Method of compressing and decompressing an audio signal

Details Method of compressing and decompressing an audio signal Method of compressing and decompressing an audio signal

1999-03-30

2002-05-14

Korzuch, William (Department: 2741)

Data processing: speech signal processing, linguistics, language

Speech signal processing

For storage or transmission

C704S501000

Reexamination Certificate

active

06389390

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to the compression of impulse response signals such as those derived from an impulse response measurement of a room or environment.
BACKGROUND OF THE INVENTION
Room impulse responses are heavily utilised in convolution of audio signals so as to produce improved audio responses.
Turning initially to
FIG. 1
, there is illustrated the first 10,000 samples of a room impulse response signal. It can be seen from
FIG. 1
that most room impulse response, signals have the characteristic of having several regions of significant energy surrounded by large regions of very low energy including a “tail” that tends to diminish to zero.
Unfortunately, given a predetermined level of quantisation, the number of bits necessary to represent the high energy sections eg 1 will be substantially greater than the number required for the low energy sections eg 2.
It would therefore be desirable if a method could be provided for a small compact form of representation of the room impulse response.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention, there is provided a method of compressing an audio signal comprising a series of values, the method comprising dividing the audio signal into a series of blocks of a predetermined length; and for each of the blocks: computing the maximum number of bits required to represent the values within a block; packing an indicator of the maximum number of bits in an output stream; and packing only the maximum number of bits of each coefficient value in the value in the bitstream.
In accordance with a second aspect of the present invention, there is provided a method of compressing an audio signal comprising a series of values, the method comprising: utilising a predetermined maximum number of bits B for representing values; dividing the audio signal into a series of blocks of a predetermined length N; and for each of the blocks:
computing the maximum number of bits b required to represent the values within a block;
packing an indicator of b bits in an output stream; and
for each value within the block:
where the value exceeds 2
B
writing the value to the output stream.
The aforementioned methods are well suited to compressing impulse response functions.
In accordance with ta further aspect of the present invention, there is provided a method fo decoding an audio signal encoded by the aforementioned methods.


REFERENCES:
patent: 3723879 (1973-03-01), Kaul et al.
patent: 4870685 (1989-09-01), Kadokawa et al.
patent: 5696876 (1997-12-01), Lee
patent: 5893065 (1999-04-01), Fukuchi
patent: 5924060 (1999-07-01), Brandenburg
patent: 6016111 (2000-01-01), Park et al.
patent: RE36683 (2000-05-01), Tsutsui
patent: 6122618 (2000-09-01), Park

Affiliated with

Also associated with

Rating

Method of compressing and decompressing an audio signal does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of compressing and decompressing an audio signal, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of compressing and decompressing an audio signal will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2906242