STEREO ACOUSTIC SIGNAL ENCODING APPARATUS, STEREO ACOUSTIC SIGNAL DECODING APPARATUS, AND METHODS FOR THE SAME

• US 20110288872A1
• Filed: 01/21/2010
• Published: 11/24/2011
• Est. Priority Date: 01/22/2009
• Status: Active Grant

• Current Assignee: III Holdings 12, LLC (Intellectual Ventures LLC)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Chong, Kok Seng, Liu, Zongxian
• Granted Patent: US 8,504,378 B2
• Time in Patent Office: Days
• US Class Current: 704/500
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing

Abstract

Disclosed is a stereo acoustic signal encoding apparatus in which the signal quality does not deteriorate if there are a plurality of sound sources. A peak tracing unit (401) splits frames of a right channel signal and a left channel signal into a plurality of sub frames; detects the peaks of wave shapes of the split sub frames; and estimates a frame delay time D for each frame of the right channel signal and the left channel signal by comparing the positions of the detected peaks. A time adjusting unit (402) adjusts the time of the right channel signal on the basis of the frame time delay D. A down-mix operation is carried out using the right channel signal which has been subjected to the time adjustment and the left channel signal to generate a mono signal and a sub signal. A mono signal encoding unit (403) encodes the mono signal. A sub signal encoding unit (404) encodes the sub signal. The time delay encoding unit (405) encodes the frame time delay D.

Claims

1. A stereo acoustic sound signal encoding apparatus comprising:

a peak tracking section that divides a frame of a right channel signal and a left channel signal into a plurality of sub frames, detects peaks in waveforms of the divided sub frames, and compares the positions of the detected peaks, thereby estimating a frame time delay of each frame of the right channel signal and the left channel signal;

a time alignment section that performs time alignment on one of the right channel signal and the left channel signal on the basis of the frame time delay; and

an encoding section that encodes the other of the right channel signal and the left channel signal, the time-aligned one of the right channel signal and the left channel signal, and the frame time delay.

2. The stereo acoustic sound signal encoding apparatus according to claim 1, wherein the peak tracking section obtains sub-frame time delays of the sub frames, and regards the estimated frame time delay as invalid in a case where the number of sub frames in each of which a difference between the frame time delay and the sub-frame time delay is than a predetermined value or more is a threshold value or more.

3. The stereo acoustic sound signal encoding apparatus according to claim 1, wherein the peak tracking section discards the peaks of the sub frames in which the values of the peaks are smaller than a threshold value and estimates the frame time delay.

4. The stereo acoustic sound signal encoding apparatus according to claim 1, further comprising a time delay estimation section that estimates a time delay of the frame by a method different from the frame time delay estimated in the peak tracking section, wherein the peak tracking section obtains sub-frame time delays of the sub frames, and outputs the time delay estimated in the time delay estimation section, instead of the frame time delay, in a case where the number of sub frames in each of which a difference between the time delay estimated in time delay estimation section and the sub-frame time delay is than a predetermined value or more is less than a threshold value.

5. The stereo acoustic sound signal encoding apparatus according to claim 1, wherein:

the time alignment section performs time alignment on both of the right channel signal and the left channel signal on the basis of the frame time delay; and

the encoding section encodes the time-aligned right channel signal, the time-aligned left channel signal, and the frame time delay.

6. A stereo acoustic sound signal decoding apparatus comprising:

a separation section that separates a bit stream into a right channel signal, a left channel signal, and a frame time delay, the bit stream generated by dividing a frame of the right channel signal and the right channel signal into a plurality of sub frames, detecting peaks in waveforms of the divided sub frames, estimates the frame time delay of each frame of the right channel signal and the left channel signal by comparing the positions of the detected peaks, performing time alignment on one of the right channel signal and the left channel signal on the basis of the frame time delay, and encoding and multiplexing the other of the right channel signal and the left channel signal, the time-aligned one of the right channel signal and the left channel signal, and the frame time delay;

a decoding section that decodes the separated right channel signal, the separated left channel signal, and the separated frame time delay; and

a time restoring section that restores the right channel signal to a time before the time alignment, on the basis of the separated frame time delay.

7. A stereo acoustic sound signal encoding method comprising the steps of:

dividing a frame of a right channel signal and a left channel signal into a plurality of sub frames, detecting peaks in waveforms of the divided sub frames, and comparing the positions of the detected peaks, thereby estimating a frame time delay of each frame of the right channel signal and the left channel signal;

performing time alignment on one of the right channel signal and the left channel signal on the basis of the frame time delay; and

encoding the other of the right channel signal and the left channel signal, the time-aligned one of the right channel signal and the left channel signal, and the frame time delay.

8. A stereo acoustic sound signal decoding method comprising the steps of:

separating a bit stream into a right channel signal, a left channel signal, and a frame time delay, the bit stream generated by dividing a frame of the right channel signal and the right channel signal into a plurality of sub frames, detecting peaks in waveforms of the divided sub frames, estimating the frame time delay of each frame of the right channel signal and the left channel signal by comparing the positions of the detected peaks, performing time alignment on one of the right channel signal and the left channel signal on the basis of the frame time delay, and encoding and multiplexing the other of the right channel signal and the left channel signal, the time-aligned one of the right channel signal and the left channel signal, and the frame time delay;

decoding the separated right channel signal, the separated left channel signal, and the separated frame time delay; and

restoring the right channel signal to a time before the time alignment, on the basis of the separated frame time delay.