Rate-controlled digital video editing method and system which controls bit allocation of a video encoder by varying quantization levels

• US 5,623,424 A
• Filed: 06/06/1995
• Issued: 04/22/1997
• Est. Priority Date: 05/08/1995
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Warner Bros Entertainment Incorporated (Warner Bros. Discovery, Inc.)
• Original Assignee: Time Warner Entertainment Company LP (Charter Communications Incorporated), Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yamakage, Tomoo, Rosen, Andrew D., Koto, Shin-ichiro, Unno, Hiroaki, Mimura, Hideki, Kitamura, Tetsuya, Cookson, Christopher J., Azadegan, Faramarz, Thagard, Greg B.
• Primary Examiner(s): Ramirez, Ellis B.
• Application Number:
  US08/466,766
• Time in Patent Office: 686 Days
• Field of Search: 364/514 R, 364/514 A, 364/514 C, 364/715.02, 348/404, 348/405, 348/420
• US Class Current: 708/203
• CPC Class Codes: G11B 2220/2562 DVDs [digital versatile discs]; Digital video discs; MMCDs; HDCDs
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 2220/913 Digital audio tape [DAT] format
• CPC Class Codes: G11B 27/031 Electronic editing of digitised analogue information signals, e.g. audio or video signals
• CPC Class Codes: G11B 27/034 on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: G11B 27/3027 used signal is digitally coded
• CPC Class Codes: G11B 27/329 on a disc [VTOC]
• CPC Class Codes: G11B 27/34 Indicating arrangements indicating means incorporated in magazine or cassette G11B23/046 and G11B23/0875; indicating measured values in general G01D
• CPC Class Codes: G11B 27/36 Monitoring, i.e. supervising the progress of recording or reproducing for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/146 Data rate or code amount at the encoder output
• 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 19/157 Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/162 User input
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/192 the adaptation method, adaptation tool or adaptation type being iterative or recursive
• CPC Class Codes: H04N 19/30 : using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/503 : involving temporal prediction adaptive coding with adaptive selection between spatial and temporal predictive coding H04N19/107; adaptive coding with adaptive selection among a plurality of temporal predictive coding modes H04N19/109
• CPC Class Codes: H04N 19/60 : using transform coding
• CPC Class Codes: H04N 19/61 : in combination with predictive coding
• CPC Class Codes: H04N 5/9262 : using predictive coding
• CPC Class Codes: H04N 7/52 : Systems for transmission of a pulse code modulated video signal with one or more other pulse code modulated signals, e.g. an audio signal or a synchronizing signal assembling of a multiplex stream by combining a video stream with other content or additional data, remultiplexing of multiplex streams, insertion of stuffing bits into the multiplex stream, assembling of a packetised elementary stream at server side H04N21/236; disassembling of a multiplex stream, remultiplexing of multiplex streams, extraction or processing of Service Information, disassembling of packetised elementary stream at client side H04N21/434
• CPC Class Codes: H04N 9/8042 : involving data reduction
• CPC Class Codes: H04N 9/8063 : using time division multiplex of the PCM audio and PCM video signals

Abstract

A method and system for re-encoding frames of a digital video stream in which selected areas are designated to have increased or reduced image quality, i.e., decreased or increased quantization levels, respectively, as compared to a previously run automatic encoding process, but without changing the previously calculated bit length of the stream. A set of macroblocks at a time are re-encoded, the number of resulting bits is calculated and the deviation from an estimated number of bits is calculated, either set-by-set or cumulatively. Based on the accuracy of the estimate and the remaining number of sets of macroblocks to re-encode, a correction factor for the quantization level of the next set of macroblocks is chosen from a lookup table. The correction factor is added to the quantization level of the next set of macroblocks and the results stored as the new quantization level of the set. This sequential process is done for all sets of macroblocks in the digital stream which are to be recoded according to changed image qualities.

Claims