uint8), cv2.IMREAD_COLOR)

    # 显示 BGR 格式图像
    cv2.imshow("BGR Image", bgr_frame)
    if cv2.waitKey(1) == ord('q'):
        break

# 释放资源
openh264_encoder_destroy(openh264_encoder)
cap.release()
cv2.destroyAllWindows()

需要注意的是，此代码中假设海康网络相机的 IP 地址为 `192.168.1.64`，端口为 `8000`，用户名为 `admin`，密码为 `12345`，需要根据实际情况修改这些参数。另外，此代码中将海康网络相机的 YUV 格式图像编码为 H264 格式，然后解码为 BGR 格式图像，需要使用 `imdecode` 函数进行解码。