JPH11112964A - Image transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To instantaneously switch over plural coded video streams with a simple configuration. SOLUTION: This transmitter is provided with a digital network interface 1 that interfaces plural communication paths which receive plural coded image information sets fixedly or selectively, a video decoder 5 that expands coded video streams, and a changeover control section 8 that selects an arbitrary path among plural the communication paths interfaced by the digital network interface 1 and connects the selected path to the video decoder 5 and the plural coded video streams are instantaneously switched over on a TV monitor 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoded image (moving picture, moving picture, etc.) via a digital network such as ATM (asynchronous transfer mode) or STM (synchronous transfer mode).
The present invention relates to an image transmission device for transmitting and receiving (still image) information.

[0002]

2. Description of the Related Art In a system in which a plurality of cameras are installed and image information from each camera is transmitted and monitored by an image transmission device, when an abnormality occurs, the cameras are immediately switched to carry out a check operation using images. Therefore, high-speed camera switching is required. FIG. 16 shows a general system example in which a plurality of encoded streams are decompressed and camera images are instantaneously switched and displayed. ATM interface unit 1
For example, PVC (Permanent Virtual)
A plurality of encoded streams are received through a connection (fixed connection), and a video decoder unit 41 is provided for each of the received streams.
Perform decoding processing. The decoded digital video data is input to the video switching unit 42, and switches the video to be displayed on the television monitor (TV) according to a video switching instruction from a PC (personal computer), WS (workstation), or the like.

[0003]

[Problems to be solved by the invention]

(1) The conventional device as described above has a problem that an expensive video decoder 41 is required according to the number of PVC connections of the ATM interface unit 1. Further, the ATM interface unit 1 is connected to an SVC (Switched Vir
As a method of switching (selection connection), a method of switching a communication path on the network N to control switching of a camera image can be considered. The release / new connection processing of the SVC connection also depends on the number of ATM switches. However, it usually takes more than 10 seconds,
Instant switching is not possible. (2) In the case of monitoring a plurality of coded streams collectively, for example, an external device such as a four-screen splitting device is arranged, or a frame memory is arranged at the output unit of each decoder as hardware equivalent thereto. However, a configuration for performing multi-display by controlling the reduction of the frame memory is required.

(3) In a case where a plurality of encoded streams are sequentially switched at certain intervals and displayed on a TV,
In the VC connection, a connection delay of about 10 seconds occurs after the switching instruction is issued. Further, in the PVC connection, it is necessary to connect all encoded streams on the network. (4) In the case where the connection of the SVC is switched according to the instruction of the operator, the connection delay after issuing the switching instruction is inevitable.

(5) When a certain part of the screen is cut out and divided and displayed, and the divided and displayed screen is panned / tilted by an operator, the pan / tilt is transmitted from the decoder to the encoder.
It is necessary to transmit chilled information and encode the pan and tilde parameters on the encoding side. For this reason, a transmission delay for transmitting pan / tilde information to the encoder, an encoding delay for encoding including pan / tilde information, a transmission delay for transmitting encoded data to the decoder, and decoding of pan / tilde information Decoding delay occurs.

[0006] (6) In the case of split display in a reduced size, hardware for arranging a frame memory at an output section of the decoder and performing reduction control is required. (7) As an instruction to switch a plurality of encoded streams, the operator can only instruct or switch after a certain period of time elapses using a timer. Therefore, an object of the present invention is to solve the above problems (1) to (7).

[0007]

According to the first aspect of the present invention, a plurality of communication paths for receiving a plurality of encoded image information are fixedly or selectively connected. Possible digital network interface means, a switching control unit for selecting an arbitrary communication path among a plurality of communication paths connected by the digital network interface means, and decompression of an encoded video stream including time stamp information A video decoder, a video stream buffer provided at the input side of the video decoder for storing at least one screen of a compressed video stream, and an initializing unit for initializing a time reference value of the video decoder when switching by the switching control unit. Means for generating video timing for the video decoder. And a video output interface for displaying video data decompressed by a video decoder on a television monitor, and switching and decoding a plurality of encoded video streams to enable switching and display on the television monitor. ing.

According to a second aspect of the present invention, a digital network interface means capable of fixedly or selectively connecting a plurality of communication paths for receiving a plurality of encoded image information, and the digital network interface A video decoder for expanding a coded video stream including time stamp information for a switching control unit for selecting an arbitrary communication path among a plurality of communication paths connected by the means, and an input unit for the video decoder A video stream buffer for storing at least one screen of the compressed video stream;
A plurality of sets are provided in combination with initialization means for initializing a time reference value of the video decoder at the time of switching by the switching control unit, while the plurality of video decoders are operated at a common display timing, and A video control unit that enables the output to be switched by video frame synchronization timing or a division timing obtained by dividing a video frame, and a video decoder that sets offset information in advance so that a monitoring point in the screen is at the center of the screen by a video decoder. And a video output interface section for displaying video data decompressed by a video decoder on a television monitor, switching and decoding a plurality of encoded video streams, and switching and displaying on the television monitor. , Split display The other is to allow the switching division display.

In the invention of claim 1 or 2,
Said digital network interface means;
An n + 1 communication path, which is one more than the number n of systems that can be decoded, is selected from a plurality of communication paths to enable connection, and the switching control unit selects the n + 1 communication paths connected to the digital network interface means. Any one of them is selected and connected to the video decoder, and the monitoring destination registration means storing the monitoring destination information for switching by the switching control unit, and the other one not connected to the video decoder By using the next connection destination read from the monitoring destination information to connect the communication path, adding a selective connection means for switching the communication path, after a certain time elapses a plurality of encoded video streams,
It is possible to switch and decode instantly and display on a television monitor without causing a switching delay (the invention of claim 3).

In the first or second aspect of the present invention,
Said digital network interface means;
An n + 1 communication path, which is one more than the number n of systems that can be decoded, is selected from a plurality of communication paths to enable connection, and the switching control unit selects the n + 1 communication paths connected to the digital network interface means. Any n of them are selected and connected to the video decoder, and the remaining one not connected to the video decoder is used to infer a communication path to be connected next from past and present connection information, and Addition of selective connection means for switching the communication path of the network in advance, when switching a plurality of encoded video streams, switch and decode without causing connection delay, instantaneous switching on the TV monitor Display can be enabled (the invention of claim 4).

According to the second aspect of the present invention, a setting means for setting pan / scan information for each of the divided windows is added to the video decoder, and based on the set pan / scan information, It is possible to change or add a coded video stream on the video decoder side (the invention of claim 5), or set the horizontal / vertical resolution of each window to be divided and displayed on the video decoder side. Resolution setting means and the set horizontal and
A transmitting means for transmitting the vertical resolution to a video encoder as a transmitting side is added. On the video encoder side, a changing means for changing the horizontal and vertical resolution of the encoding process from the received horizontal and vertical resolution is added. In addition, it is possible to switch a plurality of encoded video streams and display the divided video streams while suppressing the spread of the network bandwidth (the invention of claim 6).

[0012] In the second aspect of the present invention, information including the presence of a person detected by a sensor in a predetermined format in the user data area of the video stream and occurrence of abnormal noise is added to the video encoder. On the video decoder side, information extraction means for extracting user data information from all video streams on a communication path connected to the network, and user data information of the extracted video stream are provided. And switching means for switching the video stream connected to the network based on the video switching information determined by the switching control unit and connecting the video stream to the video decoder. The presence of a person added by the video encoder and the generation of abnormal noise Including information subjected to under the priority control, switching of the plurality of encoded video streams can allow the split display (the invention of claim 7).

According to the second aspect of the present invention, all the video streams on the communication path connected to the network are once received, and the number of bytes of the valid data excluding the dummy data of the video stream generated within a certain fixed time is determined. Extraction means for counting and extracting a quantization parameter for each picture, and monitoring the counted number of bytes and the quantization parameter with the passage of time, detecting a change in image information from both information, and switching the image display. A determination means for determining the priority is added, and the switching control unit switches the video stream connected to the network based on the video switching information and connects the video stream to the video decoder. From the coded stream of a certain time period. You can perform priority control to (the invention of claim 8).

[0014]

FIG. 1 is a block diagram showing a first embodiment of the present invention.
(Pocketized Elementary Sy
stem) stream buffer 2, MPEG-ES (E
elementary Stream) / PTS (Pre
Sentation Time Stamp (SEP) separation unit 3, STC (System Time Clock) updating unit 4, MPEG video decoder 5, D / A converter 6 as a video output interface, and T as a monitor
V7, a switching control unit 8, a video control unit 9, and the like.

The ATM interface unit 1 connects a plurality of predetermined communication paths by PVC and temporarily stores received data in reception buffers corresponding to the plurality of communication paths. There are as many receive buffers as there are communication paths.
The PES stream buffer 2 is a system clock (a clock corresponding to each pixel) of the encoder and the decoder.
Is a buffer for absorbing a shift in display timing, which is generated due to differences in the display timing. The MPEG-ES / PTS separation unit 3 separates the PES packet stream to which the time stamp information has been added into the time stamp information and the MPEG elementary stream (MPEG-ES).

The STC updating unit 4 monitors the PTS supplied to the MPEG video decoder and initializes the STC existing in the MPEG video decoder. Where PT
S is a cyclic counter that counts based on the system clock of the encoder, and STC is a cyclic counter that counts based on the system clock of the decoder. The PTS and the STC have a unit of a period of 90 KHz obtained by dividing a system clock 27 MHz by 300 with a numerical value of 33 bits. Here, the system clocks of the encoder and the decoder operate asynchronously.

Also, the MPEG video decoder has an MPE
It decodes a G video elementary stream and generates video data corresponding to screen display. In this example, since the PTS and the STC are asynchronous, the video decoder decodes and displays the PTS and the STC while comparing them. If the PTS is smaller than (STC + allowable value), the video decoder discards the current screen without decoding. Processing, PTS and S
Repeat until TC matches. In addition, PTS is (STC +
PTS is (STC + allowable value)
It operates to repeatedly display the current screen until it is within. The video controller 9 generates a system clock (clock corresponding to each pixel) and display timing, and the D / A converter 6 converts digital video data corresponding to screen display into an analog video signal. An external video switching request in accordance with an instruction from an operator or the like is input to the switching control unit 8. The switching control unit 8 controls the stream before switching to Pause, New Channel.
After issuing a command such as l to the video decoder and confirming the state of the MPEG video decoder 5, it switches to a receiving buffer corresponding to the switching instruction among the plurality of receiving buffers.

FIG. 2 is an explanatory diagram of a buffer connected to and disconnected from the video decoder. FIG. 2A shows a buffer to which a video decoder is not connected, and the number thereof is the number of communication paths -1 (FIG. 1).
In the example, only n-1) exist. FIG. 2B shows a buffer connected to the video decoder, and the number of buffers is one (there is a total of n buffers). Each buffer has a ring buffer format, writes received data at a position corresponding to a write pointer (WP), and updates the write pointer at the time of writing. The read operation is not performed in the buffer not connected to the video decoder in FIG.
Performs a read operation only on the buffer connected to the video decoder. The buffer data at the position corresponding to the read pointer (RP) is read, and the read pointer is updated at the time of reading. When the buffer is switched, the current WP is copied to the RP, and the buffer read operation is always performed so that WP ≧ RP.

When receiving the switching instruction from the switching control unit 8, the STC updating unit 4 detects the discontinuity of the PTS which is a cyclic counter, and then re-initializes the STC for the MPEG video decoder 5. The above operation is performed, and the size of the sequence (a series of screen groups having the same attribute) of the MPEG stream is set to 1 GOP (Gro
up of Pictures: a screen group that is a unit of random access), and by making one GOP the number of frames as small as possible, one sequence size time + reception buffer delay time + PE
The switching video is displayed with the S stream buffer delay time.

