JP2001251650A - System and method for testing compressed digital broadcast video during operation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system and a method for testing broadcast video signals that are analog/digital converted or digital/analog converted during operation. SOLUTION: An MPEG-2 encoder/decoder applies analog/digital conversion or digital/analog conversion and compression to a video frame received via a network. Each gateway includes a test pattern generator and a test memory analyzer that are used for an in-operation test of the video signal. The test pattern generator dynamically arranges a test signal to a line selected in advance for a VBI period in the video frame at a period of the frame by adopting a concealment technology. The test pattern generator and the test memory analyzer are synchronized by using a vertical integral time code and a trigger packet sent from a transmission station.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to video data transmission systems and, more particularly, to in-service testing of compressed digital broadcast video.
testing).

[0002]

2. Description of the Related Art In a video communication network, MP
Moving Picture Expert Group (EG) 2 compression algorithms and ATM networks can create perturbations in video transmission signals that are not normally found in analog-only networks. In order to detect network abnormalities and faults in real time, live circuit tests are performed so that service is restored with minimal circuit downtime. EIA
Techniques for in-service testing of the / TIA 250C are well known in the television industry. Broadcasters have historically used both fields of video blanking interval (VBI) lines 10-20 to insert test signals. The VBI also includes Closed Caption Text and Motion Picture and Television Engineers Association (SMP).
TE) time code is also incorporated. The VBI is not part of the active video area and is therefore not visible to the viewer.

However, since the MPEG-2 video encoder filters each screen or frame except for VBI lines 1 and 21 to reduce the transmitted bandwidth, the encoder pre-filters in-service testing. are doing. The video encoder copies the SMPTE time code into a group of pictures (GOP) and converts the closed caption text to MPEG
-2 sent as user data in the form of a transport stream. The test signal is ignored. At the end of the reception, the VBI line is reproduced by the MPEG-2 decoder and the SMPTE time code and closed caption text are reinserted. However, VBI has no test signals at all. Therefore, the in-service test is limited to the following two tests. That is, (1) a sync pulse amplitude test, and (2) a chrominance burst amplitude test that basically confirms the presence or absence of video. These tests cannot measure or evaluate the quality of the video.

[0004] Such limitations of the MPEG-2 video encoder often require that a test signal be inserted into the VBI at the point of signal generation in order to test end-to-end video quality. It is an obstacle for broadcasters. Their video transmission is MPEG-2
If compression is received at any stage, the VBI test signal will be lost.

The prior art relating to in-service testing of video transmission systems includes the following patents. That is, 1992
U.S. Pat. No. 5,617,148, filed Sep. 15, 1997 and issued on Apr. 1, 1997 (inventor: Montgome
ry) is a controlled element for spectral attenuation or a secondary signal to the video signal without distorting the blanking interval of the video signal or the closed caption data contained in the blanking interval. Discloses a control filter used to aid insertion of the control filter.

US Pat. No. 4,969,041 issued on Nov. 6, 1990 (O'Grady) teaches that data is added to a video signal by adding a low-level waveform to the video signal. It is disclosed to be incorporated.
The low level waveform has a level below the noise level of the video signal and corresponds to the data. To detect the data embedded in the video signal, the video signal is correlated with a low-level waveform corresponding to the data to generate a correlation coefficient. A high correlation coefficient indicates the presence of a low-level waveform that is converted to data. Because the low-level waveform spreads over many video lines, to avoid fixed pattern noise anomalies that can be detected by the viewer,
It does not occur at or near the same location within one video frame for many frames.

[0007] filed on April 15, 1994,
U.S. Patent No. 5,585,8 issued December 17, 2006
No. 58 (Harper) discloses a system for simulcasting fully interactive programs and legitimate general programs at the same standard video signal bandwidth.
The unused lines of the video are preferably used to incorporate additional interactive response audio channels and graphics and control data. Alternatively, the interactive audio segments may be provided continuously or one at a time on an audio subcarrier or on a cable guard band, or may be pre-stored in memory in an interactive program box. More audio and graphics can be provided through the use of external storage or game cartridges. Additional data is entered into designated trigger points in the system through the use of overlaid logic sent in embedded code in the signal or software resident at the receiver location in software.

[0008] filed on June 14, 1991,
U.S. Pat. No. 5,572,24 issued Nov. 5, 2006
No. 7 (Montgomery) discloses a signal processor for enabling transparent reception of data signals in the video bandwidth of a cable television system. The received signal has video and data components frequency-interleaved in the video bandwidth with active video intervals. The data signal is modulated with a carrier at non-zero times the horizontal scanning rate of the video signal. The receiver selects a forward channel for transmitting the combined signal in response to the control signal,
Extract the data portion of the transmitted combined signal.

Filed on February 24, 1994, 199
U.S. Pat. No. 5,557,33, issued Sep. 17, 2006
No. 3 and US Pat. No. 5,327,237 filed Jun. 14, 1994 (Jungo) permit transparent simultaneous transmission and reception of secondary data signals with video signals in the video band. A signal processor is disclosed. A signal processor at the transmitter rasterizes the data at the horizontal scan rate and modulates the data with a data carrier at a non-integer multiple of the horizontal scan rate to obtain frequency interleaving. Data is transmitted during the active video portion of each video line.

[0010] filed on October 31, 1994,
US Patent No. 5,663,76, issued September 2, 1997
No. 6 (Sizer) discloses a system for communicating digital information with a video signal. The system includes an encoder configured to add a carrier signal modulated with digital information to a video signal. A carrier signal modulated at a frequency other than a certain frequency corresponds to a peak in the video spectrum. The receiver is configured to optionally sense the video signal and to recover the encoded digital information in the video signal.

In view of the prior art, in order to measure or evaluate the quality of the video in a way that is transparent to the viewer, a video test signal is inserted into the VBI or the overscan area or the active area, the MPE.
In-service testing of video transmission needs to be performed according to the G-2 compression algorithm.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide an MP
It is an object of the present invention to provide a system and method for performing live testing of a video transmission subject to EG compression.

It is another object of the present invention to provide a method for inserting a test signal for evaluating video quality in a video transmission when the video transmission is subjected to MPEG-2 compression.

It is another object of the present invention to provide a system and method for concealing a video test signal in a video transmission in a manner that makes the test transparent to the viewer.

It is another object of the present invention to provide a system and method for dynamically placing a video test signal within an active display area of a base video transmission based on the content of a video broadcast. .

Another object of the present invention is to remove the video test signal from the video blanking interval and periodically insert the test signal into the active video area of the video transmission to provide MPEG-2 video. -To provide a system and method for avoiding encoder filtering.

Another object of the present invention is to provide a system and method for retrieving a test signal from an active video area of a transmission and placing the test signal in a newly created video blanking interval. It is in.

It is another object of the present invention to provide a system and method for generating a continuous test signal at a recovered video blanking interval while receiving an intermittent test signal of varying period. Is to do.

[0019]

SUMMARY OF THE INVENTION These and other objects,
Features and advantages are achieved in a video transmission system that includes a command and control (CAC) operations center coupled to a wide area TCP / IP network for remotely controlling local video stations. Each station has a POP (Points of Presen)
ce) coupled to an Asynchronous Transfer Mode (ATM) network through a gateway. Each POP is A
Interfaces with the network through a TM switch. In the startup POP, the subscriber video feed is routed to an analog video switch coupled to a vertical interval test signal (VITS) generator and signal analyzer. The switch is MPEG-
It is connected to a multiplexer via two encoders. The multiplexer multiplexes the output of the MPEG-2 encoder into a series of I / Os for delivery to the ATM switch.
A single OC-3 video transport stream of pictures occurring in frames, B frames, and / or P frames. To test video quality, the VITS generator sends an NTSC color bar test pattern to the remote POP.

The test signal is placed in the video blanking interval (VBI) of the frame without affecting the active video. The modified digital stream is sent to an MPEG video encoder for encoding. A test signal insertion controller forms a trigger data packet that is sent to a downstream test signal extractor. If a CRC error is detected, each trigger data packet is sent twice just in case. The trigger data packet is stored in the VBI test signal table. The test signal is brought out of the display area using a concealment technique. Video logic determines the concealment of the test signal. The overscan area of the frame is tested to determine if there is available space for the test signal. If such space exists, one line is selected and the concealment mode is calculated. If the overscan area is full, all available safe action lines are ranked by motion and content. Test signals already inserted reduce the number of available lines.
The line separation parameter excludes other lines from consideration so that test signals are not juxtaposed. A concealment score is calculated for each line. Safelines are ranked by concealment score.

