Method and apparatus for recovering lost frames

An audio signal decoding apparatus, comprising:

• a processor, and a storage medium storing programming instructions for execution by the processor,
• wherein the programming instructions, when executed by the processor, cause the decoding apparatus to perform a process of recovering lost frames in an audio signal,
• wherein the process comprises:
• receiving and decoding a bit stream to obtain the audio signal, wherein the audio signal is transmitted in consecutive frames, and at least one frame of the audio signal is lost;
• obtaining an initial high-frequency band signal of a current lost frame of the audio signal, wherein the initial high-frequency band signal is obtained according to a global gain, a subframe gain, and an encoding type of a previous frame of the current lost frame;
• calculating a ratio R, wherein the ratio R is a ratio of a high frequency excitation energy of the previous frame to a high frequency excitation energy of the current lost frame, wherein the high frequency excitation energy of the current lost frame is obtained according to a low-frequency band signal energy of the current lost frame;
• obtaining a global gain of the current lost frame according to the ratio R and the global gain of the previous frame;
• obtaining a high-frequency band signal of the current lost frame according to the initial high-frequency band signal of the current lost frame and the global gain of the current lost frame;
• reconstructing the current lost frame according to the high-frequency band signal of the current lost frame;
• and
• outputting the audio signal including the reconstructed current lost frame.