FIG. 3 is a block diagram showing a second embodiment of the present invention. This is the PES stream buffer 2,
In this example, a plurality of (here, four) MPEG-ES / PTS separation units 3, STC update units 4, and MPEG video decoders 5 are arranged in parallel, and a plurality of MPEG video decoders 5 are operated by a common system clock. PES
The stream buffer 2 is a buffer for absorbing a shift of a display screen caused by a difference in display timing when video streams encoded by different system clocks are switched and displayed in real time. The video control unit 9 controls each MPEG video decoder 5
Supplies a common system clock (clock corresponding to each pixel) and display timing, and controls output of video data output from each video decoder in synchronization with the display timing.

FIG. 4 shows an example of output control of the video decoder. For example, when there is a request for switching from the video decoders A to B, the output enable control of each video decoder is controlled in synchronization with the vertical synchronization signal as shown in FIG. (B), (c). As a result, the display screen can be switched without shifting when switching. In addition, in order to realize split screen display, output control is performed at timings at which the inside of the frame is accurately divided. FIG. 5 shows an example in the case of performing the 4-split display. That is, the output of each decoder is enabled in each of the horizontal and vertical periods in accordance with the divided display. For example, in the case of region A, Hac is used as a horizontal enable signal, and Vab is used as a vertical enable signal.
The output of the decoder displayed in the area A is enabled.

Further, the pan (P) displayed on the encoder side
By setting an offset including (an) and scan (Scan) in advance, it is possible to display the monitor point at the center position of the divided display area as shown in FIG. The display offset is determined by the FCHO (Frame Center Horizon) in the MPEG stream.
ntal Offset: the amount by which the display area is moved in the horizontal direction) and FCVO (Frame Center)
Vertical Offset: the amount by which the display area is moved in the vertical direction). As described above, it is possible to display a plurality of MPEG streams in a multi-mode without arranging a frame memory or the like in the output unit of the decoder.

FIG. 7 is a configuration diagram showing a third embodiment of the present invention. In this configuration, a display time control unit 21, a monitoring destination control unit 22, a monitoring destination registration unit 23, a connection control unit 24, and the like are added to the configuration shown in FIG. Is a feature that can be connected. 8 is a switching control unit. The display time control unit 21 outputs a switching instruction to the switching control unit 8 and the monitoring destination control unit 22 at regular intervals. Switching control unit 8
Selects four out of the five reception buffers at the switching instruction timing from the display time control unit 21 and connects them to each decoder. The monitoring destination control unit 22 reads out five communication paths from the monitoring destination registration unit 23 as the monitoring destinations registered in advance,
Output to the connection control unit 24. The connection control unit 24 issues a connection request to connect to the ATM network by SVC, and performs control for forming a communication path with a connection partner.

FIG. 8 is an explanatory diagram of an example of a receiving buffer selection procedure in the ATM interface unit 1. That is,
FIG. 8A shows an initial state, in which the first to fifth communication paths of the n communication paths are connected to the receiving buffer for the ATM network N, and the first to fourth receiving paths are connected to the decoder. Connect the buffer. After a certain period of time, as shown in FIG. 8B, the connection to the decoder 1 is switched from the reception buffer 1 to the reception buffer 5, and the communication path 1 for the ATM network N is disconnected, and the communication path 6 is disconnected. A connection request is issued to newly establish a connection, and the connection procedure starts.