If the highest score is greater than a predetermined quality threshold, the line, mode and score are returned. Otherwise, the available title safe lines are ranked according to the motion content score. Scoring is weighted for lines with missing content and lines with static motion. Then, in synchronization with the display of each frame, a test signal from the test signal storage is inserted into the video blanking area for each active video blanking interval line entry. The test signal in the active video area is concealed by inserting the video lines retrieved and formed from the stored pictures according to the concealment mode included in the trigger packet. The restored video line is sent for digital-to-analog conversion. The test signal insertion controller determines when and where to insert a test signal into the digital video transport stream. At the end of the reception, an analog switch switches the output to a test signal analyzer for measurement and analysis. The time code associated with the frame is compared to the current frame. The entry is removed from the extractor test signal trigger table and a flag is set in the VBI line table.

During frame reconstruction, the test signal extractor loops through the active VBI table entries and inserts the stored test signal. If the concealment flag is set, the currently processed frame is moved from the current picture to the test signal line. There, the test signal is copied from the signal line storage to the target VBI line field of the current picture. If the current frame contains a concealment flag, the video line is concealed. The concealment mode in the VBI table is decoded. The line with the test signal is repaired using the next line above and below the line requiring repair. Thus, in-service testing is accomplished on digitally compressed video using concealed video test signals inserted in the video blanking area of the I-frame. In that case, the concealed video test signal is identified by the extractor's test signal trigger table and the extractor's VBI line table during frame reconstruction of the I-frame.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an asynchronous transfer mode (AT
M) three POPs (Po
ints of Presence) or gateways 100, 105,
1 shows a video transmission system 10 including: AT
M-network 115 sends high bandwidth broadcast video to gateways by digitizing and compressing analog signals. The digitized signal is converted to an analog signal at the receiving gateway and sent to the subscriber. Command and Control Center (CAC) 1
20 remotely controls their POP gateways.

The POP gateway is an ATM switch 1
40 to an ATM network 115 via an OC-3 (155 Mbps) access line 118. The POP gateway has a set of access lines 128, 129 that carry analog video signals to and from the subscriber. The access lines are connected to an analog video switch 132, which allows the access line 118 to be switched to a dedicated MPEG-2 encoder 136 or decoder 137. The POP gateway interfaces with the ATM network 115 via the ATM switch 140. On the sending side, AT
The M-switch is connected to a multiplexer (Mux) 138 that multiplexes the output of the MPEG-2 encoder into a single OC-3 transport stream. A vertical interval test signal (VITS) generator 130 and a signal analyzer 134 are wired to switch 132 to test the video quality of each newly established video circuit.

The network data addressed to the POP gateway is routed to a demultiplexer 139 that demultiplexes the OC-3 data into a separate MPEG-2 transport stream. Output subscriber line 129 provides signals to the subscriber.

The CAC 120 is connected to the computers 172, 1
The video connection is established and released by commands generated under the program control of the software executive at 73. These computers are TCP / I
Maintain a continuous connection to each POP gateway via the P wide area network 174 to control the POP devices and monitor alarm conditions.

FIG. 2 shows a typical video connection from a POP gateway 300 in Los Angeles to a POP gateway 400 in Washington DC. The gateway 300 is connected to the analog tape from the video tape recorder 321 via the customer's private access line 328.
Supply video. Analog switch 384 routes path 380 to the first available MPEG-2 encoder 336. The signal is the multiplexer 3
Continue to 38. So the signal is that it is an ATM
An ATM address is provided that allows it to be properly routed by the switch 340 and the ATM network 445. In the receiving POP gateway 400, the demultiplexer 452 is connected to the ATM switch 450.
Demultiplexes the collective OC-3 signal received from
The demultiplexed MPEG-2 transport stream is routed to a dedicated MPEG-2 decoder 454. The analog video output of the MPEG-2 decoder is sent to analog switch 456, where the analog video
The switch switches those signals to the customer's private access line 463 for display on the video monitor 470.

Immediately after establishing a connection, but before switching the subscriber lines 328, 463 to connection paths 380, 485, a vertical interval test signal (VITS)
Device 332 can switch connection to switch 382 to send the NTSC color bar test pattern to remote POP gateway 400. At the receiving POP gateway 400, an analog video switch 456 switches the output of the decoder 454 to a test signal analyzer 458 for measurement and analysis. After a test period of a few seconds, the test equipment switches the output and subscriber lines to an active connection and the circuit is switched to the subscriber. If the color bar test fails, the circuit will be deactivated and a new video connection will be established using a completely different set of network resources. There, the new connection will be tested before release to the subscriber.

FIG. 3 shows the components of CAC center 402. The CAC center maintains a database 418 of each subscriber reservation. The subscriber makes a reservation for the video circuit from his computer 405 with a web browser. After connecting to the booking web server 416, the subscriber is printed a web page requiring the booking data. A reservation request is sent to the reservation system 414.
The system 414 controls the network resource manager 4 to ensure that there are sufficient resources in the network to establish the circuit at the time of the request.
Request 10 Meanwhile, the network resource manager 410 requests the network resource database 412 to check the availability of access lines, encoders and decoders, and network bandwidth. If no resources are available to take on future connections, network resource manager 410 updates resource database 412 and responds positively to reservation system 414. Thus, the network reservation system 414 updates its reservation database 418. Booking Web Server 416
Informs the subscriber of the confirmed reservation by refreshing the reservation request web page.

FIG. 4 shows a pre-order web page in which the subscriber reserves bandwidth for future video transmissions. The subscriber has the connection start date (Start Date) and start time (St
artTime) 605 and an end date (Stop Date) and an end time (Stop Time) 610. In addition, start port (O
rigin Port 615 and destination port 62
A POP location of 0 is also specified. At the time of submitting the reservation (Submit) 640, the web page will refer to the calculated Duration (Duration) 625 of the connection, the Reservation Status Confirmed 630, and the reservation for future transmissions. Is updated, the unique reservation ID (Reservation ID) 650 used for is updated.

Returning to FIG. 3, the network resources
In addition to accepting the new reservation, the manager creates a new video connection at the requested time and destroys the connection when the reservation expires. This process is called AT
M switch control 430, analog switch control 432, test equipment control 43
4 and by issuing commands to the MPEG-2 device control 436 to a set of program executives. On the other hand, these program executives generate hardware-specific commands to slave devices in the wide area network 445 accessed through the IP router 440. Each executive runs on a separate computer with a user console that allows the network operator to perform manual control of the POP device when operator intervention is deemed necessary. However, control of the entire network is controlled by the network resource manager 41.
Activated fully under control of zero. As each executive issues a command and detects a POP alert condition, the network status is updated at the operator console 438 and printer 425, which are continuously monitored by the network operator.

Each POP includes an IP hub 490 which is a gateway to the network 445. From that hub, an Ethernet line 495 connects to each set of networking devices and terminal server 462. The terminal server communicates with the test equipment controller 434 from the wide area IP network 445 through the RS.
-Enables remote control and monitoring of all test signal generators and measurement sets via the -322 control interface. The present invention provides MPEG-2 video
Incorporated as an accessory into the encoder / decoder system. MPEG-2 is based on "moving picture
Expert Group (MPEG) standards, video coding and related audio ITU Recommendation H.262 (Moving
PicturesExpert Group (MPEG) Standard, Coding of Mov
ing Pictures and Associated Audio ITU Recommendati
on H.262) ". We will now review some relevant aspects of MPEG-2 compression to facilitate an understanding of the present invention.

FIG. 5 shows the prior art relating to the MPEG-2 video layer hierarchy. In FIG.
An MPEG-2 data stream consists of a video stream and an audio stream, both of which are packed into a stream of the system. There is another layer in the video stream. The highest layer is the video sequence layer 80, which contains information relating to the entire sequence. Video sequence 8
0 is divided into picture groups (Group of Pictures-GOP) 82 containing one or more video frames. Video frames, the odd and even fields interlaced to create a 525 line frame, form the third layer, the picture layer 84.
The picture is further divided into horizontal section 85 slices. The slice layer consists of a continuous macro block 87, which consists of the bottom layer of an 8 × 8 pixel block 89.

In FIGS. 6 and 7, MPEG-2 encoding is referred to as the type of sampling used to encode the luminance (Y) and chrominance (CrCb) video components 4: 2:
Use 0 or 4: 2: 2 format. In FIG. 6, 4: 2: 2 or 4: 2: 0 format sampling gives 2Cr and 2Cb samples for every 4 luminance samples. CrCb samples are reduced to 1 each in 4: 2: 0 format. The location of a single CrCb for the Y sample is shown in FIG. When compressed at a rate of 15 Mbps or more, as shown in FIG. 7, excellent results are obtained using 4: 2: 2 sampling. One MPEG-2 encoder supporting 4: 2: 2 sampling format
It became available in 998.

