METHOD FOR OUTPUTTING AUDIO SIGNALS AND AUDIO DECODER

• US 20080240464A1
• Filed: 02/12/2008
• Published: 10/02/2008
• Est. Priority Date: 03/31/2007
• Status: Active Grant

• Current Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Original Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Inventors: Noethlings, Rolf, Spalink, Gerd
• Granted Patent: US 8,160,277 B2
• Time in Patent Office: Days
• US Class Current: 381/94.5
• CPC Class Codes: H04S 1/007 in which the audio signals are in digital form data reduction aspects thereof based on psychoacoustics G10L19/02

Abstract

Method for outputting an audio signal to an audio output, comprising outputting a first audio signal to said audio output; providing a second audio signal; determining a point in time, wherein at said point in time said first audio signal or a derivative of said first audio signal or a derivative of said second audio signal is essentially equal to zero; switching, at said point in time, said audio output from outputting said first audio signal to outputting said second audio signal.

Claims

1. Method for outputting an audio signal to an audio output, comprising

outputting a first audio signal to said audio output;

providing a second audio signal;

determining a point in time, wherein at said point in time said first audio signal or a derivative of said first audio signal or a derivative of said second audio signal is essentially equal to zero or crosses zero;

switching, at said point in time, said audio output from outputting said first audio signal to outputting said second audio signal.

2. Method according to claim 1, wherein said first audio signal is a mono audio signal and said second audio signal is a stereo audio signal, and wherein said derivative of said second audio signal corresponds to a difference signal of a left channel of said stereo audio signal and a right channel of said stereo audio signal.

3. Method according to claim 1, wherein said first audio signal is a stereo audio signal and said second audio signal is a mono audio signal, and wherein said derivative of said first audio signal corresponds to a difference signal of a left channel of said stereo audio signal and a right channel of said stereo audio signal.

4. Method according to any of the preceding claims, comprising determining an intermediate audio signal, wherein said intermediate audio signal corresponds to a mixture of said first and second audio signals.

5. Method according to claim 4, comprising outputting said intermediate audio signal starting at said point in time for a predetermined period of time.

6. Method according to claim 5, wherein, within said predetermined period of time, said first audio signal is faded out and said second audio signal is faded in, wherein said first and second audio signals are superimposed.

7. Method according to claim 1, comprising determining a further point in time, wherein at said further point in time said second audio signal is essentially equal to zero wherein outputting said second audio signal is started at said further point in time.

8. Method according to claim 7, wherein between said point in time and said further point in time no audio is output.

9. Integrated circuit configured to perform a method according to any of claims 1 to 8.

10. Audio decoder, comprising

a zero crossing detector configured to receive a first and second audio signal and to determine a point in time, wherein at said point in time said first audio signal or a derivative of said first audio signal or a derivative of said second audio signal is essentially equal to zero or crosses zero, and further configured to output a switching signal at said point in time;

a channel decoding unit configured to tune to said first audio signal and to said second audio signal and to output said first and/or second audio signal depending on said switching signal.

11. Audio decoder according to claim 10, wherein said first audio signal is output by said channel decoding unit before receiving said switching signal and said second audio signal is output afterwards.

12. Audio decoder according to claim 10 or 11, wherein said first audio signal is a mono audio signal and said second audio signal is a stereo audio signal, and said channel decoding unit is configured to determine a difference signal of a left channel of said stereo audio signal and a right channel of said stereo audio signal and further configured to determine said derivative based on a respective difference result.

13. Audio decoder according to claim 10 or 11, wherein said first audio signal is a stereo audio signal and said second audio signal is a mono audio signal, and said channel decoding unit is configured to determine a difference signal of a left channel of said stereo audio signal and a right channel of said stereo audio signal and further configured to determine said derivative based on a respective difference result.

14. Audio decoder according to claim 10, wherein said zero crossing detector is further configured to determine a further point in time, wherein at said further point in time said second audio signal is essentially equal to zero or crosses zero wherein outputting said second audio signal is started at said further point in time.

15. Audio decoder according to claim 11, comprising

a fading mechanism configured to receive said first and second audio signals and to fade out said first audio signal and to fade in said second audio signal.

16. A computer program product including computer program instructions that cause a computer to execute a method for outputting an audio signal to an audio output, comprising

outputting a first audio signal to said audio output;

providing a second audio signal;

determining a point in time, wherein at said point in time said first audio signal or a derivative of said first audio signal or a derivative of said second audio signal is essentially equal to zero or crosses zero;

switching, at said point in time, said audio output from outputting said first audio signal to outputting said second audio signal.