Source: http://www.google.com/patents/US8238562?dq=4168396
Timestamp: 2016-05-28 21:17:34
Document Index: 557698472

Matched Legal Cases: ['application No. 60', 'application No. 60', 'arte 2', 'art 1', 'art 1', 'art 1', 'art 1', 'Application No. 2007']

Patent US8238562 - Diffuse sound shaping for BCC schemes and the like - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsIn one embodiment, C input audio channels are encoded to generate E transmitted audio channel(s), where one or more cue codes are generated for two or more of the C input channels, and the C input channels are downmixed to generate the E transmitted channel(s), where C>E≧1. One or more of the C input...http://www.google.com/patents/US8238562?utm_source=gb-gplus-sharePatent US8238562 - Diffuse sound shaping for BCC schemes and the likeAdvanced Patent SearchPublication numberUS8238562 B2Publication typeGrantApplication numberUS 12/550,519Publication dateAug 7, 2012Filing dateAug 31, 2009Priority dateOct 20, 2004Fee statusPaidAlso published asCA2583146A1, CA2583146C, CN101044794A, CN101044794B, CN101853660A, CN101853660B, DE602005010894D1, EP1803325A1, EP1803325B1, US8204261, US20060085200, US20090319282, WO2006045373A1Publication number12550519, 550519, US 8238562 B2, US 8238562B2, US-B2-8238562, US8238562 B2, US8238562B2InventorsEric Allamanche, Sascha Disch, Christof Faller, Juergen HerreOriginal AssigneeFraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V., Agere Systems Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (104), Non-Patent Citations (52), Referenced by (4), Classifications (9), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetDiffuse sound shaping for BCC schemes and the like
US 8238562 B2Abstract
In one embodiment, C input audio channels are encoded to generate E transmitted audio channel(s), where one or more cue codes are generated for two or more of the C input channels, and the C input channels are downmixed to generate the E transmitted channel(s), where C>E≧1. One or more of the C input channels and the E transmitted channel(s) are analyzed to generate a flag indicating whether or not a decoder of the E transmitted channel(s) should perform envelope shaping during decoding of the E transmitted channel(s). In one implementation, envelope shaping adjusts a temporal envelope of a decoded channel generated by the decoder to substantially match a temporal envelope of a corresponding transmitted channel.
1. A method for encoding C input audio channels to generate E transmitted audio channel(s), the method comprising:
(a) generating one or more cue codes for two or more of the C input channels;
(b) downmixing the C input channels to generate the E transmitted channel(s), where C>E≧1; and
(c) analyzing one or more of the C input channels and the E transmitted channel(s) to generate a flag indicating whether or not a decoder of the E transmitted channel(s) should perform envelope shaping during decoding of the E transmitted channel(s), wherein step (c) comprises performing one or more of transient detection, randomness detection, and tonality detection to generate the flag, wherein:
the transient detection comprises detecting a transient in the one or more of the C input channels and the E transmitted channel(s), such that the flag is generated to indicate that the decoder should perform the envelope shaping if the transient is detected
the randomness detection comprises detecting that temporal envelope of the one or more of the C input channels and the E transmitted channel(s) is fluctuating pseudo-randomly, such that the flag is generated to indicate that the decoder should perform the envelope shaping if pseudo-random fluctuation is detected; and
the tonality detection comprises detecting that tonality of the one or more of the C input channels and the E transmitted channel(s) is higher than a specified threshold, such that the flag is generated to indicate that the decoder should perform the envelope shaping if high tonality is detected.
2. The invention of claim 1, wherein the envelope shaping adjusts a temporal envelope of a decoded channel generated by the decoder to substantially match a temporal envelope of a corresponding transmitted channel.
3. The invention of claim 1, wherein the flag is transmitted to the decoder along with the E transmitted channel(s) and the one or more cue codes.
4. The invention of claim 1, wherein step (c) comprises detecting a transient in the one or more of the C input channels and the E transmitted channel(s), such that the flag indicates that the decoder should perform the envelope shaping if the transient is detected.
5. The invention of claim 4, wherein the transient is detected in a look-ahead manner to enable the decoder to shape before and after the transient in addition to shaping the transient.
6. The invention of claim 4, wherein step (c) comprises detecting the transient by determining that a rate of increase in power of a temporal envelope is greater than a specified threshold.
7. The invention of claim 1, wherein step (c) comprises detecting that temporal envelope of the one or more of the C input channels and the E transmitted channel(s) is fluctuating pseudo-randomly, such that the flag indicates that the decoder should perform the envelope shaping if pseudo-random fluctuation is detected.
8. The invention of claim 1, wherein step (c) comprises detecting that tonality of the one or more of the C input channels and the E transmitted channel(s) is higher than a specified threshold, such that the flag indicates that the decoder should perform the envelope shaping if high tonality is detected.
the envelope shaping adjusts a temporal envelope of a decoded channel generated by the decoder to substantially match a temporal envelope of a corresponding transmitted channel;
the flag is transmitted to the decoder along with the E transmitted channel(s) and the one or more cue codes; and
(c1) detecting a transient in the one or more of the C input channels and the E transmitted channel(s), such that the flag indicates that the decoder should perform the envelope shaping if the transient is detected;
(c2) detecting that temporal envelope of the one or more of the C input channels and the E transmitted channel(s) is fluctuating pseudo-randomly, such that the flag indicates that the decoder should perform the envelope shaping if pseudo-random fluctuation is detected; and
(c3) detecting that tonality of the one or more of the C input channels and the E transmitted channel(s) is higher than a specified threshold, such that the flag indicates that the decoder should perform the envelope shaping if high tonality is detected.
10. Apparatus for encoding C input audio channels to generate E transmitted audio channel(s), the apparatus comprising:
a code estimator apparatus adapted to generate one or more cue codes for two or more of the C input channels; and
a downmixer apparatus adapted to downmix the C input channels to generate the E transmitted channel(s), where C>E≧1, wherein the code estimator apparatus is further adapted to analyze one or more of the C input channels and the E transmitted channel(s) to generate a flag indicating whether or not a decoder of the E transmitted channel(s) should perform envelope shaping during decoding of the E transmitted channel(s), wherein the code estimator apparatus is adapted to perform one or more of transient detection, randomness detection, and tonality detection to generate the flag, wherein:
for the transient detection, the code estimator apparatus detects a transient in the one or more of the C input channels and the E transmitted channel(s), such that the code estimator apparatus generates the flag to indicate that the decoder should perform the envelope shaping if the transient is detected
for the randomness detection, the code estimator apparatus detects that temporal envelope of the one or more of the C input channels and the E transmitted channel(s) is fluctuating pseudo-randomly, such that the code estimator apparatus generates the flag to indicate that the decoder should perform the envelope shaping if pseudo-random fluctuation is detected; and
for the tonality detection, the code estimator apparatus detects that tonality of the one or more of the C input channels and the E transmitted channel(s) is higher than a specified threshold, such that the code estimator apparatus generates the flag to indicate that the decoder should perform the envelope shaping if high tonality is detected.
the system comprises the code estimator apparatus and the downmixer apparatus.
12. The invention of claim 10, wherein the envelope shaping adjusts a temporal envelope of a decoded channel generated by the decoder to substantially match a temporal envelope of a corresponding transmitted channel.
13. The invention of claim 10, wherein the flag is transmitted to the decoder along with the E transmitted channel(s) and the one or more cue codes.
14. The invention of claim 10, wherein the code estimator apparatus is adapted to detect a transient in the one or more of the C input channels and the E transmitted channel(s), such that the flag indicates that the decoder should perform the envelope shaping if the transient is detected.
15. The invention of claim 10, wherein the code estimator is adapted to detect that temporal envelope of the one or more of the C input channels and the E transmitted channel(s) is fluctuating pseudo-randomly, such that the flag indicates that the decoder should perform the envelope shaping if pseudo-random fluctuation is detected.
16. The invention of claim 10, wherein the code estimator is adapted to detect that tonality of the one or more of the C input channels and the E transmitted channel(s) is higher than a specified threshold, such that the flag indicates that the decoder should perform the envelope shaping if high tonality is detected.
the code estimator apparatus is adapted to:
(c1) detect a transient in the one or more of the C input channels and the E transmitted channel(s), such that the flag indicates that the decoder should perform the envelope shaping if the transient is detected;
(c2) detect that temporal envelope of the one or more of the C input channels and the E transmitted channel(s) is fluctuating pseudo-randomly, such that the flag indicates that the decoder should perform the envelope shaping if pseudo-random fluctuation is detected; and
(c3) detect that tonality of the one or more of the C input channels and the E transmitted channel(s) is higher than a specified threshold, such that the flag indicates that the decoder should perform the envelope shaping if high tonality is detected.
18. A non-transitory machine-readable storage medium, having encoded thereon program code, wherein, when the program code is executed by a machine, the machine implements a method for encoding C input audio channels to generate E transmitted audio channel(s), the method comprising:
generating one or more cue codes for two or more of the C input channels;
downmixing the C input channels to generate the E transmitted channel(s), where C>E≧1; and
analyzing one or more of the C input channels and the E transmitted channel(s) to generate a flag indicating whether or not a decoder of the E transmitted channel(s) should perform envelope shaping during decoding of the E transmitted channel(s), wherein step (c) comprises performing one or more of transient detection, randomness detection, and tonality detection to generate the flag, wherein:
This application is a divisional of U.S. application Ser. No. 11/006,492, filed on Dec. 7, 2004 which claims the benefit of the filing date of U.S. provisional application No. 60/620,401, filed on Oct. 20, 2004 the teachings of which are incorporated herein by reference.
U.S. application Ser. No. 09/848,877, filed on May 4, 2001, U.S. application Ser. No. 10/045,458, filed on Nov. 7, 2001, which itself claimed the benefit of the filing date of U.S. provisional application No. 60/311,565, filed on Aug. 10, 2001; U.S. application Ser. No. 10/155,437, filed on May 24, 2002; U.S. application Ser. No. 10/246,570, filed on Sep. 18, 2002; U.S. application Ser. No. 10/815,591, filed on Apr. 1, 2004; U.S. application Ser. No. 10/936,464, filed on Sep. 8, 2004; U.S. application Ser. No. 10/762,100, filed on Jan. 20, 2004 (Faller 13-1); and U.S. application Ser. No. 10/006,482, filed on the same date as this application as The subject matter of this application is also related to subject matter described in the following papers, the teachings of all of which are incorporated herein by reference:
According to one embodiment, the present invention is a method and apparatus for encoding C input audio channels to generate E transmitted audio channel(s). One or more cue codes are generated for two or more of the C input channels. The C input channels are downmixed to generate the E transmitted channel(s), where C>E≧1. One or more of the C input channels and the E transmitted channel(s) are analyzed to generate a flag indicating whether or not a decoder of the E transmitted channel(s) should perform envelope shaping during decoding of the E transmitted channel(s).
FIG. 2 is a block diagram of a generic binaural due coding (BCC) audio processing system;
FIG. 10 shows a block diagram representing at least a portion of a BCC decoder, according to one embodiment of the present invention;
FIG. 11 illustrates an exemplary application of the envelope shaping scheme of FIG. 10 in the context of the BCC synthesizer of FIG. 4;
FIG. 12 illustrates an alternative exemplary application of the envelope shaping scheme of FIG. 10 in the context of the BCC synthesizer of FIG. 4, where envelope shaping is applied to in the time domain;
FIGS. 13( a) and (b) show possible implementations of the TPA and the TP of FIG. 12, where envelope shaping is applied only at frequencies higher than the cut-off frequency fTP;
FIG. 14 illustrates an exemplary application of the envelope shaping scheme of FIG. 10 in the context of the late reverberation-based ICC synthesis scheme described in U.S. application Ser. No. 10/815,591, filed on Apr. 1, 2004;
FIG. 15 shows a block diagram representing at least a portion of a BCC decoder, according to an embodiment of the present invention that is an alternative to the scheme shown in FIG. 10;
FIG. 16 shows a block diagram representing at least a portion of a BCC decoder, according to an embodiment of the present invention that is an alternative to the schemes shown in FIGS. 10 and 15;
FIG. 17 illustrates an exemplary application of the envelope shaping scheme of FIG. 15 in the context of the BCC synthesizer of FIG. 4; and
FIGS. 18( a)-(c) show block diagrams of possible implementations of the TPA, ITP, and TP of FIG. 17.
FIG. 2 is a block diagram of a generic binaural cue coding (BCC) audio processing system 200 comprising an encoder 202 and a decoder 204. Encoder, 202 includes downmixer 206 and BCC estimator 208.