Returning to FIG. 5, the GOP includes the following 3
Two types of pictures, I-frames,
There are frames; P frames, ie, predictively motion compensated frames; and B frames, ie, bidirectionally motion compensated frames. The B frame is a picture of the minimum size. This is because they are encoded using motion estimation from both the previous I or P frame and the next I or P frame. P frames are predicted from previous I or P frames, which are large in size. I-frames are independently coded and are much larger.

A GOP series frame begins with an I frame. The I frame is followed by a series of B and / or P frames. The more B-frames used, the more efficient compression at reduced video quality prices. The IBP sequence is a video encoder configuration parameter set by the user according to the requirements of the application. I-frames may be generated automatically for changing conditions or when motion compensation cannot be used effectively.

FIG. 8 shows some well-known television test signals used to test video performance and quality over a transmission system. FC
C multiburst 700 provides a test signal for frequency response. NTC7 composite 710 allows for amplitude and phase measurements. NTC7 combination 72
0 provides frequency response and distortion testing. FCC color bar 730 provides amplitude and timing measurements.
One or more of these test signals can be included in a video blanking interval for in-service testing as described below.

A. Operation of Test Signal Injector FIG. 9 shows a block diagram of the test signal injector 1102. Video signal input 1100 is SMPTE time
It is processed to monitor the code and the VBI of each frame, and to detect the presence of the VBI test signal in the VBI test signal detector 1110. Any non-black signal on the VBI lines 10 to 20 in either field is treated as a test signal. When test signals are detected, they are stored in test signal storage 1170.
Is stored. The motion detector 1130 examines the incoming video for changes in motion and context, while the video concealer 1140 compares the video line from the current frame with the video lines from the previous and next frames. Individual video lines are scored by the completion of the restoration. Compressing and decompressing the signal at the injector to accurately score the concealment results likely to occur at the downstream extractor for the compressed and decompressed video, and current forward and reverse picture storage It is necessary to process.
An MPEG-2 video encoder 1195 is used as a quasi-pass encoder to obtain a picture store that predicts I-frame generation. This will be described in more detail later.

The test signal insertion controller 1150 includes:
The test signal is transmitted to the digital video stream 1100.
Is determined when and where to insert (1155). There, a modified serial digital video 1160 is converted to an MPEG-2 video for encoding.
Sent to the encoder. Controller 1150 may further include a T
Trigger data packet 1 sent downstream to alert the S extractor (see FIGS. 18 and 19)
Form 180. VBI test signal table 1197
Stores insertion controller status data.

In FIG. 10, the injector trigger
The packet is stored in the VBI test signal table 1200. The VBI test signal table indicates that the packet has 2
Transmission count 120 to ensure that the
4, including an I-frame count 1202 that tracks the number of times an I-frame was sent without an inserted test signal. No test signal is inserted into the I-frame during important scene changes or when concealment is deemed ineffective. This does not affect the output of the TS extractor as the TS extractor continues to repeat the test signal on the VBI line. Up to three consecutive I frames can be skipped without effect. After the extractor sees four consecutive I-frames without a test signal,
It drops the test signal and restores the VBI line to black. The signal transmitted flag 1206 is T
Indicates that the S extractor has processed at least one I-frame with one inserted test signal.

The injector test signal trigger packet 1208 is shown in Table 1209. The modified I-frame time code 1210 is sent in the first field. The time code has the same value and format as the time code found in the GOP header preceding the I frame. Markers 1215 and 1235 are included in the data structure to eliminate start code emulation according to the MPEG-2 specification. The next two fields are a VBI line ID / field 1220 from which the test signal is taken out and a video line ID / field 1220 to which the test signal is moved.
Field 1230. A line count 1240 is sent indicating that one or three lines have been used to transmit the test signal. The three lines are 4:
Used in 2: 0 format. The recommended concealment mode 1250 is also sent to optimize the restoration of lost video lines. The hidden mode field is
Store up to three concealment mode values (3 × 16 bits) to facilitate the restoration of three lines in 4: 2: 0 mode. Each concealment mode value 1255 is a 16-bit structure containing the lines used to form the concealment mode, pixel shift count, and repair. The entire data packet is protected by CRC 1270 for error detection. The packet is sent as PES personal data, which is 128-bit personal data obtained in the PES header. Stuffing field 12
60 is used to embed the data block to 128 bits. If multiple test signals are present in the VBI, separate trigger packets are generated for each.

If a CRC error is detected in the first packet, each trigger packet is sent twice, just in case. When a test signal is detected, it is scheduled to be sent on the next I frame. If there is a certain amount of encoding delay and latency inside the video encoder, the downstream TS extractor will receive several frames of the trigger packet before the arrival of the test signal. Using time codes to detect target I-frames makes injector / extractor interactions insensitive to frame buffering or latency in the system.

In FIG. 11, the text signal trigger data 1280 is packetized as video program elementary stream (PES) personal data embedded in the video private elementary stream. Therefore, the test signal is transmitted to the transport stream multiplexer 1284 by the audio PES 1288 and the program system information 1.
Multiplexed with the MPEG transport stream. Incorporating the trigger packet into the video PES strongly couples the test signal trigger packet with the video. Multiple video PEs, each carrying its own test signal and trigger packet
The S stream may be multiplexed.

FIG. 12 shows the logic flow of the test signal insertion controller shown in FIG. For each frame, a loop is entered (blocks 1510-1570) to see if there are any trigger packets to transmit (block 1520). If there is such a trigger packet, the packet is sent (block 1530) and the transmission count is zeroed (block 1535).

Each VBI line in both fields is tested for the presence of a non-black signal (block 1).
540). If found, the test signal is copied to test signal storage (block 1550). If the current frame is an I-frame (block 156)
0), additional I-frame logic is called (block 1570). After the last VBI line has been processed, the process ends (block 1580).

FIG. 13 illustrates the injector I frame processing invoked in the operation (block 1570) shown in FIG. It is checked whether each line in the test signal portion of VBI is a line to VBI lines 10-20 (block 131).
0) If so, it is checked again for the presence of a test signal (block 1320). If it is not found, the VBI table entry for that line is cleared (block 1325). If it is found, the motion score is searched (block 1330) and a test is performed to determine if there is currently a high motion or if this is an out-of-sequence I-frame (block 1340).
At the time of a rapid scene change, an MPEG-2 video encoder may encode an I-frame even if the I-frame is not the expected frame type in the GOP sequence. If any of these conditions are tested to be true, a test is performed to see if a test signal has been sent to the TS extractor at least once (block 1350). If the test result is negative, the I-frame can be safely skipped. If that is the case, the I-frame count is checked to ensure that the I-frame has not been suppressed for more than three frames. If the result of that check is negative,
The I-frame count is incremented (block 1360) and the loop repeats. If the result of the check is positive, the test signal is always inserted into the video.

Another test is performed at block 1345 to determine if the video encoder is configured for I-frame only mode. If the test result is positive, the test signal is suppressed again. The test signal is transmitted every four frames when operating in I-frame only mode. I-frame only coding consumes very high bandwidth and is rarely used when transmitting video. The highest ranked line in hidden mode is retrieved (block 1365) and its score is compared to a user specified quality threshold (block 13).
70). If the score is higher, a test signal is sent. If the score is not higher, the I-frame count is checked again (block 1375) and a test signal is sent only if the count is greater than three. A trigger packet is formed and transmitted (block 1380). A test signal is inserted into the video input sent to the MPEG-2 video encoder (block 1)
385).

In FIG. 14, the trigger packet is
Is formed by the injector shown in FIG. Trigger
The packet contains all the information that the TS extractor needs to remove the test signal from the active video area and put the signal on the correct VBI line. The trigger packet is formed by the following sequence of steps. At block 1420, the transmission count is set to one. At block 1430, the I-frame is cleared. At block 1435, the time code is stored. Block 144
At 0, the concealment mode is stored. Block 144
At 5, the video line ID field is stored. At block 1450, the VBI line ID field is stored. At block 1455, 4:
A test is performed to determine the presence of the 2: 2 format. The resulting positive condition stores a line count of one at block 1460. Negative status is 4:
Store a line count of 3 for the 2: 0 format. Note that in that format, three consecutive video lines are used to signal instead of one as in the 4: 2: 2 format. The negative condition stores a line count of 3 at block 1480. Both blocks 1460 and 1480 proceed to block 1465 to calculate and store the CRC for the trigger packet. At block 1470, the trigger packet is transmitted and block 147
At 5, a signaled flag is set which indicates that the downstream TS extractor now has an active test signal at VBI. Thereafter, at block 1490, the process ends.

