Packet loss concealment

Abstract

A method of processing an audio signal for packet loss concealment is described. The audio signal comprises a sequence of frames, each frame containing a representation of a plurality of audio channels and reconstruction parameters for upmixing the plurality of audio channels into a predetermined channel format. A method includes: receiving the audio signal; and generating a reconstructed audio signal in the predefined channel format based on the received audio signal. Generating the reconstructed audio signal includes: determining whether at least one frame of the audio signal has been lost; and fade-in and fade-out the reconstructed audio signal to a predefined spatial configuration if the number of consecutive lost frames exceeds a first threshold. A method of encoding an audio signal is also described. Apparatus for carrying out the method, as well as corresponding programs and computer-readable storage media, are also further described.

Description

Abstract Described are methods of processing an audio signal for packet loss concealment. The audio signal comprises a sequence of frames, each frame containing representations of a plurality of audio channels and reconstruction parameters for upmixing the plurality of audio channels to a predetermined channel format. One method includes: receiving the audio signal; and generating a reconstructed audio signal in the predefined channel format based on the received audio signal. Generating the reconstructed audio signal comprises: determining whether at least one frame of the audio signal has been lost; and if a number of consecutively lost frames exceeds a first threshold, fading the reconstructed audio signal to a predefined spatial configuration. Also described is a method of encoding an audio signal. Yet further described are apparatus for carrying out the methods, as well as corresponding programs and computer-readable storage media.

Claims

1. A method comprising: Receive an audio signal, the audio signal including a frame sequence, each frame containing representations of multiple audio channels and reconstruction parameters for upmixing the multiple audio channels to a predefined channel format; Based on the received audio signal, a reconstructed audio signal is generated in the predefined channel format. The generation of the reconstructed audio signal includes: Determine whether at least one frame of the audio signal has been lost; If the number of consecutively lost frames exceeds a first threshold, then the reconstructed audio signal is faded in and out to a predefined spatial configuration; and If the number of consecutively lost frames exceeds a second threshold equal to the first threshold, then the reconstructed audio signal gradually fades out; and The method further includes: If at least one frame of the audio signal has been lost, then an estimate of the reconstruction parameters of the at least one lost frame is generated based on the reconstruction parameters of the previous frame; The reconstructed audio signal of the at least one lost frame is generated using the estimation of the reconstruction parameters of the at least one lost frame; Each reconstruction parameter is explicitly encoded once per given number of frames in the frame sequence and differentially encoded between the remaining frames; and The estimation of the given reconstruction parameters for the lost frames involves: Estimate the given reconstruction parameters of the lost frame based on the most recently determined value of the given reconstruction parameters; or The given reconstruction parameter of the lost frame is estimated based on the most recently determined value of one, two or more reconstruction parameters other than the given reconstruction parameter.

2. The method of claim 1, wherein each frame contains reconstruction parameters associated with a corresponding frequency band, and wherein the given reconstruction parameters of the lost frame are estimated based on one or more reconstruction parameters associated with a frequency band different from the frequency band associated with the given reconstruction parameters.

3. The method of claim 2, wherein the given reconstruction parameter is estimated by interpolation between reconstruction parameters associated with a frequency band different from the frequency band associated with the given reconstruction parameter.

4. The method of claim 2, wherein the given reconstruction parameter is estimated by interpolation among reconstruction parameters associated with a frequency band adjacent to the frequency band associated with the given reconstruction parameter, or, if the frequency band associated with the given reconstruction parameter has a unique adjacent frequency band, then it is estimated by interpolation from the reconstruction parameter associated with that adjacent frequency band.

5. An apparatus comprising: processor; and a memory coupled to the processor and storing instructions for the processor, wherein the processor is configured to perform all steps of the method according to any one of claims 1 to 4.

6. A non-transitory computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computing device, cause the computing device to perform the method according to any one of claims 1 to 4.

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