Apparatus and method realizing improved concepts for TCX LTP
First Claim
1. An apparatus for decoding an encoded audio signal to acquire a reconstructed audio signal, wherein the apparatus is configured to receive a plurality of frames, and wherein the apparatus comprises:
- an inverse modified discrete cosine transform module for decoding the plurality of frames by conducting an inverse modified discrete cosine transform to acquire audio signal samples of the decoded audio signal, anda long-term prediction unit for conducting long-term prediction, comprising;
a delay buffer for storing the audio signal samples of the decoded audio signal,a sample selector for selecting a plurality of selected audio signal samples from the audio signal samples being stored in the delay buffer, anda sample processor for processing the selected audio signal samples to acquire reconstructed audio signal samples of the reconstructed audio signal,wherein the sample selector is configured to select, if a current frame is received by the apparatus and if the current frame being received by the apparatus is not corrupted, the plurality of selected audio signal samples from the audio signal samples being stored in the delay buffer depending on a pitch lag information being comprised by the current frame, andwherein the sample selector is configured to select, if the current frame is not received by the apparatus or if the current frame being received by the apparatus is corrupted, the plurality of selected audio signal samples from the audio signal samples being stored in the delay buffer depending on a pitch lag information being comprised by another frame being received previously by the apparatus,wherein the sample selector is configured to acquire the reconstructed audio signal samples by rescaling the selected audio signal samples depending on a modified gain, wherein the modified gain is defined according to the formula;
gain=gain_past*damping;
wherein gain is the modified gain,wherein the sample selector is configured to set gain_past to gain after gain has been calculated, andwherein damping is a real value with 0≤
damping≤
1.
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Abstract
An apparatus for decoding an encoded audio signal to obtain a reconstructed audio signal is provided. The apparatus includes a receiving interface, a delay buffer and a sample processor for processing the selected audio signal samples to obtain reconstructed audio signal samples of the reconstructed audio signal. The sample selector is configured to select, if a current frame is received by the receiving interface and if the current frame being received by the receiving interface is not corrupted, the plurality of selected audio signal samples from the audio signal samples being stored in the delay buffer depending on a pitch lag information being included by the current frame.
91 Citations
13 Claims
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1. An apparatus for decoding an encoded audio signal to acquire a reconstructed audio signal, wherein the apparatus is configured to receive a plurality of frames, and wherein the apparatus comprises:
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an inverse modified discrete cosine transform module for decoding the plurality of frames by conducting an inverse modified discrete cosine transform to acquire audio signal samples of the decoded audio signal, and a long-term prediction unit for conducting long-term prediction, comprising; a delay buffer for storing the audio signal samples of the decoded audio signal, a sample selector for selecting a plurality of selected audio signal samples from the audio signal samples being stored in the delay buffer, and a sample processor for processing the selected audio signal samples to acquire reconstructed audio signal samples of the reconstructed audio signal, wherein the sample selector is configured to select, if a current frame is received by the apparatus and if the current frame being received by the apparatus is not corrupted, the plurality of selected audio signal samples from the audio signal samples being stored in the delay buffer depending on a pitch lag information being comprised by the current frame, and wherein the sample selector is configured to select, if the current frame is not received by the apparatus or if the current frame being received by the apparatus is corrupted, the plurality of selected audio signal samples from the audio signal samples being stored in the delay buffer depending on a pitch lag information being comprised by another frame being received previously by the apparatus, wherein the sample selector is configured to acquire the reconstructed audio signal samples by rescaling the selected audio signal samples depending on a modified gain, wherein the modified gain is defined according to the formula;
gain=gain_past*damping;wherein gain is the modified gain, wherein the sample selector is configured to set gain_past to gain after gain has been calculated, and wherein damping is a real value with 0≤
damping≤
1. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for decoding an encoded audio signal to acquire a reconstructed audio signal, wherein the method comprises:
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receiving a plurality of frames, decoding the plurality of frames by conducting an inverse modified discrete cosine transform to acquire audio signal samples of the decoded audio signal, conducting long-term prediction by storing the audio signal samples of the decoded audio signal, selecting a plurality of selected audio signal samples from the audio signal samples being stored in a delay buffer, and processing the selected audio signal samples to acquire reconstructed audio signal samples of the reconstructed audio signal, wherein, if a current frame is received and if the current frame being received is not corrupted, selecting the plurality of selected audio signal samples from the audio signal samples being stored in the delay buffer is conducted depending on a pitch lag information being comprised by the current frame, and wherein, if the current frame is not received or if the current frame being received is corrupted, selecting the plurality of selected audio signal samples from the audio signal samples being stored in the delay buffer is conducted depending on a pitch lag information being comprised by another frame being received previously, wherein the method further comprises rescaling the selected audio signal samples depending on a modified gain, wherein the modified gain is defined according to the formula;
gain=gain_past*damping;wherein gain is the modified gain, wherein gain_past is set to gain after gain has been calculated, and wherein damping is a real value with 0≤
damping≤
1. - View Dependent Claims (13)
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Specification