Error correction overwrite for audio artifact reduction
Audio communication methods, devices, and systems, are provided with error correction overwrite for audio artifact reduction. One illustrative low-latency audio streaming method includes: receiving packets of digital audio data; applying an error correction code decoder to obtain a data stream that includes error-corrected data samples; providing a correction-limited data stream by replacing any of the error-corrected data samples that are outliers; and converting the correction-limited data stream into an audio signal.
1 . A low-latency audio streaming method that comprises:
receiving packets of digital audio data;
applying an error correction code decoder to obtain a data stream that includes error-corrected data samples and error-free data samples;
providing a correction-limited data stream by replacing any of the error-corrected data samples that are outliers while forwarding the error-free data samples and any of the error-corrected data samples that are not outliers; and
converting the correction-limited data stream into an audio signal.
2 . The method of claim 1 , wherein said providing includes:
deriving a threshold from the correction-limited data stream; and
replacing the error-corrected data samples that exceed the threshold.
3 . The method of claim 2 , wherein said deriving includes:
calculating an error between a previous envelope value and a magnitude of a current data sample; and
estimating a current envelope value as a weighted sum based on the error and the previous envelope value.
4 . The method of claim 3 , wherein the weighted sum includes a constant offset.
5 . The method of claim 3 , wherein the weighted sum scales the error by a factor that depends at least in part on the error.
6 . The method of claim 3 , wherein the weighted sum scales the error by a factor that depends at least in part on the previous envelope value.
7 . The method of claim 6 , wherein the factor increases as the previous envelope value decreases.
8 . The method of claim 3 , wherein said estimating includes limiting the weighted sum to a predetermined range.
9 . The method of claim 3 , wherein the threshold is proportional to the previous envelope value.
10 . The method of claim 3 , wherein the error-corrected data samples that exceed the threshold are replaced with a predetermined fraction of the previous envelope value.
11 . A low-latency audio streaming device that comprises:
an error correction code decoder that produces a data stream having error-corrected data samples and error-free data samples;
a correction limiter that provides a correction-limited data stream by replacing any of the error-corrected data samples that are outliers and by forwarding the error-free data samples and any of the error-corrected data samples that are not outliers; and
a decompressor that converts the correction-limited data stream into an audio signal.
12 . The device of claim 11 , wherein the correction limiter includes:
an envelope estimation circuit having:
a difference element to calculate an error between a previous envelope value and a magnitude of a current data sample; and
a summation element to calculate a current envelope value based on the error and the previous envelope value; and
a compare and select (CAS) circuit having:
a comparator that compares the current data sample to a threshold based on the previous envelope value; and
a selector that replaces any of the error-corrected data samples that exceed the threshold.
13 . The device of claim 12 , wherein the current envelope is a weighted sum that includes a constant offset.
14 . The device of claim 12 , wherein the current envelope is a weighted sum that includes the error scaled by a factor that depends at least in part on the error.
15 . The device of claim 12 , wherein the current envelope is a weighted sum that includes the error scaled by a factor that depends at least in part on the previous envelope value.
16 . The device of claim 15 , wherein the factor increases as the previous envelope value decreases.
17 . The device of claim 12 , wherein the selector replaces the error-corrected data samples that exceed the threshold with a predetermined fraction of the previous envelope value.
18 . A wireless system that comprises:
a first hearing aid for a first ear, the first hearing aid including:
a microphone to capture and digitize an input audio signal;
a transmit chain that compresses the digitized audio signal into packets of digital audio data with error correction code protection; and
a first wireless transceiver that operates to transmit the packets of digital audio data; and
a second hearing aid for a second ear, the second hearing aid including:
a second wireless transceiver that operates to receive said packets of digital audio data;
an error correction code decoder that produces a data stream having error-corrected data samples and error-free data samples;
a correction limiter that provides a correction-limited data stream by replacing any of the error-corrected data samples that are outliers and by forwarding the error-free data samples and any of the error-corrected data samples that are not outliers; and
a decompressor that converts the correction-limited data stream into an audio signal.
19 . The system of claim 18 , wherein the correction limiter includes:
an envelope estimation circuit having:
a difference element to calculate an error between a previous envelope value and a magnitude of a current data sample; and
a summation element to calculate a current envelope value based on the error and the previous envelope value; and
a compare and select (CAS) circuit having:
a comparator that compares the current data sample to a threshold based on the previous envelope value; and
a selector that replaces any of the error-corrected data samples that exceed the threshold.
20 . The system of claim 19 , wherein the current envelope is a weighted sum that includes the error scaled by a factor that depends at least in part on the error, and wherein the selector replaces the error-corrected data samples that exceed the threshold with a predetermined fraction of the previous envelope value.