US 6,192,083 B1 · Statistical multiplexed video encoding using pre-encoding a priori statistics and a priori and a posteriori statistics

Abstract

A statistical multiplexing apparatus and method for generating and combining a plurality of encoded video bit streams. A storage device contains pre-stored a priori statistics indicative of the encoding complexity of the video signals from which the encoded video bit streams will be generated. The pre-stored a priori statistics may include inter-pixel differences in the same picture or between multiple pictures or pre-encoding a priori statistics generated during a preliminary encoding of the video signals. Examples of pre-encoding a priori statistics include the number of bits per picture at a given quantization level, an average quantization level, picture types, scene change locations and repeat field for one or more of the video bit streams. The video signals are applied to encoders which compress the signals in accordance with bit allocation decisions generated by a statistics computer. The statistics computer uses only pre-encoding a priori statistics from the storage device to generate bit allocation decisions. Alternatively, the statistics computer may use any type of a priori statistics in conjunction with a posteriori statistics received from the encoders in allocating bits. The resulting compressed video bit streams are applied to a multiplexer and combined into a single multiplexed bit stream for transmission on a single channel. The statistics computer thus has access to additional information regarding the encoding complexity of the video bit streams to be encoded and combined, and can therefore generate more accurate bit allocations and better maintain consistent video quality across multiple encoded bit streams.

Claims42

Dependent claims

A method for multiplexing at least two bit streams, each comprising encoded video signals, into a single multiplexed bit stream, comprising the steps of:

(a) pre-encoding a plural of to-be-encoded pictures of each of said video signals, in each of said at least two bit streams, having mutually independent timing, wherein said pre-encoding includes the step of performing motion compensation,
(b) during said step (a), generating pre-encoding a priori statistics indicative of a complexity involved in pre-encoding each of said video signals,
(c) statistically allocating a bit rate to each of said video signals, in each corresponding bit stream, based on said pre-encoding a priori statistics generated in said step (b),
(d) independently re-encoding each of said video signals, in each corresponding bit stream, to produce a corresponding compressed video bit stream depending on said bit rate allocated in said step (c), and
(e) combining each of said compressed video bit streams into a single multiplexed bit stream.

2 more elements

A statistical multiplexer for multiplexing at least two bit streams, each comprising encoded video signals into a single multiplexed bit stream, comprising:

a source of said at least two bit streams, each having plural video signals,
a statistics gatherer receiving said video signals from said video source, for pre-encoding a plural of to-be-encoded pictures of each of said video signals, in each of said bit streams, having mutually independent timing, and for generating pre-encoding a priori statistics indicative of a complexity involved in pre-encoding each of said video signals, wherein said pre-encoding includes performing motion compensation,
a statistics computer connected to statistics gatherer for statistically allocating a bit rate to each of said video signals, in each corresponding bit stream, based on said pre-encoding a priori statistics generated in said statistics gatherer,
one or more encoders connected to said statistics computer for independently re-encoding each of said video signals, in each corresponding bit stream, to produce a corresponding compressed video bit stream depending on said bit rate allocated in said statistics computer, and
a multiplexer for combining each of said compressed video bit streams with at least one other compressed video bit stream into a single multiplexed bit stream.

2 more elements

A statistical multiplexer for multiplexing plural encoded video signals into a single multiplexed bit stream comprising:

a statistics gatherer for gathering a priori statistics, during a pre-encoding stage, regarding a plural of to-be-encoded pictures of each of plural video signals having mutually independent timing, said a priori statistics indicating a complexity involved in encoding said to-be-encoded pictures, wherein said pre-encoding stage includes performing motion compensation,
a plurality of encoders for encoding to-be-encoded pictures of said plural video signals and for generating a posteriori statistics regarding one or more previously encoded pictures of each of said video signals, indicating a complexity involved in encoding each of said previously encoded pictures,
a statistics computer for statistically allocating a bit rate to each of said video signals based on said a priori and a posteriori statistics generated by said statistics gatherer and said plurality of encoders,
wherein said encoders independently encode each of said to-be-encoded pictures of said video signals to produce a corresponding compressed video bit stream depending on said bit rate allocated by said statistics computer, and
a multiplexer for combining each of said compressed video bit streams into a multiplexed bit stream.

2 more elements

Dependencies are inferred from the claim text.

Statistical multiplexed video encoding using pre-encoding a priori statistics and a priori and a posteriori statistics

Life of this patent

Statistical multiplexed video encoding using pre-encoding a priori statistics and a priori and a posteriori statistics

Life of this patent

Abstract

Claims42