Patent Publication Number: US-2007098370-A1

Title: Digital video recorder

Description:
FIELD OF THE INVENTION  
      The present invention relates to video recording devices, and particularly to digital video recorders and network video recorders.  
     BACKGROUND OF THE INVENTION  
      Video recording devices, such as digital hard disk video recorders or digital network recorders, are used in video monitoring, surveillance and security systems. Conventionally, such a device receives a video signal, continuously records the signal and outputs the recorded signal for viewing by a user.  
      Digital Video Recorders (DVRs) and Network Video Recorders (NVRs) are commonly used with associated video cameras and monitors. Video data is recorded in digital format on a digital medium, such as a hard disk drive. Further included within the DVR or NVR is an encoder for digitizing the received signal (in the case of an analog input signal), encoding the signal and compressing the signal for storage on the hard drive. Decoder functionality then decodes and decompresses the stored television signal and outputs a signal to a monitor for viewing by a user.  
      Typically, when video is written to a drive of a DVR or NVR system, it is written temporarily until the video has stopped recording. The file is then closed and the data is written to the hard drive. If the encoder malfunctions and stops at a point during the recording, the data is lost. Additionally, certain industries have specific requirements for monitoring applications. For example, interrogation video for law enforcement applications may be required to have a particular resolution, audio and a time code.  
      Accordingly, it is desirable to have a DVR or NVR system that is better able to maintain data in the event of a system disruption. Additionally, a video monitoring system and method with specialized features for particular industries, such as law enforcement, is needed.  
     BRIEF SUMMARY OF THE INVENTION  
      The present invention provides a digital video recording system and method for recording video data. The digital video recording system has a video recording device configured to receive video input from the video input device. The video recording device includes a server, a plurality of video encoder cards, and a storage control module. Each encoder card is configured to convert analog video data to digital Mpeg4 video at a sustained rate of at least FD1. The storage control module is configured to write user defined video segments to the storage device. The system also includes a video input device, a storage device, an activation device configured to provide an activation signal to the video recording device, and an output device capable of displaying video data recorded by the video recording device. The video recording device can be in communication with a computer network.  
      Additional features of the present invention will be apparent from the following detailed description and drawings, which illustrate exemplary embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a block diagram representing a digital video recorder system according to an exemplary embodiment of the invention;  
       FIG. 2  is a diagram of a configuration for the circuitry components of a digital video recorder according to an exemplary embodiment of the invention;  
       FIG. 3  is a block diagram showing the signaling flow of the digital video recorder of  FIG. 2  according to an exemplary embodiment of the invention;  
       FIG. 4  is a block diagram depicting the interface connections of the digital video recorder of  FIG. 2 ; and  
       FIG. 5  is a diagram of a network video recorder system according to an exemplary embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      In the following detailed description, reference is made to the accompanying drawings, which form a part hereof and show by way of illustration specific embodiments that the invention may be practiced. In the drawings, like reference numerals refer to like elements. The illustrated embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized, and that structural and logical changes may be made without departing from the spirit and scope of the present invention. The progression of process steps described is exemplary of embodiments of the invention; however, the sequence of steps is not limited to that set forth herein and may be changed, with the exception of steps necessarily occurring in a certain order.  
       FIG. 1  is a block diagram representing a digital video recorder system according to an exemplary embodiment of the invention. The system  100  includes an integrated DVR device  200 . The DVR  200  can provide reliable video and audio data storage that is compatible with law enforcement applications.  
      The DVR  200  includes a server  101 , such as, but not limited to a standard Intel-based server. Any form of operating system  102 , including Windows 2000 or 2003 operating system, and a control module  103  configured to control processes of the DVR  200  running on the server  101 . The server  101  also includes a storage control module  111 , an activation control module  112 , and, optionally, at least one other feature module  113 . Each of the modules  103 ,  111 ,  112 ,  113  can be computer program applications running on the server  101  or hardware/software devices or entirely hardware elements. The DVR  200  also has a user interface  105  for accepting inputs. Further, the DVR  200  also includes video/audio encoder cards  110 , for example Mpeg4 cards; and a storage device  104 , such as a hard drive, disk or an array of drives.  
      The DVR  200  is in communication with one or more video and/or audio input devices  120 . The input devices  120  are, for example, video cameras having audio recording devices.  