In FIG. 8C, the connection to the decoder 2 is switched from the reception buffer 2 to the reception buffer 1 while the communication path 6 is in the connection completed state and the reception buffer is fetching data. , The communication path 2 is disconnected, a connection request is issued to newly connect the communication path 7, and the connection procedure starts. In FIG. 8D, the connection to the decoder 3 is switched from the reception buffer 3 to the reception buffer 2, and the communication path 3 for the ATM network N is disconnected.
Issue a connection request to newly connect the communication path 8;
Enter the connection procedure. Hereinafter, the same operation is repeated every elapse of a predetermined time, and after a communication path to be connected next is first connected using one more reception buffer, the communication path can be instantaneously switched upon a switching request. Generally, SVC
When connection processing for disconnection and reconnection is performed by the user, it usually takes ten and several seconds, and it takes ten and several seconds + buffer delay from when a switching request is issued to when an image is displayed. Since the communication path to be connected next is secured first based on the information of the registration unit, the screen can be switched instantaneously.

FIG. 9 is a block diagram showing a fourth embodiment of the present invention. In this configuration, a connection control unit 24, a connection information unit 25, a connection inference unit 26, and the like are added to the configuration shown in FIG.
The feature is that two communication paths can be connected. In the connection information section 25, information on a communication path currently connected and communication path connected in the past is stored in a memory. The connection inference unit 26 outputs a connection instruction that is considered to have a high probability of being connected first as a connection instruction based on current and past connection information. The connection control unit 24 is similar to FIG.
A connection request is issued to connect to the ATM network by SVC, and control is performed to form a communication path with the connection partner.

The function of the connection inference unit will be specifically described. As a first example, a reception buffer larger than the number that can be decoded is used as a connection cache of the ATM interface.
A method is conceivable in which a new communication path is formed by using an unused reception buffer without disconnecting the communication path of M, and connecting to the corresponding decoder after the connection is completed. In addition,
If all the receiving buffers are used, the oldest communication path among the connected communication paths is disconnected, and a new connection is made. In this way, switching to the video before several connections is performed without switching off the communication path of the ATM interface, so that only the reception buffer in the ATM interface section needs to be switched, and the video is displayed instantaneously. As another example, every time a video switching instruction is input from a certain connection state A, for example, A → B, A
The number of times of switching is counted by a counter corresponding to all switching patterns of → C, A → D... Before a switching instruction is input, a communication path having a large switching pattern count value is connected by an unconnected reception buffer. There is a way to do it. In the example of FIG. 9, four connection buffers and four non-connection buffers are used. However, by mounting more non-connection buffers, the probability of hitting the connection cache, which is a non-connection buffer, increases, and instantaneous switching can be performed. It becomes possible.

FIG. 10 is a block diagram showing a fifth embodiment of the present invention. This is achieved by adding a pan / scan information setting unit 10 and a stream changing unit 11 to the one shown in FIG.
The CVO is changed or added to the set pan scan value. That is, the MPEG-ES picture layer includes an ESCI (Extension Star).
t Code Identifier: indicates which extension data has been sent) and the ESCI is 0111
(Binary), Picture Displ
aExtension, followed by FCHO,
FCVO follows. Pi of each picture of MPEG-ES
Detects the Start Code, and searches for a stream in a predetermined bit unit.
It is checked whether Display Extension exists, and if it exists, FCHO and FCVO are rewritten. Conversely, if not present, PictureDisp
Add a layer extension and add FCHO, F
Add CVO. The above processing is performed by an operator or the like.
By performing the processing in real time on the decoder side based on the input pan / scan information, pan / scan within the divided screen becomes possible. Here, the MPEG video decoder uses the pan / scan information in the stream to
It is intended for a decoder whose screen offset position can be changed.

FIGS. 11 and 12 are block diagrams showing a sixth embodiment of the present invention. FIG. 11 shows an example of a decoder, and FIG. 12 shows an example of an encoder. In the decoder of FIG.
3 is different from that shown in FIG. 3 in that a compression parameter transmitting unit 27 for receiving compression resolution information and setting resampling on / off is provided. Resampling means that the compression resolution is 352 which is a standard in MPEG1.
Pixel x 240 lines, resolution standard CCIR-6
The pixel is complemented to 720 pixels × 480 lines having a resolution of 01.

