Recovering high frequency band signal of a lost frame in media bitstream according to gain gradient
First Claim
1. A method for recovering a lost frame of a media bitstream, wherein the bitstream is being decoded by an audio signal decoder, comprising:
- obtaining a synthesized high frequency band signal of a current lost frame;
obtaining recovery information related to the current lost frame, wherein the recovery information comprises a coding mode of a last frame received before the current lost frame, and a frame class of the last frame received before the current lost frame;
determining a global gain gradient of the current lost frame according to the recovery information;
determining a global gain of the current lost frame according to the global gain gradient of the current lost frame and a global gain of each of M frames prior to the current lost frame, wherein M is a positive integer;
determining a subframe gain of the current lost frame; and
adjusting the synthesized high frequency band signal of the current lost frame according to the global gain of the current lost frame and the subframe gain of the current lost frame to obtain a high frequency band signal of the current lost frame.
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Abstract
A method for recovering lost frame in a media bitstream is provided. When a frame loss event occurs, a decoder obtains a synthesized high frequency band signal of a current lost frame, and recovery information related to the current lost frame. The decoder determines a global gain gradient of the current lost frame, and further determines a global gain of the current lost frame according to the global gain gradient and a global gain of each frame in previous M frames of the current lost frame. A high frequency band signal of the current lost frame is obtained by adjusting the synthesized high frequency band signal of the current lost frame according to the global gain and a subframe gain of the current lost frame. The process enables natural and smooth transitions of the high frequency band signal between the frames, and attenuates noises in the high frequency band signal.
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Citations
19 Claims
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1. A method for recovering a lost frame of a media bitstream, wherein the bitstream is being decoded by an audio signal decoder, comprising:
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obtaining a synthesized high frequency band signal of a current lost frame; obtaining recovery information related to the current lost frame, wherein the recovery information comprises a coding mode of a last frame received before the current lost frame, and a frame class of the last frame received before the current lost frame; determining a global gain gradient of the current lost frame according to the recovery information; determining a global gain of the current lost frame according to the global gain gradient of the current lost frame and a global gain of each of M frames prior to the current lost frame, wherein M is a positive integer; determining a subframe gain of the current lost frame; and adjusting the synthesized high frequency band signal of the current lost frame according to the global gain of the current lost frame and the subframe gain of the current lost frame to obtain a high frequency band signal of the current lost frame. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for recovering a lost frame of a media bitstream, wherein the bitstream is being decoded by an audio signal decoder, comprising:
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obtaining a synthesized high frequency band signal of a current lost frame; obtaining recovery information related to the current lost frame, wherein the recovery information comprises a coding mode of a last frame received before the current lost frame, and a frame class of the last frame received before the current lost frame; determining a subframe gain gradient of the current lost frame according to the recovery information; determining a subframe gain of the current lost frame according to the subframe gain gradient of the current lost frame and a subframe gain of each of N frames prior to the current lost frame, wherein N is a positive integer; determining a global gain of the current lost frame; and adjusting the synthesized high frequency band signal of the current lost frame according to the subframe gain of the current lost frame and the global gain of the current lost frame to obtain a high frequency band signal of the current lost frame. - View Dependent Claims (10, 11)
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12. A decoder for decoding a media bitstream, comprising a processor and a memory storing program codes, wherein the program codes, when executed by the processor, cause the decoder to perform a process to recover a lost frame of a media bitstream, wherein the process comprises:
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obtaining a synthesized high frequency band signal of a current lost frame; obtaining recovery information related to the current lost frame, wherein the recovery information comprises a coding mode of a last frame received before the current lost frame, and a frame class of the last frame received before the current lost frame; determining a global gain gradient of the current lost frame according to the recovery information; determining a global gain of the current lost frame according to the global gain gradient of the current lost frame and a global gain of each of M frames prior to the current lost frame, wherein M is a positive integer; determining a subframe gain of the current lost frame; and adjusting the synthesized high frequency band signal of the current lost frame according to the global gain of the current lost frame and the subframe gain of the current lost frame to obtain a high frequency band signal of the current lost frame. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification