FRAME LOSS MANAGEMENT IN AN FD/LPD TRANSITION CONTEXT

• US 20170213561A1
• Filed: 07/27/2015
• Published: 07/27/2017
• Est. Priority Date: 07/29/2014
• Status: Active Grant

• Current Assignee: Orange S.A.
• Original Assignee: Orange S.A.
• Inventors: Faure, Julien, Ragot, Stephane
• Granted Patent: US 10,600,424 B2
• Time in Patent Office: Days
• CPC Class Codes: G10L 19/005 Correction of errors induced by the transmission channel, if related to the coding algorithm
• CPC Class Codes: G10L 19/022 Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring
• CPC Class Codes: G10L 19/20 using sound class specific coding, hybrid encoders or object based coding

Abstract

A method for decoding a digital signal encoded using predictive coding and transform coding, comprising the following steps: predictive decoding of a preceding frame of the digital signal, encoded by a set of predictive coding parameters; detecting the loss of a current frame of the encoded digital signal; generating by prediction, from at least one predictive coding parameter encoding the preceding frame, a frame for replacing the current frame; generating by prediction, from at least one predictive coding parameter encoding the preceding frame, an additional segment of digital signal; temporarily storing said additional segment of digital signal.

Claims

1. A method for decoding a digital signal encoded using predictive coding and transform coding, wherein the method comprises the following operations:

predictive decoding of a preceding frame of the digital signal, encoded by a set of predictive coding parameters;

detecting the loss of a current frame of the encoded digital signal;

generating, by prediction, from at least one predictive coding parameter encoding the preceding frame, a replacement frame for the current frame;

generating, by prediction, from at least one predictive coding parameter encoding the preceding frame, an additional segment of digital signal;

temporarily storing said additional segment of digital signal.

2. The method according to claim 1, further comprising the operations of:

receiving a next frame of encoded digital signal comprising at least one segment encoded by transform; and

decoding the next frame, comprising a sub-step of overlap-adding the additional segment of digital signal and said segment encoded by transform.

3. The method according to claim 2, wherein the next frame is entirely encoded by transform coding, and

wherein the lost current frame is a transition frame between the preceding frame encoded by predictive coding and the next frame encoded by transform coding.

4. The method according to claim 2, wherein the preceding frame is encoded by predictive coding via a core predictive coder operating at a first frequency, and

wherein the next frame is a transition frame comprising at least one sub-frame encoded by predictive coding via a core predictive coder operating at a second frequency that is different from the first frequency.

5. The method according to claim 4, wherein the next frame comprises a bit indicating the frequency of the core predictive coding used.

6. The method according to claim 2, wherein the overlap-add is given by applying the following formula:

7. The method according to claim 1, wherein the step of generating, by prediction, the replacement frame further comprises an updating of the internal memories of the decoder, and

wherein the step of generating, by prediction, an additional segment of digital signal comprises the following sub-operations:

copying to a temporary memory, from memories of the decoder that were updated during the step of generating, by prediction, the replacement frame;

generating the additional segment of digital signal, using the temporary memory.

8. The method according to claim 1, wherein the step of generating, by prediction, an additional segment of digital signal comprises the following sub-operations:

generating, by prediction, an additional frame from at least one predictive coding parameter encoding the preceding frame;

extracting a segment of the additional frame; and

wherein the additional segment of digital signal corresponds to the first half of the additional frame.

9. A non-transitory computer readable storage medium, with a program stored thereon, said program comprising instructions for implementing the method according to claim 1, when these instructions are executed by a processor.

10. A decoder for a digital signal encoded using predictive coding and transform coding, wherein the decoder comprises:

a detection unit for detecting the loss of a current frame of the digital signal;

a predictive decoder comprising a processor arranged to carry out the following operations;

predictive decoding of a preceding frame of the digital signal, coded by a set of predictive coding parameters;

generating, by prediction, from at least one predictive coding parameter encoding the preceding frame, a replacement frame for the current frame;

generating, by prediction, from at least one predictive coding parameter encoding the preceding frame, an additional segment of digital signal;

temporarily storing said additional segment of digital signal in temporary memory.

11. Decoder The decoder according to claim 10, further comprising a transform decoder comprising a processor arranged to carry out the following operations:

receiving a next frame of encoded digital signal comprising at least one segment encoded by transform; and

decoding the next frame by transform;

said decoder further comprising a decoding unit comprising a processor arranged to perform an overlap-add between the additional segment of digital signal and said segment coded by transform.