FIG. 15 shows a television screen including an active video area 1700 in NTSC broadcasting. It should be noted that each of the NTSC broadcasts has 26
525 video lines (not shown) including two interlaced fields of 2.5 lines. The active video area further includes a title safe area 1705 and an action safe area 1710. These areas serve as boundaries to guide the author in framing the scene and placing the title text. Lines 22-33 and 250-262 of each interlaced field are overscan area 171
5 The size of the overscan will vary for each television, and will vary for the same television due to perturbations in power supply voltage regulation.
Overscan is generally set for 5% of active video to prevent viewers from seeing the non-video portions of the horizontal and vertical scans. this is,
Approximately 12 lines of each field at the top of the screen are effectively hidden.

The overscan area provides a high degree of confidence that the concealment of the test signal is transparent to the viewer regardless of the video content. However, since each test signal requires three lines of active video for transmission, the number of signals that can be passed in the overscan area is limited in 4: 2: 0 mode. It should be noted that To optimize the restoration of three consecutive video lines, adjacent lines must not be used. This is because only four test signals can be passed in the upper or lower overscan area. Video blanking
The interval (VBI) 1702 consists of video lines 1 to 21 and completes the frame of the video signal.

When the overscan area is fully utilized, video lines are ranked or scored by the effect of concealment. Thus, by comparing the highest concealment score to a predetermined threshold, it is determined to place the test signal on the active video. The lower the threshold, the less the concealment effect. When the score falls below an acceptable threshold, one to three frames may be skipped if no test signal is inserted.

Although the preferred embodiment teaches placing the test signal outside the display area, the concealment technique used in the present invention is the title safe area 171.
0 allows other embodiments to pass signals or other data. This is because the current video content in this area facilitates optimal concealment. TS Injector offers a way to optimally repair a missed video line
By instructing the S extractor, concealment is enhanced. A lost video line is replaced using a spatio-temporally adjacent video line in one of several modes using the following (1)-(5): The same line from the opposite field of the frame, (2) the same line from the opposite field of the next frame, (3) adjacent (upper) in the current frame
Line, (4) adjacent (lower) in current frame
Line, (5) a composite line formed from two of the four lines.

These repair techniques, when combined with optimally placing the test signal in the video area by the TS injector, result in a high degree of concealment.

FIG. 16 shows the concealment process. At test block 1600, a test signal is applied to determine if there is space available for the signal. A positive condition places the signal in the overscan area at block 1610, and the concealment score is calculated at block 1620, after which block 169
At 0, the process ends. A negative condition indicates that the overscan area is full, block 16
The line separation distance is loaded at 25 and then
At block 1630, all available safe
Action lines (33-45 and 238-25
0: see FIG. 16) is ranked by motion and content. At test block 1635, each available line receives a concealment score at block 1640 until all lines have a concealment score. Thereafter, block 1635 ends in a negative state and the safe action lines are ranked at block 1645 by the concealment score.

At test block 1650, the concealment score for each line is compared to a threshold. If the highest score is greater than the predetermined threshold, the affirmative state returns the line, mode, and score at block 1690, terminating the process. On the other hand, a negative condition ranks available title safe lines 46-237 according to motion and content at block 1655. Scoring is for content (black,
(Continuous colors or patterns) are weighted for missing lines and lines with static motion for three frames. At test block 1660, the 25 highest ranked lines are recognized, and at block 1665 each is calculated for the concealment score. When all concealment scores have been calculated, a negative condition at block 1660 advances the process to block 1670. At block 1670, the title safe lines are ranked by concealment score, and the top candidates are returned to block 1690.

FIG. 17 shows the process for calculating the line concealment score. At block 1800, a determination is made as to whether each line is temporarily adjacent to calculate a line difference between the target video line and the same video line in the previous and next frames. An affirmative condition is indicated at block 1805 by the luma component and chroma.
Perform calculations to determine line differences between components. At block 1810, the temporary adjacent line is tested for a difference of zero representing an exact match. A positive condition gives the line the maximum score at block 1865, and the mode is recorded at block 1870. Thereafter, the process returns to test block 1800.

A negative condition in test block 1810 returns the process to block 1800. Block 18
A negative condition from 00 returns each adjacent line to the test block 1820 temporarily. A positive condition initiates block 1825 for each spatially adjacent line. Block 1825 calculates the difference between the target video line and two spatially adjacent lines in other fields of the current frame. Then, test block 1830 compares the difference between the target video line and two spatially adjacent lines to zero. A positive condition thereof indicates that a match has occurred and at block 1865 the highest score is provided. It is stored at block 1870, after which the process returns to block 1800.

If the negative condition from block 1830 indicates a temporary mismatch indicating that the difference between adjacent lines is not zero, the process returns to block 1820 to determine another concealment score. A negative condition to block 1820 references the spatially adjacent lines in block 1835 and uses the motion vectors calculated by the video encoder to determine the direction of the motion. At block 1840, the same line from the previous frame is shifted in that direction until the luma difference is minimized. Next, at block 1845 pixels are taken from the same video line of the next field, and at block 1850 the luma / chroma difference is calculated. Test block 1855 compares the difference to zero and a positive condition outputs the output to block 1865.
Return to Block 1865 stores the mode at block 1870 following the award of the maximum score, and the process returns from block 1875 to block 1800. If the difference is not zero at test block 1855,
The highest score of the previous five calculations is stored at block 1860, the mode is stored at block 1870, and a return to block 1800 follows.

B. Operation of Test Signal Extractor FIG. 18 shows the transport data stream flow in the MPEG-2 demultiplexer. ATM
Transport stream 2100 from switch 140 (see FIG. 1) is received by demultiplexer 2110, which converts the stream to video PES 2160, audio PES 2162,
And to the system control 2164. The video PES2
160 is sent to the test signal extractor,
Demultiplex the trigger signal. The video PES is also sent to a video decoder 2122, which provides the decoded video. Audio PES2
162 is provided to an audio decoder 2124, which provides a decoded audio output.

FIG. 19 shows a test signal extractor 290.
0 is a block diagram of FIG. The extractor is a video
Includes a demultiplexer 2901, which is a video PES
The signal stream is demultiplexed and S embedded in the GOP header used to identify the I frame
Extract the MPTE time code. Trigger signal demultiplexer 2905 and depacketizer 2908 extract the test signal triggers and store them in test signal trigger table 2205. In synchronization with the decoding of each frame, the interframe processor 2910 receives the picture type and GOP time code,
The time code of the decoded I frame is compared with the trigger table entry in table 2205. An entry is made in the video blanking interval (VBI) line table 2605 for each matched I-frame and trigger packet.

The test signal insertion and concealment unit 2915, which may be software or hardware, receives the current picture indicator, the forward picture indicator, the backward picture indicator, and the picture type, and then the I frame, B The test signal line storage device 2 is synchronized with the display of the frame and the P frame.
From 930, a test signal is generated. The test signal is inserted into the video blanking interval 2940 for each active VBI line entry in table 2605. In addition, the test signal in the active video area of the I frame
It is concealed (using the process of FIG. 16) by the insertion of a video line retrieved / formed from picture storage according to the concealment mode included in the packet. The restored video 2945 is sent for digital-to-analog conversion and for subsequent display on a television screen.

FIG. 20 shows the test signal trigger for lines 1 through 22 of the video blanking interval.
The data structure (table) 2200 is shown. Each test signal data structure is a test signal component in column 1,
Stored in a table 2205 that contains the number of bits in the column 2 component and the mnemonic for the column 3 component. The components of the signal trigger data structure are: time code at block 2210, marker at block 2215, video blanking interval line ID / field at block 2220, video line and ID / field at block 2230, block 22
This includes the marker at 35, the line count at block 2240, the concealment mode at block 2250, the stuffing and padding digits at block 2260, and the cyclic redundancy check code at block 2270.

FIG. 21 shows the processing of a trigger packet received at the extractor. Block 2300
At, the packet is checked for a CRC failure. A positive condition discards the trigger packet at block 2320. A negative condition forwards the packet to test block 2310, where the VBI contained in the packet is
It is determined whether an entry for the line ID already exists. A negative condition initiates test block 2325 to determine whether the time code for the packet has expired. Positive state blocks process 2
Proceed to 320 and discard the packet. A negative condition advances the process to block 2360 where a new entry is created in the test signal trigger table 2200,
Thereafter, the process is terminated. Video blanking interval line test block 2310
The affirmative if there is an entry for, advances the process to block 2330.

