JP2005210160A - Video receiving terminal having communication state display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video reception terminal for informing a viewer about the cause of image quality deterioration and about the interruption in display, when receiving a television video signal which utilizes best-effort type communication network. <P>SOLUTION: An RTP-processing section 32 of a receiver side unit 31 of the video reception terminal 40 detects a communication fault. An error-processing section 34 notified with detection of error due to the communication fault transmits a display instruction to a communication state display section 35, and the communication state display section 35 lights up a state display lamp 38 for displaying the communication state to indicate the occurrence of the communication abnormality. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is an information communication terminal that receives video information via a communication network, particularly an information communication terminal that is suitable for application when video information is compressed.

  With the increase in the speed of communication networks that transmit digital signals, video signals can be transmitted and received through the communication network. For example, a television video signal is compressed in accordance with the international standard MPEG-2 (Motion Picture Experts Group 2) standard, and the digitized video signal is put into an ATM (Asynchronous Transfer Mode) cell, and these cells are used for SDH (Synchronous). A method of constructing and transmitting a Digital Hierarchy signal is described in the recommendation of the International Telecommunication Union Telecommunication Standardization Sector (ITU-T), which is an international communication federation (see non-patent literature).

  Conventionally, since transmission of a television video signal requires real-time performance (real-time performance), the television video signal is a communication network in which sufficient connection guarantee is made between transmission and reception of ATM cells and SDH signals, that is, data. It was transmitted using a ganty (band guaranteed) communication network in which transmission and reception transmission bands and quality were ensured. In such a communication network, transmission / reception of a television image signal is performed in a state where there is no frame missing on the time axis or there is no large delay variation.

  In recent networks such as ADSL (Asymmetrical Digital Subscriber Line) and FTTH (Fiber to the Home), a best-effort (communication quality non-guaranteed) communication network is formed. In the best effort type, transmission / reception of TV images instead of guarantee type, which is very expensive due to the widespread use of the IP (Internet Protocol) method with a bandwidth of about 1 Mbit / s or less, at a low charge. A service for transmitting IP in the IP format has begun.

  When a compressed television video signal is transmitted / received over an IP network, the signal divided into packets is referred to as TCP (Transmission Control Protocol) / IP in order to ensure the throughput (bandwidth utilization efficiency) and reality of the television video signal. The video signal is transmitted / received by a method of continuously transmitting without error retransmission such as UDP (User Datagram Protocol) / IP, instead of a method of retransmitting at the time of error detection and ensuring data reliability.

  Unlike the guarantee method, the best effort method such as UDP / IP that does not guarantee the signal quality inevitably causes a packet loss due to a data error or transmission delay. Therefore, when a compressed video signal such as MPEG-2 is transmitted by the best-effort method, it is unavoidable that a decoded TV video has a block (mosaic) error, a band error, or sometimes an error that does not display the frame itself. It was not.

  For example, a television video signal of NTSC (National Television System Committee) system adopted in Japan is encoded by quantization of 8 bits / sample at a sampling frequency of 13.5 MHz and becomes 108 Mbit / s. -2 etc., this signal is compressed to about 8 Mbit / s by intra-frame and inter-frame compression. In such compression, there is a portion in which data of one frame is used for a plurality of frames. Therefore, if there is a data error at the time of transmission, the influence may be exerted on a plurality of frames at the time of decoding, and the influence may extend to a length of about 0.5 seconds, resulting in a clearly visible video distortion.

  As a technique for improving data error, an example of Patent Document 1 that reduces the abnormality of a signal transmitted by requesting retransmission when an abnormality of a moving image signal is detected, or Patent Document that issues a retransmission request when packet loss is detected A method such as the second example is disclosed. However, this alone cannot eliminate errors even if the error rate is reduced.

  On the other hand, an apparatus for determining video quality via a communication network having a data error is disclosed in Patent Document 3, for example. This device is a device that detects a transmission error for each packet by a decoder (decoder) or detects a packet delay, and totalizes the detection results to evaluate the image quality. In this apparatus, the received abnormal frames, slices, macroblocks, and blocks are totaled to obtain an evaluation value, and the evaluation value is notified to a remote counting computer.

