Position-dependent hybrid domain packet loss concealment
First Claim
1. A method for concealing one or more consecutive lost packets;
- wherein a lost packet is a packet which is deemed to be lost by a transform-based audio decoder;
wherein the transform-based audio decoder applies an overlapped transform;
wherein each of the one or more lost packets comprises a set of transform coefficients;
wherein each set of transform coefficients comprises N transform coefficients, with N>
1;
wherein for each set of transform coefficients, the overlapped transform generates a corresponding aliased intermediate frame of 2N samples;
wherein for each received packet, wherein the overlapped transform generates the corresponding frame of the audio signal, based on a first half of the corresponding aliased intermediate frame and based on a second half of the aliased intermediate frame of a packet which precedes the received packet; and
wherein a set of transform coefficients is used by the transform-based audio decoder to generate a corresponding frame of a time domain audio signal;
the method comprising;
determining a last received packet comprising a last received set of transform coefficients;
wherein the last received packet is directly preceding the one or more lost packets;
determining contents of a first buffer based on a last received frame of the audio signal;
wherein the last received frame corresponds to the last received packet;
determining contents of a second buffer based on the second half of the aliased intermediate frame of the last received packet;
determining for a current lost packet of the one or more lost packets a number of preceding lost packets from the one or more lost packets;
wherein the determined number is referred to as a loss position;
determining a packet loss concealment, referred to as PLC, scheme based on the loss position of the current packet; and
determining an estimate of a current frame of the audio signal using the determined PLC scheme;
wherein the current frame corresponds to the current lost packet.
1 Assignment
0 Petitions
Accused Products
Abstract
The present document relates to audio signal processing in general, and to the concealment of artifacts that result from loss of audio packets during audio transmission over a packet-switched network, in particular. A method (200) for concealing one or more consecutive lost packets is described. A lost packet is a packet which is deemed to be lost transform-based audio decoder. Each of the one or more lost packets comprises a set of transform coefficients. A set of transform coefficients is used by the transform-based audio decoder to generate a corresponding frame of a time domain audio signal. The method (200) comprises determining (205) for a current lost packet of the one or more lost packets a number of preceding lost packets from the one or more lost packets; wherein the determined number is referred to as a loss position. Furthermore, the method comprises determining a packet loss concealment, referred to as PLC, scheme based on the loss position of the current packet; and determining (204, 207, 208) an estimate of a current frame of the audio signal using the determined PLC scheme (204, 207, 208); wherein the current frame corresponds to the current lost packet.
41 Citations
20 Claims
-
1. A method for concealing one or more consecutive lost packets;
- wherein a lost packet is a packet which is deemed to be lost by a transform-based audio decoder;
wherein the transform-based audio decoder applies an overlapped transform;
wherein each of the one or more lost packets comprises a set of transform coefficients;
wherein each set of transform coefficients comprises N transform coefficients, with N>
1;
wherein for each set of transform coefficients, the overlapped transform generates a corresponding aliased intermediate frame of 2N samples;
wherein for each received packet, wherein the overlapped transform generates the corresponding frame of the audio signal, based on a first half of the corresponding aliased intermediate frame and based on a second half of the aliased intermediate frame of a packet which precedes the received packet; and
wherein a set of transform coefficients is used by the transform-based audio decoder to generate a corresponding frame of a time domain audio signal;
the method comprising;determining a last received packet comprising a last received set of transform coefficients;
wherein the last received packet is directly preceding the one or more lost packets;determining contents of a first buffer based on a last received frame of the audio signal;
wherein the last received frame corresponds to the last received packet;determining contents of a second buffer based on the second half of the aliased intermediate frame of the last received packet; determining for a current lost packet of the one or more lost packets a number of preceding lost packets from the one or more lost packets;
wherein the determined number is referred to as a loss position;determining a packet loss concealment, referred to as PLC, scheme based on the loss position of the current packet; and determining an estimate of a current frame of the audio signal using the determined PLC scheme;
wherein the current frame corresponds to the current lost packet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
- wherein a lost packet is a packet which is deemed to be lost by a transform-based audio decoder;
-
18. A system configured to conceal one or more consecutive lost packets;
- wherein a lost packet is a packet which is deemed to be lost by a transform-based audio decoder;
wherein the transform-based audio decoder applies an overlapped transform;
wherein each of the one or more lost packets comprises a set of transform coefficients;
wherein each set of transform coefficients comprises N transform coefficients, with N>
1;
wherein for each set of transform coefficients, the overlapped transform generates a corresponding aliased intermediate frame of 2N samples;
wherein for each received packet, wherein the overlapped transform generates the corresponding frame of the audio signal, based on a first half of the corresponding aliased intermediate frame and based on a second half of the aliased intermediate frame of a packet which precedes the received packet; and
wherein a set of transform coefficients is used by the transform-based audio decoder to generate a corresponding frame of a time domain audio signal;
the system comprising;means for determining a last received packet comprising a last received set of transform coefficients;
wherein the last received packet is directly preceding the one or more lost packets;means for determining contents of a first buffer based on a last received frame of the audio signal;
wherein the last received frame corresponds to the last received packet;means for determining contents of a second buffer based on the second half of the aliased intermediate frame of the last received packet; a lost position detector configured to determine for a current lost packet of the one or more lost packets a number of preceding lost packets from the one or more lost packets;
wherein the determined number is referred to as a loss position;a decision unit configured to determine a packet loss concealment, referred to as PLC, scheme based on the loss position of the current packet; and a PLC unit configured to determine an estimate of a current frame of the audio signal using the determined PLC scheme;
wherein the current frame corresponds to the current lost packet.
- wherein a lost packet is a packet which is deemed to be lost by a transform-based audio decoder;
-
19. A method for concealing one or more consecutive lost packets;
- wherein a lost packet is a packet which is deemed to be lost by a transform-based audio decoder;
wherein each of the one or more lost packets comprises a set of transform coefficients;
wherein a set of transform coefficients is used by the transform-based audio decoder to generate a corresponding frame of a time domain audio signal;
wherein the transform-based audio decoder applies an overlapped transform;
wherein each set of transform coefficients comprises N transform coefficients, with N>
1;
wherein for each set of transform coefficients, the overlapped transform generates a corresponding aliased intermediate frame of 2N samples;
wherein for each received packet, the overlapped transform generates the corresponding frame of the audio signal, based on a first half of the corresponding aliased intermediate frame and based on a second half of the aliased intermediate frame of a packet which precedes the received packet;
the method comprisingdetermining a last received packet comprising a last received set of transform coefficients;
wherein the last received packet is directly preceding the one or more lost packets; anddetermining contents of a first buffer based on a last received frame of the audio signal;
wherein the last received frame corresponds to the last received packet;determining contents of a second buffer based on the second half of the aliased intermediate frame of the last received packet; determining contents of a third buffer in which one or more frames of a decoded and decorrelated signal, corresponding with the last received packet, are stored; and determining, based on the contents of at least one of the first buffer or the second buffer whether to use the contents of the third buffer to conceal the current lost packet.
- wherein a lost packet is a packet which is deemed to be lost by a transform-based audio decoder;
-
20. A non-transitory medium having software stored thereon, the software including instructions for controlling one or more devices to perform a method for concealing one or more consecutive lost packets;
- wherein a lost packet is a packet which is deemed to be lost by a transform-based audio decoder;
wherein the transform-based audio decoder applies an overlapped transform;
wherein each of the one or more lost packets comprises a set of transform coefficients;
wherein each set of transform coefficients comprises N transform coefficients, with N>
1;
wherein for each set of transform coefficients, the overlapped transform generates a corresponding aliased intermediate frame of 2N samples;
wherein for each received packet, wherein the overlapped transform generates the corresponding frame of the audio signal, based on a first half of the corresponding aliased intermediate frame and based on a second half of the aliased intermediate frame of a packet which precedes the received packet; and
wherein a set of transform coefficients is used by the transform-based audio decoder to generate a corresponding frame of a time domain audio signal;
the method comprising;determining a last received packet comprising a last received set of transform coefficients;
wherein the last received packet is directly preceding the one or more lost packets;determining contents of a first buffer based on a last received frame of the audio signal;
wherein the last received frame corresponds to the last received packet;determining contents of a second buffer based on the second half of the aliased intermediate frame of the last received packet; determining for a current lost packet of the one or more lost packets a number of preceding lost packets from the one or more lost packets;
wherein the determined number is referred to as a loss position;determining a packet loss concealment, referred to as PLC, scheme based on the loss position of the current packet; and determining an estimate of a current frame of the audio signal using the determined PLC scheme;
wherein the current frame corresponds to the current lost packet.
- wherein a lost packet is a packet which is deemed to be lost by a transform-based audio decoder;
Specification