At test block 2330, the video line ID field of the entry and the trigger
Packets are compared. If the packet video line is equal to the entry video line, a positive state advances the process to block 2350, which causes the entry for that packet in the trigger table to be updated. If the packet video line is not equal to the entry video line, the process proceeds to block 2340, which removes the entry from the test signal trigger table and creates a new entry in the test signal trigger table at block 2360 And then the process ends. A feature of the present invention is to dynamically move the test signal within the active video area. Blocks 2340 and 2360 allow the test signal to be relocated on the I-frame,
Causes the extractor to respond to the injector based on the I-frame.

FIG. 22 shows the processing of an I frame in the test signal extractor. At the arrival of each I-frame,
Test block 2400 includes a timing signal trigger
Determine if an entry exists in the table. A positive condition initiates a test block 2410 to determine whether the I-frame time code (TC) is equal to the table entry time code. Its negation returns the process to block 2400. A positive condition initiates block 2420 to cause the VBI line active flag to be set, and then, at block 2430, an I in the VBI line table.
The frame count is cleared. Block 2435
The concealment flag is set at block 2440
The new concealment mode is moved to the video blanking interval line table. Block 2
At 445, the video line ID field and count are also moved to the video blanking interval table, and then at block 2450 the video blanking line ID and field are moved to the video blanking interval table. , The I frame is deleted from the timing signal trigger table at block 2455 and the process proceeds to block 2455.
Return to 00. If there is no entry in the timing signal trigger table, the frame is placed in the video blanking interval line table 2 shown in FIG.
Transfer to 605. Next, FIG. 23 will be described, and after such description, we will return to the process of FIG.

In FIGS. 23 and 24, an entry exists in the video blanking interval line table 2600. That is, there is one entry for each video blanking line from line 10 to line 20 exclusive in each field. Each entry in table 2600 is shown in block 2605. At block 2610 a video blanking interval line active flag is installed. The flag signals the TS extractor to move the test signal from the video storage device onto the video blanking interval line. I
Frame count block 2615 is used to time out a test signal if it originates from a test signal injector input. The test signal injector does not generate a separate trigger to signal that it removes the test signal from the video blanking interval. If three consecutive I frames are received without the embedded test signal,
The test signal extractor removes the entry from the video blanking interval line table,
Stop generating test signals. The timeout of three I-frames in a video network is 12 GOPs
Use counting.

Block 2620 stores the concealment flag, and block 2630 stores the concealment mode.
The concealment flag and the concealment mode are used during I-frame reconstruction to repair the video line used to carry the test signal. At block 2640,
Video blanking interval line and ID
The fields are stored. Block 2650 stores the video line ID field and block 2660
Stores the video line count. video·
The line ID field identifies the video line to be repaired, and the video line count indicates the number of lines used to transmit the test signal.

Returning to FIG. 22, for the test signal in the video area, the I-frame process 2400 loops through each entry in the extractor test signal trigger table. When leaving the loop, V
To determine if the BI line has been marked "active", the VBI
Each entry in the line table is examined. A negative condition ends the process. A positive condition initiates test block 2465 to determine if the VBI line is marked as active. A negative condition returns the process to block 2460. An affirmative condition indicates the table entry 2605 at block 2470
The I frame count 2615 in is incremented and the process moves to test block 2475. At block 2475, the I-frame count is examined to determine if it has exceeded three. An affirmative condition causes block 2480 to commence and the table 260
The VBI line "active" flag at 5 is reset. At block 2480, the VBI entry is marked as "inactive" and block 24
At 85, the test signal is cleared from video storage. Operation blocks 2460 to 2485
After all VBI lines have been examined in a loop consisting of, the process ends at block 2490.

Turning now to FIG. 24, a frame reconstruction is shown. During frame reconstruction, the TS extractor loops through each "active" VBI line entry in test block 2500. A negative condition terminates the process. A positive condition initiates test block 2510 to determine if the VBI line is active. Negative state tests process
Return to block 2500. The affirmative condition determines whether the I-frame and concealment flags are set in test block 2515. If the concealment flag is set, the frame currently being processed is the I-frame that carried the test signal, so the test signal is moved from the current picture to the test signal line at block 2520. Thus, at block 2525, the test signal is copied from the stored signal line to the target VBI line field of the current picture. Test block 2530 determines whether the I-frame and concealment flags are set.
A negative condition returns the process to test block 2500. An affirmative condition hides the video line at block 2540. The process of concealing a video line will now be described with reference to FIG. video·
After the line is concealed, the concealment flag is cleared at block 2550, after which the process returns to block 2500.

Turning to FIG. 25, the process of concealing a video line is based on line 2630 of VBI line table 2605 in VBI table 2600 of FIG.
Implements the concealment mode stored in. At block 2700, the video line ID field and count in the VBI entry table are loaded into the process. The concealment mode is loaded at block 2705, after which test block 271 determines whether the concealment mode is on the same line of the previous frame.
0 is determined. A positive condition moves the video line from the reverse frame store at block 2750;
Thereafter, the process ends. Test block 27
A negative condition from 10 initiates test block 2715 to determine if the same line is in the next frame. A positive condition initiates block 2760 to move the video line from the forward frame store, after which the process ends. A negation condition initiates a test block 2720 where a determination is made as to whether it is the upper line in another field.

A positive condition at block 2720 moves the video line from the current frame store at block 2770, after which the process ends.
A negative condition initiates test block 2730 to determine if the concealment is on the lower line in another field. A positive condition initiates block 2780.
The block moves the video line from the current frame store, after which the process ends. A negative condition initiates test block 2740 to determine if a composite line should be formed. Positive state is block 2
At 785, a synthesis line is formed. The synthesis line is
Formed by shifting the carrier line and backfilling with the next line, after which the process ends. A negative condition ends the process.

In summary, blocks 2750 and 276
0 repairs the line using the same line / field from the previous and next frames, respectively. Blocks 2770 and 2780 use the next line above and below the line in need of repair. These lines are taken from another field of the current frame. Block 2
730 and 2740 involve averaging temporally or spatially separated lines. At block 2785, the line uses a portion of the line from the previous frame (represented by the pixel shift count),
Thereafter, a composite line is formed by filling the shifted out pixels with the pixels from the next frame, thereby being obscured.

FIG. 26 shows another embodiment of the present invention. FIG.
At 6, in-service testing is accomplished by using a video test signal inserted into the VBI. At startup POP 3500, subscriber's video feed 3
528 is a vertical interval test signal (VITS) device 353 via an analog video switch 3582
2 is routed. The VITS unit 3532 converts the test signal to VB without affecting the active video.
Insert into I. An analog video switch 3582 routes the output of VITS 3532 to an MPEG-2 encoder 3536 for encoding and transmission.
Injector 3534 moves the test signal from VBI to the active area before the video is encoded. At the receiving end 3505, the extractor 538
4 moves the test signal from the active area to the VBI, and the decoded signal 3585 is routed by the analog switch 3556 to the two output ports.
One port is connected to VITS and the other port is a measurement set 35 for analyzing and measuring video test signals.
58. VITS 3557 receives the video test signal 3546 and effectively removes the test signal from the broadcast by inserting black containing the in-service test signal into the line. Next, the video is routed back to analog switch 3556. In its analog switch, it is switched to the subscriber's output access line 3562. In this manner, the network 115 (see FIG. 1) is end-to-end without affecting the displayed broadcast or the subscriber's VBI signal or data.
Tested at the end.

In further summary, the present invention provides for the detection of test signals placed in a vertical blanking interval. That is, the present invention extracts the signal and moves it to the active video, conceals the line used to send this test signal, and places this in the display area according to the area of the screen that optimally conceals it. Position the line dynamically. Its dynamic positioning can change where it is positioned many times per second.
Finally, the extractor removes the signal, thus
It provides a continuous signal to the measurement test set even if the test signal is only sent downstream about 2.5 times per second. The test signal appears to the extractor as a uniform continuous signal.

Although the present invention has been described in particular embodiments, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention.

In summary, the following items are disclosed regarding the configuration of the present invention.