Not only the low bitrate of BCC coding, but also its backwards compatibility aspect is of interest. A single transmitted sum signal corresponds to a mono downmix of the original stereo or multi-channel signal. For receivers that do not support stereo or multichannel sound reproduction, listening to the transmitted sum signal is a valid method of presenting the audio material on low-profile mono reproduction equipment. BCC coding can therefore also be used to enhance existing services involving the delivery of mono audio material towards multi-channel audio. For example, existing mono audio radio broadcasting systems can be enhanced for stereo or multi-channel playback if the BCC side information can be embedded into the existing transmission channel. Analogous capabilities exist when downmixing multi-channel audio to two sum signals that correspond to stereo audio.
Each filter bank 302 converts each frame (e.g., 20 msec) of a corresponding digital input channel xi(n) in the time domain into a set of input coefficients {tilde over (x)}i(k) in the frequency domain. Downmixing block 304 downmixes each sub-band of C corresponding input coefficients into a corresponding sub-band of E downmixed frequency-domain coefficients. Equation (1) represents the downmixing of the kth sub-band of input coefficients ({tilde over (x)}1(k),{tilde over (x)}2(k), . . . ,{tilde over (x)}C(k)) to generate the kth sub-band of downmixed coefficients (ŷ1(k), ŷ2(k), . . . ,ŷE(k)) as follows:
Optional scaling/delay block 306 comprises a se of multipliers 310, each of which multiplies a corresponding downmixed coefficient ŷi(k) by a scaling factor ei(k) to generate a corresponding scaled coefficient {tilde over (y)}i(k). The motivation for the scaling operation is equivalent to equalization generalized for downmixing with arbitrary weighting factors for each channel. If the input channels are independent, then the power p{tilde over (y)} i (k) of the downmixed signal in each sub-band is given by Equation (2) as follows:
e ( k ) = ∑ c = 1 C p x ~ c ( k ) p x ~ ( k ) , ( 5 ) where p{tilde over (x)} i (k) is a short-time estimate of the power of {tilde over (x)}c(k) at time index k, and p{tilde over (x)}(k) is a short-time estimate of the power of Σc=1 C{tilde over (x)}c(k). The equalized subbands are transformed back to the time domain resulting in the sum signal y(n) that is transmitted to the BCC decoder.
FIG. 4 shows a block diagram of a BCC synthesizer 400 that can be used for decoder 204 of FIG. 2 according to certain implementations of BCC system 200. BCC synthesizer 400 has a filter bank 402 for each transmitted channel yi(n), an upmixing block 404, Belays 406, multipliers 408, correlation block 410, and an inverse filter bank 412 for each playback channel {circumflex over (x)}i(n).
Each filter bank 402 converts each frame of a corresponding digital, transmitted channel yi(n) in the time domain into a set of input coefficients {tilde over (y)}i(k) in the frequency domain. Upmixing block 404 upmixes each sub-band of E corresponding transmitted channel coefficients into a corresponding sub-band of C upmixed frequency-domain coefficients. Equation (4) represents the upmixing of the kth sub-band of transmitted-channel coefficients ({tilde over (y)}1(k), {tilde over (y)}2(k), . . . , {tilde over (y)}E(k)) to generate the kth sub-band of upmixed coefficients ({tilde over (s)}1(k), {tilde over (s)}2(k), . . . , {tilde over (s)}C(k)) as follows:
[ s ~ 1 ( k ) s ~ 2 ( k ) ⋮ s ~ C ( k ) ] = U CE [ y ~ 1 ( k ) y ~ 2 ( k ) ⋮ y ~ E ( k ) ] , ( 6 ) where UEC is a real-valued E-by-C upmixing matrix. Performing upmixing in the frequency-domain enables upmixing to be applied individually in each different sub-band.
Each delay 406 applies a delay value di(k) based on a corresponding BCC code for ICTD data to ensure that the desired ICTD values appear between certain pairs of playback channels. Each multiplier 408 applies a scaling factor ai(k) based on a corresponding BCC code for ICLD data to ensure that the desired ICLD values appear between certain pairs of playback channels. Correlation block 410 performs a decorrelation operation A based on corresponding BCC codes for ICC data to ensure that the desired ICC values appear between certain pairs of playback channels. Further description of the operations of correlation block 410 can be found in U.S. patent application Ser. No. 10/155,437, filed on May 24, 2002 as Baumgarte 2-10.
One goal may be to apply relatively few signal codifications for synthesizing ICTD and ICC values. As such, the BCC data might not include ICTD and ICC values for all channel pairs. In that case, BCC synthesizer 400 would synthesize ICTD and ICC values only between certain channel pairs.
ICTD [samples]: τ 12 ( k ) = arg max d { Φ 12 ( d , k ) } , ( 7 ) with a short-time estimate of the normalized cross-correlation function given by Equation (8) as follows:
Φ 12 ( d , k ) = p x ~ 1 x ~ 2 ( d , k ) p x ~ 1 ( k - d 1 ) p x ~ 2 ( k - d 2 ) , where ( 8 ) d 1 = max { - d , 0 } d 2 = max { d , 0 } , ( 9 ) and p{tilde over (x)} 1 {tilde over (x)} 2 (d, k) is a short-time estimate of the mean of {tilde over (x)}1(k−d1){tilde over (x)}2(K−d2).
ICLD [dB]: Δ
Note that the absolute value of the normalized ross-correlation is considered and c12(k) has a range of [0,1].
When there are more than two input channels, it is typically sufficient to define ICTD and ICLD between a reference channel (e.g., channel number 1) and the other channels, as illustrated in FIG. 6 for the case of C=5 channels where τ1c(k) and ΔL12(k) denote the ICTD and ICLD, respectively, between the reference channel 1 and channel c.
As opposed to ICTD and ICLD, ICC typically as more degrees of freedom. The ICC as defined can have different values between all possible input channel pairs. For C channels, there are C(C−1)/2 possible channel pairs; e.g., for 5 channels there are 10 channel pairs as illustrated in FIG. 7( a). However, such a scheme requires that, for each subband at each time index, C(C−1)/2 ICC values are estimated and transmitted, resulting in high computational complexity and high bitrate.
Other related and unrelated ICC synthesis techniques for stereo signals (or audio channel pairs) have been presented in E. Schuijers, W. Oomen, B. denBrinker, and J. Breebaart, “Advances in parametric coding for high-quality audio,” in Preprint 114th Conv. Aud. Eng. Soc., March 2003, and J. Engdegard, H. Purnhagen, J. Roden, and L. Liljeryd, “Synthetic ambience in parametric stereo coding,” in Preprint 117th Conv. Aud. Eng. Soc., May 2004, the teachings of both of which are incorporated here by reference.