      The DVR can also be in communication with an activation device  130 . The activation device  130  is configured to provide an activation signal. In response to this signal, the DVR  200  begins recording video data. Examples of possible activation devices include a switch, a client computer, a voice input device, a motion detector, a timer, an alarm device, among others. Optionally, the activation device can be included in the DVR  200 .  
      The DVR  200  is also in communication with one or more output devices  140 , which are configured to display the video data and output the audio data recorded by the DVR  200 . The DVR  200  can support multiple outputs from a single input.  
      The encoder cards  110  enable the DVR  200  to convert analog video to digital Mpeg4 video compliant with the MPEG4 (ISO 14496) standard including all levels of the SP (Simple Profile) and levels 1 thru 5 of the ASP (Advanced Simple Profile). In one embodiment the encoder cars  110  enable the DVR  200  to convert analog video to digital MPEG4 video at a sustained rate of FD1 (720×506 pixels, 30 frames per second, up to 4 Mbits per second) or better. Preferably, the cards  110  also enable audio recording that is synchronized with the video recording. The DVR  200  can process multiple simultaneous streams of video and synchronized audio. In contrast, conventional DVR devices can do one stream or less with synchronized audio, and are limited to one stream or less FD1 stream per DVR device.  
      Law enforcement video typically has different requirements than surveillance video. Surveillance video is generally 320×240 pixels in size, 5 to 12 frames a second and about 100 to 250 Kbs data rate. Certain law enforcement video, particularly interrogation video, must be 640×480 pixels in size (720×480 pixels is preferred), about 30 frames a second and a data rate of at least 1.5 Mbs. Interrogation video must also have audio, whereas surveillance video does not typically have audio. Therefore, the system  100  is suitable for law enforcement applications.  
      According to one exemplary embodiment, the DVR  200  can sustain simultaneous FD1 captures of video and audio for more than 200 hours without failure or loss of data. Conventional systems that capture video do so by writing the data to a disk drive. If the conventional system were to crash during the recording, all video and audio data would be lost. To address this problem, other systems write each frame of the video as an image. This method consumes enormous amounts of disk space and it is processor-intensive to reassemble the image back into a video. This process also does not work in real time.  
      To support reliable storage, the DVR  200  includes the storage control module  111 . The storage control module  111  provides a more efficient method of managing disk storage than conventional DVR devices. Additionally, storage occurs during recording, rather than subsequent to recording.  
      The storage control module  111  writes temporal video segments to the storage device  104 . The length of a video segment is set to a default length, but can be redefined as desired by the user. The segments can range in length from seconds or less to hours or more. During recording, the video data recorded during a segment is written to the storage device  104  upon the expiration of the segment. For example, where the defined segment length is one hour, every hour during recording, the video data is closed and permanently written to the storage device  104 . Where recording is stopped prior to the expiration of a full segment, the final segment portion is written to the storage device  104  upon termination of recording. In this way, loss of video is limited should the system  100  fail during recording.  
      Optionally, the video storage control module  111  is also configured to provide a redundancy function. For this, the DVR  200  is configured such that two encoder cards  110  record the same video and audio simultaneously. If one encoder card  110  fails, the redundant secondary encoder card  110  can provide the video and audio that was lost. This function also works for video segments. If a segment recorded by the primary encoder card  110  is defective, the video storage control module  111  transfers the corresponding segment from the secondary encoder card  110  back to the primary to repair the defective file.  
      The activation control module  112  responds to an activation signal received from the activation device  130  and initiates recording. The DVR  200  can be activated to begin recording by one or more types of activation signals. For example, recording can be activated by an event, motion, an alarm, as scheduled by a user, or manually. Additionally, the DVR  200  can be activated for recording by voice or by a computer program application running on the activation device  130 .  
      Optionally, the DVR  200  can support additional features. Each additional feature can be provided as a respective feature module  113  (shown as a single module in  FIG. 1 ). For example, the DVR  200  can include a module  113  configured to translate languages, a module  113  configured to transcribe spoken words from recorded audio data, a module  113  configured for streaming of video and audio content (both live and on demand) to output device  140 , and/or a module  113  configured to provide layered voice analysis and analyze audio data for deceptive or false statements.  