The encoder shown in FIG. 12 comprises a camera 31, a video control unit 32, an A / D converter 33, an MPEG video encoder 34, a parameter change unit 35, a PES stream generation unit 36, an ATM interface unit 1A, and the like. The A / D converter 33 converts an analog video signal into digital data. The video control unit 32 generates a synchronizing signal and a pixel clock (system CLK: 27 MHz) from the input video signal.
5 sets the received compression parameters in the MPEG video encoder 34, the MPEG video encoder 34 performs MPEG compression based on the set parameters, and
The S stream generator 36 adds a time stamp generated from the system clock to the MPEG-ES, and the ATM interface 1A performs connection processing with the decoder and transmits and receives input / output data. For example, when the parameter at the time of compression is set to 352 pixels × 240 lines, the encoder performs sub-sampling (decimation processing) from the resolution of CCIR-601, compresses the data at the set resolution, and the decoder responds to the resolution in the stream. Decoding is performed, but by turning off resampling, conversion to full screen (720 pixels × 480 lines) is not performed, and the image is displayed in a designated display area at a resolution of 352 pixels × 240 lines. By doing as described above, the reduced display of the divided screen can be performed without arranging a frame memory or the like for the reduced display.

FIG. 13 is a block diagram showing a seventh embodiment of the present invention. This is characterized in that a user data extraction unit 28 and a priority control unit 29 are added to the configuration shown in FIG. UDSC (User Data Start Code) is included in the sequence header of MPEG-ES.
e: Synchronous command 0000 indicating start of user data
01B2 [H]) and UD (User Data). The UD has a bit length of 8 × n, and the format is free. On the encoder side, abnormal information detected by a sensor or the like is inserted into the UD in a predetermined format in a predetermined format, and the user data extracting unit 28 on the decoder side is inserted.
Then, the stream is read from the reception buffers corresponding to all the communication paths connected to the ATM, and the UD present in each sequence header is extracted. The extraction of the UD is performed by detecting the synchronization code of 000001B2 [H] for the received data, and only the subsequent UD is transmitted to the priority control unit 29. The priority control unit 29 detects the presence or absence of an abnormality, determines the priority of the video display based on the abnormality level,
A switching instruction request is sent to the switching control unit 8.

FIG. 14 is a block diagram showing an eighth embodiment of the present invention. This is characterized in that a valid data count unit 20 and a priority control unit 29 are added to the configuration shown in FIG. By the way, as shown in FIG. 15, there are three types of MPEG-PES streams: private 1 packet, private 2 packet, and padding packet. All padding packets are composed of padding bytes. There is something called a stuffing byte. The padding byte and the stuffing byte are dummy data bytes, and have no sign.
It is used to keep the packet data length constant and the bit rate constant.

The MPEG compression system includes an intra frame (compressed frame within a frame) and an inter frame (compressed frame between frames). Interframe compresses the difference from the motion compensated screen,
If the quantization parameter is the same when there is a lot of movement,
The code amount increases. To keep the bit rate constant,
The operation is performed so as to increase the quantization parameter value to lower the in-frame image quality. Here, the valid data counting unit 2
0 means that valid data generated within a certain time is counted by subtracting padding bytes and stuffing bytes from the total data amount, and MPEG
-Extract the quantization parameter value of each frame in the ES and send out valid data and quantization parameters to the priority control unit 29. The priority control unit 29 compares the effective data extracted from each stream with a change in the quantization parameter, and issues a video switching request. As described above, the moving image is decoded and displayed after being automatically switched.

[0034]

According to the first aspect of the present invention, a plurality of encoded streams can be instantaneously switched and displayed on a TV monitor by a single or a limited number of video decoders. Equivalent functions can be maintained. According to the second aspect of the present invention, it is possible to multi-display decoded digital video data without arranging a frame memory in an output section of a video decoder. According to the invention of claim 3, without causing a delay at the time of switching the encoded stream in the SVC connection,
It is possible to sequentially switch and display the information on the TV monitor at certain time intervals.

