Digital broadcast system having transmission apparatus and receiving apparatus
First Claim
1. A broadcast system including a transmission apparatus and a receiving apparatus, the transmission apparatus including:
- a generating unit operable to generate a first digital stream and a second digital stream by encoding a same signal at different encoding bit rates, where an encoding bit rate for the first digital stream is lower than an encoding bit rate for the second digital stream; and
a transmission unit operable to transmit the first and second digital streams onto a transmission path while delaying the second digital stream relative to the first digital stream,the receiving apparatus including;
a reproduction unit operable to reproduce the second digital stream in a normal state;
a reproduction control unit operable to, when a transmission path failure occurs, cause the reproduction unit to reproduce, instead of the second digital stream, a portion of the first digital stream that has been received before the occurrence of the transmission path failure;
a receiving unit operable to receive packets constituting the first and second digital streams for each digital stream;
an accumulating unit operable to accumulate one or more packets of the first digital stream received by the receiving unit during a predetermined time period until a current time, whereinthe predetermined time period is determined based on statistics of a time period for which a transmission path failure continues, andthe reproduction control unit causes the reproduction unit to reproduce the one or more packets of the first digital stream accumulated in the accumulating unit, when a transmission path failure occurs; and
a write control unit operable to, each time the receiving unit newly receives a packet, write the newly received packet into the accumulating unit after deleting an oldest packet among the one or more packets accumulated in the accumulating unit.
1 Assignment
0 Petitions
Accused Products
Abstract
A broadcast system has digital receiving apparatuses that imitate deteriorated reproduction that is observed in analog receiving apparatuses when a transmission path failure occurs, thus preventing the audiences, who are accustomed to the analog broadcasting, from sensing discomfort at the digital broadcasting. A transmission apparatus causes encoding units 11 and 12 to generate low- and high-quality streams based on the same contents, and transmits these streams onto a transmission path while delaying the high-quality stream. In the receiving apparatuses, a reproduction unit 25 reproduces the high-quality stream in a normal state, while packets of the low-quality stream received during a time period T until the current time are accumulated in an accumulation unit 22. If a transmission path failure occurs, a reproduction control unit 26 causes the reproduction unit 25 to reproduce, instead of the high-quality stream, the accumulated packets of the low-quality stream.
16 Citations
25 Claims
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1. A broadcast system including a transmission apparatus and a receiving apparatus, the transmission apparatus including:
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a generating unit operable to generate a first digital stream and a second digital stream by encoding a same signal at different encoding bit rates, where an encoding bit rate for the first digital stream is lower than an encoding bit rate for the second digital stream; and a transmission unit operable to transmit the first and second digital streams onto a transmission path while delaying the second digital stream relative to the first digital stream, the receiving apparatus including; a reproduction unit operable to reproduce the second digital stream in a normal state; a reproduction control unit operable to, when a transmission path failure occurs, cause the reproduction unit to reproduce, instead of the second digital stream, a portion of the first digital stream that has been received before the occurrence of the transmission path failure; a receiving unit operable to receive packets constituting the first and second digital streams for each digital stream; an accumulating unit operable to accumulate one or more packets of the first digital stream received by the receiving unit during a predetermined time period until a current time, wherein the predetermined time period is determined based on statistics of a time period for which a transmission path failure continues, and the reproduction control unit causes the reproduction unit to reproduce the one or more packets of the first digital stream accumulated in the accumulating unit, when a transmission path failure occurs; and a write control unit operable to, each time the receiving unit newly receives a packet, write the newly received packet into the accumulating unit after deleting an oldest packet among the one or more packets accumulated in the accumulating unit. - View Dependent Claims (2, 3, 4)
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5. A broadcast system including a transmission apparatus and a receiving apparatus, the transmission apparatus including:
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a generating unit operable to generate a first digital stream and a second digital stream by encoding a same signal at different encoding bit rates, where an encoding bit rate for the first digital stream is lower than an encoding bit rate for the second digital stream; and a transmission unit operable to transmit the first and second digital streams onto a transmission path while delaying the second digital stream relative to the first digital stream, the receiving apparatus including; a reproduction unit operable to reproduce the second digital stream in a normal state; and a reproduction control unit operable to, when a transmission path failure occurs, cause the reproduction unit to reproduce, instead of the second digital stream, a portion of the first digital stream that has been received before the occurrence of the transmission path failure, wherein the receiving apparatus superposes a signal resembling a noise on the portion of the first digital stream that is reproduced due to occurrence of a transmission path failure. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A broadcast system including a transmission apparatus and a receiving apparatus, the transmission apparatus including:
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a generating unit operable to generate a first digital stream and a second digital stream by encoding a same signal at different encoding bit rates, where an encoding bit rate for the first digital stream is lower than an encoding bit rate for the second digital stream; and a transmission unit operable to transmit the first and second digital streams onto a transmission path while delaying the second digital stream relative to the first digital stream, the receiving apparatus including; an accumulating unit operable to accumulate one or more packets of the first digital stream received during a predetermined time period until a current time, wherein the predetermined time period is determined based on statistics of a time period for which a transmission path failure continues; a reproduction unit operable to reproduce the second digital stream in a normal state; a reproduction control unit operable to, when a transmission path failure occurs, cause the reproduction unit to reproduce, instead of the second digital stream, a portion of the first digital stream that has been received before the occurrence of the transmission path failure; an operation receiving unit operable to receive input of an operation by a user to request real time reproduction; and a switch unit operable to switch from reproduction of the second digital stream to reproduction of the first digital stream when the operation receiving unit receives the input of the operation by the user. - View Dependent Claims (13, 14)
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15. A receiving apparatus for use in a broadcast system including a transmission apparatus that generates a first digital stream and a second digital stream by encoding a same signal at different encoding bit rates, where an encoding bit rate for the first digital stream is lower than an encoding bit rate for the second digital steam, and transmits the first and second digital streams onto a transmission path while delaying the second digital stream relative to the first digital stream, the receiving apparatus comprising:
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a reproduction unit operable to reproduce the second digital stream in a normal state; a reproduction control unit operable to, when a transmission path failure occurs, cause the reproduction unit to reproduce, instead of the second digital stream, a portion of the first digital stream that has been received before the occurrence of the transmission path failure; a receiving unit operable to receive packets constituting the first and second digital streams for each digital stream; and an accumulating unit operable to accumulate one or more packets of the first digital stream received by the receiving unit during a predetermined time period until a current time, wherein the predetermined time period is determined based on statistics of a time period for which a transmission path failure continues, and the reproduction control unit causes the reproduction unit to reproduce the one or more packets of the first digital stream accumulated in the accumulating unit, when a transmission path failure occurs; and a write control unit operable to, each time the receiving unit newly receives a packet, write the newly received packet into the accumulating unit after deleting an oldest packet among the one or more packets accumulated in the accumulating unit. - View Dependent Claims (16, 17)
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18. A receiving apparatus for use in a broadcast system including a transmission apparatus that generates a first digital stream and a second digital stream by encoding a same signal at different encoding bit rates, where an encoding bit rate for the first digital stream is lower than an encoding bit rate for the second digital stream, and transmits the first and second digital streams onto a transmission path while delaying the second digital stream relative to the first digital stream, the receiving apparatus comprising:
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a reproduction unit operable to reproduce the second digital stream in a normal state; and a reproduction control unit operable to, when a transmission path failure occurs, cause the reproduction unit to reproduce, instead of the second digital stream, a portion of the first digital stream that has been received before the occurrence of the transmission path failure, wherein the receiving apparatus superposes a signal resembling a noise on the one or more packets accumulated in the accumulating unit when the one or more packets are reproduced due to occurrence of a transmission path failure. - View Dependent Claims (19, 20, 21, 22, 23)
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24. A receiving apparatus for use in a broadcast system including a transmission apparatus that generates a first digital stream and a second digital stream by encoding a same signal at different encoding bit rates, where an encoding bit rate for the first digital stream is lower than an encoding bit rate for the second digital stream, and transmits the first and second digital streams onto a transmission path while delaying the second digital stream relative to the first digital stream, the receiving apparatus comprising:
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a receiving unit operable to receive packets constituting the first and second digital streams for each digital stream; an accumulating unit operable to accumulate one or more packets of the first digital stream received by the receiving unit during a predetermined time period until a current time, wherein the predetermined time period is determined based on statistics of a time period for which a transmission path failure continues; a reproduction unit operable to reproduce the second digital stream in a normal state; a reproduction control unit operable to, when a transmission path failure occurs, cause the reproduction unit to reproduce, instead of the second digital stream, a portion of the first digital stream that has been received before the occurrence of the transmission path failure, an operation receiving unit operable to receive input of an operation by a user to request real time reproduction; and a switch unit operable to switch from reproduction of the second digital stream to reproduction of the first digital stream when the operation receiving unit receives the input of the operation by the user. - View Dependent Claims (25)
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Specification