BCC with one transmission channel provides a backwards compatible path for upgrading existing mono systems for stereo or multi-channel audio playback. The upgraded systems transmit the BCC downmixed sum signal through the existing mono infrastructure, while additionally transmitting the BCC side information. C-to-E BCC is applicable to E-channel backwards compatible coding of C-channel audio. C-to-E BCC introduces scalability in terms of different degrees of reduction of the number of transmitted channels. It is expected that the mote audio channels that are transmitted, the better the audio quality will be.
Diffuse Sound Shaping
In certain implementations, BCC coding involves algorithms for ICTD, ICLD, and ICC synthesis. ICC cues can be synthesized by means of de-correlating the signal components in the corresponding subbands. This can be done by frequency-dependent variation of ICLD, frequency-dependent variation of ICTD and ICLD, all-pass filtering, or with ideas related to reverberation algorithms.
When these techniques are applied to audio signals, the temporal envelope characteristics of the signals are not preserved. Specifically, when applied to transients, the instantaneous signal energy is likely to be spread over a certain period of time. This results in artifacts such as “pre-echoes” or “washed-out transients.”
A generic principle of certain embodiments of the present invention relates to the observation that the sound synthesized by a BCC decoder should not only have spectral characteristics that are similar to that of the original sound, but also resemble the temporal envelope of the original sound quite closely in order to have similar perceptual characteristics. Generally, this is achieved in BCC-like schemes by including a dynamic ICLD synthesis that applies a time-varying scaling operation to approximate each signal channel's temporal envelope. For the case of transient signals (attacks, percussive instruments, etc.), the temporal resolution of this process may, however, not be sufficient to produce synthesized signals that approximate the original temporal envelope closely enough. This section describes a number of approaches to do this with a sufficiently fine time resolution.
Furthermore, for BCC decoders that do not have access to the temporal envelope of the original signals, the idea is to take the temporal envelope of the transmitted “sum signal(s)” as an approximation instead. As such, there is no side information necessary to be transmitted from the BCC encoder to the BCC decoder in order to convey such envelope information. In summary, the invention relies on the following principle:
The transmitted audio channels (i.e., “sum channel(s)”)—or linear combinations of these channels which BCC synthesis may be based on—are analyzed by a temporal envelope extractor for their temporal envelope with a high time resolution (e.g., significantly finer than the BCC block size). The subsequent synthesized sound for each output channel is shaped such that—even after ICC synthesis—it matches the temporal envelope determined by the extractor as closely as possible. This ensures that, even in the case of transient signals, the synthesized output sound is not significantly degraded by the ICC synthesis/signal de-correlation process.
FIG. 10 shows a block diagram representing at least a portion of a BCC decoder 1000, according to one embodiment of the present invention. In FIG. 10, block 1002 represents BCC synthesis processing that includes, at least, ICC synthesis. BCC synthesis block 1002 receives base channels 1001 and generates synthesized channels 1003. In certain implementations, block 1002 represents the processing of blocks 406, 408, and 410 of FIG. 4, where base channels 1001 are the signals generated by upmixing block 404 and synthesized channels 1003 are the signals generated by correlation block 410. FIG. 10 represents the processing implemented for one base channel 1001′ and its corresponding synthesized channel. Similar processing is also applied to each other base channel and its corresponding synthesized channel.
Envelope extractor 1004 determines the fine temporal envelope a of base channel 1001′, and envelope extractor 1006 determines the fine temporal envelope b of synthesized channel 1003′. Inverse envelope adjuster 1008 uses temporal envelope b from envelope extractor 1006 to normalize the envelope (i.e., “flatten” the temporal fine structure) of synthesized channel 1003′ to produce a flattened signal 1005′ having a flat (e.g., uniform) time envelope. Depending on the particular implementation, the flattening can be applied either before or after upmixing. Envelope adjuster 1010 uses temporal envelope a from envelope extractor 1004 to re-impose the original signal envelope on the flattened signal 1005′ to generate output signal 1007′ having a temporal envelope substantially equal to the temporal envelope of base channel 1001.
Depending on the implementation, this temporal envelope processing (also referred to herein as “envelope shaping”) may be applied to the entire synthesized channel (as shown) or only to the orthogonalized part (e.g., late-reverberation part, de-correlated part) of the synthesized channel (as described subsequently). Moreover, depending on the implementation, envelope shaping may be applied either to time-domain signals or in a frequency-dependent fashion (e.g., where the temporal envelope is estimated and imposed individually at different frequencies).
Inverse envelope adjuster 1008 and envelope adjuster 1010 may be implemented in different ways. In one type of implementation, a signal's envelope is manipulated by multiplication of the signal's time-domain samples (or spectral/subband samples) with a time-varying amplitude modification function (e.g., 1/b for inverse envelope adjuster 1008 and a for envelope adjuster 1010l ). Alternatively, a convolution/filtering of the signal's spectral representation over frequency can be used in a manner analogous to that used in the prior art for the purpose of shaping the quantization noise of a low bitrate audio coder. Similarly, the temporal envelope of signals may be extracted either directly by analysis the signal's time structure or by examining the autocorrelation of the signal spectrum over frequency.
FIG. 11 illustrates an exemplary application of the envelope shaping scheme of FIG. 10 in the context of BCC synthesizer 400 of FIG. 4. In this embodiment, there is a single transmitted sum signal s(n), the C base signals are generated by replicating that sum signal, and envelope shaping is individually applied to different subbands. In alternative embodiments, the order of delays, scaling, and other processing may be different. Moreover, in alternative embodiments, envelope shaping is not restricted to processing each subband independently. This is especially true for convolution/filtering-based implementations that exploit covariance over frequency bands to derive information on the signal's temporal fine structure.
In FIG. 11( a), temporal process analyzer (TPA) 1104 is analogous to envelope extractor 1004 of FIG. 10, and each temporal processor (TP) 1106 is analogous to the combination of envelope extractor 1006, inverse envelope adjuster 1008, and envelope adjuster 1010 of FIG. 10.
FIG. 11( b) shows a block diagram of one possible time domain-based implementation of TPA 1104 in which the base signal samples are squared (1110) and then low-pass filtered (1112) to characterize the temporal envelope a of the base signal.
FIG. 11( c) shows a block diagram of one possible time domain-based implementation of TP 1106 in which the synthesized signal samples are squared (1114) and then low-pass filtered (1116) to characterize the temporal envelope b of the synthesized-signal. A scale factor (e.g., sqrt (a/b)) is generated (1118) and then applied (1120) to the synthesized signal to generate an output signal having a temporal envelope substantially equal to that of the original base channel.
