Method and apparatus for providing scalable pre-compressed digital video with reduced quantization based artifacts (continuation)

• US 20030072370A1
• Filed: 11/12/2002
• Published: 04/17/2003
• Est. Priority Date: 11/27/1996
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: RealNetworks, Inc.
• Inventors: Farber, Nikolaus, Girod, Bernd, Ericsson, Staffan, Resznik, Yuriy A.
• Granted Patent: US 7,075,986 B2
• Time in Patent Office: Days
• US Class Current: 375/240.13
• CPC Class Codes: H04N 19/105 Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
• CPC Class Codes: H04N 19/12 Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/187 the unit being a scalable video layer
• CPC Class Codes: H04N 19/39 involving multiple description coding [MDC], i.e. with separate layers being structured as independently decodable descriptions of input picture data
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/23439 for generating different versions
• 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 21/6379 directed to encoder , e.g. for requesting a lower encoding rate
• CPC Class Codes: H04N 21/64769 for rate control flow control in packet networks H04L47/10
• CPC Class Codes: H04N 9/8042 involving data reduction

Abstract

A method for generating a digital motion video sequence at a plurality of bit rates uses a transitional coding source when switching between bitstreams having different bit rates during transmission of a video sequence. The transitional data may be frames coded using reconstructed frames reconstructed for a first bitstream using the characteristics of the second bitstream. These “low bit rate insert frames,” or LBIFs, contain the image characteristics of a signal coded at the lower bit rate. With a bitstream having a higher bit rate being periodically coded using an LBIF, a point of image continuity between the two bitstreams is provided. Thus, switching from one bitstream to the other at this point in the video sequence minimizes the production of artifacts caused by differences in bit rate. In another embodiment of the invention, a separate set of transitional data is created, taking the form of “switch” frames, or S-frames. The S-frames are typically the difference between a frame of a first bitstream and a frame of a second bitstream. These frames are inserted into the decoded bitstream during the transition from one bitstream to the other, and compensate for any visual artifacts that might otherwise occur due to the difference in bit rate of the two bitstreams.

Claims

1. An apparatus for generating a video sequence comprising:

a first interframe coder operative to receive and interframe code an input video signal with a first predetermined coarseness of quantization and to generate a first interframe coded bitstream having a first bit rate;

a reconstructor operative to reconstruct a frame of the video signal from the first interframe coded bitstream and to generate a reconstructed frame having a quantization error corresponding to the first predetermined coarseness of quantization;

a second or an additional interframe coder operative to receive the video signal and interframe code the input video signal with a second predetermined coarseness of quantization to generate a second interframe or an additionally coded bitstream having a second bit rate which is different than the first bit rate, such that each of the first and second bitstreams is an independently viewable version of the video signal at a different coarseness of quantization, wherein said second or additional interframe coder is operative to receive the reconstructed frame with the input video signal such that the second interframe or the additionally coded bitstream includes a coded frame based on the reconstructed frame.

2. An apparatus according to claim 1 wherein the video sequence comprises a plurality of different bitstreams each having a different bit rate and data organized in a plurality of temporally sequential spatial frames.