Statistical multiplexed video encoding for diverse video formats

• US 6,674,796 B1
• Filed: 02/14/2000
• Issued: 01/06/2004
• Est. Priority Date: 02/14/2000
• Status: Expired due to Term

• Current Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Original Assignee: Harmonic Incorporated
• Inventors: Haskell, Paul, Busch, Dackary
• Primary Examiner(s): PHILIPPE, GIMS S
• Application Number:
  US09/504,335
• Time in Patent Office: 1,422 Days
• Field of Search: 375/240.01, 375/240.02, 375/240, 375/240.03, 375/240.29, 375/240.12, 348/385.1, 348/387.1, 348/388.1, 348/404.1, 348/405.1, 348/423.1, 348/441, 348/386.1, 382/239, 382/232, 382/298, 370/538, 370/468
• US Class Current: 375/240.01
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/15 by monitoring actual compressed data size at the memory before deciding storage at the transmission buffer
• CPC Class Codes: H04N 19/194 involving only two passes
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/436 using parallelised computational arrangements
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/23418 involving operations for analysing video streams, e.g. detecting features or characteristics television picture signal circuitry for scene change detection H04N5/147; filtering for image enhancement G06T5/00; methods or arrangements for recognising scenes G06V20/00; arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/234363 by altering the spatial resolution, e.g. for clients with a lower screen resolution
• CPC Class Codes: H04N 21/2365 Multiplexing of several video streams
• CPC Class Codes: H04N 21/23655 Statistical multiplexing, e.g. by controlling the encoder to alter its bitrate to optimize the bandwidth utilization
• CPC Class Codes: H04N 21/2385 Channel allocation H04N21/266 takes precedence; Bandwidth allocation H04N21/24 takes precedence ; allocation of channels according to the instantaneous demands of the users in time-division multiplex systems H04J3/1682; admission control, resource allocation in open networks H04L12/5692; arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896; negotiating bandwidth in wireless networks H04W28/16
• CPC Class Codes: H04N 21/4347 Demultiplexing of several video streams

Abstract

A statistical multiplexing apparatus and method for encoding and combining a diversity of video signal resolutions and formats. Higher resolution signals are reduced to lower resolution signals for simplifying the a priori statistics gathering process. Alternately, input video signals in multiple formats are converted to a single common format prior to their application to an a priori statistics gatherer. A storage device contains the a priori statistics which are indicative of the encoding complexity of the video signals from which the encoded video bit streams will be generated. The original 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 the a priori statistics from the storage device to generate bit allocation decisions. Subsequently, the statistics computer may use both the a priori statistics and the 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.

Claims

1. A method for encoding and multiplexing a plurality of original resolution video signals having mutually independent timing into a single multiplexed bit stream, comprising the steps of:

(a) scaling each original resolution video signal of said plurality of original resolution video signals to produce a plurality of scaled video signals, where each scaled video signal of said plurality of scaled video signals is a reduced resolution version of a corresponding original resolution video signal of said plurality of video signals from which said respective scaled video signal was produced by scaling,

(b) processing each scaled video signal of said plurality of scaled video signals to gather a priori statistics from said respective scaled video signal;

(c) statistically allocating a first bit rate to each original resolution video signal of said plurality of original resolution video signals based on said gathered a priori statistics, wherein said first bit rate allocated to each particular original resolution video signal is generated from said a priori statistics gathered for said corresponding scaled video signal that is a reduced resolution version thereof,

(d) independently encoding each original resolution video signal of said plurality of original resolution video signals at said respective original resolution to produce a corresponding compressed video bit stream depending on said allocated first bit rate, and

(e) combining each of said compressed video bit streams into a multiplexed bit stream.

2. The method of claim 1, wherein said step (d) further comprises:

generating a posteriori statistics regarding each original resolution video signal of said plurality of original resolution video signals, indicating a complexity involved in encoding each of said full resolution video signals,

statistically allocating a second bit rate to each of said original resolution video signals based on said a priori and a posteriori statistics generated in said steps (b) and (d), and

independently encoding each of said original resolution video signals to produce a corresponding compressed video bit stream depending on said second bit rate allocated in said step (d).

