在使用 CCTV 相机的视频管理系统的情况下，视频录制是指从相机捕获视频并录制它以通过移动应用和浏览器应用进行观看的过程。In the context of a video management system for CCTV cameras, video recording refers to the process of capturing video from the cameras and recording it for viewing via mobile and browser apps. 视频录制可分为连续视频录制和基于事件的视频录制两类。Video recording can be categorized as continuous video recording and event-based video recording.
连续视频录制Continuous video recording
连续视频录制 (CVR) 是指连续录制从视频源捕获的所有视频的过程。Continuous video recording (CVR) refers to the process of continuously recording all the video being captured from a video source. CVR 可确保所有视频都可在以后的某个时间点进行分析和/或审核（由录制策略指定）。CVR ensures that all the video is available (dictated by the recording policy) to analyze and/or audit at a later point in time.
基于事件的视频录制Event-based video recording
基于事件的视频录制 (EVR) 是指由事件触发的视频录制过程。Event-based video recording (EVR) refers to the process of recording video triggered by an event. 相关事件可能源于视频信号本身的处理，也可能来自独立源（例如，来自门传感器）。The event in question, could originate due to processing of the video signal itself or could be from an independent source (for example, from a door sensor). 基于事件的视频录制 (EVR) 可以节省存储空间，但需要额外的组件来生成事件并触发视频录制（根据预定义的策略）。Event-based video recording (EVR) can result in storage savings, but it requires additional components that generate the events and trigger the video recording (per a pre-defined policy). 换句话说，EVR 需要对那些应触发视频录制的事件以及与视频录制相关的策略（也称为录制策略）做出附加决策。In other words, EVR requires making additional decisions regarding the events that should trigger video recording and the policy associated with video recording (also known as recording policy). 策略的示例如下所示：从事件时间之前的 30 秒开始录制 2 分钟的视频。An example of a policy could be something like: record the video for 2 minutes starting from 30 seconds prior to the event time. 相关事件可能源自相机本身的视频处理。The events in question could originate due to video processing on the camera itself. 例如，在相机视区中预先配置的感兴趣区域内检测到运动时，多个相机支持生成运动检测信号事件。As an example, several cameras support generating a motion detection signal event when motion is detected within a pre-configured zone of interest in the camera’s viewport. 事件也可以通过在另一个设备上处理视频来生成，该设备从相机捕获视频并使用简单的图像处理技术或复杂的机器学习模型对其进行分析。The events could also be generated by processing the video on another device that captures the video from the camera and analyzes it using simple image-processing techniques or sophisticated machine learning models.
选择录制模式Choosing recording modes
选择使用 CVR 还是使用 EVR 取决于业务目标。The choice of whether to use CVR or EVR depends on the business goals. IoT Edge 上的实时视频分析同时为 CVR 和 EVR 提供平台功能。Live Video Analytics on IoT Edge provides platform capabilities for both CVR and EVR. 有关详细信息，可参阅 CVR 和 EVR 方案文章。You can learn more about it in the CVR and EVR scenario articles.
录制策略是指规定录制开始/停止时间（如果是 EVR）、录制持续时间和录制删除操作的策略。Recording policy refers to the policies that dictate the recording start/stop time (in case of EVR), recording duration, and recording deletion. 录制策略使你能够均衡存储成本和业务需求。Recording policies enable you to balance storage cost with business requirements. 录制策略在 CVR 和 EVR 中有所不同。Recording policies differ between CVR and EVR. 对于 CVR，录制策略定义应存储多少天的视频（例如，过去 7 天的视频）。For CVR, recording policy defines how many days of video should be stored (for example, the last 7 days). 对于 EVR，录制策略定义录制开始时间和结束时间以及视频的持续时间。For EVR, recording policy defines when recording should start and end, along with the duration of the video. 有关详细信息，可参阅 CVR 和 EVR 方案文章。You can learn more about it in the CVR and EVR scenario articles.