According to the fourth aspect of the present invention, when switching is performed by an operator's instruction in the SVC connection, the switching is performed while the connection delay is minimized, and decoding is performed.
Can be displayed. According to the fifth aspect of the present invention, each screen divided and displayed can be displayed on the TV monitor by panning / tilting without transmitting pan / tilt information to the encoder. According to the sixth aspect of the present invention, it is possible to perform a reduced-split display without hardware for arranging a frame memory in an output section of a decoder and performing reduction control.

According to the seventh aspect of the present invention, it is possible to perform a priority control on the decoder side based on the information on the abnormality detected on the encoder side, and to switch and display the screen. According to the eighth aspect of the present invention, image change information is detected from each encoded video stream, and priority control is performed based on the information, thereby enabling switching display of a screen.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the buffer shown in FIG. 1;

FIG. 3 is a configuration diagram showing a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of an output control method of a video decoder.

FIG. 5 is an explanatory diagram of a multi-screen display method.

FIG. 6 is an explanatory diagram of a display method of a split screen.

FIG. 7 is a configuration diagram showing a third embodiment of the present invention.

FIG. 8 is an explanatory diagram of a connection transition example of a reception buffer in FIG. 7;

FIG. 9 is a configuration diagram showing a fourth embodiment of the present invention.

FIG. 10 is a configuration diagram showing a fifth embodiment of the present invention.

FIG. 11 is a configuration diagram showing a sixth embodiment of the present invention.

FIG. 12 is a configuration diagram illustrating an example of an encoder corresponding to FIG. 6;

FIG. 13 is a configuration diagram showing a seventh embodiment of the present invention.

FIG. 14 is a configuration diagram showing an eighth embodiment of the present invention.

FIG. 15 is an explanatory diagram of a data structure of an MPEG-PES stream.

FIG. 16 is a configuration diagram showing a conventional example.

[Explanation of symbols]

1, 1A ATM interface unit, 2 PES stream buffer memory, 3 MPEG / ES-PTS separation unit, 4 STC update unit, 5 MPEG video decoder, 6 D / A converter, 7 TV (television) Monitor), 8
... Switching control unit, 9 ... Video control unit, 10 ... Pan / scan information setting unit, 11 ... Stream change unit, 20 ... Valid data count unit, 21 ... Display time control unit, 22 ... Monitoring destination control unit, 23 ... Monitoring Destination registration unit, 24 ... connection control unit, 2
5 Connection information section, 26 Connection inference section, 27 Compression parameter transmission section, 28 User data extraction section, 29 Priority control section, 31 Camera, 32 Video control section, 33 A /
D converter, 34: MPEG video encoder, 35: parameter changing unit, 36: PES stream generating unit, 41
... video decoder section, 42 ... video switcher.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 7/081

Claims (8)

[Claims] 1. Digital network interface means capable of fixedly or selectively connecting a plurality of communication paths for receiving a plurality of encoded image information, and a plurality of communication paths connected by the digital network interface means A switching control unit for selecting an arbitrary communication path from among the communication paths, a video decoder for expanding an encoded video stream including time stamp information,
A video stream buffer provided at the input side of the video decoder for storing at least one screen of the compressed video stream, initialization means for initializing a time reference value of the video decoder at the time of switching by the switching control unit, A video control unit for generating video timing for a video decoder and a video output interface unit for displaying video data expanded by the video decoder on a television monitor are provided for switching and decoding a plurality of encoded video streams. An image transmission apparatus characterized in that it can be switched and displayed on a television monitor. 2. Digital network interface means capable of fixedly or selectively connecting a plurality of communication paths for receiving a plurality of encoded image information, and connected by the digital network interface means. A video decoder for expanding an encoded video stream including time stamp information for a switching control unit for selecting an arbitrary communication path among a plurality of communication paths, and a compressed video signal provided at an input unit of the video decoder. A video stream buffer for storing at least one screen of a stream; and a plurality of initialization means for initializing a time reference value of a video decoder at the time of switching by the switching control unit. Operate at the same display timing, A video control unit that enables the output from the video decoder to be controlled by video frame synchronization timing or division timing obtained by dividing the video frame, and offset information is preset by the video decoder so that the monitoring point in the screen is at the center of the screen. And a video output interface for displaying video data decompressed by a video decoder on a television monitor, switching and decoding a plurality of encoded video streams, and An image transmission apparatus characterized in that a switching display, a division display, or a switching division display is made possible by using (1). 3. The digital network interface means selects n + 1 communication paths, which is one more than the number n of systems that can be decoded, from a plurality of communication paths, enables connection, and sets the digital path by the switching control unit. Monitoring destination registering means for selecting any n out of n + 1 communication paths connected to the network interface means, connecting to the video decoder, and storing monitoring destination information for switching by the switching control unit; And selecting connection means for reading the next connection destination from the monitoring destination information using the remaining one not connected to the video decoder, connecting the communication path, and switching the communication path, and adding a plurality of codes. After a certain period of time has elapsed, the switched video stream is instantaneously switched and decoded, and switching delay on the TV monitor is delayed. The image transmission apparatus according to claim 1, wherein the image transmission apparatus can perform display without generating the image. 4. The digital network interface means selects n + 1 communication paths, which is one more than the number n of systems that can be decoded, from a plurality of communication paths, enables connection, and controls the digital control by the switching control unit. Any n of n + 1 communication paths connected to the network interface means are selected and connected to the video decoder, and the next one is connected using the remaining one not connected to the video decoder Is inferred from past and present connection information, and selective connection means for switching the communication path of the network in advance is added,
3. The method according to claim 1, wherein, when a plurality of encoded video streams are switched, switching and decoding are performed without causing a connection delay, and instantaneous switching display is enabled on a television monitor. An image transmission device according to any one of the above. 5. A video decoder is provided with setting means for setting pan-scan information for each of the windows displayed in a divided manner, and the video decoder encodes the pan-scan information based on the set pan-scan information. 3. The method according to claim 2, wherein the video stream can be changed or added.
An image transmission device according to claim 1. 6. The video decoder comprises: resolution setting means for setting the horizontal and vertical resolution of each window to be divided and displayed; and transmission means for transmitting the set horizontal and vertical resolution to a video encoder as a transmission side. While adding
On the video encoder side, a change means for changing the horizontal and vertical resolution of the encoding process from the received horizontal and vertical resolution is added, and switching of a plurality of encoded video streams is performed while suppressing the spread of the network bandwidth. 3. The image transmission apparatus according to claim 2, wherein divided display is enabled. 7. On the video encoder side, an information adding means for adding information including presence of a person detected by a sensor and occurrence of abnormal sound in a predetermined format in a user data area of a video stream is added. On the video decoder side, on the other hand, information extraction means for extracting user data information from all video streams on a plurality of communication paths connected to the network and user data information of the extracted video stream are compared, and video display is performed. By adding a determination means for determining the priority of switching, by switching the video stream connected to the network based on the video switching information determined by the switching control unit and connecting to a video decoder, the video encoder Priority control based on information including the presence of persons added and the occurrence of abnormal noise 3. The image transmission apparatus according to claim 2, wherein a plurality of encoded video streams can be switched and divided and displayed. 8. A method of receiving all video streams of a plurality of communication paths connected to a network once, counting the number of bytes of valid data excluding dummy data of a video stream generated within a certain period of time, and Extracting means for extracting the quantization parameter of the above, monitoring the counted number of bytes and the quantization parameter with the passage of time, detecting a change in image information from the information of both, and determining the priority of video display switching Means for switching the video stream connected to the network based on the video switching information and connecting the video stream to the video decoder by the switching control unit, so that all of the encoded streams connected to the network can be switched from one to another. Priority control by detecting image change information that occurs during a certain period of time The image transmission device according to claim 2, wherein: