System and method for concealment of data loss in digital audio transmission

• US 20020133764A1
• Filed: 01/24/2001
• Published: 09/19/2002
• Est. Priority Date: 01/24/2001
• Status: Active Grant

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Wang, Ye
• Granted Patent: US 7,069,208 B2
• Time in Patent Office: Days
• US Class Current: 714/707
• CPC Class Codes: G10H 1/0058 Transmission between separate instruments or between individual components of a musical system G10H1/0083 takes precedence
• CPC Class Codes: G10H 2240/061 MP3, i.e. MPEG-1 or MPEG-2 Audio Layer III, lossy audio compression
• CPC Class Codes: G10H 2240/185 Error prevention, detection or correction in files or streams for electrophonic musical instruments
• CPC Class Codes: G10H 2240/245 ISDN [Integrated Services Digital Network]
• CPC Class Codes: G10H 2240/251 Mobile telephone transmission, i.e. transmitting, accessing or controlling music data wirelessly via a wireless or mobile telephone receiver, analogue or digital, e.g. DECT, GSM, UMTS
• CPC Class Codes: G10H 2240/295 Packet switched network, e.g. token ring
• CPC Class Codes: G10H 2240/305 Internet or TCP/IP protocol use for any electrophonic musical instrument data or musical parameter transmission purposes
• CPC Class Codes: G10L 19/005 Correction of errors induced by the transmission channel, if related to the coding algorithm
• CPC Class Codes: G10L 19/0212 using orthogonal transformation

Abstract

A system and method for the concealment of errors resulting from missing or corrupted data in the transmission of audio signals in compressed digital packet formats is disclosed. The system utilizes a circular FIFO buffer to store audio frames from the transmitted audio signal, and a beat detector, to identify the presence of beats in the audio signal. The error concealment method replaces erroneous audio frames with error-free audio frames by a process which takes into account the presence and location of the detected beats.

Claims

1. A method for concealing errors detected in an input audio bit stream, the digital audio bit stream configured as a series of packets, said method comprising the steps of:

detecting a first beat and a subsequent plurality of beats in the audio bit stream;

defining a first inter-beat interval extending between said first beat and a (k+1)^th subsequent beat;

storing at least a portion of the audio bit stream occurring within said first inter- beat interval;

detecting an erroneous audio segment occurring in a second inter-beat interval extending between said (k+1)^th beat and a (2k+1)^th subsequent beat; and

replacing at least a first part of said erroneous audio segment with a corresponding part of said stored digital audio bit stream portion.

2. A method as in claim 1 wherein ‘

k’

is an integer greater than or equal to 2.

3. A method as in claim 1 wherein said stored audio bit stream portion includes at least one packet positioned on at least one said beat.

4. A method as in claim 1 wherein said step of detecting a first beat comprises a step of computing the variance of the audio bit stream using decoded IMDCT coefficients.

5. A method as in claim 1 wherein said step of detecting a first beat comprises the step of utilizing a window-switching pattern.

6. A method as in claim 1 wherein said step of detecting a first beat comprises a step of computing the envelope of the audio bit stream using decoded IMDCT coefficients.

7. A method as in claim 1 wherein said step of detecting a first beat comprises the steps of computing the variance of the audio bit stream using decoded IMDCT coefficients and utilizing a window-switching pattern.

8. A method as in claim 1 wherein said step of storing at least a portion of the audio bit stream includes a step of storing said portion in a circular first-in first-out (FIFO) buffer.

9. A method for error concealment in a process of digital audio streaming, said method comprising the steps of:

providing a bitstream;

detecting at least two beats extracted from said bitstream, said beats extracted from a signal having repetitive sequences; and

determining an inter-beat interval between said at least two beats.

10. A method as in claim 9 wherein said signal having repetitive sequences comprises at least one signal from the group consisting of a music signal and an audio signal.

11. A method as in claim 9 wherein said signal having repetitive sequences includes an error pattern.

12. A method as in claim 9 wherein said signal having repetitive sequences includes a packet loss from an IP network and a burst error from a wireless channel.

13. A method as in claim 9 further comprising the step of decoding at least a portion of said signal having repetitive sequences.

14. A method as in claim 9 wherein said signal having repetitive sequences comprises at least one element from the group consisting of a rhythm element, a beat element, and a bar element.

15. A method as in claim 11 further comprising the step of replacing said error pattern with music content.

16. A method as in claim 9 further comprising the step of replacing one said beat with another said beat from a preceding bar.

17. A method for error concealment in a process of digital audio streaming in a wireless terminal, said method comprising the step of storing two consecutive inter-beat intervals of the compressed audio bitstream

18. A memory for error concealment in a process of digital audio streaming in a wireless terminal, said memory comprising:

storing means for storing a signal history of musical beats of two consecutive inter-beat intervals of the compressed audio bitstream.