ZERO-GAP PLAYBACK USING PREDICTIVE MIXING

• US 20090083047A1
• Filed: 09/25/2007
• Published: 03/26/2009
• Est. Priority Date: 09/25/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Lindahl, Aram, Guetta, Anthony J.
• Granted Patent: US 8,069,051 B2
• Time in Patent Office: Days
• US Class Current: 704/504
• CPC Class Codes: G10L 21/04 Time compression or expansion
• CPC Class Codes: G11B 27/038 Cross-faders therefor
• CPC Class Codes: G11B 27/105 of operating discs
• CPC Class Codes: G11B 27/28 by using information signals recorded by the same method as the main recording G11B27/22 takes precedence

Abstract

Circuits and methods for providing zero-gap playback of consecutive data streams in portable electronic devices, such as media players, are described. In some embodiments, a circuit includes a decoder circuit configured to receive encoded audio data and to output decoded audio data including data streams associated with a data file and a subsequent data file. Moreover, a predictive circuit, which is electrically coupled to the decoder circuit, is configured to selectively generate additional samples based on samples in the data file, where the additional samples correspond to times after the end of a data stream associated with the data file. Additionally, a filter circuit, which is electrically coupled to the decoder circuit and selectively electrically coupled to the predictive circuit, is configured to selectively combine or blend samples at a beginning of the subsequent data file with the additional samples. Note that the circuit may be included in an integrated circuit.

Claims

1. An integrated circuit, comprising:

a decoder circuit configured to receive encoded audio data and to output decoded audio data including data streams associated with a data file and a subsequent data file;

a predictive circuit electrically coupled to the decoder circuit, which is configured to selectively generate additional samples based on samples in the data file, wherein the additional samples correspond to times after the end of a data stream associated with the data file; and

a filter circuit electrically coupled to the decoder circuit and selectively electrically coupled to the predictive circuit, which is configured to selectively combine samples at a beginning of the subsequent data file with the additional samples.

2. The integrated circuit of claim 1, wherein the combining includes fading out the additional samples and fading in the samples at the beginning of the subsequent data file.

3. The integrated circuit of claim 1, wherein the decoder circuit is configured to remove an end portion of the data file and/or a beginning portion of the subsequent data file.

4. The integrated circuit of claim 1, wherein the combining reduces a discontinuity in samples at the end of the data file and samples at the beginning of the subsequent data file.

5. The integrated circuit of claim 4, wherein the discontinuity comprises an intensity discontinuity.

6. The integrated circuit of claim 4, wherein the discontinuity comprises a phase discontinuity.

7. The integrated circuit of claim 1, further comprising control logic which is configured to detect the end of the data file and configured to selectively electrically couple the predictive circuit to the filter circuit.

8. The integrated circuit of claim 7, wherein the control logic is configured to enable the selective combining.

9. The integrated circuit of claim 7, wherein the control logic is configured to activate the predictive circuit when the end of the data file is detected.

10. The integrated circuit of claim 9, wherein the predictive circuit is trained when it is activated.

11. The integrated circuit of claim 1, wherein the predictive circuit comprises a filter.

12. The integrated circuit of claim 11, wherein the filter has a finite impulse response.

13. The integrated circuit of claim 11, wherein the filter has an infinite impulse response.

14. The integrated circuit of claim 11, wherein the filter comprises an adaptive filter.

15. The integrated circuit of claim 1, further comprising a memory buffer electrically coupled to the decoder circuit and the filter circuit.

16. The integrated circuit of claim 1, wherein generation of the additional samples involves extrapolating the samples in the data file.

17. A circuit, comprising:

a decoder circuit configured to receive encoded audio data and to output decoded audio data including data streams associated with a data file and a subsequent data file;

a predictive circuit electrically coupled to the decoder circuit, which is configured to selectively generate additional samples based on samples in the data file, wherein the additional samples correspond to times after the end of a data stream associated with the data file; and

a filter circuit electrically coupled to the decoder circuit and selectively electrically coupled to the predictive circuit, which is configured to selectively combine samples at a beginning of the subsequent data file with the additional samples.

18. A circuit, comprising:

a decoder circuit configured to decode encoded audio data and configured to trim portions of two adjacent data files;

a predictive circuit electrically coupled to the decoder circuit, which is configured to selectively extrapolate samples in a first of the two adjacent data files to generate additional samples; and

a filter circuit electrically coupled to the decoder circuit and selectively electrically coupled to the predictive circuit, which is configured to selectively blend the additional samples with samples in a second of the two adjacent data files.

19. A portable device, comprising an audio codec configured to decode and playback encoded data files and configured to reduce a discontinuity in samples at the end of a data file and samples at the beginning of a subsequent data file by combining the samples in the subsequent data file with additional samples extrapolated from the samples in the data file.

20. A method for reducing media discontinuities, comprising:

detecting the end of a data file which includes audio data;

removing an end portion of the data file and/or a beginning portion of a subsequent data file;

generating additional samples based on samples in the data file, wherein the additional samples correspond to times after the end of a data stream associated with the data file; and

combining samples at the beginning of the subsequent data file with the additional samples.