In alternative implementations of TPA 1104 and TP 1106, the temporal envelopes are characterized using magnitude operations rather than by squaring the signal samples. In such implementations, the ratio a/b may be used as the scale factor without having to apply the square root operation.
Although the scaling operation of FIG. 11( c) corresponds to a time domain-based implementation of TP processing, TP processing (as well as TPA and inverse TP (ITP) processing) can also be implemented using frequency-domain signals, as in the embodiment of FIGS. 17-18 (described below). As such, for purposes of this specification, the term “scaling function” should be interpreted to cover either time-domain or frequency-domain operations, such as the filtering operations of FIGS. 18( b) and (c).
In general, TPA 1104 and TP 1106 are preferably designed such that they do not modify signal power (i.e., energy). Depending on the particular implementation, this signal power may be a short-time average signal power in each channel, e.g., based on the total signal power per channel in the time period defined by the synthesis window or some other suitable measure of power. As such, scaling for ICLD synthesis (e.g., using multipliers 408) can be applied before or after envelope shaping.
Note that in FIG. 11( a), for each channel, there are two outputs, where TP processing is applied to only one of them. This reflects an ICC synthesis scheme that mixes two signal components: unmodified and orthogonalized signals, where the ratio of unmodified and orthogonalized signal components determines the ICC. In the embodiment shown in FIG. 11( a), TP is applied to only the orthogonalized signal component, where summation nodes 1108 recombine the unmodified signal components with the corresponding temporally shaped, orthogonalized signal components.
FIG. 12 illustrates an alternative exemplary application of the envelope shaping scheme of FIG. 10 in the context of BCC synthesizer 400 of FIG. 4, where envelope shaping is applied to in the time domain. Such an embodiment may be warranted when the time resolution of the spectral representation in which ICTD, ICLD, and ICC synthesis is carried out is not high enough for effectively preventing “pre-echoes” by imposing the desired temporal envelope. For example, this may be the case when BCC is implemented with a short-time Fourier transform (STFT).
As shown in FIG. 12( a), TPA 1204 and each TP 1206 are implemented in the time domain, where the full-band signal is scaled such that it has the desired temporal envelope (e.g., the envelope as estimated from the transmitted sum signal). FIGS. 12( b) and (c) shows possible implementations of TPA 1204 and TP 1206 that are analogous to those shown in FIGS. 11( b) and (c).
In this embodiment, TP processing is applied to the output signal, not only to the orthogonalized signal components. In alternative embodiments, time domain-based TP processing can be applied just to the orthogonalized signal components if so desired, in which case unmodified and orthogonalized subbands would be converted to the time domain with separate inverse filterbanks.
Since full-band scaling of the BCC output signals may result in artifacts, envelope shaping might be applied only at specified frequencies, for example, frequencies larger than a certain cut-off frequency fTP (e.g., 500 Hz). Note that the frequency range for analysis (TPA) may differ from the frequency range for synthesis (TP).
FIGS. 13( a) and (b) show possible implementations of TPA 1204 and TP 1206 where envelope shaping is applied only at frequencies higher than the cut-off frequency fTP. In particular, FIG. 13( a) shows the addition of high-pass filter 1302, which filters out frequencies lower than fTP prior to temporal envelope characterization. FIG. 13( b) shows the addition of two-band filterbank 1304 having with a cut-off frequency of fTP between the two subbands, where only the high-frequency part is temporally shaped. Two-band inverse filterbank 1306 then recombines the low-frequency part with the temporally shaped, high-frequency part to generate the output signal.
FIG. 14 illustrates an exemplary application of the envelope shaping scheme of FIG. 10 in the context of the late reverberation-based ICC synthesis scheme described in U.S. application Ser. No. 10/815,591, filed on Mar. 1, 2004. In this embodiment, TPA 1404 and each TP 1406 are applied in the time domain, as in FIG. 12 or FIG. 13, but where each TP 1406 is applied to the output from a different late reverberation (LR) block 1402.
FIG. 15 shows a block diagram representing at least a portion of a BCC decoder 1500, according to an embodiment of the present invention that is an alternative to the scheme shown in FIG. 10 In FIG. 15, BCC synthesis block 1502, envelope extractor 1504, and envelope adjuster 1510 are analogous to BCC synthesis block 1002, envelope extractor 1004, and envelope adjuster 1010 of FIG. 10. In FIG. 15, however, inverse envelope adjuster 1508 is applied prior to BCC synthesis, rather than after BCC synthesis, as in FIG. 10. In this way, inverse envelope adjuster 1508 flattens the base channel before BCC synthesis is applied.
FIG. 16 shows a block diagram representing at least a portion of a BCC decoder 1600, according to an embodiment of the present invention that is an alternative to the schemes shown in FIGS. 10 and 15. In FIG. 16, envelope extractor 1604 and envelope adjuster 1610 are analogous to envelope extractor 1504 and envelope adjuster 1510 of FIG. 15. In the embodiment of FIG. 15, however, synthesis block 1602 represents late reverberation-based ICC synthesis similar to that shown in FIG. 16. In this case, envelope shaping is applied only to the uncorrelated late-reverberation signal, and summation node 1612 adds the temporally shaped, late-reverberation signal to the original base channel (which already has the desired temporal envelope). Note that, in this case, an inverse envelope adjuster does not need to be applied, because the late-reverberation signal has an approximately flat temporal envelope due to its generation process in block 1602.
FIG. 17 illustrates an exemplary application of the envelope shaping scheme of FIG. 15 in the context of BCC synthesizer 400 of FIG. 4. In FIG. 17, TPA 1704, inverse TP (ITP) 1708, and TP 1710 are analogous to envelope extractor 1504, inverse envelope adjuster 1508, and envelope adjuster 1510 of FIG. 15.
In this frequency-based embodiment, envelope shaping of diffuse sound is implemented by applying a convolution to the frequency bins of (e.g., STFT) filterbank 402 along the frequency axis. Reference is made to U.S. Pat. No. 5,781,888 (Herre) and U.S. Pat. No. 5,812,971 (Herre), the teachings of which are incorporated herein by reference, for subject matter related to this technique.
FIG. 18( a) shows a block diagram of one possible implementation of TPA 1704 of FIG. 17. In this implementation, TPA 1704 is implemented as a linear predictive coding (LPC) analysis operation that determines the optimum prediction coefficients for the series of spectral coefficients over frequency. Such LPC analysis techniques are well-known e.g., from speech coding and many algorithms for efficient calculation of LPC coefficients are known, such as the autocorrelation method (involving the calculation of the signal's autocorrelation function and a subsequent Levinson-Durbin recursion). As a result of this computation, a set of LPC coefficients are available at the output that represent the signal's temporal envelope.
FIGS. 18( b) and (c) show block diagrams of possible implementations of ITP 1708 and TP 1710 of FIG. 17. In both implementations, the spectral coefficients of the signal to be processed are processed in order of (increasing or decreasing) frequency, which is symbolized here by rotating switch circuitry, converting these coefficients into a serial order for processing by a predictive filtering process (and back again after this processing). In the case of ITP 1708, the predictive filtering calculates the prediction residual and in this way “flattens” the temporal signal envelope. In the case of TP 1710, the inverse filter re-introduces the temporal envelope represented by the LPC coefficients from TPA 1704.
For the calculation of the signal's temporal envelope by TPA 1704, it is important to eliminate the influence of the analysis window of filterbank 402, if such a window is used. This can be achieved by either normalizing the resulting envelope by the (known) analysis window shape or by using a separate analysis filterbank which does not employ an analysis window.
The convolution/filtering-based technique of FIG. 17 can also be applied in the context of the envelope shaping scheme of FIG. 16, where envelope extractor 1604 and envelope adjuster 1610 are based on the TPA of FIG. 18( a) and the TP of FIG. 18( c), respectively.
BCC decoders can be designed to selectively enable/disable envelope shaping. For example, a BCC decoder could apply a conventional BCC synthesis scheme and enable the envelope shaping when the temporal envelope of the synthesized signal fluctuates sufficiently such that the benefits of envelope shaping dominate over any artifacts that envelope shaping may generate. This enabling/disabling control can be achieved by:
(1) Transient detection: If a transient is detected, then TP processing is enabled. Transient detection can be implemented in a look-ahead manner to effectively shape not only the transient but also the signal shortly before and after the transient. Possible ways of detecting transients include:
Observing the temporal envelope of the transmitted BCC sum signal(s) to determine when there is a sudden increase in power indicating the occurrence of a transient; and Examining the gain of the predictive (LPC) filter. If the LPC prediction gain exceeds a specified threshold, it can be assumed that the signal is transient or highly fluctuating. The LPC analysis is computed on the spectrums autocorrelation. (2) Randomness detection: There are scenarios when the temporal envelope is fluctuating pseudo-randomly. In such a scenario, no transient might be detected but TP processing could still be applied (e.g., a dense applause signal corresponds to such a scenario). Additionally, in certain implementations, in order to prevent possible artifacts in tonal signals, TP processing is not applied when the tonality of the transmitted sum signal(s) is high.
Furthermore, similar measures can be used in the BCC encoder to detect when TP processing should be active. Since the encoder has access to all original input signals, it may employ more sophisticated algorithms (e.g., a part of estimation block 208) to make a decision of when TP processing should be enabled. The result of this decision (a flag signaling when TP should be active) can be transmitted to the BCC decoder (e.g., as part of the side information of FIG. 2).
The present invention can be embodied in the form of methods and apparatuses for practicing those methods. The present invention can also be embodied in the form of program code embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other machine-readable storage medium, wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the intention. The present invention can also be embodied in the form of program code, for example, whether stored in a storage medium, loaded into and/or executed by a machine, or transmitted over some transmission medium or carrier, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. When implemented on a general-purpose processor, the program code segments combine with the processor to provide a unique device that operates analogously to specific logic circuits.
It will be further understood that various chants in the details, materials, and arrangements of the parts which have been described and illustrated in order to explain the nature of this invention may be made by those skilled in the art without departing from the scope of the invention as expressed in the following claims.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS4236039Jul 19, 1976Nov 25, 1980National Research Development CorporationSignal matrixing for directional reproduction of soundUS4815132Aug 29, 1986Mar 21, 1989Kabushiki Kaisha ToshibaStereophonic voice signal transmission systemUS4972484Nov 20, 1987Nov 20, 1990Bayerische Rundfunkwerbung GmbhMethod of transmitting or storing masked sub-band coded audio signalsUS5371799Jun 1, 1993Dec 6, 1994Qsound Labs, Inc.Stereo headphone sound source localization systemUS5463424Aug 3, 1993Oct 31, 1995Dolby Laboratories Licensing CorporationMulti-channel transmitter/receiver system providing matrix-decoding compatible signalsUS5579430Jan 26, 1995Nov 26, 1996Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.Digital encoding processUS5583962Jan 8, 1992Dec 10, 1996Dolby Laboratories Licensing CorporationEncoder/decoder for multidimensional sound fieldsUS5677994Apr 11, 1995Oct 14, 1997Sony CorporationHigh-efficiency encoding method and apparatus and high-efficiency decoding method and apparatusUS5682461Mar 17, 1993Oct 28, 1997Institut Fuer Rundfunktechnik GmbhMethod of transmitting or storing digitalized, multi-channel audio signalsUS5701346Feb 2, 1995Dec 23, 1997Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V.Method of coding a plurality of audio signalsUS5703999Nov 18, 1996Dec 30, 1997Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.Process for reducing data in the transmission and/or storage of digital signals from several interdependent channelsUS5706309Nov 2, 1993Jan 6, 1998Fraunhofer Geselleschaft Zur Forderung Der Angewandten Forschung E.V.Process for transmitting and/or storing digital signals