3. The method of claim 1, wherein said step (b) further comprises:

pre-encoding each scaled video signal of said scaled plurality of video signals to generate information to be used in said encoding step (d).

4. The method of claim 1, wherein each original resolution video signal of said plurality of original resolution video signals is a high definition (HD) signal.

5. The method of claim 1, wherein each scaled resolution video signal of said scaled plurality of video signals is a standard definition (SD) signal.

6. The method of claim 1, wherein said plurality of original resolution video signals and/or said plurality of scaled video signals are live or pre-stored signals.

7. A method for encoding and multiplexing a plurality of video signals having mutually independent timing into a single multiplexed bit stream comprising the steps of:

(a) processing each original resolution video signal of said plurality of video signals to gather a priori statistics from said respective original resolution video signal of said plurality of video signals,

(b) statistically allocating a first bit rate corresponding to each of said processed video signal of said plurality of video signals based on said generated a priori statistics,

(c) processing each original resolution video signal of said plurality of video signals to up-convert said original resolution video signal to a higher resolution, thereby generating a higher resolution video signal corresponding to each respective original resolution video signal,

(d) independently encoding each of said higher resolution video signals to produce a corresponding compressed video bit stream depending on said allocated first bit rate, and

(e) combining each of said compressed video bit streams into a multiplexed bit stream.

8. The method of claim 7, wherein said step (d) further comprises:

generating a posteriori statistics regarding each of said higher resolution video signals, indicating a complexity involved in encoding each of said higher resolution video signals,

statistically allocating a second bit rate to each of said higher resolution video signals based on said a priori and a posteriori statistics generated in said steps (a) and (d), and

independently encoding each of said higher resolution video signals to produce a corresponding compressed video bit stream depending on said second bit rate allocated in said step (d).

9. A method for encoding and multiplexing a first plurality of video signals of non-uniform format, in which at least one video signal of said first plurality has a different format than a second video signal of the first plurality, into a single multiplexed bit stream comprising the steps of:

(a) processing said video signals of non-uniform format, including format converting one or more video signals of said first plurality, to produce a second plurality of video signals of common format in which each video signal of said second plurality of common format video signals has the same format,

(b) ingathering a priori statistics for each video signal of the second plurality of common format video signals,

(c) statistically allocating a first bit rate to each video signal of said first plurality of non-uniform format video signals based on said ingathered a priori statistics,

(d) independently encoding each video signal of said first plurality video signals of non-uniform format, including said first and said second video signals that have mutually different formats, to produce a corresponding compressed video bit stream depending on said allocated first bit rate, and

(e) combining each of said compressed video bit streams into a multiplexed bit stream.

10. The method of claim 9, wherein said step (d) further comprises:

generating a posteriori statistics for each video signal of said first plurality of video signals of non-uniform format, including said first and second video signals that have mutually different formats, indicating a complexity involved in encoding each of said video signals of said first plurality of non-uniform format video signals,

statistically allocating a second bit rate to each of said video signals of said first plurality of non-uniform format video signals based on said a priori and a posteriori statistics generated in said steps (b) and (d), and

independently encoding each of said video signals of said first plurality of non-uniform format video signals to produce a corresponding compressed video bit stream depending on said second bit rate allocated in said step (d).

11. A statistical multiplexer for multiplexing plural encoded video signals having mutually independent timing into a single multiplexed bit stream comprising:

(a) a source of plural original resolution video signals,

(b) a video scaler, receiving said plurality of original resolution video signals from said video source, for scaling each original resolution video signal of said plurality of original resolution video signals to produce a plurality of scaled video signals, where each scaled video signal of said plurality of scaled video signals is a reduced resolution version of a corresponding original resolution video signal of said plurality of original resolution video signals from which said respective scaled video signal was produced by scaling,

(c) a statistics gatherer, receiving said plurality of scaled video signals from said video scaler, for pre-encoding said plurality of scaled video signals, and for generating pre-encoding a priori statistics indicative of a complexity involved in pre-encoding each of said plurality of scaled video signals,

(d) a statistics computer, connected to said statistics gatherer, for statistically allocating a first bit rate to each of said original resolution video signals based on said pre-encoding a priori statistics generated in said statistics gatherer,

(e) one or more encoders, connected to said statistics computer, for independently re-encoding each of said original resolution video signals to produce a corresponding compressed video bit stream depending on said first bit rate allocated in said statistics computer, and

(f) a multiplexer for combining each of said compressed video bit streams with a least one other compressed video bit stream into a multiplexed bit stream.

