TRANSCODER WITH DYNAMIC AUDIO CHANNEL CHANGING

• US 20130117032A1
• Filed: 11/08/2011
• Published: 05/09/2013
• Est. Priority Date: 11/08/2011
• Status: Active Grant

• Current Assignee: VIXS Systems Incorporated (Pixelworks Incorporated)
• Original Assignee: VIXS Systems Incorporated (Pixelworks Incorporated)
• Inventors: Lo, Kenny, Ip, Kent
• Granted Patent: US 9,183,842 B2
• Time in Patent Office: Days
• US Class Current: 704/501
• 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
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes
• CPC Class Codes: G10L 19/173 Transcoding, i.e. converting between two coded representations avoiding cascaded coding-decoding

Abstract

A transcoder is arranged to transcode a stream having a dynamically changing audio configuration, such as a changing number of audio channels. The transcoder can receive an input stream whereby changes in the content associated with the input stream causes corresponding changes to the configuration of audio data encoded in the input stream. The transcoder is arranged to detect the change in audio configuration and, in response, to dynamically reconfigure its decoder and encoder modules to continue to transcode the audio data after the audio configuration change.

Claims

1. A method of transcoding an input stream at a transcoder, the method comprising:

in response to a change in audio configuration of the input stream from a first number of audio channels to a second number of channels, automatically reconfiguring the transcoder to transcode the input stream according to the second number of channels.

2. The method of claim 1, further comprising:

detecting the change in audio configuration at the transcoder.

3. The method of claim 2, wherein detecting the change in the audio configuration format comprises:

determining an encoding format for the input stream;

mapping a set of audio channels associated with the encoding format to a set of predefined tags to determine a channel mapping; and

detecting the change in the audio configuration based on the channel mapping.

4. The method of claim 3, wherein detecting the change in the audio configuration format comprises comparing the channel mapping to a stored channel mapping.

5. The method of claim 4, further comprising determining the stored channel mapping based on the first number of channels.

6. The method of claim 1, wherein reconfiguring the transcoder comprises:

emptying a buffer of decoded audio samples associated with the input stream; and

reconfiguring an encoder module of the transcoder after emptying the buffer.

7. The method of claim 6, wherein reconfiguring the transcoder further comprises:

reconfiguring a decoder module of the transcoder in response to the change in audio configuration.

8. The method of claim 7, wherein reconfiguring the transcoder further comprises:

setting a first flag in response to determining the change in audio configuration; and

in response to the first flag being set, determining whether the buffer is empty of decoded samples.

9. The method of claim 8, further comprising:

setting a second flag in response to determining the buffer is empty of decoded samples; and

in response to the second flag being set, modifying stored channel mapping information to reflect the second number of channels.

10. The method of claim 9, further comprising clearing the first flag in response to modifying the stored channel mapping information.

11. The method of claim 6, further comprising resetting the buffer to an initial state in response to emptying the buffer of decoded samples, the initial state reflecting an empty buffer state.

12. A method, comprising:

in response to determining a change in the number of audio channels included in a received input stream, synchronizing reconfiguration of a decoder module and an encoder module to transcode the input stream.

13. The method of claim 12, wherein synchronizing reconfiguration comprises waiting to reconfigure the encoder module until it has completed encoding a set of audio samples received prior to the change in the number of audio channels.

14. The method of claim 12, further comprising determining the change in the number of audio channels by mapping a set of audio channels included in the received input stream to a set of tags to determine a mapped set of tags, and determining whether there has been a change in the mapped set of tags relative to a previously mapped set of tags.

15. The method of claim 12, wherein the change in the number of audio channels represents a change in television programs represented by the input stream.

16. A device, comprising a transcoder to receive an input stream, the transcoder arranged to automatically reconfigure a decoder and an encoder in response to a change in audio configuration of the input stream from a first number of audio channels to a second number of channels so that the decoder and encoder automatically transcode the input stream according to the second number of channels.

17. The device of claim 16, wherein the transcoder is arranged to:

determine an encoding format for the input stream;

map a set of audio channels associated with the encoding format to a set of predefined tags to determine a channel mapping; and

detecting the change in the audio configuration based on the channel mapping.

18. The device of claim 17, wherein the transcoder is arranged to detect the change in the audio configuration format by comparing the channel mapping to a stored channel mapping.

19. The device of claim 18, wherein the transcoder is arranged to detect the stored channel mapping based on the first number of channels.

20. The device of claim 16, wherein the transcoder comprises a buffer, the transcoder arrange to:

emptying a buffer of decoded audio samples associated with the input stream in response to detecting the change in audio configuration.