      Preferably, the DVR can also include a module  113  for image and/or audio processing. Audio processing improves the quality of the audio while recording, and compensates for poor acoustics in the recording room. Image processing improves image quality and can include color correction, gamma correction, and transitions between input device  120  (e.g., camera) angles in real time should there be more than one device  120  recording a common location. The DVR  200  can also be configured to support other features that are known in the art.  
      Preferably, the DVR  200  also includes a feature module  113  configured to enable customized metadata (data about data) capture along with the video and audio recording. The metadata is stored along with the video and audio data and can be retrieved through search methods. The metadata also can be integrated with data assets systems for storing and managing data and databases outside the system  100 . Law enforcement video must include a time code associated with the video, which includes a display for milliseconds. Accordingly, the time code is included as metadata associated with the video data. Desirably, the time code is displayed upon playback of the video data.  
       FIG. 2  is a diagram of an exemplary configuration for the circuitry components of the DVR  200 . The present invention can be configured differently so long as the functionality shown in  FIG. 1  can be provided. The DVR  200  includes a motherboard  222 , which includes dual central processing units (CPUs)  207 . In the illustrated embodiment, the CPUs are Pentium 4 class with 2 GB RAM although any other conventionally known CPU can be used. The motherboard  222  also includes a Peripheral Component Interconnect (PCI) bus  206  for digital input/output components and a PCI bus  211  for the encoder cards  110 . Drive control logic circuitry  261  and memory and interface circuitry  210  are also included on the motherboard  222 . The DVR  200  also includes the storage device  104 . In the illustrated embodiment, the storage device  104  is a managed storage array having six Ultra320 SCSI drive bays for hard drives. Further, the DVR  200  includes a power supply  260  and control circuitry  203  for controlling the DVR  200  functions and features.  
       FIG. 3  is a block diagram showing the signaling flow of the DVR  200  of  FIG. 2  according to an exemplary embodiment of the invention. In the embodiment illustrated in  FIG. 3 , the activation device  130  is a plurality of wall switches. Each of the switches  130  serves to activate a particular encoder card  110  or set of cards  110 , where the redundancy function is employed.  
      The DVR  200  takes an analog input from the input devices  120  ( FIG. 1 ), which triggers a digital signal from a digital input output/device  301  to the control module  103 . The control module  103  activates video and audio encoding on specific cards  110  in the DVR  200 . The particular cards  110  activated depend on the particular switch or switches  130  activated. The encoder cards  110  use a buffer to store encoded video and audio data which is written to the storage device  104 . Preferably the video data is written to the storage device  104  in temporal segments by the storage control module  111 , as described above in connection with  FIG. 1 .  
      The control module  103  also signals the digital switch card  302  to activate an output device  140  through the digital switch card  302 . In the illustrated embodiment, the output device  140  is a plurality of display monitors  305 . The DVR  200  can be configured such that the particular display monitor(s)  305  activated depends on the particular switch or switches  130  activated.  
      Optionally, the output device can include a device  304  for signaling the status of the activity of the system  100  ( FIG. 1 ). For example, in the illustrated embodiment, the device  304  could be configured to show whether a particular switch is activated or deactivated so that users of the system  100  are readily aware of the status of the system&#39;s activity. In the illustrated embodiment, the device  304  is a light indicating that a particular switch or switches  130  have been activated.  
       FIG. 4  is a block diagram depicting the interface connections of the DVR  200  of  FIG. 2 . The DVR  200  includes a number of encoder cards  110  and a digital input/output card  301 , which are PCI interface cards. The DVR also includes fiber channel drive control circuitry  402  for controlling the interface with the storage device  104  and PCI Interface control circuitry  401  for controlling the PCI interfaces. These components  110 ,  402 ,  401 ,  301  use the PCI bus  206  to communicate with each other. The DVR  200  further includes a Digital Input/Output (I/O) Card  302  that operates on the accelerated graphics port (AGP) interface on the server  101  ( FIG. 1 ). The digital I/O card  301  and the Digital Switch card use a serial connector to communicate, which is an RS488 serial connector in the illustrated embodiment, but can be any other serial connector.  
      It should be understood that  FIGS. 2-4  illustrate exemplary configurations only and that structural, electrical and other changes, substitutions and supplements can be made.  
       FIG. 5  illustrates a network video recorder (NVR) system  500  according to an exemplary embodiment of the invention. The system  500  includes a NVR  501  according to an exemplary embodiment of the invention. Preferably, the NVR  501  is capable of supporting harsh environments and uses solid state electronics so that it can withstand extreme vibration while recording. The NVR  501  is in communication with a computer network  555 .  
      The NVR  501  is similar to the DVR  200  ( FIGS. 1-4 ). The NVR  501  includes a server  101 , such as a standard Intel-based server. An operating system  102 , such as Windows 2000 or 2003 operating system and a control module  103  configured to control processes of the NVR  501  are also included. The server  101  also includes a storage control module  111 , an activation control module  112 , and, optionally, at least one other feature module  113 . Each of the modules  103 ,  111 ,  112 ,  113  can be computer program applications running on the server  101  and function as described above in connection with  FIG. 1 . The NVR  501  also includes and video/audio encoder cards  110 , for example Mpeg4 cards; and may include a storage device  140 .  
      As shown in  FIG. 5 , additional devices can be part of the system  500  and in communication with the computer network  555 . In the illustrated embodiment, the system  500  further includes video/audio input devices  520 , a second NVR  501 , a DVR  200  (which can be in further communication with devices  120 ,  130 ), one or more output devices  540 , one or more activation devices  530  and one or more network storage devices  570 .  
      The activation device(s)  530  is configured to signal the NVR  501  to begin recording video and audio data from the input devices  520 . The activation device can be any device capable of communicating with the NVR  501  over the network  555  and providing an activation signal. Examples of possible activation devices include a switch, a client computer, a voice input device, a motion detector, a timer, an alarm device, among others. The input devices  520  are, for example, video cameras having audio recording devices. Additionally, since the NVR is in communication with the computer network  555 , the NVR  501  can capture digital video and audio from any network-based source.  
      Since the NVR  501  is in communication with the network  555 , the NVR can communicate with network storage devices  570 . Accordingly, the storage control module  111  can write data to the network storage device(s)  570 . Similar to the DVR  200 , the NVR  501  storage module  111  can write user defined video segments to the storage device(s)  570  and can support a redundancy function.  
      The output device(s)  540  can be any device capable of communicating with the network  555  and outputting the video or audio data recorded by the NVR  501 . Like the DVR  200 , the NVR  501  can support multiple outputs from the input. In one embodiment, the NVR  501  can output four different streams (both audio and video) from a single input.  
      The system  500  also includes at least one user interface  505 . In the illustrated example the user interface  505  is provided through a client computer in communication with the network  555 .  
      Additionally, the NVR  501  is designed to consume considerably less power and less space than the DVR. The solid state design of the cards  110  in the unit consume very little power compared to a standard computer server, which can be used in the DVR  200 . It particular, the DVR  200  can have Pentium 4 processors, which consume a large amount of power. The NVR  501  can include very low power microcontrollers, including Transmeta, AMD, National Semiconductor and Texas Instruments microcontrollers. Each encoder card  110  contains the circuitry to capture, encode and transmit the recoded video to a network storage array. The cards  110  operate individually without a central processor. Storage of the data is accomplished through the network  555 . Therefore, internal storage on the NVR  500  can be eliminated. With fewer components than the DVR  200 , the NVR  500  can also be configured to consume less space. For example, the DVR  200  can be about 4U (about 7 inches high) whereas the NVR  500  can be about 1U (about 1.75 inches high), where the other dimensions of the DVR  200  and NVR  500  are similar.  
      The DVR  200  and NVR  501  are self aware, meaning that they recognize their existence in the network  555  architecture and automatically configure themselves to broadcast their capabilities to the software hosted by, for example, the user interface  505 . System administrators (not shown) then use this information to coordinate video captures through the network  555 . Therefore, the network  555  can be readily scaled to include additional DVR  200  and/or NVR  501  devices to support thousands of simultaneous captures from both remote and local locations, as long as the network architecture supports the bandwidth and the connectivity.  
      The processes and devices described above illustrate preferred methods and typical devices of many that could be used and produced. The above description and drawings illustrate exemplary embodiments, which achieve the objects, features, and advantages of the present invention. It is not intended, however, that the present invention be strictly limited to the above-described and illustrated embodiments. Any modifications of the present invention that come within the spirit and scope of the following claims should be considered part of the present invention.