(1) A plurality of gateways for receiving or transmitting analog broadcast video are provided as a switched digital broadcast network for testing analog broadcast video subjected to MPEG-2 compression during operation and non-operation. A switched packet network, wherein each gateway is coupled to an analog broadcast video source or analog broadcast video sink through an analog switch, and at each gateway, the analog broadcast video in a series of frames. Means for encoding / decoding as a digital video transport stream in a compressed digital format, and a test signal input for installing a test signal in said frame, installed on at least one gateway. Jector means, a test signal insertion control means for arranging a video test signal in the frame and concealing the arrangement, and installed in at least one gateway, for performing the test from the frame without impairing the quality of the frame Test signal extractor means for finding and extracting signals. (2) The switched digital broadcast network of (1), further comprising means for generating and storing an injector VBI test signal table defining locations of test signals in a video blanking interval (VBI) of the frame. (3) means for monitoring the time code, detecting the presence of a video test signal in each frame and providing a first output signal, and inspecting the incoming analog video for motion and scene changes; Comparing the analog video line from the current frame with the analog video lines of the previous and next frames, and scoring the concealment of the video test signal in the frame; The exchange according to (1), further comprising: means for supplying a third output signal; and means for supplying the first, second, and third output signals to the test signal insertion control means. Digital broadcasting network. (4) The switched digital broadcasting network according to (3), further comprising means for generating and storing a VBI test signal table, and coupling the table to the test signal insertion control means. (5) The switched digital broadcast network according to (4), further comprising means for generating a trigger packet coupled to said test signal insertion control means and providing an output to said network. (6) coupled to the test signal insertion control means and a VBI test signal detector, storing the video test signal, and converting the video test signal to the analog video signal as directed by the test signal insertion control means; The switched digital broadcasting network according to the above (5), further comprising means for inserting into the network. (7) The extractor means includes a trigger packet
Receiving data and responding to a trigger signal demultiplexer coupled to a test signal trigger table and a group of picture type signals and picture time codes, the test signal trigger table and video blanking interval ( VBI) an intra-frame processor coupled to the line table and a current picture signal, a forward picture signal, a reverse picture signal,
A test signal concealment device responsive to the picture type signal and the VBI line table and coupled to a test signal line storage, for combining the test signal line storage with the decoded digital video stream. Means, wherein the test signal is indicative of the quality of the decoded digital video stream from a transmission standpoint. The switched digital broadcast network of (1). (8) The exchange digital circuit according to (7), wherein the test signal trigger table of the extractor means includes an entry for each VBI line of the frame, the entry defining a location of the trigger signal in the frame. Broadcast network. (9) The exchange digital system according to (7), wherein the VBI line table includes an entry for each VBI line, the entry defining a location of the line in a frame, a concealment flag, and a concealment mode. Broadcast network. (10) The exchange digital system according to the above (1), further comprising means for maintaining a continuous connection to each gateway via a TCP / IP network to the gateway connection device and monitoring an alarm condition at the gateway. Broadcast network. (11) The means for encoding / decoding is M
The switched digital broadcast network according to (1), wherein the switched digital broadcast network implements a PEG-2 encoding / decoding algorithm. (12) The means for encoding / decoding the 4: 2: 0 or 4: 2: 4: encoding the luminance and chrominance components of the video signal.
2. The switched digital broadcasting network according to the above (1), wherein two samplings are implemented. (13) A plurality of gateways for receiving or transmitting analog broadcast video, each gateway being coupled to a source or sink for analog broadcast video through an analog switch, and at each gateway, a series of I / Os. Means for encoding / decoding analog broadcast video in frames, B frames, and P frames as a digital video transport stream in compressed digital format; and a test signal installed in at least one gateway and inserted into said frames. Test signal injector means for arranging a video test signal in the frame and concealing the arrangement thereof, and test signal insertion control means for concealing the arrangement; In exchange digital broadcast networks including, a test signal extractor means for finding and extracting the test signal from the frame without compromising the quality, in order to evaluate the video quality,
A method for inserting a test signal into an MPEG-2 compressed video transmission, comprising: (a) processing each frame with a test signal in said injector means; and (b) converting each I frame in said injector means. Processing, (c) forming a trigger packet in the injector means and transmitting the trigger packet to the extractor means;
(D) processing the test signal in the I frame for concealment mode; (e) calculating an concealment score for each test signal in the I frame;
(F) concealing a test signal in an I-frame transmitted to said extractor means; (g) processing said trigger packet to alert said extractor means about a test signal in a received I-frame. (H) processing the I frame with respect to the test signal in the extractor means; and (i) processing each I frame in the extractor means.
Reconstructing a frame; and (j) copying the test signal in every frame to the VBI line under test. (14) In addition, to process each frame at the injector, the frame is tested for the presence of video blanking interval (VBI) lines 10-20, and a negative condition indicating that no VBI line is identified terminates the process. A positive state indicating that the VBI line has been identified moves the process to the next step, determining the count of trigger packets to be transmitted, and each VBI line for the presence of a non-black signal. A positive state copies the test signal to the test signal storage, a negative state initiates I-frame processing, and ends processing of the frame after the last VBI has been processed. The method according to the above (13), comprising: (15) testing the frame for the presence of a video blanking interval (VBI) line 10-20 containing a test signal to further process the I-frame at the test signal injector; a negative condition terminates the process; A positive condition clears the VBI table for the tested VBI line if no test signal is identified for that line, and if so, moves the process to the next step. Retrieving a motion score for the VBI line containing the signal; and testing the I-frame to determine if there is a high motion or out-of-sequence I-frame; To determine if it was sent Checking the I-frame count to ensure that the I-frame has not been suppressed for more than three frames if it has not been sent once; Increments the I-frame count,
Returning to steps. (16) setting a transmission trigger packet counter to 1 to form a trigger packet; and clearing an I frame counter.
Storing a trigger signal time code; storing a trigger signal concealment mode; storing a trigger signal video line ID field; storing a trigger signal VBI line ID field; : 2: 2 format tested, negative state stores VBI line count of 3, positive state stores processing to next step, storing VBI line count of 1, cyclic redundancy check The method of claim 13 including calculating and storing a (CRC) code, transmitting a trigger packet, and setting a transmitted trigger signal transmitted flag. (17) determining whether there is available space in the active video area to hide the trigger signal in the active video area;
A negative state indicates that the overscan video screen area is full, and a positive state calculates the concealment score following the storage of the signal in the overscan area of the video screen and terminates the process. Storing the video line separation parameters if the overscan video area is full; ranking available video screen safe areas by motion / content; Calculating the concealment score for the area line, ranking the video safe lines by the concealment score, comparing each concealment score to a threshold, and whether the highest concealment score exceeds the threshold Affirmative state terminates the process A negative condition advances the process to the next step; ranks available video safe lines that do not exceed the threshold according to motion / content; and ranks available video that does not exceed the threshold. Calculating a concealment score for the safe line, selecting the highest ranked video safe line that does not exceed the threshold, and terminating the process (13). The method described in. (18) generating and storing a time code to form a test signal trigger data structure; generating and storing a marker for eliminating start code emulation by a multiplexer; VBI line ID from which the signal is extracted
Generating and storing a / field, generating and storing a video line ID / field to which the test signal is sent, and which one or three lines should be used when transmitting the test signal. Generating and storing a video active area line count representative of the video signal; generating and storing a concealment mode to optimize the repair of the taken video line; and Generating and storing the stuffing bits of the first and second bits, and generating and storing a cyclic redundancy check (CRC) code. (19) In addition, to process the trigger packet at the extractor, check the trigger packet for a CRC failure, discard the packet if a positive state, and move the process to the next step if the negative state;
Determining if an entry exists for the BI line, a negative condition determines whether the time code has expired, discarding the packet if the time code has expired, and not expiring the time code If a new entry is made in the test signal trigger table and a positive state indicating that an entry for the VBI line exists, processing proceeds to the next step, where the packet video line is Determining if equal to a line, a positive state updates an entry in the test signal trigger signal table, and then terminates the process; a negative state advances the process to the next step; Removing an entry from a table; said test signal To create a new entry in Riga table, after which the method according to (13), characterized in that it comprises a step of terminating the process, the. (20) Further, in order to process the I frame in the extractor, a determination is made as to whether an entry is present in the timing signal trigger table, and (a) the positive result of the determination is that the I frame code is Initiate a test to determine if it is equal to the entry time code, (a1) a negative status of the test result returns the process to the start, (a2) a positive status of the test result is VBI Set line active flag, clear I frame count in VBI line table, set concealment flag, move video line ID / field and count to VBI table, set VBI line ID / field to V
Moving to the BI table, deleting the entry from the test signal trigger table and returning to the start; (b) the negative result of the decision is a VBI line
Initiating a test for the presence or absence of each entry in the table, (b1) a negative status of the test result terminates the process, and (b2) a positive status of the test result advances the process to the next step, where the VBI line Makes a decision whether (b2) is active, (b21) a negative state of the result of the decision causes the process to return to the previous state, and (b2)
2) a positive result of the decision causes the process to proceed to the next step, in which the I-frame count is incremented, and a determination is made whether the I-frame count exceeds three; A negative state causes the process to return to step (b), and a positive state of the result of the determination advances the process to the next step, resetting the VBI line active flag and testing in the test signal storage. Clearing the signal and returning the process to step (b). (21) Further, to reconstruct a frame at the extractor, determine whether there is an entry in the VBI line, a negative state ends the process, a positive state starts the next step, and , VB
Determining whether the I line is active, a negative state initiates the process, an affirmative state advances the process to the next step, determining the steps and whether the I frame and concealment flags are set; A positive state advances the process to the next step, a negative state skips the next step and advances the process to the next step, and moves the video line test signal from the picture storage to the test signal storage. Causing the target VBI to be stored in the test signal storage device.
Copying the test signal to a line / field; determining whether the I-frame and concealment flags are set; a negative state returns the process to the start; a positive state advances the process to the next step; The method of (13), comprising: concealing the video line; and clearing the concealment flag. (22) loading the video line ID / field and count to conceal a video line; loading the concealment mode; and wherein the concealment mode is on the same line or a previous line. A positive state moves the video frame from the backward frame store, then terminates the process, and a negative state starts the next step. Determining if it is in the next frame, a positive state moves the video line out of the forward frame store, and then terminates the process; a negative state causes the process to proceed to the next step; Determine if the concealment is in the upper line, and if yes, the video Moving the line from the current frame memory, thereafter, the process is terminated, determining causes advances the process to the next step in the case of negative state, and a step, whether said concealment is below the line,
A positive state moves the video line from the current frame store, and then terminates the process; a negative state causes the process to proceed to the next step;
Deciding whether to form a composite line, a negative state terminates the process, a positive state causes a composite line to be formed by shifting the carrier line and backfilling with the next line, and then the process (13). The method according to the above (13), comprising: (23) A switched packet having a plurality of gateways for receiving or transmitting analog broadcast video, as an switched digital broadcast network for testing MPEG-2 compressed analog broadcast video during operation and non-operation. A switched network, wherein each gateway is coupled to a source or sink of analog broadcast video through an analog switch, and at each gateway, the analog broadcast video in a series of frames is converted to digital video in a compressed digital format. Means for encoding / decoding as a transport stream; signal injector means installed on at least one gateway for inserting a signal into said frame; and applying said signal to said frame. Signal insertion control means for locating and concealing the arrangement; signal extractor means installed on at least one gateway for finding and extracting the signal from the frame without compromising the quality of the frame; An exchange digital broadcasting network including:

