Hikvision devices support multiple protocols. For direct SDK communication, use:
struLoginInfo.byProtoType = 0; // 0 = TCP (most stable)
// OR
struLoginInfo.byProtoType = 1; // 1 = HTTP (if TCP fails)
If byProtoType remains uninitialized (random garbage), error 9 is inevitable. hcnetsdk.dll 9 hikvision error
Add logging right before each SDK call.
| Likely Cause | Immediate Action |
|--------------|------------------|
| Missing dwSize initialization | Set struName.dwSize = sizeof(struName) for every struct |
| Wrong channel index | Use channel 1 for live view, test with device’s native software |
| Uninitialized byProtoType | Explicitly set to 0 (TCP) |
| Called before NET_DVR_Init() | Call NET_DVR_Init() at application start |
| Corrupted DLL | Re-download SDK from Hikvision and replace all DLLs |
| Unicode/ANSI mismatch | Use _V40W functions for Unicode strings | Hikvision devices support multiple protocols
Common mistake: Assuming cameras start at index 0. Common mistake: Assuming cameras start at index 0
Debug tip: Try channel 1 first. If that fails, log the response from NET_DVR_GetLastError().
Even if error 9 is from a specific call, SDK may have a more detailed last error.
NET_DVR_USER_LOGIN_INFO loginInfo = 0;
loginInfo.dwSize = sizeof(NET_DVR_USER_LOGIN_INFO);
// Check IP string is valid, port >0, user/pass not empty