Method for computational graceful degradation in an audiovisual compression system

• US 20010001621A1
• Filed: 01/02/2001
• Published: 05/24/2001
• Est. Priority Date: 10/24/1997
• Status: Active Grant

• Current Assignee: Sun Patent Trust
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Tan, Thiow Keng
• Granted Patent: US 6,421,465 B2
• Time in Patent Office: Days
• US Class Current: 382/233
• CPC Class Codes: H04N 19/127 Prioritisation of hardware or computational resources
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/146 Data rate or code amount at the encoder output
• CPC Class Codes: H04N 19/149 by estimating the code amount by means of a model, e.g. mathematical model or statistical model
• 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 19/154 Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion use of rate-distortion criteria H04N19/147
• CPC Class Codes: H04N 19/156 Availability of hardware or computational resources, e.g. encoding based on power-saving criteria
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/234318 by decomposing into objects, e.g. MPEG-4 objects
• CPC Class Codes: H04N 21/235 Processing of additional data, e.g. scrambling of additional data or processing content descriptors
• CPC Class Codes: H04N 21/23614 Multiplexing of additional data and video streams arrangements for simultaneous broadcast of plural pieces of information H04H20/28
• CPC Class Codes: H04N 21/25808 Management of client data terminal profiles in network data switching protocols H04L67/303
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 21/4348 : Demultiplexing of additional data and video streams
• CPC Class Codes: H04N 21/45452 : applied to an object-based stream, e.g. MPEG-4 streams
• CPC Class Codes: H04N 21/4621 : Controlling the complexity of the content stream or additional data, e.g. lowering the resolution or bit-rate of the video stream for a mobile client with a small screen arrangements for using the results of monitoring on user's side in broadcast systems H04H60/65; flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/8133 : specifically related to the content, e.g. biography of the actors in a movie, detailed information about an article seen in a video program

Abstract

The invention disclosed here is a method for an encoder to encode audiovisual information for transmission to the decoder without any prior knowledge of the computational capabilities of the decoder. A descriptor containing parameters that can be used to estimate the complexity of the decoding process is embedded in the system stream. The encoder also encodes the video information in such a manner that the decoder can choose to ignore some of the information and only decode a subset of the encoded information in order to reduce the computational requirements. This method allows more than one decoder to decode the same bitstream giving different resolutions depending on the computational capability of the decoder.

Claims

1. A method for decoding an input bitstream, comprising:

receiving an input bitstream that contains a compressed coded data obtained by encoding a visual object, and a descriptor obtained by encoding information associated with a computational complexity, wherein the computational complexity represents a complexity that decodes the compressed coded data;

extracting the descriptor from the input bitstream; and

decoding the compressed coded data.

2. The method of

claim 1

, further comprising:

entropy decoding a position and a dimension of a sub-region from a compressed coded representation within the input bitstream;

selecting only blocks that are within a sub-region of interest to be decoded;

entropy decoding the compressed coded representation to obtain quantized transformed coefficients;

inverse transforming the transform coefficients to obtain a spatial domain motion compensated prediction difference;

entropy decoding a motion vector from the compressed coded representation within the input bitstream;

performing a motion compensation for blocks using only pixels from a reconstructed picture that belongs to sub-regions having at least a same numeric order as said blocks; and

reconstructing the picture and storing the picture in a frame memory to predict a next picture.

3. The method of

claim 1

, further comprising:

entropy decoding a position and a dimension of a sub-region from a compressed coded representation within the input bitstream;

selecting only blocks that are within a sub-region of interest to be decoded;

entropy decoding the compressed coded representation to obtain quantized transformed coefficients;

performing a quantized transform coefficient prediction for blocks using only corresponding quantized transform coefficients from blocks above and to a left that belong to a sub-region having at least a same numeric order as the blocks;

inverse quantizing the corresponding quantized transformed coefficients to obtained transformed coefficients;

inverse transforming the transform coefficients to obtain spatial domain pixel values; and

reconstructing a picture and storing the picture in a frame memory to predict a next picture.