Your cache administrator is webmaster. A particular embodiment of the present invention utilizes a low-complexity design that introduces no added delay and that is particularly well-suited for applications such as Bluetooth® wireless audio devices which have For example, if no packets have been lost in the recent past, PLR would be close to zero (or equal to zero). BER-Based Threshold Biasing Module 202  BER-based threshold biasing module 202 is configured to estimate a rate of audible clicks caused by bit errors and to use this information to bias this contact form
DETAILED DESCRIPTION OF THE INVENTION I. The system of claim 27, wherein the threshold biasing module is configured to estimate the rate at which audible distortions are detected by limiting the estimated rate to a function of II. Responsive to detecting that the decoded audio frame includes the distortion, operations are performed on the decoded audio signal to conceal the distortion.  A system is also described herein.
CVSD memory compensation module 208 attempts to compensate for a mismatch in encoder and decoder state memory after a frame has been corrupted by bit errors.  F. Provisional Patent Application No. 61/051,981, filed May 9, 2008, the entirety of which is incorporated by reference herein. The system of claim 16, wherein the bit error detection module is configured to analyze at least the decoded audio signal to detect whether the decoded audio frame includes the distortion The method of claim 1, further comprising: analyzing non-speech segments of the decoded audio signal to estimate a rate at which audible distortions are detected; determining whether the estimated rate is
Wada, and H. A false detection degrades the speech because a perfectly fine portion of audio is replaced with a concealment waveform. These differences render the prior art techniques mostly ineffective. In one embodiment, pitch estimator 302 comprises a simple, low-complexity pitch estimator based on an average mean difference function (AMDF).
Images(8)Claims(30) 1. Therefore, what is needed is a low complexity bit error concealment algorithm that addresses the challenging requirements and constraints described above. Thus a click is detected and used to update BER only when BER-based threshold biasing module 202 detects an active region of signal 114 that is quickly followed by an inactive In one embodiment, A VMWL is set to 40.  Note that the above algorithm uses the samples in xwp(n) from the frame preceding the current frame.
Cookies help us deliver our services. The computer program product comprises a computer-readable medium having computer program logic recorded thereon for enabling a processing unit to perform bit error concealment. DV packets provide no FEC on a data payload of 10 bytes. For example, matched filtering relies on knowledge of the noise pulse shape which in the prior art is simply an impulse.
Zero crossings tracker 308 is further configured to calculate a running average for the current frame, denoted zc_ave(k), in accordance with:  zc_ave(k)=(1−βzc)·zc+β zc ·zc_ave(k−1) (10)  where k is a value The first means are for enabling the processing unit to decode a portion of an encoded bit stream to generate a decoded audio frame, wherein the decoded audio frame comprises a In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. However, unvoiced regions are not very predictable, and the concealment waveform may not closely match the original speech.
The system of claim 24, further comprising: a re-encoding module configured to perform a state memory update of the audio decoder based on re-encoding of the synthesized audio frame responsive to weblink To understand this, consider a signal with no bit errors. With CVSD, the audio output quality degrades gracefully as the occurrence of random bit errors increases. Since there are no clicks, the signal can only be degraded by false detections.
As shown in FIG. 3, bit error detection module 204 includes a pitch estimator 302, a three-tap pitch prediction analysis and filtering module 304, an LPC analysis and filtering module 306, CVSD Memory Compensation Module 208  BEC system 110 may optionally include CVSD memory compensation module 208. However, in practice, it is not that simple. navigate here Read, highlight, and take notes, across web, tablet, and phone.Go to Google Play Now »High-fidelity Multichannel Audio CodingDai Tracy Yang, Chris Kyriakakis, C.-C.
In order to avoid a scenario where a clean input signal tricks BER to falsely increase, a packet loss rate, denoted PLR, is monitored and BER is limited to be a The bit error indicator indicates whether a click is present in the current frame. If the pitch track classification is “tracking,” then it is more likely that if a segment of speech from the current frame does not match well with the past, it is
The system of claim 25, wherein the re-encoding module is configured to perform the state memory update of the audio decoder based on re-encoding of the synthesized audio frame responsive to The method of claim 1, wherein analyzing at least the decoded audio signal to detect whether the decoded audio frame includes the distortion comprises: determining if a maximum absolute sample value At least the decoded audio signal is analyzed to detect whether the decoded audio frame includes a distortion that will be audible during playback thereof, the distortion being due to bit For example, such bit-errors may prevent proper demodulation of the bit stream or may be detected by a forward error correction (FEC) scheme and the frame or packet discarded.  It
This feature is used to save battery life of the audio device. This is understandable since it would be expected that as the frequency of click-causing bit errors that hit only the user-data portion of the packet increases, the frequency of bit errors Your cache administrator is webmaster. http://performancepccanada.com/bit-error/bit-error-rate-analysis-jamming-ofdm-systems.php The method of claim 3, further comprising: determining the average signal level of the prediction residual for the decoded audio frame by computing an energy level of the prediction residual for
In one embodiment, the short-term predictor order M is 8.  Once the short-term predictor coefficients are computed, LPC analysis and filtering module 306 obtains a short-term residual signal by inverse As noted above, the pitch track classification for the current frame is provided by pitch track classifier 310.  i. Thus, embodiments beyond those shown in the accompanying drawings, such as modified versions of the illustrated embodiments, may nevertheless be encompassed by the present invention.  References in the specification to The BEC method includes two distinct aspects: (1) detection of bit errors capable of introducing an audible artifact in an audio output signal, and (2) concealment of the artifact.
The method of claim 1, wherein analyzing at least the decoded audio signal to detect whether the decoded audio frame includes the distortion comprises: analyzing a pitch history of the decoded This erroneously large step-size can cause a large energy increase in background noise well after the occurrence of the bit-errors.