Japanese Unexamined Patent Publication No. 7-322248

JP 2003-23462 A JP 2000-341688 A ITU-T J.I. 132 (Transport of MPEG-2 signal in SDH networks 03/1998)

  When the viewer of the decoded video appreciates the video, if it is a guarantee type, it can be understood that if the video has a mosaic or intentionally inferior video screen, that is the intention of the creator. However, when video signals are transmitted and received via a best-effort transmission network such as an IP network, whether the video on such a screen is an original video or a disturbance caused by an error or packet loss that occurs during transfer. It is difficult to determine whether the image contains video. In addition, the device according to Patent Document 3 also does not describe consideration for notifying an observer (viewer) of an evaluation value of a television image.

  In addition, when the packet discard is high in the best effort type communication network and the video data can be obtained only intermittently, the video display may be interrupted in the video signal decoding process. At this time, there is no video on the screen, but it is because the connection between the receiving device and the TV monitor has not been established, or it is due to a disconnection, poor connection, or the interruption of video processing due to communication deterioration. In the past, it was impossible to determine whether or not

  If the cause of image quality deterioration or interruption can be understood, the observer can be satisfied and use the best-effort video service, and the marketability can be improved.

  An object of the present invention is to provide a video receiving terminal that notifies an observer of the cause of image quality deterioration or display interruption in receiving a TV video signal using a best effort type communication network.

  Another object of the present invention is to provide a video receiving terminal capable of prompting the determination of the factor when no video is shown.

  When an abnormality is detected from the received video signal packet, a retransmission request or error correction processing is performed. Depending on the abnormal state, the processing exceeds the delay of about 0.5 seconds necessary to maintain real-time performance. May be performed. A video receiving terminal that receives video services via a best-effort communication network can maintain the real-time property even if the error cannot be completely eliminated by, for example, about 0.5 seconds. 2 is performed, and a received video image with degraded image quality is displayed on the television monitor. The present invention is directed to a video receiving terminal that may be accompanied by such image quality degradation.

  In order to achieve the above object, a video receiving terminal according to the present invention includes a receiving means for receiving an encoded video signal sent via a communication network, a decoding means for decoding the video signal, and a display of the decoded video signal. Image display means, a detection means for detecting a communication abnormality in which a part of the video signal is lost during transmission through the communication network, and a communication status display means for indicating that the communication abnormality has been detected by display. Features. In the video receiving terminal having such characteristics, for example, as will be described in detail later, if an error (for example, packet loss) is included in the compressed video signal that is finally input to the decoder, the receiving unit erroneously reports the error. Receiving terminal in which the processing unit notifies the processing unit, the error processing unit receiving the notification issues a display instruction to the communication state display unit that drives the display element, and the communication state display unit that receives the display instruction drives the display element to display an error As realized. When such a display causes video degradation due to a transmission error, for example, a block error, the observer recognizes that the video degradation is caused by packet loss that has inevitably occurred in a best-effort communication network. can do.

  Here, it is desirable to consider the timing and duration of communication state display for video communication using video compression technology. In video compression such as MPEG-2, significant image compression is obtained by creating a B picture that encodes only the difference information between the video predicted from the previous and next frame video called inter-frame compression and the actual captured frame. ing. In order to explain the present invention, it is necessary to understand the delay time associated with the MPEG-2 playback flow, which will be described with reference to FIG.

  In MPEG-2, when the difference information of the P picture (4) is received based on the information of the first received I picture (1), the P picture (4) is reproduced. The B picture (2,3) is reproduced based on the I picture (1) and the P picture (4) in combination with the difference information of the B picture (2,3). The P picture (7) is reproduced based on the P picture (4), the B picture (5, 6) is reproduced based on the P picture (4) and the P picture (7), and the B picture (8, 9) is reproduced. Playback is based on P picture (7) and I picture (10).

  In this way, in order to completely restore the B picture image, information on the P picture and I picture after the frame is also required, and a time delay of about 0.1 seconds occurs in the restoration. In an actual best effort communication network, it is necessary to consider the arrival time of packets. Since a phenomenon in which information called jitter is mixed in the transmission path may occur in the transmission path, buffering for accumulating information and switching the front and back is performed in the receiving terminal in order to absorb the arrival time difference. Therefore, a delay of the buffering processing time is added. Further, in the compression of the frame screen, the amount of information changes depending on the screen configuration, so that the variation is absorbed and buffering is performed to output the video signal to the television monitor at a constant rate. One more delay is added.

