JP2019047219A - Receiving device, data receiving method, and program - Google Patents

Abstract

To reduce adverse effect when content data is communicated in a communication environment in which data loss may occur.SOLUTION: A receiving device detects loss of content data to be received from a transmitting device 101 (S901) and determines according to a processing amount of the content data whether to restore the loss on the basis of redundant data (S904).SELECTED DRAWING: Figure 9

Description

  The present invention relates to a receiver for receiving data, a method of receiving data, and a program.

  Content data (image data, audio data, etc.) may be streamed in real time from a smartphone, a camera with a wireless function, etc. via a communication network. In general, an asynchronous transmission method such as User Datagram Protocol (UDP) is used for data transmission for which real-time performance is required. Further, there is known a method of transmitting redundant data from a transmitting device to a receiving device in order to recover data loss in data transmission by UDP.

  There is Patent Document 1 as a document disclosing a method of performing an error correction based on redundant data. In Patent Document 1, when it is determined that the communication environment is bad, processing of the error correction coding unit and the error determination unit is stopped, and the error correction decoding unit is made to execute error correction decoding of input data. Have been described.

JP, 2005-252709, A

  However, depending on the situation of data loss, there is a possibility that the reproduction of the content is adversely affected. For example, a large amount of loss occurs, and as a result of using resources for the recovery process, there is a possibility that the decoding process of the properly received content data may not be in time, and the reproduction of the content may be stopped.

  The present invention has been made in view of the above problems, and an object thereof is to reduce an adverse effect in the case of communicating content data in a communication environment where data loss may occur.

  In order to solve the above problems, a receiving device of the present invention has, for example, the following configuration. That is, receiving means for receiving content data and redundant data from a transmitting device, detecting means for detecting loss of content data to be received by the receiving means, and receiving loss detected by the detecting means by the receiving means And recovery means for recovering based on the redundant data, and control means for limiting recovery processing by the recovery means in accordance with the processing amount of the content data received by the receiving means.

  According to the present invention, it is possible to reduce the adverse effect of communicating content data in a communication environment where data loss may occur.

System configuration diagram in the embodiment Functional configuration diagram of transmitting apparatus in the embodiment Hardware configuration diagram of transmitting apparatus in the embodiment Functional configuration diagram of the receiving device in the embodiment Hardware configuration diagram of the receiving device in the embodiment Sequence diagram in the embodiment Table in the embodiment Flow chart for explaining the operation of the receiving device in the embodiment Flow chart for explaining the operation of the receiving device in the embodiment Flow chart for explaining the operation of the transmission apparatus in the embodiment

  Hereinafter, the present invention will be described in detail based on preferred embodiments thereof with reference to the attached drawings. In addition, the structure shown in the following embodiment is only an example, and this invention is not limited to the illustrated structure.

  FIG. 1 is a diagram showing a system configuration in the present embodiment. The transmitter 101 transmits and receives data to and from the receiver 103 via the network 102. In the present embodiment, it is assumed that the processing performance bottleneck is in the receiver 103. That is, it is assumed that the processing performance of the reception apparatus 103 is inferior to the data transmission performance of the transmission apparatus 101 and the communication performance (including the data transfer performance) of the network 102. The system configuration is not limited to the example of FIG. 1, and a plurality of transmission devices 101 and reception devices 103 may exist, and the network 102 may be a wireless network or the like.

  FIG. 2 is a block diagram showing a functional configuration of the transmission apparatus 101 in the present embodiment. The functions of each block will be described in detail below. The input unit 1100 includes an imaging unit 1101 and an encoding unit 1102. An imaging unit 1101 controls an imaging apparatus including an optical system to acquire a captured image. The encoding unit 1102 compresses the captured image acquired by the imaging unit 1101. The captured image (compressed image) obtained by the compression processing is transmitted to the control unit 1110.

  The control unit 1110 processes a captured image (compressed image) acquired from the input unit 1100 and information from the external device (the receiving device 103 in the example of the present embodiment) acquired by the network unit 1130. Also, the control unit 1110 causes the display unit 1120 to display the results of these processes. The transmission control unit 1111 transmits the video packet generated by the packetizing unit 1114 based on the captured image (compressed image) and the redundant packet generated by the redundant packet unit 1113 to the receiving apparatus 103 using the network unit 1130. The reception control unit 1112 processes the data acquired from the reception device 103 by the network unit 1130.

  The redundant packet unit 1113 generates a redundant packet based on the redundant packet method instructed by the quality management unit 1115 and its redundancy. The redundant packet generated by the redundant packet unit 1113 is transmitted to the receiving apparatus 103 using the transmission control unit 1111 and the network unit 1130.

  The packetizing unit 1114 packetizes the captured image (compressed image) acquired from the input unit 1100 so that it can be transmitted via the network 102. The packet (video packet) generated by the packetizing unit 1114 is transmitted to the receiving apparatus 103 using the transmission control unit 1111 and the network unit 1130.

  The quality management unit 1115 determines the transmission rate of the content data to be transmitted by the transmission apparatus 101 and the redundancy degree related to the redundant data based on the notification information from the reception apparatus 103. More specifically, the quality management unit 1115 acquires notification information such as loss information and / or processable bit rate information from the reception apparatus 103. In the present embodiment, the defect information is information indicating the number of defects of data in the receiving device 103, the loss rate, or the recovery results, and the processable bit rate information relates to the rate of content data that can be processed by the receiving device 103. It is information. Then, based on the notification information (defective information and / or processable bit rate information) from the reception device 103, the quality management unit 1115 transmits the transmission rate of the content data to be transmitted by the transmission device 101 and the redundancy related to redundant data. Decide. The quality management unit 1115 notifies the encoding unit 1102, the packetizing unit 1114, and / or the transmission control unit 1111 of the determined transmission rate as necessary. In addition, the quality management unit 1115 notifies the redundant packet unit 1113 and / or the transmission control unit 1111 of the determined degree of redundancy as necessary.

  The display unit 1120 includes a panel drawing unit 1121. The panel drawing unit 1121 causes the display device (for example, a liquid crystal display) to display an image based on the drawing instruction from the control unit 1110. The network unit 1130 functions as an interface for communicating with another communication apparatus (for example, the receiving apparatus 103).

  In the present embodiment, the function of each block shown in FIG. 2 is realized by the CPU 1202 described later developing a program stored in the ROM 1203 in the RAM 1204 and executing processing according to each flowchart described later. However, at least a part of the functions shown in FIG. 2 may be realized by using dedicated hardware.

  FIG. 3 is a block diagram for explaining the hardware configuration of the transmission apparatus 101. As shown in FIG. A central processing unit (hereinafter referred to as a CPU) 1202 controls the entire transmission apparatus 101 to perform various calculations and the like. The ROM 1203 is a storage device for reading out information once written. The ROM 1203 stores a program for realizing the function of each block shown in FIG. The RAM 1204 is a storage device for temporarily writing and reading data. The RAM 1204 stores, for example, temporary values obtained by execution of each program.

  The internal memory 1205 and the external memory 1209 are external storage devices for storing content data. In the present embodiment, an example in which the content data is video content based on image data will be mainly described, but the present invention is not limited to this. For example, audio content based on audio data may be used, or a combination of video and audio may be used. In addition, subtitle data and various other data may be included as part of content data.

  The imaging device 1206 is a device configured to convert light, which is a CMOS sensor or a CCD sensor, into an electrical signal, and includes a lens, a sensor, and the like. The communication IF 1211 is a device for transmitting and receiving data to and from the outside (the receiving device 103) of the transmitting device 101. Any wired or wireless network interface such as Ethernet or the like may be implemented.

  The liquid crystal panel 1207 is shown as an example of the display device. In addition to the liquid crystal panel, for example, organic EL, electronic paper, etc. may be used. The microphone 1212 is a sensor that collects voice at the time of imaging. The speaker 313 is a device for reproducing audio at the time of reproducing video content or the like. The power source 314 is a device for supplying power to the transmission device 101, and includes a battery and a charging device.

  The hardware configuration of the transmission apparatus 101 is not limited to the example shown in FIG. For example, the transmission device 101 may not have the imaging device 1206. In this case, the transmission device 101 may obtain a captured image from an imaging device or storage server (not shown). Further, for example, a plurality of processors such as the CPU 1202 may be provided. In addition, the transmission device 101 and the liquid crystal panel 1207 (display device) may not be integrated. Also, a case may be considered in which the microphone 1212 is unnecessary for the transmission device 101.

  FIG. 4 is a block diagram showing a functional configuration of the receiving device 103 in the present embodiment. The functions of each block will be described in detail below. The reception control unit 3112 passes the video packet received from the transmission apparatus 101 through the network unit 3130 to the depacketizing unit 3114. The depacketizing unit 3114 acquires a captured image (compressed image) from the video packet and passes it to the decoding unit 3116.

  The decoding unit 3116 performs a decoding process on the captured image (compressed image) to obtain the captured image (decoded), and passes the acquired image to the panel drawing unit 3121. The panel drawing unit 3121 reproduces video content based on the captured image (decoded) obtained from the decoding unit 3116. In addition, when reproducing | regenerating audio data with reproduction | regeneration of video content, each block of FIG. 4 performs the process which concerns on audio data in parallel with the process which concerns on a captured image.

  Also, the quality management unit 3115 generates notification information (defective information and / or processable bit rate information), and transmits the notification information to the transmission apparatus 101 via the transmission control unit 3111 and the network unit 3130.

  Further, the depacketizing unit 3114 detects a loss of content data to be received from the transmission device 101. Specifically, the depacketizing unit 3114 checks the continuity of the sequence numbers of each video packet acquired from the transmission apparatus 101. Then, when there is a drop in the sequence number, the occurrence of the loss of the content data is detected. Note that the method of detecting loss of content data is not limited to the above method. As another detection method, for example, data loss may be detected by analyzing image data at the time of decoding processing in the decoding unit 3116. More specifically, when image data of a specific slice does not exist after the decoding processing of image data, it is possible to detect that a video packet related to the slice is missing.

  The reception control unit 3112 receives data from the network unit 3130 and transfers the data to the depacketizing unit 3114 if it is content data (video packet) or to the redundant packet unit 3113 if it is redundant data (redundant packet).

  The redundant packet unit 3113 uses the redundant packet acquired from the transmission apparatus 101 via the reception control unit 3112 and the network unit 3130 to perform the above-described recovery process for recovering from the loss. Also, the redundant packet unit 3113 detects that the redundancy of the redundant packet transmitted by the transmission apparatus 101 has been changed. When a change in redundancy is detected, the quality management unit 3115 is notified of the update of the redundancy.

  In addition, the depacketizing unit 3114 notifies the quality management unit 3115 of the loss information (information indicating the number of loss of data in the receiving apparatus 103, the loss rate, the recovery performance, and the like). Then, the quality management unit 3115 notifies the transmitting apparatus 101 of the defect information acquired from the depacketizing unit 3114 via the transmission control unit 3111 and the network unit 3130. Also, the quality management unit 3115 notifies the transmitting apparatus 101 of processable bit rate information (information regarding the rate of content data that can be processed by the receiving apparatus 103) in addition to or instead of the loss information. The network unit 3130 functions as an interface for communicating with the transmission apparatus 101.

  In the present embodiment, the function of each block shown in FIG. 4 is realized by the CPU 3202 described later developing a program stored in the ROM 3203 in the RAM 3204, and executing processing according to each flowchart described later. However, at least a part of the functions of the blocks shown in FIG. 4 may be realized by using dedicated hardware.

  FIG. 5 is a block diagram for explaining the hardware configuration of the receiving apparatus 103. As shown in FIG. The hardware configuration of the receiving apparatus 103 is basically the same as that of the transmitting apparatus 101, and therefore detailed description will be omitted. In the present embodiment, in principle, the processing of the control unit 3110 will be described focusing on an example in the case of being executed by one or a plurality of CPUs 3202.

  Next, processing performance of the control unit 3110 of the reception apparatus 103 will be described using FIG. 7. The table 700 includes a bit rate that can be processed by the receiving apparatus 103 (processable bit rate), and the number of lost data recovery (information on the number of recoverable packets even if there is a loss among a plurality of video packets corresponding to one image frame) Shows the relationship between In the table 700, the vertical axis represents the number of lost data recovery, and the horizontal axis represents the processable bit rate. It is possible to process the combination of the missing data recovery number and the processable bit rate in which “o” is described in the table 700, and the combination of the missing data recovery number and the processable bit rate in which “x” is described is not processed. It shows that it is possible.

  The number of lost data recovery and the processable bit rate are in a trade-off relationship. This is because the processing resources of the control unit 3110 (CPU 3202) that performs recovery processing for recovery of lost data and processing (for example, reception processing, decoding processing, and display control processing) of normally received content data are common. It is because there is. Therefore, for example, when priority is given to recovery processing, there is a possibility that decoding processing will not be in time. Further, in the present embodiment, processing for transmitting notification information to the transmission apparatus 101 is also performed by processing resources of the control unit 3110 (CPU 3202), in addition to recovery processing and processing of content data.

  According to the example of the table 700, when the number of lost data recovery is “0” (701), it can be understood that the maximum value of the processable bit rate is 17 Mbps (717). On the other hand, when the number of lost data recovery is “1” (702), it is understood that the maximum value of the processable bit rate is 16 Mbps (717).

  In addition, when the number of lost data recovery is extremely large as “7” (708), the maximum value of the processable bit rate is lowered to 10 Mbps (710). For example, the following phenomenon may occur when the reception bit rate of content data is 11 Mbps (711) or more even though the number of lost data recovery is “7”. That is, a phenomenon may occur in which the reception control unit 1112 can not receive the video packet from the transmission device 101 or a phenomenon in which the notification information to be transmitted by the quality management unit 3115 can not be transmitted to the transmission device 101. In the present embodiment, in order to reduce the possibility of occurrence of these phenomena, control of redundancy and transmission bit rate is performed. A specific control method will be described later using a flowchart.

  In this embodiment, the table 700 shown in FIG. 7 shows the comparison between the maximum value of the processable bit rate and the number of lost data recovery. However, it is not limited to this example. For example, the maximum value of the processable bit rate may be obtained by calculation using the processing amount (recovery processing cost) related to the recovery processing of the missing data as a variable. The recovery processing cost can be calculated from the operation time of the exclusive OR used for recovery processing of the missing data in the CPU 3202 and the data fetching time from the RAM 3204 to the CPU 3202. Also, the processable bit rate can be calculated from the amount of processing per received packet of the CPU 3202.

  Note that the maximum recovery number of lost data is determined by the degree of redundancy. Therefore, when the transmission apparatus 101 transmits redundant packets with high redundancy, the resistance to loss increases. However, if the degree of redundancy is increased, the processable bit rate in the receiver 103 is reduced. That is, it is important that the transmitting apparatus 101 transmit redundant packets to the receiving apparatus 103 with an appropriate degree of redundancy. Therefore, the transmission device 101 according to the present embodiment controls the degree of redundancy based on the notification information from the reception device 103. Details of the method of determining the degree of redundancy will be described later using a flowchart.

  FIG. 6 shows an example of the sequence of data communication between the transmitter 101 and the receiver 103. The receiving apparatus 103 notifies the transmitting apparatus 101 of the maximum value (upper limit rate) of the processable bit rate (601). That is, the receiving apparatus 103 notifies the transmitting apparatus 101 of 17 Mbps, which is the maximum value of the processable bit rate corresponding to the number of missing data recovery being "0". As a method of notification, for example, SDP (Session Description Protocol) may be carried using SIP (session initiation protocol) or the like, and notified as bandwidth-value.

  The transmitting apparatus 101 receives notification of the maximum value of the processable bit rate (601), and transmits the video packet 610 and the redundant packet 602 to the receiving apparatus 103. The reception apparatus 103 determines the maximum value of the processable rate by the method described later with reference to FIG. 8 triggered by the reception of the redundant packet 602, and updates the value held in the RAM 3204 in the reception apparatus 103. For example, here, when the redundancy of the redundant packet 602 corresponds to the lost data recovery number “4”, according to FIG. 7, since the maximum value of the processable rate is 13 Mbps, this becomes the processable rate after change. .

  The receiving apparatus 103 notifies the transmitting apparatus 101 of the updated processable rate as the upper limit rate after the change (603). The notification method may set the lower limit bandwidth-value in SDP.

  The transmitting apparatus 101 changes the transmission rate of the content data and the redundant data based on the processable rate after the change acquired from the receiving apparatus 103 (608). Specifically, the transmission device 101 controls so that the total of the transmission rates of the content data and the redundant data does not exceed the processable rate after the change. As a result, even if the load of recovery processing in the receiving apparatus 103 is maximized (in this example, even if four video packets are lost among a plurality of video packets corresponding to one image frame), It can be expected to make the regeneration successful.

  The transmitting apparatus 101 transmits content data (video packet) and redundant data (redundant packet) to the receiving apparatus 103 in accordance with the transmission rate specified by the receiving apparatus 103. The receiving device 103 detects a defect from the video packet transmitted by the transmitting device 101, and transmits the number of occurrences of the defect and the recovery result thereof to the transmitting device 101 as notification information (605).

  The transmitting apparatus 101 determines the redundancy required for the recovery process for the loss based on the loss information from the receiving apparatus 103, and changes the redundancy as needed (609). Then, the transmitting apparatus 101 transmits a redundant packet to the receiving apparatus 103 with the changed redundancy (606).

  Similar to steps 602 and 607, the receiving apparatus 103 updates the maximum value of the processable rate, and notifies the transmitting apparatus 101 of the updated processable rate as the upper limit rate. As described above, by dynamically executing the operation of changing the redundancy according to the situation of the loss and changing the maximum value of the processable rate according to the change of the redundancy, the reproduction of the content with little loss is achieved. It becomes possible.

  Next, details of the operation of the reception apparatus 103 will be described using FIG. When the redundant packet unit 3113 of the receiving device 103 receives a redundant packet from the transmitting device 101 (S801), it determines the redundancy corresponding to the redundant packet (S802). Then, the redundant packet unit 3113 determines whether to change the determined degree of redundancy (S803). Specifically, the redundant packet unit 3113 determines that the redundancy should be increased if the video packet lost can not be recovered with the redundancy determined in S802. On the other hand, if it is determined that the redundancy determined in S802 is excessive, the redundant packet unit 3113 determines that the redundancy should be reduced. That is, the redundant packet unit 3113 changes the degree of redundancy related to redundant data transmitted by the transmission apparatus 101 according to the amount of occurrence of loss. If it is determined that the redundant packet unit 3113 does not change the redundancy, the process returns to step S801.

  On the other hand, if it is determined that the redundant packet unit 3113 changes the degree of redundancy, the number of recovered lost data is updated (S804). In this embodiment, for convenience, it is assumed that the lost data recovery number represents the number of lost data (video packet number) that can be recovered in image frame units. However, it should be noted that the definition of the number of lost data differs depending on the generation method of redundant data.

  The redundant packet unit 3113 notifies the quality management unit 3115 of the number of recovered lost data after the change. By referring to the table 700 described in FIG. 7, the quality management unit 3115 obtains the maximum value of the processable bit rate corresponding to the number of recovered missing data after the change. The quality management unit 3115 writes the acquired maximum value of the processable bit rate in the RAM 3204 as the upper limit rate after the change (805). The upper limit rate after the change represents a bit rate at which the reception process can be performed even if video packets of the same number as the number of recovered lost data after the change are lost and recovery processing is performed on them.

  The quality management unit 3115 determines whether the upper limit rate (transmission rate) after the change is equal to or less than the threshold (S806), and when it is determined to be equal to or less than the threshold, transmits a predetermined error notification to the transmission apparatus 101 (S808). ). The predetermined threshold can be calculated from the time required for the loss recovery process and the frame time that is the reciprocal of the frame rate. For example, the quality management unit 3115 sends an error notification if the loss recovery process is longer than the frame time. The error notification may be transmitted to the transmission apparatus 101 and displayed on the display unit 3120 of the reception apparatus 103. In this way, the user can review the communication settings of the network and change the playback content.

  If the quality control unit 3115 determines that the upper limit rate after change is higher than a predetermined threshold (that is, the transmission rate after change is not less than the predetermined transmission rate), the quality control unit 3115 notifies the transmitting apparatus 101 of the upper limit rate after change. (S807).

  Next, the loss recovery process in the receiving apparatus 103 will be described in detail with reference to FIG. The depacketizing unit 3114 of the reception device 103 receives the video packet from the transmission device 101, and detects a defect (S901). If a defect is detected, the quality information is notified to the quality management unit 3115.

  In addition, the redundant packet unit 3113 determines whether or not it is possible to execute recovery processing for the defect detected by the depacketizing unit 3114. Specifically, based on the number of video packets having a defect and the degree of redundancy, it is determined whether or not the recovery process can be performed. If it is determined in S902 that the execution of the recovery process is not possible, the quality management unit 3115 sends loss information to the transmission apparatus 101 (information indicating the number of loss of data in the reception apparatus 103, loss rate, or recovery results, etc.) Is sent back to S901.

  If it is determined in S902 that the recovery processing can be performed, the redundant packet unit 3113 determines the remaining capacity information held in the RAM 3204 (S903). If the remaining capacity indicated by the remaining capacity information is larger than the threshold value, the redundant packet unit 3113 executes recovery processing for the loss (S905). On the other hand, if the remaining capacity is smaller than the threshold value, the recovery processing is canceled (S909). If recovery processing is performed when the remaining capacity is below the threshold, processing (such as reception processing and decoding processing) for a normal video packet may not be performed. If the recovery process is canceled, a part of the video content is reproduced in a lost state, but the reproduction of the video content itself is avoided. Further, by canceling the recovery process, the quality management unit 3115 can transmit the defect information to the transmitting apparatus 101 (S911).

  Note that the process of S 909 can also be expressed as restricting the recovery process according to the processing amount of the content data received from the transmission apparatus 101. If the bit rate of the content data is high, the remaining capacity is insufficient as a result, and the recovery processing is canceled. Moreover, although the process of S909 determines whether recovery processing is to be performed based on the comparison between the remaining capacity and the threshold value, it is not limited to this. For example, whether or not to execute the recovery process may be determined by comparing the processing amount of the content data from the transmission apparatus 101 with the total value of the processing amount for the recovery process for the loss and the threshold value.

  When the redundant packet unit 3113 executes the recovery processing, the redundant packet unit 3113 updates the remaining capacity information held in the RAM 3204. Specifically, the remaining capacity indicated by the remaining capacity information is subtracted. The quality management unit 3115 performs resource adjustment of the processing system when the remaining capacity after the update falls below the threshold. Although this process performs processing such as increasing the clock of the CPU 3202 to be used or increasing the usage amount of the high-speed performance portion of the RAM 3204, other processing resource addition processing may be performed. As described above, the power consumption of the receiving apparatus 103 can be reduced by normally executing processing with low resources and adding resources at high load. However, the process of S910 is not essential.

  If it is determined in S 907 that the remaining capacity does not fall below the threshold, and after S 910, the quality management unit 3115 transmits notification information (lack information and / or processable bit rate information) to the transmission apparatus 101. (S911).

  Next, the operation of the transmission apparatus 101 will be described in detail using FIG. The reception control unit 1112 of the transmission device 101 acquires the maximum value (upper limit rate) of the processable bit rate from the reception device 103 (S1001). The quality management unit 1115 determines, based on the acquired upper limit rate, whether the current transmission rate should be changed (S1002). Specifically, when the current transmission rate is higher than the upper limit rate, it is determined that the current transmission rate should be lowered. If the current transmission rate is significantly lower than the upper limit rate, the quality management unit 1115 determines that the current transmission rate should be increased.

  If the quality management unit 1115 determines that the current transmission rate should be changed, the quality management unit 1115 outputs a change instruction to the encoding unit 1102. The encoding unit 1102 changes the bit rate by changing the compression rate of the content data in accordance with the change instruction (1006).

  Also, when receiving reception information (information indicating the number of data loss in the reception device 103, the loss rate, the recovery performance, etc.) from the reception device 103, the reception control unit 1112 passes the data to the redundant packet unit 1113 (S1003). ). Then, the redundant packet unit 1113 determines whether to change the redundancy based on the loss information from the receiving apparatus 103 (S1004). For example, the redundant packet unit 1113 determines that the degree of redundancy should be increased when there are a number of defects that can not be recovered with the current degree of redundancy. On the other hand, the redundant packet unit 1113 determines that the redundancy should be reduced if high redundancy is set even though no loss occurs. As described above, the redundant packet unit 1113 changes the degree of redundancy related to redundant data transmitted by the transmission apparatus 101 according to the amount of occurrence of a defect detected by the reception apparatus 103.

  When determining that the degree of redundancy should be changed, the redundant packet unit 1113 generates a redundant packet in accordance with the new degree of redundancy (1005). If the redundant packet unit 1113 determines that it is not necessary to change the redundancy, the process returns to step S1001.

  The present invention provides a program that implements the functions of the above-described embodiments to a system or apparatus via a network or storage medium, and is also a process in which one or more processors in the computer of the system or apparatus read and execute the program. It is feasible. It can also be implemented by a circuit (eg, an ASIC) that implements one or more functions.

Claims (13)

Receiving means for receiving content data and redundant data from the transmitting device;
Detection means for detecting loss of content data to be received by the reception means;
Recovery means for recovering the defect detected by the detection means based on the redundant data received by the reception means;
A control unit configured to limit recovery processing by the recovery unit according to the processing amount of content data received by the reception unit.   The content data includes at least one of image data and audio data, and the processing amount of the content data includes at least one of reception processing of the content data, decoding processing, and display control processing. The receiver according to claim 1.   The receiving apparatus according to claim 1, wherein the detecting unit detects a defect based on continuity of a sequence number of a packet received by the receiving unit.   The receiving apparatus according to claim 1, wherein the detecting unit detects a defect by analyzing image data as content data received by the receiving unit. Decryption means for decrypting the content data received by the receiving means;
The receiving device according to any one of claims 1 to 4, further comprising: reproduction means for reproducing content data already decrypted by the decryption means.   The control means is configured to perform the recovery process according to the recovery means when the sum of the processing amount of the recovery process for the defect detected by the detection means and the processing amount of the content data received by the reception means exceeds a predetermined threshold. The receiver according to any one of claims 1 to 5, which limits recovery processing.   The method according to any one of claims 1 to 6, further comprising changing means for changing the redundancy related to the redundant data transmitted by the transmission device according to the generation amount of the defect detected by the detection means. Receiver. A determination unit configured to determine a transmission rate of data by the transmission apparatus according to the degree of redundancy of the redundant data;
The receiving device according to any one of claims 1 to 7, further comprising notifying means for notifying the transmitting device of the transmission rate determined by the determining means. A storage unit configured to store a table indicating a relationship between the degree of redundancy of the redundant data and the transmission rate of data by the transmission apparatus;
The receiving apparatus according to claim 8, wherein the determining means determines the transmission rate corresponding to the redundancy of the redundant data received by the receiving means by referring to the table.   The receiving apparatus according to claim 8, wherein the determining means determines the transmission rate by using an operation with a processing amount of recovery processing based on redundant data received by the receiving means as a variable.   The receiving apparatus according to any one of claims 8 to 10, wherein the notifying unit notifies an error to the transmitting apparatus when the transmission rate determined by the determining unit is less than a predetermined transmission rate. A receiving step of receiving content data and redundant data from a transmitting device;
Detecting the loss of content data to be received by the receiving step;
Recovering a defect detected by the detection step based on redundant data received by the reception step;
A control step of limiting recovery processing by the recovery step according to the processing amount of the content data received by the receiving step.   A program for causing a computer to execute the data reception method according to claim 12.

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