Speech Bitstream Decoding with Adjacent-Frame Post-Processing
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Solution Overview
Problem
Existing redundancy coding algorithms for VoIP systems suffer from signal instability due to low bit rate encoding, leading to poor quality speech/audio signals, especially during packet loss and delay jitter issues.
Innovation Solution
A speech/audio bitstream decoding method that acquires and post-processes decoding parameters from current and adjacent frames to recover stable speech/audio signals, using a decoder with a parameter acquiring unit, post-processing unit, and recovery unit to handle redundant and normal frames, and FEC recovered frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundancy coding algorithm encodes speech/audio frame information at lower bit rate, then packet loss compensation capability is improved, but signal stability deteriorates
Solution Approach 1:
The patent changes the encoding parameters by using the same bit rate for both current and redundant speech/audio frame information, rather than using lower bit rate for redundancy. This parameter change maintains signal stability while still providing packet loss compensation capability through the redundancy coding mechanism.
Solution Approach 2:
The patent creates a copy of the current speech/audio frame information and transmits it as redundant information at the same bit rate. This copying approach ensures that the redundant information maintains the same quality and stability as the original, avoiding the signal instability caused by low bit rate encoding while still enabling packet loss compensation.
2Reliability
If jitter buffer buffers speech/audio frames to compensate delay jitter, then speech/audio quality is improved, but transmission delay increases
Solution Approach 1:
The patent performs preliminary encoding of redundant speech/audio frame information at the same bit rate as current frame information, before transmission. This preliminary action ensures that high-quality redundant data is ready for immediate use in case of packet loss, improving speech/audio quality without requiring excessive buffering that would increase transmission delay.
Data Source
AI summary
A speech/audio bitstream decoding method includes acquiring a speech/audio decoding parameter of a current speech/audio frame, where the foregoing current speech/audio frame is a redundant decoded frame or a speech/audio frame previous to the foregoing current speech/audio frame is a redundant decoded frame, performing post processing on the acquired speech/audio decoding parameter according to speech/audio parameters of X speech/audio frames, where the foregoing X speech/audio frames include M speech/audio frames previous to the foregoing current speech/audio frame and/or N speech/audio frames next to the foregoing current speech/audio frame, and recovering a speech/audio signal using the post-processed speech/audio decoding parameter of the foregoing current speech/audio frame. The technical solutions of the speech/audio bitstream decoding method help improve quality of an output speech/audio signal.