[Brief description of the drawings]

FIG. 1 is a schematic representation of a command and control facility (CAC) that handles the point of presence (POP) location and incorporates the principles of the present invention.

FIG. 2 is a schematic representation of a video in-service test signal generator at a first POP and a test signal analyzer at a second POP included in the system of FIG. 1;

FIG. 3 shows components of the CAC center of FIG.

FIG. 4 is a schematic representation of a bandwidth reservation order by a video subscriber for future video transmission.

FIG. 5 is a prior art representation of an MPEG-2 video layer hierarchy.

FIG. 6 is a prior art representation of the MPEG-2 sampling equation 4: 2: 2.

FIG. 7 is a prior art display of the MPEG-2 sampling equation 4: 2: 0.

FIG. 8 illustrates some well-known television test signals used to test video performance and quality over a transmission system.

FIG. 9 shows the test signal injector 130 shown in FIG.
FIG.

FIG. 10 is a schematic representation of a test signal trigger data structure.

FIG. 11 shows an example of MPEG-multiplexing the data structure of FIG.
2 shows a two multiplexer.

FIG. 12 is a flowchart for processing each frame in an MPEG-2 encoder.

FIG. 13 is a flowchart for processing an I frame in the test signal injector of FIG. 9;

FIG. 14 is a flow chart for forming a trigger packet.

FIG. 15 shows a television screen showing an area for inserting a test signal.

FIG. 16 is a flowchart for video line hiding in the text injector of FIG. 9;

FIG. 17 is a flowchart for calculating a concealment score for the injector of FIG. 9;

FIG. 18 shows an MPEG-2 demultiplexer.

FIG. 19 is a block diagram of a test signal extractor.

FIG. 20 is a schematic representation of an extractor test signal trigger table for the extractor of FIG. 19;

FIG. 21 is a flowchart for processing a trigger packet in the extractor of FIG. 18;

FIG. 22 is a flowchart for processing an I frame in the extractor of FIG. 19;

FIG. 23 is a display of a VBI line table for the extractor of FIG. 19;

FIG. 24 is a flowchart for frame reconstruction in the test signal extractor of FIG. 19;

FIG. 25 is a flowchart for concealing a video line in the extractor of FIG. 19;

FIG. 26 is another embodiment of the present invention.

[Explanation of symbols]

 300 POP gateway 321 Video tape recorder 332 Vertical interval test signaling device 338 Multiplexer 400 POP gateway 452 Demultiplexer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor John Mark Tets, 22043 United States, Kirby Court, Forests Church, Virginia 6640 F-term (reference) 5C059 KK45 MA00 RA00 RB02 RC00 RE09 SS02 UA02 UA05 5C061 BB02 BB07 BB13 CC01 CC03 CC05 5C063 AB03 AC01 AC05 CA11 CA36 DA07 DA13 DB10

Claims (23)

[Claims] 1. A switched digital broadcast network for testing MPEG-2 compressed analog broadcast video during operation and non-operation, comprising a plurality of gateways for receiving or transmitting analog broadcast video. A switched packet network, wherein each gateway is coupled to an analog broadcast video source or analog broadcast video sink through an analog switch, and, at each gateway, compresses the analog broadcast video in a series of frames. Means for encoding / decoding as a digital video transport stream in digital format; and a test signal indicator installed at at least one gateway for inserting a test signal into said frame. Test signal insertion control means for arranging a video test signal in the frame and concealing the arrangement, installed in at least one gateway, and performing the test from the frame without deteriorating the quality of the frame. Test signal extractor means for finding and extracting signals; and a switched digital broadcast network. 2. The switched digital broadcast network according to claim 1, further comprising means for generating and storing an injector VBI test signal table defining locations of test signals in a video blanking interval (VBI) of the frame. . 3. A means for monitoring a time code, detecting the presence of a video test signal in each frame and providing a first output signal, and inspecting incoming analog video for motion and scene changes. Means for providing a second output signal, comparing the analog video line from the current frame with the analog video lines of the previous and next frames and scoring the concealment of the video test signal in said frame. The method of claim 1, further comprising: means for providing a third output signal; and means for providing the first, second, and third output signals to the test signal insertion control means. Switched digital broadcast network. 4. The switched digital broadcast network according to claim 3, further comprising means for generating and storing a VBI test signal table, and coupling said table to said test signal insertion control means. 5. The switched digital broadcast network according to claim 4, further comprising means for generating a trigger packet coupled to said test signal insertion control means and providing an output to said network. 6. A test signal insertion control means coupled to said VBI test signal detector for storing said video test signal and for converting said video test signal to said analog signal as directed by said test signal insertion control means. The switched digital broadcast network of claim 5, further comprising means for inserting into the video. 7. The extractor means receives trigger packet data and is responsive to a trigger signal demultiplexer coupled to a test signal trigger table and to a group of picture type signals and picture time codes. An intra-frame processor coupled to the test signal trigger table and a video blanking interval (VBI) line table; a current picture signal, a forward picture signal, a reverse picture signal, and the picture type signal. , The VBI line
A test signal concealment device responsive to the table and coupled to a test signal line storage device; and means for combining the test signal line storage device and the decoded digital video stream, wherein the test signal is 2. The switched digital broadcast network according to claim 1, wherein it indicates the quality of the decoded digital video stream from a transmission standpoint. 8. The exchange of claim 7, wherein the test signal trigger table of the extractor means includes an entry for each VBI line of the frame, the entry defining a location of the trigger signal in the frame. Digital broadcasting network. 9. The exchange of claim 7, wherein the VBI line table includes an entry for each VBI line, the entry defining the location of the line in a frame, a concealment flag, and a concealment mode. Digital broadcasting network. 10. TCP / IP to gateway connection device
2. The switched digital broadcast network according to claim 1, further comprising means for maintaining a continuous connection to each gateway over the network and monitoring alarm conditions at the gateway. 11. The encoding / decoding means according to claim 1, wherein said means for encoding / decoding comprises:
The switched digital broadcast network of claim 1, wherein the switched digital broadcast network implements an algorithm. 12. The method of claim 11, wherein said means for encoding / decoding implements 4: 2: 0 or 4: 2: 2 sampling to encode the luminance and chrominance components of said video signal. 2. The switched digital broadcast network of claim 1. 13. A plurality of gateways for receiving or transmitting analog broadcast video, each gateway being coupled to a source or sink for analog broadcast video through an analog switch; Means for encoding / decoding analog broadcast video in I-, B-, and P-frames as a digital video transport stream in a compressed digital format; Test signal injector means for inserting a video test signal in the frame, and test signal insertion control means for concealing the arrangement; installed in at least one gateway, Test signal extractor means for finding and extracting the test signal from the frame without compromising the quality of the frame, the MPEG-2 compression being applied to evaluate the video quality in a switched digital broadcast network comprising: A method for inserting a test signal into a video transmission, comprising: (a) processing each frame with a test signal in the injector means; (b) processing each I frame in the injector means; (c) Forming a trigger packet in the injector means and transmitting the trigger packet to the extractor means; (d) processing the test signal in the I frame with respect to the concealment mode; (e) each test in the I frame Concealment about signal Calculating a core; (f) concealing a test signal in an I-frame transmitted to the extractor means; (g) the trigger to alert the extractor means about a test signal in a received I-frame. Processing packets; (h) processing said I-frames with respect to said test signal in said extractor means; (i) reconstructing each I-frame in said extractor means; and (j) all A method comprising copying a test signal in a frame to a VBI line under test. 14. A method for processing each frame in an injector, comprising the steps of:
I) Test for the presence of lines 10-20, VBI
A negative state indicating that the line has not been identified terminates the process, and a positive state indicating that the VBI line has been identified moves the process to the next step, determining the steps and the count of trigger packets to be transmitted. Testing each VBI line for the presence of a non-black signal; a positive state copies the test signal to the test signal storage; a negative state initiates I-frame processing. Ending the processing of the frame after being performed. 15. A method for processing an I-frame in a test signal injector, wherein the frame is tested for the presence of a video blanking interval (VBI) line 10-20 containing a test signal, and a negative condition terminates the process. Causing the affirmative state to clear the VBI table for the tested VBI line if no test signal is identified for that line, and to proceed to the next step if the test signal is identified, Retrieving a motion score for the VBI line containing the test signal in the I-frame; testing the I-frame to determine if there is high motion or an out-of-sequence I-frame; Whether it was sent to the Kuta at least once Or to start the test for determining the,
Checking the I-frame count to ensure that the I-frame was not suppressed for more than three frames if the test signal was never sent; and incrementing the I-frame count And returning to the initial process steps. 16. A method for setting a transmission trigger packet counter to one to form a trigger packet, clearing an I frame counter, and storing a trigger signal time code. Storing a trigger signal concealment mode; storing a trigger signal video line ID field; storing a trigger signal VBI line ID field; testing and negating the trigger signal for a 4: 2: 2 format. The state stores a VBI line count of 3;
The affirmative state proceeds to the next step; storing a VBI line count of 1; calculating and storing a cyclic redundancy check (CRC) code; transmitting a trigger packet; Setting a trigger signal transmitted flag. 17. A method for concealing a trigger signal in an active video area, the method comprising: determining whether available space is present in the active video area;
Indicates that the video screen area is full,
The affirmative state includes storing the signal in an overscan area of the video screen followed by calculating a concealment score and terminating the process; and, if the overscan video area is full, a video line separation parameter. Storing the video safe areas by motion / content; calculating an concealment score for each video safe area line; Ranking by concealment score; comparing each concealment score to a threshold; determining if the highest concealment score exceeds the threshold; a positive state terminates the process; a negative state terminates the process. Proceeding to step, and do not exceed the threshold Ranking available video safe lines according to motion / content; calculating concealment score for ranked available video safe lines not exceeding the threshold; highest not exceeding the threshold 14. The method of claim 13, comprising: selecting a ranked video safe line of the following and terminating the process. 18. A method for generating and storing a time code to form a test signal trigger data structure, and generating and storing a marker for eliminating start code emulation by a multiplexer. Generating and storing a VBI line ID / field from which the test signal is derived; generating and storing a video line ID / field from which the test signal is sent; and one or more when transmitting the test signal. Generating and storing a video active area line count that indicates which of the three lines is to be used; and generating and storing a concealment mode to optimize the restoration of the taken video line. And stuffing for the trigger packet. 14. The method of claim 13, comprising: generating and storing signaling bits; and generating and storing a cyclic redundancy check (CRC) code. 19. The method according to claim 19, further comprising the step of:
To process the packet, check the trigger packet for a bad CRC, a positive state discards the packet, a negative state determine the step to move the process to the next step, and determine if there is an entry for the VBI line. And a negative condition determines whether the time code has expired, discards the packet if the time code expires, and a new entry in the test signal trigger table if the time code does not expire. And a positive state indicating that an entry exists for the VBI line proceeds to the next step;
Determining whether the packet video line is equal to the entry video line, a positive state updates an entry in the test signal trigger signal table, and then terminates the process; Advancing the process to steps, removing the entry from the test signal trigger table, creating a new entry in the test signal trigger table, and then terminating the process. 14. The method of claim 13, wherein the method comprises: 20. A method for processing an I-frame at an extractor, the method comprising: determining whether an entry is present in a timing signal trigger table; Is the table entry time
Initiate a test to determine if the code is equal to: (a1) a negative status of the test result returns the process to the start; , Clear the I-frame count in the VBI line table, set the concealment flag, and set the video line ID / field and count to VBI.
Moving the VBI line ID / field to the VBI table, deleting the entry from the test signal trigger table and returning to the start; (B1) a negative result of the test terminates the process, and (b2) a positive condition of the test result advances the process to the next step, where the VBI line is (B21) a negative state of the result of the decision causes the process to return to the previous state; and (b22) a positive state of the result of the decision moves the process to the next step. Incrementing the I-frame count and determining whether the I-frame count exceeds three. A negative result of the decision causes the process to return to step (b), a positive state of the result of the decision advances the process to the next step, resetting the VBI line active flag, 14. The method of claim 13, comprising: clearing a test signal in a test signal storage device and returning the process to step (b). 21. Furthermore, to reconstruct a frame at the extractor, determine if there is an entry on the VBI line, a negative state ends the process, and a positive state starts the next step; Determining whether the VBI line is active, a negative state initiates the process, an affirmative state advances the process to the next step, and determining whether the I-frame and concealment flags are set. Determining, a positive state advances the process to the next step, a negative state skips the next step and advances the process to the next step, and a video line test from the picture storage to the test signal storage. Moving a signal; and a target VBI line from the test signal storage device.
Copying the test signal into a field; determining whether the I-frame and concealment flags are set; a negative state returns the process to the start; a positive state advances the process to the next step; 14. The method of claim 13, comprising: concealing the video line; and clearing the concealment flag. 22. Loading the video line ID / field and count for concealing a video line; loading the concealment mode; and the same or previous line with the concealment mode. A positive state moves the video frame from the backward frame store, then terminates the process, and a negative state starts the next step. Determining whether a line is in the next frame, a positive state moves the video line out of the forward frame store, and then terminates the process; a negative state causes the process to proceed to the next step; Determining if the concealment is in the line above, and if affirmative, Moving the video line out of the current frame store, and then terminating the process and, if negative, causing the process to proceed to the next step; determining whether the concealment is in the line below. Determining, a positive state moves the video line out of the current frame store, and then terminates the process; a negative state causes the process to proceed to the next step, comprising the steps of: Determining, the negative state terminates the process, and the positive state comprises shifting the carrier line and forming a composite line by backfilling with the next line, and then terminating the process. 14. The method of claim 13, wherein: 23. A switched digital broadcast network for testing MPEG-2 compressed analog broadcast video during operation and non-operation, and having a plurality of gateways for receiving or transmitting analog broadcast video. A switched packet network, wherein each gateway is coupled to an analog broadcast video source or sink through an analog switch, and at each gateway, the analog broadcast video in a series of frames is converted to a digital form in a compressed digital form. Means for encoding / decoding as a video transport stream; signal injector means installed on at least one gateway for inserting a signal into said frame; Signal insertion control means for arranging the signal and concealing the arrangement; a signal extractor installed on at least one gateway for finding and extracting the signal from the frame without compromising the quality of the frame Means, and a switched digital broadcast network comprising: