Statistical multiplexing
First Claim
1. A method of transmitting a plurality of digital signals through a plurality of channels, the channels collectively having a predetermined total allocated bitrate, the method comprising:
- encoding each of the plural digital signals to produce a plurality of encoded signals;
multiplexing the plural encoded signals;
adjusting a distribution of bitrate allocation between the plural channels in response to a control system;
providing to the control system an indication of a target quality for each of the plural channels;
providing in the control system an indication of the actual quality of each of the plural channels; and
repeatedly adjusting the distribution of the bitrate allocation between and among the plural channels in response to differences between the indicated actual quality and the indicated target quality for each channel so as to substantially equalize the differences between the actual and target quality across at least some of the channels.
4 Assignments
0 Petitions
Accused Products
Abstract
A transmitter for transmitting a plurality of digital signals through a plurality of channels, the channels having a predetermined total allocated bitrate, includes a plurality of encoders each associated with one channel, a multiplexer for receiving the encoded digital signals and for transmitting the encoded signals as a stream of data, and operable for adjusting the distribution of the bitrate allocation between and among the encoded signals, and a processing device for providing an indication of a target quality and an actual quality for each channel and for causing the multiplexer to repeatedly adjust the distribution of the bitrate allocation in response to differences between the indicated actual quality and the indicated target quality for each channel so as to equalize differences between the actual and target quality across at least some of the channels. By grouping encoders together in "statistical multiplex groups", and making real time decisions about the bitrate requirements for those encoders, bitrate can be allocated to maximize picture quality for the group. For a variety of different picture sources in a statistical multiplex group, to achieve a target picture quality the bitrate requirements of each will vary with coding difficulty. Thus, a channel within the statistical multiplex group that is experiencing little difficulty in encoding its picture can free bits to channels that are having greater difficulty. The effect is to smooth the picture quality and subjectively improve it.
94 Citations
24 Claims
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1. A method of transmitting a plurality of digital signals through a plurality of channels, the channels collectively having a predetermined total allocated bitrate, the method comprising:
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encoding each of the plural digital signals to produce a plurality of encoded signals; multiplexing the plural encoded signals; adjusting a distribution of bitrate allocation between the plural channels in response to a control system; providing to the control system an indication of a target quality for each of the plural channels; providing in the control system an indication of the actual quality of each of the plural channels; and repeatedly adjusting the distribution of the bitrate allocation between and among the plural channels in response to differences between the indicated actual quality and the indicated target quality for each channel so as to substantially equalize the differences between the actual and target quality across at least some of the channels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A transmitter operable for transmitting a plurality of digital signals through a plurality of channels, the channels having a predetermined total allocated bitrate, comprising:
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a plurality of encoders, one of said encoders being associated with each of the plural channels for receiving a digital signal and for providing an encoded digital signal; a multiplexer for receiving the encoded digital signals and for transmitting the encoded signals as a stream of data, and operative for adjusting a distribution of bitrate allocation among and between the plural encoded signals; and processing means for defining a target quality and an actual quality for each channel and for causing the multiplexer to repeatedly adjust the distribution of the bitrate allocation in response to differences between the actual quality and the target quality for each channel so as to substantially equalize the differences between the actual and target quality across at least some of the channels. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A statistical multiplexer for a transmitter, comprising:
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a multiplexer for receiving a plurality of encoded signals from a plurality of encoders each associated with a signal channel and for transmitting the encoded signals a stream of data, and operable for adjusting a distribution of bitrate allocation between and among the plural encoded signals; and processing means for defining a target quality and an actual quality for each channel and for causing the multiplexer to repeatedly adjust the distribution of the bitrate allocation in response to differences between the actual quality and the target quality for each channel so as to substantially equalize the differences between the actual and target quality across at least some of the channels. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification