Portrait of a digital video recorder.
Portrait of a digital video recorder
A wide range of equipment based on digital video recorders is presented on the Russian video surveillance systems market under the RVi trademark. The line of these devices is dynamically developing and expanding. The RVi line of video recorders has been expanded with new products – the LB, MA and PA series, which are distinguished by their wide functionality.
The primary requirement for digital video recorders is the quality of the recorded image, and the second important parameter is productivity, which usually means the recording speed at a given resolution. Thanks to the use of modern components and image processing technologies, RVi video recorders provide excellent quality of the recorded image.
The modern H.264 algorithm is used to compress the digital video signal, which allows not only to increase the archive depth, but also to reduce the required bandwidth when viewing video via a local network or the Internet. The settings for the compressed video stream are set in two ways: either through a generalized image quality parameter, or through a strictly specified bit rate, which can reach four Mbit/s when recording full frames at a speed of 25 fps. At the same time, the quality of the compressed image is almost as good as the quality obtained with frame-by-frame compression. Moreover, improved video signal processing allows the video recorder to record images with a high degree of detail. When recording full frames or fields, the horizontal resolution exceeds 520 TV lines. This fully justifies the use of high-resolution video cameras, since when recording an image on the RVi video recorder, the user gets really high image quality.
All series of video recorders have excellent network performance. This is achieved due to dual encoding of video streams. This means that the video stream can be transmitted over the network with any characteristics, and this will not affect the quality of the image recorded on the internal hard drives. This function is especially useful when viewing video via mobile devices using the iPhone, Android, Symbian, Windows Mobile OS. In addition, RVi video recorders can send an e-mail message in the event of any alarm, which can be a loss of signal from a video camera, blocking the lens of a video camera, motion detection, a signal from alarm sensors, a hard drive error. The reaction to an alarm event can be turning on the recording of an arbitrary number of video cameras, displaying an alarm message, activating alarm outputs, uploading images to an ftp server, as well as displaying an image of the corresponding video camera on the monitor screen and installing a high-speed dome video camera in a specified position. An interesting feature of RVi video recorders is the large depth of pre-alarm recording. It is configured from 0 to 30 seconds independently for all channels at any image quality settings. If it is necessary to backup the archive over the network, the video recorder can automatically optimize the use of network resources for the fastest backup. It is also possible to set a priority either a lower image display delay (it can be less than one second) or a higher image quality. For example, when viewing a real-time image from a stationary video camera, high display quality may be more important, and when controlling a high-speed dome video camera, minimal delay is more important. To control and view images from several video recorders at a remote workplace, it is proposed to use RVi PSS software, which also allows remote video recording and playback of the archive (both local and remote). It should be noted that all settings performed locally can also be performed at a remote workplace. Access to the video recorder over the network can be limited not only by multi-level password protection, but also by limiting the number of connections, as well as by using an IP address filter.The video from the video cameras, as well as the archive recordings, can be output via the composite video output, as well as via the VGA and HDMI video outputs simultaneously with a resolution of 720p. The distinctive feature is that the VGA and HDMI outputs actually output high-quality images. While many video recorders have a VGA converter, which receives the original composite video signal at the input, on RVi video recorders the image is sent to the VGA interface directly from the processing processor, due to which high image quality is achieved. Of course, this difference is striking when viewing in multi-screen mode.
The above functionality is available for all three series of video recorders LB, MA and PA. The main differences between the series are in performance and maximum archive depth. For example, the LB and MA series of video recorders allow recording images at a speed of up to 25 fps in CIF resolution, 12 fps — 2 CIF, 6 fps — 4CIF. This is a traditional «layout» for budget real-time class video recorders. However, these models have an interesting feature that allows recording video on the first and ninth channels at a speed of 25 fps in full frames regardless of the settings for other channels. For the LB and MA series of video recorders, installation of one and four hard drives is provided, respectively. The PA series of video recorders belongs to the class of professional devices and allows recording video on each channel in full frames at a speed of 25 fps. Despite the use of a highly efficient H.264 compression codec, storing an archive with such recording parameters on a 16-channel model will require a lot of disk space. For this, installation of up to eight hard drives is provided. When installing 2 TB hard drives, the archive depth can be 6 weeks of continuous recording with high image compression quality settings. In this case, during installation, you simply will not need to install external disk arrays, and in order to ensure the safety of especially important fragments, it is proposed to use the «mirroring» function of the video archive both for all and for selected channels. By the way, the «mirroring» function is also available on the MA series.
Another function that unites the MA and PA series is the ability to back up the archive via an external eSATA interface, which allows not only to significantly increase the volume of connected media, but also to significantly increase the copying speed compared to the USB 2.0 interface, which is also present on all three media.
Thanks to the presence of audio inputs, video recorders of all three series allow recording synchronized with the video image of selected video cameras, as well as broadcasting audio to the Internet. An important advantage of the new models is the support of bidirectional transmission of audio signals between the video surveillance zone and the remote workplace. In this case, along with listening to the protected area, the operator can remotely transmit voice messages.
Most of the video recorders present on the Russian market of video surveillance systems support the telemetry function for controlling high-speed PTZ video cameras, but not all have such a wide list of supported protocols as RVi video recorders, which have more than 30. The video recorder itself is controlled using a USB mouse, IR remote control, buttons on the front panel, which, together with a clear Russian-language graphic menu, makes it simple and easy to use.
The scope of application of the LB series video recorders covers primarily low-budget installations for which it is important to obtain high image quality with low requirements for the archive depth, and at the same time, an inexpensive solution is important. Such objects can be private properties, office premises, gas stations, car washes, etc. The MA series of video recorders differs from the more budget LB series primarily in greater archive depth and the ability to install in a 19” rack, which makes them more convenient for installation in large objects where several devices can probably be used. First of all, these are retail facilities, shopping and entertainment centers, educational institutions, office buildings. And for those cases when the specifics of the object require maximum recording speed of video in high resolution, the best choice would be the RVi PA series video recorder, which belongs to the professional class of video surveillance systems.
The main distinguishing features of these video recorders can be summarized as follows:
- H.264 compression codec
- Video recording in full frames at a speed of 25 fps
- Dual encoding of video streams
- Audio recording
- Wide functionality for network operation
- Support for hard drives up to 2 TB
- HDMI interface
- More than 30 telemetry protocols
Image quality of Rvi video recorders:
352×288 25 fps, avi, 2.8 MB
704×575 25 fps, avi, 10.5 MB
704×576 12 fps, avi, 4.2 MB