Method and apparatus for predecoding hybrid bitstream

• US 20060083302A1
• Filed: 10/18/2005
• Published: 04/20/2006
• Est. Priority Date: 10/18/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jae-young, Lee, Kyo-hyuk, Cha, Sang-chang, Lee, Bae-keun, Han, Woo-Jin, Ha, Ho-Jin
• Granted Patent: US 7,839,929 B2
• Time in Patent Office: Days
• US Class Current: 375/240.80
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/127 Prioritisation of hardware or computational resources
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• 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 19/136 Incoming video signal characteristics or properties
• 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 19/152 by measuring the fullness of 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 19/162 User input
• CPC Class Codes: H04N 19/164 Feedback from the receiver or from the transmission channel
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/177 the unit being a group of pictures [GOP]
• CPC Class Codes: H04N 19/187 the unit being a scalable video layer
• CPC Class Codes: H04N 19/31 in the temporal domain
• CPC Class Codes: H04N 19/34 Scalability techniques involving progressive bit-plane based encoding of the enhancement layer, e.g. fine granular scalability [FGS]
• CPC Class Codes: H04N 19/36 Scalability techniques involving formatting the layers as a function of picture distortion after decoding, e.g. signal-to-noise [SNR] scalability
• 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 19/517 by encoding
• CPC Class Codes: H04N 19/577 : Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/587 : involving temporal sub-sampling or interpolation, e.g. decimation or subsequent interpolation of pictures in a video sequence
• 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 19/615 : using motion compensated temporal filtering [MCTF]
• CPC Class Codes: H04N 19/63 : using sub-band based transform, e.g. wavelets
• CPC Class Codes: H04N 19/70 : characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/86 : involving reduction of coding artifacts, e.g. of blockiness

Abstract

A method and apparatus for efficiently predecoding a hybrid bitstream generated by a plurality of coding schemes are provided. The method includes obtaining a first bit-rate for a boundary between the lower layer bitstream and the upper layer bitstream and a second bit-rate for a boundary between motion information and texture information of the upper layer bitstream from the input hybrid bitstream, determining the target bit-rate according to variable network circumstances, and when the target bit-rate is between the first and second bit-rates, skipping the motion information of the upper layer bitstream and truncating all bits of the texture information of the upper layer bitstream from the tail, except bits corresponding to the difference between the target bit-rate and the first bit-rate.

Claims

1. A method for predecoding a hybrid bitstream including a lower layer bitstream and an upper layer bitstream obtained by encoding a video with a predetermined resolution according to a target bit-rate, the method comprising:

obtaining a first bit-rate for a boundary between the lower layer bitstream and the upper layer bitstream and a second bit-rate for a boundary between motion information and texture information of the upper layer bitstream from the hybrid bitstream;

determining the target bit-rate according to variable network circumstances; and

when the target bit-rate is between the first bit-rate and the second bit-rate, skipping the motion information of the upper layer bitstream and truncating all bits of the texture information of the upper layer bitstream from a tail end of the upper layer bitstream, except bits corresponding to a difference between the target bit-rate and the first bit-rate.

2. The method of claim 1, further comprising truncating all bits of the texture information of the upper layer bitstream from the tail end of the upper layer bitstream, except bits corresponding to a difference between the target bit-rate and the second bit-rate when the target bit-rate is higher than the second bit-rate.

3. The method of claim 1, further comprising truncating the upper layer bitstream when the target bit-rate is lower than the first bit-rate.

4. The method of claim 1, wherein texture information of the lower layer bitstream is encoded using Advanced Video Coding (AVC) while the texture information of the upper layer bitstream is encoded using wavelet coding.

5. The method of claim 4, wherein the texture information of the upper layer bitstream is generated by encoding a difference between a decoded version of the lower layer bitstream and an original input frame using the wavelet coding.

16. A recording medium having a computer readable program recorded therein, the program for executing the method of claim 1.

6. A method for predecoding a hybrid bitstream including a lower layer bitstream and an upper layer bitstream obtained by encoding a video with a predetermined resolution according to a target bit-rate, the method comprising:

obtaining a first bit-rate for a boundary between the lower layer bitstream and the upper layer bitstream from the hybrid bitstream;

determining the target bit-rate according to variable network circumstances;

determining a critical bit-rate used to determine whether to skip motion information of the upper layer bitstream; and

when the target bit-rate is between the first bit-rate and the critical bit-rate, skipping the motion information of the upper layer bitstream and truncating all bits of texture information of the upper layer bitstream from a tail end of the upper layer bitstream, except bits corresponding to a difference between the target bit-rate and the first bit-rate.

7. The method of claim 6, further comprising truncating all bits of the texture information of the upper layer bitstream from the tail end of the upper layer bitstream, except bits corresponding to a difference between the target bit-rate and the second bit-rate when the target bit-rate is higher than the second bit-rate.

8. The method of claim 6, further comprising truncating the upper layer bitstream when the target bit-rate is lower than the first bit-rate.

9. The method of claim 6, further comprising truncating all bits of the texture information of the upper layer bitstream from the tail end of the upper layer bitstream, except bits corresponding to a difference between the target bit-rate and the critical bit-rate when the target bit-rate is higher than the critical bit-rate.

10. The method of claim 9, wherein the critical bit-rate refers to a bit-rate obtained when a visual quality when portion of the texture information of the upper layer bitstream is truncated is the same as that when the motion information of the upper layer bitstream is skipped and bits saved by skipping the motion information are allocated to the texture information.

11. The method of claim 6, wherein the critical bit-rate refers to a bit-rate obtained when a ratio between the motion information of the upper layer bitstream and the texture information of the upper layer bitstream reaches a predetermined value.

12. The method of claim 6, wherein texture information of the lower layer bitstream is encoded using Advanced Video Coding (AVC) while the texture information of the upper layer bitstream is encoded using wavelet coding.

13. An apparatus for predecoding a hybrid bitstream including a lower layer bitstream and an upper layer bitstream obtained by encoding a video with a predetermined resolution according to a target bit-rate, the apparatus comprising:

a bitstream parser which obtains a first bit-rate for a boundary between the lower layer bitstream and the upper layer bitstream and a second bit-rate for a boundary between motion information and texture information of the upper layer bitstream from the hybrid bitstream;

a target bit-rate determiner which determines the target bit-rate according to variable network circumstances; and

a predecoding unit which skips the motion information of the upper layer bitstream and truncates all bits of the texture information of the upper layer bitstream from a tail end of the upper layer bitstream, except bits corresponding to a difference between the target bit-rate and the first bit-rate when the target bit-rate is between the first bit-rate and the second bit-rate.

14. An apparatus for predecoding a hybrid bitstream including a lower layer bitstream and an upper layer bitstream obtained by encoding a video with a predetermined resolution according to a target bit-rate, the apparatus comprising:

a bitstream parser which obtains a first bit-rate for a boundary between the lower layer bitstream and the upper layer bitstream from the hybrid bitstream;

a target bit-rate determiner which determines the target bit-rate according to variable network circumstances; and

a predecoding unit which determines a critical bit-rate used to determine whether to skip motion information of the upper layer bitstream and skips the motion information of the upper layer bitstream and truncates all bits of texture information of the upper layer bitstream from a tail end of the upper layer bitstream, except bits corresponding to a difference between the target bit-rate and the first bit-rate, when the target bit-rate is between the first bit-rate and the critical bit-rate.

15. The apparatus of claim 14, further comprising a bitstream transmitter which transmits a bitstream predecoded by the predecoding unit to a client device.