  There is a delay as described above until the video signal packet is received and reflected in the restored video. The value is generally about 0.2 to 0.3 seconds. Since a time difference of about 0.2 seconds can be recognized as human vision, if an error is detected and a communication status error is displayed immediately, there is a time delay due to the time difference in the display of the video with the error. Some observers may feel that time delay unnaturally. In particular, in the best effort type communication, the delay time varies from information to information, and general observers who have no knowledge of video compression are wondering about the communication status display.

  In the present invention, as a more preferred embodiment, an error display is provided with a delay time adjustment function in order to clearly recognize that the video disturbance is caused by communication abnormality. As a method of providing a delay adjustment function, (1) a method of displaying with a delay of 0.1 second for all error detections, or (2) identifying whether it is an I, P or B frame A method is used in which a processing delay time is assigned, and about 0.1 second such as buffering is displayed with a delay time obtained by adding the processing delay time to the above processing delay time.

  A feature of the method (1) that uses 0.1 second is that a person hardly recognizes it in about 0.1 second. As an implementation means, in the processing up to the communication status display unit, a method for performing time control between the detection time and the display time by software and processing the delay time, a timer circuit (for example, RC time constant circuit), and separation by detecting each signal There is a method of providing a delay time in a circuit by combining processing.

  Next, in the inter-frame compression such as MPEG-2, for example, image disturbance generated in an I picture is reflected as it is in the following B picture or P picture, and the video disturbance continues until the next I picture. . If the image changes anew for each frame, the video disturbance associated with one packet loss is 1/30 second and is hardly perceived by the observer, but the above-mentioned video disturbance with inter-frame compression is , Lasts about 0.3 seconds at the maximum.

  In another preferred embodiment of the present invention, the communication state display time of the packet loss is related to the time of the video disturbance by displaying the communication state abnormality during the duration of the video disturbance. Is done. By setting the duration of the communication state display in this way, it becomes possible to appropriately convey the influence of the communication state to general viewers.

  As an actual duration setting method, (1) a method of always having a duration of 0.2 seconds, which is an average of human recognizable time, and (2) discriminating a frame type (I, P, B) Then, there is a method of continuing 0.3 seconds for the I frame, 0.1 seconds for the P frame, and 0.07 seconds for the B frame. As a means of realization, in the technique of continuing the display circuit for a specific time by software, the technique (2) obtains frame type information from the MPEG-2 processing circuit and selects the duration, and a timer circuit (for example, (RC time constant circuit) and a method of providing a continuous time in a circuit by combining separation processing by signal detection.

  In order to achieve the above object, another video receiving terminal of the present invention, when the communication network is congested and the frequency of packet anomalies or the frequency of packet loss is unbearable for appreciating video, In addition to the observer, notification is also made to the transmitting side. Specifically, since viewing cannot be withstood when the packet loss exceeds 10%, the time stamp added to the transmitted packet is not detected within the allowable time range, and the frequency considered as packet loss is an average of 1 second. When the value becomes 10% or more, the state is notified to the observer and the sender. By the notification, selection is made to change the received video to information that can withstand a congested communication network with a further limited amount of information, or to change reception to a time zone that avoids another congestion.

  Next, when no video is displayed on the television monitor, (1) the phone is not in an incoming state, (2) the video is interrupted due to a poor communication state, but (3) the television monitor from the receiving terminal. It is required to distinguish the situation where the signal path to is not established.

  In order to achieve this distinction, the video receiving terminal of the present invention for achieving the another object is in the incoming state when entering the incoming state based on the transmission / reception rule of the video signal via the communication network. Both notification display and communication status display are performed. By comparing the status indications of the two, the observer is not in the incoming status if there is no incoming indication, and if the incoming status is bad but the communication status indication is poor, the observer is in a poor communication status, incoming status If the communication is normal, it can be determined that the signal path from the receiving terminal to the television monitor has not been established.

  According to the present invention, in a video receiving terminal that reproduces a video signal via a communication network whose communication quality is not sufficiently guaranteed, such as a best-effort communication network that is prone to packet loss, a video observer can easily Can be returned to the communication state. Therefore, it is possible to avoid having suspicion about the AV apparatus and the video communication terminal when the video quality deteriorates or when no display is performed. Therefore, a low-cost communication network can be used while being convinced of its transmission quality, and the marketability of video services using the best-effort communication network can be enhanced.

Hereinafter, a video receiving terminal according to the present invention will be described in more detail with reference to some embodiments shown in the drawings. In addition, the same code | symbol in FIG.1, FIG.2, FIG.6 and FIG.8 shall display the same thing or a similar thing.
<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a configuration of an entire system that encodes a video signal captured by a video camera, subsequently transmits the video signal via a best effort communication network, decodes the received video signal, and displays the decoded video signal on a television monitor. In FIG. 1, reference numeral 40 denotes a video receiving terminal according to this embodiment.

  Analog video information photographed by the video camera 10 is input to the MPEG-2 encoder 12 of the transmission-side device 11, converted into digital information, encoded and compressed for each frame, and further I-picture, P-picture, Divided into B pictures and compressed between frames. The compression-coded MPRG-2 data is converted into a data code called TS (Transport Stream) and formatted into a form suitable for transmission. Subsequently, the transmission side RTP (Realtime Transport Protocol) mapping unit 13 edits the packet as a UDP / IP packet and transmits it to the best effort communication network 20.

  At this time, a time stamp is attached to the transmitted packet so that the order can be identified. The best-effort communication network 20 does not guarantee (guarantee) for delay time or arrival, such as changing the route of the packet depending on how busy the line is, or discarding the packet when it exceeds the allowable amount. It is a communication network.

  The receiving side device 31 of the video receiving terminal 40 receives the UDP / IP packet and restores it to the TS signal by the receiving side RTP processing unit 32. In that case, the lack of a timestamp number is evaluated as a packet loss. The time stamp number is detected by receiving the previous time stamp and detecting the next time stamp during a predetermined waiting time. As the predetermined waiting time, for example, a time delay of the communication network, a delay time due to a buffer for signal processing on the receiving side, and the like are allowed up to 0.1 seconds. If the packet with the next time stamp is not detected after 0.1 second, it is determined that the packet is lost. In these processes, the time stamp bit is detected in the processing of the received IP signal, the detection timer for the next time stamp is started from that time, and if it is detected within the allowable time, the next next is detected at the time of detection. The time stamp detection timer is updated to start, and if not detected, the next time stamp detection mode is updated at the end of the allowable time. Even if a packet having the next next time stamp is detected earlier within the allowable time for detecting the next time stamp, the packet is not updated and waits until the allowable time. If the packet having the next time stamp is not detected when the allowable time is reached, the next next packet has already been received, and the next time stamp is updated. Such logical processing is performed by operating a CPU (Central Processing Unit) included in the receiving-side device 31 by software. Of course, these logical processes can also be realized by a logic circuit (hardware).

  Finally, the restored TS signal is input to the MPEG-2 decoder 33, and at the same time, the error processing unit 34 is notified of error information accompanying the abnormal communication state included in the restored TS signal, that is, the occurrence of packet loss. The MPEG-2 decoder 33 decodes the compressed signals I picture, P picture, and B picture, and outputs the obtained analog video signal to the television monitor 30.

  The error processing unit 34 instructs the communication state display unit 35 to display the abnormal state when the communication state abnormality is transmitted. In response to the instruction, the communication status display 35 turns on the status display lamp 38 so that the observer (viewer) can understand it, and informs that there is an abnormality that causes an abnormality in the video from the signal from the communication network. .

  If the observer sees an abnormality in the communication status display status lamp 38 at the same time when he / she sees an abnormality in the image on the television monitor 30, the disturbance of the image is an image via the best effort communication network 20. It will be recognized that the signal is abnormal.

  In general, the communication status display according to the present invention is highly necessary in a best-effort type communication network. However, in other communication networks, image disturbance is caused by abnormal information via the communication network. It is useful when you need to recognize that it is.

In this embodiment, the video signal is sent by packet, and the loss of the packet is regarded as a communication error. However, the present invention is not limited to transmitting the video signal by packet, and the video signal is not a different signal. It may be sent in a format, and it is possible to make a communication abnormality that a part of a video signal is lost during transmission through a communication network.
<Embodiment 2>
A second embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a functional block diagram of a video receiving terminal in which the receiving side device 31 in FIG. 1 has a function of matching the display of the communication state with the video display time so as not to make the observer feel uncomfortable. FIG. 3 is a playback flow diagram showing the relationship between the MPEG-2 video frame configuration and I, P, and B pictures for video playback. The receiving side RTP processing unit 32 receives the TV video UDP / IP signal 21 from the communication network, performs RTP processing, and detects packet loss. Further, the receiving-side RTP processing unit 32 performs MPEG-2 / TS processing on the video signal that has been subjected to RTP processing, and outputs I, P, and B picture signals to the MPEG-2 decoder 33. The decoder 33 stores the input I, P, B picture signal in the I, P, B picture signal storage unit 331. The accumulating unit 331 absorbs a change in the arrival order of packets called jitter and corrects it in the time stamp order, and sends the I, P, and B picture signals free from jitter to the I, P, and B picture decoding processing unit 332. The signal decoded by the decoding processing unit 332 is input to the decoded video signal D / A output unit 333, from which an analog video signal is output. As described above, the MPEG-2 decoder 33 includes the I, P, B picture signal storage unit 331, the I, P, B picture decoding processing unit 332, and the decoded video signal D / A output unit 333.

  The I, P, and B picture decoding processing unit 332 decodes the I, P, and B picture signals and performs time-series frame reproduction of each video. The process will be described with reference to FIG. 3 showing a reproduction flow of MPEG-2. The ordinary line arrows in FIG. 3 represent a time-series reference relationship when constructing a P picture or a B picture, and the thick line arrow represents a later structure for constructing a B picture by performing inter-frame processing. It shows the flow of referring to P picture and I picture information. In MPEG-2, when the difference information of the P picture (4) is received based on the information of the first received I picture (1), the P picture (4) is reproduced. The B picture (2,3) is reproduced based on the I picture (1) and the P picture (4) in combination with the difference information of the B picture (2,3). P picture (7) is reproduced based on P picture (4), B picture (5, 6) is reproduced based on P picture (4) and P picture (7), and B picture (8, 9) is reproduced as P picture. Playback is based on picture (7) and I picture (10). In that case, in the reproduction of the B picture, the video composition from the preceding and following I and P pictures is performed, and the time for reproducing the same video frame as I from the video data obtained by compressing and subtracting the P and B pictures after the TS processing An adjustment time delay is included to perform the adjustment.

  Now, the video frames reproduced in this way are input to the decoded video signal D / A output unit 333 at regular intervals, and an analog video signal is output therefrom. The analog video signal is output to the monitor television 30, and the observer views it as a reproduced video.

  When a packet loss is detected by the receiving side RTP processing unit 32 in such video decoding and reproduction, the influence appears as a video abnormality with a time delay on the screen of the monitor television 30. For the time delay, each process in the I, P, B picture signal storage unit 331 of the MPEG-2 decoder 33, the I, P, B picture decoding processing unit 332 of the MPEG-2 and the decoded video signal D / A output unit 333 is performed. It is caused by going through. Also, video abnormalities are often block errors or screen loss errors that result in mosaic patterns.

  The packet processing CPU 61 that performs packet loss signal processing includes a receiving side RTP process 32, a delay time setting unit 341 corresponding to a delay time by MPEG-2 decoding, and a display holding time setting unit 342 corresponding to a duration by MPEG-2 decoding. It is comprised including. The delay time setting unit 341 and the display holding time setting unit 342 are provided in the error processing unit 34. Information indicating that the receiving side RTP processing unit 32 has detected a packet loss is transmitted to the delay time setting unit 341. The delay time setting unit 341 has a function of causing a time delay corresponding to the delay time in a series of processes of MPEG-2 decoding and reproduction to occur in the communication state display. Further, the display holding time setting unit 342 has a function of continuously displaying the communication state display while an abnormality is displayed on the screen.

  A simple processing method for setting the delay time is a method in which the average MPEG-2 decoding / playback processing time is grasped and the time delay is given. This is a total delay time setting of 0.2 seconds in the I, P, B picture signal storage unit 331 and the MPEG-2 I, P, B picture decoding processing unit 332. Generally, when the time difference is 0.05 seconds or less, the difference is hardly recognized, so the average value that can be recognized is 0.2 seconds. To realize the delay, there is a method by software processing using a CPU.

  As a more rigorous method, there is a method in which the I, P, B picture decoding processing unit 332 detects a delay time that changes with each processing, and notifies the delay time setting unit 341 of the detection. In the MPEG-2 playback frame, it is determined which video frame is an I, P or B picture including a packet loss. Therefore, the processing of the MPEG-2 I, P, B frame decoding processing unit 332 is completed so that the signal reflecting the packet loss corresponds to the decoding of each video frame in the reproduction signal processing step of the MPEG-2 decoder 33. Until that time, a signal reflecting the packet loss is attached, and it is detected which frame the packet loss affects. The detection result is notified to the delay time setting unit 341 and the display holding time setting 342 of the packet processing CPU 61.

  The delay time setting unit 341 strictly sets the delay time by adjusting the delay time for each frame. This makes it possible to match the start times of the communication status display and the video display. By performing the processing of the delay time setting unit 341 by software, other delay elements can be added. The delay time setting 341 sends a lighting instruction signal having a delay by the set delay time to the communication state display unit 35. The display unit 35 to which the lighting instruction signal is input can display an abnormality on the display lamp 38 in the communication state at a timing almost in accordance with the playback video of the monitor television 30.

  Next, the display hold time setting 342 receives the delay time setting 341 and the information from the I, P, B picture decoding processing unit 332, and the video disturbed by the packet loss is reproduced on the monitor TV 30. During this time, the status display lamp 38 is kept on.

  As a method for setting the duration time, a method of setting about 0.1 second, which is a reflection time of an average MPEG-2 packet loss, can be considered. Further, as a more rigorous method, information indicating which video frame corresponds to an I-, P-, or B-picture including a packet loss in the MPEG-2 playback frame is input to the display holding circuit 342, and the lighting holding time is set. Is set to 0.3 frames for each frame, for example, for an I picture frame, 0.2 seconds for a P picture frame, and 0.033 seconds for a B picture frame. By setting the holding time in this way, it is possible to match the display time of the video and the communication state. The display holding time setting 342 can also be set by software so that the holding time can be set longer so that the display can be confirmed more easily.

  The communication state reproduction delay and duration based on the present invention will be described with reference to FIG. FIG. 4A shows an example of a television image display, and FIG. 4B shows an example of a communication state display. Even if the occurrence of packet loss is detected on the receiving side, the television image in FIG. 4A is observed before receiving no packet loss because of the delay caused by the MPEG-2 decoding and reproduction processing. . At this time, even if the image of the image degradation wind on the transmission side such as a creative mosaic is observed, the observer knows that it does not accompany communication abnormality. When the subsequent MPEG-2 decoding and playback processing after the packet loss occurs and a block error due to the packet loss is seen in the TV image of FIG. 4A, the timing is adjusted. In FIG. 4B, a lamp indicating an abnormality in the communication status display is turned on. Thereby, the observer can recognize that the block error is caused by communication abnormality. In MPEG-2, since the inter-frame compression is performed, the error state may continue in the decoding, and if the communication state display in FIG. It will be recognized that the deterioration of the TV image in FIG. 4A is caused by communication abnormality.

  As a reference, FIG. 5 shows an example of communication state display when decoding, playback video delay, and continuation are not considered. In this case, when a packet loss is detected, a lamp indicating that the communication status display of FIG. 5B is abnormal lights up, but the original mosaic originally intended for the television image of FIG. If there is, it will be mistaken for deterioration due to communication abnormality. When a block error due to packet loss appears in the television image of FIG. 5A after MPEG-2 decoding and playback processing, the abnormal lighting of the communication status display is not held and is turned off. For this reason, block errors are mistaken for the intended creative mosaic. Further, even if the block error continues, the communication status display in FIG. 5B is turned off, so that the block error is further mistaken for a creative one.

By applying the present invention, when data-compressed video is received via a best-effort communication network with relatively poor transmission quality, a receiving-side device that decodes and plays back the communication status indication as video degradation due to packet loss. Since the timing can be adjusted, the observer can grasp and judge the cause of the image deterioration appropriately.
<Example 3>
A third embodiment of the present invention will be described with reference to FIGS. The video receiving terminal of this embodiment is further provided with an allowable packet loss state determination unit in addition to the second embodiment, and a superimpose insertion function for notifying the monitor television that the communication state is bad when the communication state abnormality is strong. FIG. 6 is a functional block diagram thereof. FIG. 7 is an example of a superimposition for notifying a communication abnormality, and “Currently very bad communication state and video is disturbed” is displayed on the screen.

  A flow of a process of superimposing a communication abnormality display executed by the video receiving terminal shown in FIG. 6 will be described. When detecting the packet loss, the receiving-side RTP processing unit 32 inputs the information to the allowable packet loss state determination unit 344 provided in the error processing unit 34. The allowable packet loss determination unit 344 calculates the frequency by counting the packet loss. For example, in MPEG-2, when the packet loss frequency is 1%, an error is observed on the video screen about three times per second. This state can be distinguished from what the video represents, but it is quite unsightly. When it reaches 10%, video skipping occurs in a situation where the video screen is cut, and it becomes difficult to judge what is represented. Therefore, as an example, when the frequency of packet loss is 1% or more, the allowable packet loss state determination unit 344 displays the superimpose on the television monitor 30 and displays a strong communication state abnormality on the state display lamp 38. Is sent to the strength display instruction unit 345 included in the error processing unit 34. In the present embodiment, both superimpose and strong abnormality display are used, but it is possible to notify the observer with either one of them or another notification means such as voice.

  Upon receiving the instruction, the strength abnormality display instruction unit 345 sends a superimpose instruction to the television monitor 30 to the character string insertion unit 334 that inserts a character string indicating the deterioration of the communication state, and also displays it on the communication state display unit 35. A strong abnormality display instruction is sent to the lamp 38.

  The superimpose expression notifies the observer that the video quality is difficult to see due to the deterioration of the communication state, and does not strictly define the expression. When a radio reception failure occurs in a general television broadcast in the area, a superimposition such as “Currently, the radio wave condition is very bad in some areas and the image is distorted” may be displayed. The invention is not inserted artificially at a broadcasting station, but is automatically determined and displayed at each receiving terminal. Further, the display of the strong communication status is distinguished from the normal display by changing the color of the communication status display lamp or by continuously lighting the display.

  The determination in the allowable packet loss state determination unit 344 is not instantaneous. For example, the determination is based on reception for 5 seconds, and superimpose is displayed at least 5 so that the observer can recognize the display slowly. The second continues. With these displays, the observer knows that the communication state is not suitable for video reproduction, and can determine whether to switch to another communication method or try to receive in another time zone.

Further, a notification reception video signal abnormality notification unit 321 for transmitting a TCP / IP signal to the transmission side is provided, and when the allowable packet loss state determination unit 344 determines that the packet loss state is not less than an allowable value, the allowable packet loss state determination is performed. The unit 344 issues a transmission instruction to the received video signal abnormality notification unit 321. Upon receiving the instruction, the received video signal abnormality notifying unit 321 sends a TCP / IP signal 22 for notifying the abnormality of the received video signal state to the transmission side. As a result, since the state on the receiving side can be grasped on the transmitting side, the state can be shared with the observer on the receiving side, and for example, measures such as shifting the time or changing the communication means can be easily performed.
<Example 4>
A fourth embodiment of the present invention will be described with reference to FIG. The video receiving terminal of the present embodiment performs connection establishment and incoming call display when a video signal is transmitted from the transmitting side device 11 to the receiving side device 31 via the best effort type communication network 20, and FIG. Is a functional block diagram thereof.

  The transmission side device 11 first transmits a connection establishment signal via the transmission control circuit 14 by the connection control circuit (TCP / IP) 15 in order to establish a connection with the reception side device 31. When the reception control circuit 36 receives the connection signal, the reception side device 31 notifies the connection control circuit (TCP / IP) / incoming call display unit 37 and returns a signal indicating that the connection can be established to the transmission device 15. Since these connection control establishment signals are TCP / IP signals, even if packet loss occurs in the best-effort communication network 20, the signals are retransmitted until they reach the transmission side without fail.

  The connection control circuit (TCP / IP) / incoming display 37 displays that the receiving terminal has entered the video signal receiving state by turning on the incoming display lamp 371 when it is determined that the connection has been established. The reception-side RTP processing unit 32 functions in the reception state of the video signal, and displays the communication state from the reception-side RTP processing unit 32 to the error processing unit 34 and from the error processing unit 34 to the communication state display unit 35 in the error detection state. Is sent, and the communication status display lamp 351 indicating the communication abnormality is turned on.

  If packet loss frequently occurs, the MPEG-2 decoder 33 may interrupt the video decoding / playback process and the video may not be displayed on the television monitor 30. The observer does not feel a problem when the received video is displayed on the TV monitor, but when the video to be projected does not appear, it is difficult for the observer to grasp the status. It becomes possible.

  That is, (1) when the incoming call indicator lamp 371 is not lit, there is no incoming call state and no connection between transmission and reception is established. (2) When the incoming call lamp 371 is turned on but the lamp display 38 notifying the communication state abnormality is not turned on, the signal path connecting the receiving side apparatus 31 and the television monitor 30 is not normally established. (3) When the incoming call display lamp 371 is lit and there is a lamp display that informs the communication state abnormality, the video processing is interrupted due to the communication abnormality. By making these determinations possible, it is possible to provide a video service that can be convinced by an observer in video signal reception via the best-effort communication network 20.

The block diagram for demonstrating 1st Embodiment of the video receiver terminal which concerns on this invention. The functional block diagram for demonstrating the 2nd Embodiment of this invention. The flowchart for demonstrating reproduction | regeneration of the video frame by MPEG-2. The figure which shows the relationship between the communication status display at the time of applying this invention, and a reproduction | regeneration image | video. FIG. 5 is a reference diagram illustrating a relationship between a communication state display and a reproduced video when the present invention is applied. The functional block diagram for demonstrating the 3rd Embodiment of this invention. The figure which shows the example of the superimpose which notifies communication abnormality. The functional block diagram for demonstrating the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Observer (viewer), 10 ... Video camera, 11 ... Transmission side apparatus, 12 ... MPEG-2 encoder, 13 ... Transmission side RTP mapping part, 14 ... Transmission control circuit, 15 ... Connection control circuit (TCP / IP) ), 20... Best effort type communication network, 21... TV video UDP / IP signal, 22... Received video signal state abnormality notification TCP / IP signal, 30... TV monitor, 31. 33 ... MPEG-2 decoder, 34 ... error processing unit, 35 ... communication status display unit, 36 ... reception control circuit, 37 ... connection control circuit (TCP / IP) / incoming display unit, 38 ... status display lamp, 40 ... Video receiving terminal, 61 ... Packet processing CPU, 321 ... Received video signal abnormality notifying unit, 331 ... I, P, B picture signal accumulating unit, 332 ... MPEG-2 I, P, B picture Decoder processing unit, 333 ... Decoded video signal D / A output unit, 334 ... Character string insertion unit, 341 ... Delay time setting unit, 342 ... Display hold time setting unit, 344 ... Allowable packet loss state determination unit, 345 ... Strong Anomaly display instruction section 371 .. Incoming call display lamp.

Claims (6)

  Receiving means for receiving an encoded video signal sent via a communication network, decoding means for decoding the video signal, video display means for displaying the decoded video signal, and part of the video signal A video receiving terminal comprising: a detecting unit that detects a communication abnormality that is lost during transmission through a communication network; and a communication state display unit that indicates that the communication abnormality has been detected.   2. The video receiving terminal according to claim 1, wherein the video signal is compressed and encoded and then transmitted using a packet, and the detection unit detects the communication abnormality from the loss of the packet. .   Delay time setting that substantially matches the display start time when the video display means displays the disturbance of the video that appears due to the communication abnormality and the display start time when the communication state display means indicates that the communication abnormality is detected. The video receiving terminal according to claim 1, further comprising means.   Display holding time setting means for substantially matching the length of time that the video display means displays the disturbance of the video that appears due to the communication abnormality and the length of time that the communication status display means indicates that the communication abnormality is detected. The video receiving terminal according to claim 3, further comprising:   Receiving means for receiving an encoded video signal sent via a communication network, decoding means for decoding the video signal, video display means for displaying the decoded video signal, and part of the video signal Detecting means for detecting a communication abnormality that is lost during transmission over the communication network, and when the communication abnormality in which the rate of loss of the video signal exceeds a predetermined value is detected as a strong abnormality, the video display means Video reception characterized in that at least one of superimposing a character string representing the strong abnormality on the displayed video and displaying or notifying that the strong abnormality has been detected is executed Terminal.   Receiving means for receiving an encoded video signal sent via a communication network, decoding means for decoding the video signal, video display means for displaying the decoded video signal, and part of the video signal Establishing a connection between a detecting means for detecting a communication abnormality that is lost during transmission over the communication network, a communication state display means that indicates by display that the communication abnormality has been detected, and the video signal transmitting side device A video receiving terminal comprising: connection establishing means; and incoming call display means for indicating that the connection has been established.

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