Method and a device for transmission of a variable bit-rate compressed video bitstream over constant and variable capacity networks

• US 6,529,552 B1
• Filed: 02/15/2000
• Issued: 03/04/2003
• Est. Priority Date: 02/16/1999
• Status: Expired due to Term

• Current Assignee: Nokia of America Corporation (Nokia Corporation)
• Original Assignee: PacketVideo Corporation (Nippon Telegraph and Telephone Corporation)
• Inventors: Tsai, Chun-Jen, Alshaykh, Osama, Banham, Mark R.
• Primary Examiner(s): RAO, ANAND SHASHIKANT
• Application Number:
  US09/504,359
• Time in Patent Office: 1,113 Days
• Field of Search: 375/240-2-2
• US Class Current: 375/240.05
• CPC Class Codes: H04N 19/103 Selection of coding mode or of prediction mode
• CPC Class Codes: H04N 19/124 Quantisation
• 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 19/146 Data rate or code amount at the encoder output
• 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 19/162 User input
• CPC Class Codes: H04N 19/164 Feedback from the receiver or from the transmission channel
• CPC Class Codes: H04N 19/587 involving temporal sub-sampling or interpolation, e.g. decimation or subsequent interpolation of pictures in a video sequence

Abstract

A method and device for producing and delivering constant quality digital video bitstreams over channels of any bit-rate and variability are provided. The method and device may be applicable to any standardized video coding system, but preferably within the MPEG-4 standard. For constant capacity networks, the method and the device re-distribute the coded bits in a constant-quality variable bit-rate bitstream to construct a constant bit-rate bitstream. For variable capacity networks, the method and the device achieve constant quality as described by a metric that incorporate both spatial and temporal visual quality. The method and the device incorporate user, network, and channel parameters in controlling the bit-rate while encoding video material.

Claims

1. A method for controlling a digitally compressed video bitstream for achieving constant quality video delivery over a constant capacity channel, the method comprising the steps of:

providing an encoder;

providing a digitally compressed video bitstream having frames;

analyzing a quantity of bits used to compress each frame;

imposing a constant bit budget per frame to optimize and control visual and audio quality; and

repositioning an excess set of bits above the bit budget associated with an original bitstream position in a first frame to a predetermined bitstream field associated with a second frame having a lesser number of bits than the first frame to create an altered bitstream that has a more constant quality which substantially meets the imposed bit budget.

2. The method of claim 1 further comprising the step of:

delivering the altered bitstream at a constant rate over a constant capacity channel.

3. The method of claim 1 further comprising the step of:

parsing the altered bitstream;

buffering the bits associated with the predetermined bitstream field associated with the excess set of bits; and

repositioning the excess bits into the original bitstream position.

4. The method of claim 1 further comprising the steps of:

decoding the bitstream to generate a constant quality video sequence.

5. A method of claim 1, wherein the excess bits associated with the first bitstream frame position is a set of complimentary layer bits for subsequent of prior bitstream frames.

6. The method of claim 1 wherein the bitstream is an MPEG standardized bitstream.

7. The method of claim 1 wherein the predetermined bitstream field is a user-defined data field.

8. The method of claim 1 wherein the bitstream has a variable bit-rate.

9. A method for controlling a digitally compressed video bitstream for achieving constant quality video delivery over a variable capacity channel, the method comprising the steps of:

providing a network;

providing a bitstream;

providing a user in the network;

analyzing parameters based on preferences of the user;

providing for an override of parameters by the user during run time;

allowing feedback to influence the parameters;

managing a temporal frame of the bitstream based on the parameters;

managing a spacial frame of the bitstream based on the parameters;

changing a quantization of residual frames based on the parameters;

providing a coding process both real-time and off-line; and

splitting the coding process into a layered coding process based on some of the parameters.

10. The method of claim 9, wherein the parameters relate to quality of service preferences of the user.

11. The method of claim 9, wherein the parameters include at least one of temporal quality measures, spatial visual quality measures, network capacity, network availability, enhanced feature compliance and a number of users supported by the network.

12. The method of claim 11 wherein the enhanced feature compliance includes scalability.

13. The method of claim 9, wherein some of the parameters include a range of enhanced feature compliance supported by the network and a number of users in the network.

14. The method of claim 10, further comprising the steps of:

providing a network manager; and

communicating the preferences of the user via a channel to a network manager.

15. A device for controlling a digitally compressed video bitstream for achieving constant quality video delivery over a constant capacity channel, the device comprising:

an encoder for analyzing a digitally compressed video bitstream having frames to determine a quantity of bits used to compress each frame;

wherein excess bits are stored in special user-defined data fields in prior and/or adjacent frames;

wherein the encoder repositions an excess set of bits associated with an original bitstream position in a first frame and/or a subsequent frame to a predetermined bitstream field associated with a second frame having a lesser number of bits than the first frame and/or the subsequent frame to create an altered bitstream.

16. The device of claim 15, further comprising:

a decoder for parsing the altered bitstream wherein the decoder buffers the bits associated with the predetermined bitstream field associated with the excess set of bits and further wherein the decoder repositions the excess set of bits into the original bitstream position.

17. A device for controlling a digitally compressed video bitstream for achieving constant quality video delivery over a variable capacity channel, the device comprising:

an analyzer for analyzing a digitally compressed video bitstream wherein the analyzer analyzes parameters based on preferences of a user;

providing for an override of parameters by the user during run time;

allowing feedback to influence the parameters;

a manager for managing a temporal frame rate of the bitstream based on the parameters;

means for changing a quantization of residual frames in the bitstream; and

a splitter for splitting a coding process into a layered coding process based on some of the parameters.

18. The device of claim 17, wherein the parameters include at least one of temporal visual quality measures, spatial visual quality measures, network capacity, network availability, enhanced feature compliance, and a number of users supported by the network.

19. The device of claim 17, wherein some of the parameters used to split the coding process into the layered process include a range of enhanced feature compliance supported by a network and a number of users in the network.