This SDK only works with devices released within the past 3 years. We regularly optimize and update the SDK to ensure compatibility and performance. We do not guarantee compatibility or provide technical support for devices older than 3 years.

# FAQ

Q1 How to get alarm and how to call?

The so-called defence is that the SDK actively connects the device and initiates an alarm upload command, and the device is sent to the SDK as soon as an alarm occurs. Therefore, in addition to configuring the alarm input information and the device callback function, it is necessary to call the `NET_SDK_SetupAlarmChan` interface to establish a connection between the SDK and the device.

Q2 After the alarm configuration is successful, the device can receive the alarm signal locally, why can't the client receive the alarm signal?

The reasons why the client cannot receive the alarm information are as follows:

- whether the network connection is normal.

- when the alarm mode is set, whether the setup has been set correctly.

Q3 Why did the call to `NET_SDK_SetDVRConfig` fail?

Before calling `NET_SDK_SetDVRConfig` you need to call `NET_SDK_EnterDVRConfig` lock configuration.

Q4 What should I pay attention to when using the `NET_SDK_SetDVRConfig` configuration parameter?

Because `NET_SDK_SetDVRConfig` needs to enter a fully assigned structure, it is prone to setting errors. So to avoid this problem, in general, before calling the `NET_SDK_SetDVRConfig` setting, call `NET_SDK_GetDVRConfig` to assign an initial value to the structure that needs to be modified, modify the corresponding parameters on this basis, and finally call `NET_SDK_SetDVRConfig`.

Q5 Why does `NET_SDK_PlayBackByTime` need to pass in a set of channel numbers?

When a group of channels is passed in for playback, this group of channels will automatically synchronize playback; at the same time, playing the channels in groups, rather than playing them separately, can save device performance.

Q6 Why is the time inconsistent with the device when the video data is retrieved, played back and downloaded?

When this time is inconsistent with the device, first check whether the device time zone is consistent with the PC time zone, and then check whether the time is consistent.

Q7 Why does the start time of the video on playback and download differ from the set start time?

Playback and download by time starts with a keyframe near the set start time.

Q8 `NET_SDK_PTZControl` sends control commands, why is it invalid for some PTZ?

The device will send the control code to the PTZ according to the decoder type and decoder address currently set. If the decoder currently set does not match, the corresponding decoder needs to be set on the device side. If the device does not support the decoder, it cannot use these interfaces to control the PTZ.

Q9 Is voice intercom and forwarding for devices or channels?

Voice intercom and forwarding is for devices not channels, so determining the maximum number of voice intercom and forwarding with the device is not determined by the number of channels of the device.

Q10 Can the callback function of voice intercom be set to null?

Yes, the voice is still normal, but the user cannot process the data themselves.

Q11 How to save video files?

After obtaining the data through the callback function `LIVE_DATA_CALLBACK` of `NET_SDK_SetLiveDataCallBack`, save the data to a file. The code example of this process is shown in SDKdemo's in the livedlg class, the 1170 line is followed by the process of saving the data to the file.The data obtained by the callback can be used for player playback.

Q12 Problem getting file playback progress?

The `NET_SDK_PlayBackByTime` interface can get the start and end time of the playback file to calculate the total length of the file. `NET_SDK_GetPlayBackOsdTime` can get the current playback time, playback progress = current play time/total play time of the file

Q13 Player demo report configuration error or 0XC0150002 error, unsuccessful operation?

The solution to the configuration error: install the runtime component of VS2005 on the machine, and download it on the msdn official website; the solution to the 0XC0150002 error: the next vc runtime library Try installing Microsoft Visual C + + 2005 SP1 Redistributable Package 4.

Q14 Fast forward when searching for file playback?

When searching for file playback in SDKDEMO, 2X and 4X fast retrograde effects are effective, and the speed except 1X is selected when fast forwarding, but only 8X, 6X and 32X speeds can be selected when fast forwarding. The single-frame playback button needs to be paused first, and then click the single-frame playback button to play one frame. Neither 2X nor 4X Fastback is implemented in the SDK.

Q15 Filling in the wday value in `DD_TIME`?

In the `NET_SDK_FindFile`, the start time is of type `DD_TIME`, and the value of wday in `DD_TIME` is currently invalid. It can be left blank, but it cannot be removed. If it is not blank, it can be found according to mday. If you need to look up by wday, you need to write your own function to estimate the time to the day of the week.

Q16 Playback of Saved Video Files with Player Times File Format Error Issue?

Check the following four qustions:

1. the first frame is format frame when save record file;

2. all structs in SDK are 4 bytes alignm;

3. check interface calling order;

4. the file in PlayerSDK should be:

   *frame info(`NET_SDK_FRAME_INFO`)valid data in frame

   *frame info(`NET_SDK_FRAME_INFO`)valid data in frame

   * ......

   *frame info(`NET_SDK_FRAME_INFO`)valid data in frame

   * ......

   * video info frame should be before video frame,audio info frame should be before audio frame too

Error Code