12. The statistical multiplexer of claim 11, wherein said one or more encoders generates a posteriori statistics regarding one or more of said original resolution video signals, indicating a complexity involved in encoding each of said original resolution video signals, wherein said statistics computer statistically allocates a second bit rate to each of said original resolution video signals based on said a priori and a posteriori statistics generated by said statistics gatherer and said one or more encoders, and wherein said one or more encoders independently encodes each of said original resolution video signals depending on said second bit rate.

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

(a) a source of standard definition (SD) video signals,

(b) an up-converter, receiving said SD video signals, for converting said SD video signals to high definition (HD) video signals, each of said HD video signals having a higher resolution than said respective SD video signal from which said corresponding HD video signal was derived,

(c) a statistics gatherer, receiving said SD video signals from said video source, for pre-encoding said SD video signals having mutually independent timing, and for generating pre-encoding a priori statistics indicative of a complexity involved in pre-encoding each of said SD video signals,

(d) a statistics computer, connected to said statistics gatherer, for statistically allocating a first bit rate to each of said HD video signals based on said pre-encoding a priori statistics generated in said statistics gatherer for said SD video signals,

(e) one or more encoders, connected to said statistics computer, for independently encoding each of said HD video signals to produce a corresponding compressed video bit stream depending on said first bit rate allocated in said statistics computer, and

(f) a multiplexer for combining each of said compressed video bit streams with at least one other compressed video bit stream into a multiplexed bit stream.

14. The statistical multiplexer of claim 13, wherein:

said one or more encoders generates a posteriori statistics, regarding one or more of said HD video signals, for indicating a complexity involved in encoding each of said HD video signals,

wherein said statistics computer statistically allocates a second bit rate to each of said HD video signals, based on said a priori and a posteriori statistics generated by said statistics gatherer and said one or more encoders, and

wherein said one or more encoders independently encodes each of said HD video signals depending on said second bit rate.

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

(a) a source of a plurality of video signals of non-uniform format, including first and second video signals, where the format of said first video signal is different than the format of the second video signal,

(b) a common format converter, receiving said plurality of video signals of non-uniform format, for converting said plurality of video signals of non-uniform format to a plurality of video signals of a single common format,

(c) a statistics gatherer, receiving said plurality of video signals of common format from said common format converter, for pre-encoding said plurality of video signals of common format having mutually independent timing, and for generating pre-encoding a priori statistics indicative of a complexity involved in pre-encoding each video signal of said plurality of video signals of common format,

(d) a statistics computer, connected to said statistics gatherer, for statistically allocating a first bit rate to each video signal of said plurality of video signals of non-uniform format based on said pre-encoding a priori statistics generated in said statistics gatherer,

(e) one or more encoders connected to said statistics computer for independently re-encoding each video signal of said plurality of video signals of non-uniform format to produce a corresponding compressed video bit stream depending on said first bit rate allocated in said statistics computer, and

(f) a multiplexer for combining each of said compressed video bit streams with a least one other compressed video bit stream into a multiplexed bit stream.

16. The statistical multiplexer of claim 15, wherein:

said one or more encoders generates a posteriori statistics, regarding one or more video signals of said plurality of video signals of non-uniform format, for indicating a complexity involved in encoding each video signal of said plurality of video signals of non-uniform format,

wherein said statistics computer statistically allocates a second bit rate to each video signal of said plurality of video signals of non-uniform format based on said a priori and a posteriori statistics generated by said statistics gatherer and said one or more encoders, and

wherein said one or more encoders independently encodes each video signal of said plurality of video signals of non-uniform format depending on said second bit rate.