of multiple channelsUS5771295Dec 18, 1996Jun 23, 1998Rocktron Corporation5-2-5 matrix systemUS5812971Mar 22, 1996Sep 22, 1998Lucent Technologies Inc.Enhanced joint stereo coding method using temporal envelope shapingUS5825776Feb 27, 1996Oct 20, 1998Ericsson Inc.Circuitry and method for transmitting voice and data signals upon a wireless communication channelUS5860060May 2, 1997Jan 12, 1999Texas Instruments IncorporatedMethod for left/right channel self-alignmentUS5878080Feb 7, 1997Mar 2, 1999U.S. Philips CorporationN-channel transmission, compatible with 2-channel transmission and 1-channel transmissionUS5889843Mar 4, 1996Mar 30, 1999Interval Research CorporationMethods and systems for creating a spatial auditory environment in an audio conference systemUS5890125Jul 16, 1997Mar 30, 1999Dolby Laboratories Licensing CorporationMethod and apparatus for encoding and decoding multiple audio channels at low bit rates using adaptive selection of encoding methodUS5912976Nov 7, 1996Jun 15, 1999Srs Labs, Inc.Multi-channel audio enhancement system for use in recording and playback and methods for providing sameUS5930733Mar 25, 1997Jul 27, 1999Samsung Electronics Co., Ltd.Stereophonic image enhancement devices and methods using lookup tablesUS5946352May 2, 1997Aug 31, 1999Texas Instruments IncorporatedMethod and apparatus for downmixing decoded data streams in the frequency domain prior to conversion to the time domainUS5956674May 2, 1996Sep 21, 1999Digital Theater Systems, Inc.Multi-channel predictive subband audio coder using psychoacoustic adaptive bit allocation in frequency, time and over the multiple channelsUS6016473Apr 7, 1998Jan 18, 2000Dolby; Ray M.Low bit-rate spatial coding method and systemUS6021386Mar 9, 1999Feb 1, 2000Dolby Laboratories Licensing CorporationCoding method and apparatus for multiple channels of audio information representing three-dimensional sound fieldsUS6021389Mar 20, 1998Feb 1, 2000Scientific Learning Corp.Method and apparatus that exaggerates differences between sounds to train listener to recognize and identify similar soundsUS6108584Jul 9, 1997Aug 22, 2000Sony CorporationMultichannel digital audio decoding method and apparatusUS6111958Mar 21, 1997Aug 29, 2000Euphonics, IncorporatedAudio spatial enhancement apparatus and methodsUS6131084Mar 14, 1997Oct 10, 2000Digital Voice Systems, Inc.Dual subframe quantization of spectral magnitudesUS6205430Sep 26, 1997Mar 20, 2001Stmicroelectronics Asia Pacific Pte LimitedAudio decoder with an adaptive frequency domain downmixerUS6236731Apr 16, 1998May 22, 2001Dspfactory Ltd.Filterbank structure and method for filtering and separating an information signal into different bands, particularly for audio signal in hearing aidsUS6282631Dec 23, 1998Aug 28, 2001National Semiconductor CorporationProgrammable RISC-DSP architectureUS6356870Sep 26, 1997Mar 12, 2002Stmicroelectronics Asia Pacific Pte LimitedMethod and apparatus for decoding multi-channel audio dataUS6408327Dec 22, 1998Jun 18, 2002Nortel Networks LimitedSynthetic stereo conferencing over LAN/WANUS6424939Mar 13, 1998Jul 23, 2002Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V.Method for coding an audio signalUS6434191Sep 1, 2000Aug 13, 2002Telcordia Technologies, Inc.Adaptive layered coding for voice over wireless IP applicationsUS6539357Dec 3, 1999Mar 25, 2003Agere Systems Inc.Technique for parametric coding of a signal containing informationUS6611212Apr 7, 2000Aug 26, 2003Dolby Laboratories Licensing Corp.Matrix improvements to lossless encoding and decodingUS6614936Dec 3, 1999Sep 2, 2003Microsoft CorporationSystem and method for robust video coding using progressive fine-granularity scalable (PFGS) codingUS6658117Nov 9, 1999Dec 2, 2003Yamaha CorporationSound field effect control apparatus and methodUS6763115Jul 26, 1999Jul 13, 2004Openheart Ltd.Processing method for localization of acoustic image for audio signals for the left and right earsUS6782366May 15, 2000Aug 24, 2004Lsi Logic CorporationMethod for independent dynamic range controlUS6823018Feb 23, 2000Nov 23, 2004At&T Corp.Multiple description coding communication systemUS6845163Nov 15, 2000Jan 18, 2005At&T CorpMicrophone array for preserving soundfield perceptual cuesUS6850496Jun 9, 2000Feb 1, 2005Cisco Technology, Inc.Virtual conference room for voice conferencingUS6885992Jan 26, 2001Apr 26, 2005Cirrus Logic, Inc.Efficient PCM bufferUS6934676May 11, 2001Aug 23, 2005Nokia Mobile Phones Ltd.Method and system for inter-channel signal redundancy removal in perceptual audio codingUS6940540Jun 27, 2002Sep 6, 2005Microsoft CorporationSpeaker detection and tracking using audiovisual dataUS6973184Jul 11, 2000Dec 6, 2005Cisco Technology, Inc.System and method for stereo conferencing over low-bandwidth linksUS6987856Nov 16, 1998Jan 17, 2006Board Of Trustees Of The University Of IllinoisBinaural signal processing techniquesUS7116787May 4, 2001Oct 3, 2006Agere Systems Inc.Perceptual synthesis of auditory scenesUS7181019Feb 9, 2004Feb 20, 2007Koninklijke Philips Electronics N. V.Audio codingUS7343291Jul 18, 2003Mar 11, 2008Microsoft CorporationMulti-pass variable bitrate media encodingUS7382886Jul 10, 2002Jun 3, 2008Coding Technologies AbEfficient and scalable parametric stereo coding for low bitrate audio coding applicationsUS7516066Jul 11, 2003Apr 7, 2009Koninklijke Philips Electronics N.V.Audio codingUS7644003Sep 8, 2004Jan 5, 2010Agere Systems Inc.Cue-based audio coding/decodingUS7941320Aug 27, 2009May 10, 2011Agere Systems, Inc.Cue-based audio coding/decodingUS20010031054Dec 7, 2000Oct 18, 2001Anthony GrimaniAutomatic life audio signal derivation systemUS20010031055Dec 20, 2000Oct 18, 2001Aarts Ronaldus MariaMultichannel audio signal processing deviceUS20020055796Aug 24, 2001May 9, 2002Takashi KatayamaSignal processing apparatus, signal processing method, program and recording mediumUS20030007648Apr 29, 2002Jan 9, 2003Christopher CurrellVirtual audio system and techniquesUS20030035553Nov 7, 2001Feb 20, 2003Frank BaumgarteBackwards-compatible perceptual coding of spatial cuesUS20030044034Aug 27, 2002Mar 6, 2003The Regents Of The University Of CaliforniaCochlear implants and apparatus/methods for improving audio signals by use of frequency-amplitude-modulation-encoding (FAME) strategiesUS20030081115Feb 8, 1996May 1, 2003James E. CurrySpatial sound conference system and apparatusUS20030161479May 30, 2001Aug 28, 2003Sony CorporationAudio post processing in DVD, DTV and other audio visual productsUS20030187663Mar 28, 2002Oct 2, 2003Truman Michael MeadBroadband frequency translation for high frequency regenerationUS20030219130May 24, 2002Nov 27, 2003Frank BaumgarteCoherence-based audio coding and synthesisUS20030236583Sep 18, 2002Dec 25, 2003Frank BaumgarteHybrid multi-channel/cue coding/decoding of audio signalsUS20040091118Oct 17, 2003May 13, 2004Harman International Industries, Incorporated5-2-5 Matrix encoder and decoder systemUS20050053242Jul 10, 2002Mar 10, 2005Fredrik HennEfficient and scalable parametric stereo coding for low bitrate applicationsUS20050069143Sep 30, 2003Mar 31, 2005Budnikov Dmitry N.Filtering for spatial audio renderingUS20050157883Jan 20, 2004Jul 21, 2005Jurgen HerreApparatus and method for constructing a multi-channel output signal or for generating a downmix signalUS20050226426Apr 22, 2003Oct 13, 2005Koninklijke Philips Electronics N.V.Parametric multi-channel audio representationUS20060206323Jun 19, 2003Sep 14, 2006Koninklijke Philips Electronics N.V.Audio codingUS20070094012Sep 29, 2006Apr 26, 2007Pang Hee SRemoving time delays in signal pathsCA2326495A1Nov 22, 2000Jun 3, 2001Lucent Technologies IncTechnique for parametric coding of a signal containing informationCN1295778AApr 5, 1999May 16, 2001雷�M�杜比Low bit-rate spatial coding method and systemEP1107232A2Nov 27, 2000Jun 13, 2001Lucent Technologies Inc.Joint stereo coding of audio signalsEP1376538A1Jun 24, 2003Jan 2, 2004Agere Systems Inc.Hybrid multi-channel/cue coding/decoding of audio signalsEP1479071B1Jan 17, 2003Jan 11, 2006Philips Electronics N.V.Parametric audio codingJP2000151413A Title not availableJP2001339311A Title not availableJP2003044096A Title not availableJP2004535145A Title not availableJPH1051313A Title not availableJPH07123008A Title not availableRU2214048C2 Title not availableTW347623B Title not availableTW360859B Title not availableTW444511B Title not availableTW510144B Title not availableTW517223B Title not availableTW521261B Title not availableWO2003007656A1Jul 10, 2002Jan 23, 2003Coding Technologies AbEfficient and scalable parametric stereo coding for low bitrate applicationsWO2003090207A1Apr 22, 2003Oct 30, 2003Koninklijke Philips Electronics N.V.Parametric multi-channel audio representationWO2003090208A1Apr 22, 2003Oct 30, 2003Koninklijke Philips Electronics N.V.pARAMETRIC REPRESENTATION OF SPATIAL AUDIOWO2003094369A2May 2, 2003Nov 13, 2003Harman International Industries, IncorporatedMulti-channel downmixing deviceWO2004008806A1Jul 1, 2003Jan 22, 2004Koninklijke Philips Electronics N.V.Audio codingWO2004049309A1Oct 31, 2003Jun 10, 2004Koninklijke Philips Electronics N.V.Coding an audio signalWO2004072956A1Feb 9, 2004Aug 26, 2004Koninklijke Philips Electronics N.V.Audio codingWO2004077884A1Feb 25, 2004Sep 10, 2004Helsinki University Of TechnologyA method for reproducing natural or modified spatial impression in multichannel listeningWO2004086817A2Mar 18, 2004Oct 7, 2004Koninklijke Philips Electronics N.V.Coding of main and side signal representing a multichannel signalWO2005069274A1Jan 17, 2005Jul 28, 2005Fraunhofer-Gesellschaft zur F�rderung der angewandten Forschung e.V.Apparatus and method for constructing a multi-channel output signal or for generating a downmix signalWO2006072270A1Sep 30, 2005Jul 13, 2006Fraunhofer-Gesellschaft zur F�rderung der angewandten Forschung e.V.Compact side information for parametric coding of spatial audioNon-Patent CitationsReference1"3D Audio and Acoustic Environment Modeling" by William G. Gardner, HeadWize Technical Paper, Jan. 2001, pp. 1-11.2"A Speech Corpus for Multitalker Communications Research", by Robert S. Bolia, et al., J. Acoust. Soc., Am., vol. 107, No. 2, Feb. 2000, pp. 1065-1066.3"Advances in Parametric Audio Coding" by Heiko Purnhagen Proc. 1999 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics, New Paltz, New York, Oct. 17-20, 1999, pp. W99-1-W99-4.4"Advances in Parametric Coding for High-Quality Audio", by Erik Schuijers et al., Audio Engineerying Society Convention Paper 5852, 114th Convention, Amsterdam, The Netherlands, Mar. 22-25, 2003, pp. 1-11.5"Advances in Parametric Coding for High-Quality Audio," by E.G.P. Schuijers et al., Proc. 1st IEEE Benelux Workshop on Model Based Processing and Coding of Audio (MPCA-2002), Leuven, Belgium, Nov. 15, 2002, pp. 73-79, XP001156065.6"Binaural Cue Coding Applied to Stereo and Multi-Channel Audio Compression", by Christof Faller et al., Audio Engineering Society Convention Paper, 112th Convention, Munich, Germany, May 10-13, 2002, pp. 1-9.7"Binaural Cue Coding: Rendering of Sources Mixed into a Mono Signal" by Christof Faller, Media Signal Processing Research, Agere Systems, Allentown, PA, USA, 2 pages.8"Binaural Cue Coding; Rendering of Sources Mixed into a Mono Signal" by Christof Faller, Media Signal Processing Research, in Proc. DAGA 2003, Aachen, Germany, Mar. 2003 (invited), 2 pages.9"Binaural Cue Coding-Part I: Psychoacoustic Fundamentals and Design Principles", by Frank Baumgrate et al., IEEE Transactions on Speech and Audio Processing, vol. II, No. 6, Nov. 2003, pp. 509-519.10"Binaural Cue Coding—Part I: Psychoacoustic Fundamentals and Design Principles", by Frank Baumgrate et al., IEEE Transactions on Speech and Audio Processing, vol. II, No. 6, Nov. 2003, pp. 509-519.11"Binaural Cue Coding-Part II: Schemes and Applications", by Christof Faller et al., IEEE Transactions on Speech and Audio Processing, vol. II, No. 6, Nov. 2003, pp. 520-531.12"Binaural Cue Coding—Part II: Schemes and Applications", by Christof Faller et al., IEEE Transactions on Speech and Audio Processing, vol. II, No. 6, Nov. 2003, pp. 520-531.13"Coding of Spatial Audio Compatible With Different Playback Formats", by Christof Faller, Audio Engineering Society 117th Convention, San Francisco, CA, Oct. 28-31, 2004, pp. 1-12.14"Colorless Artificial Reverberation", by M. R. Schroeder et al., IRE Transactions on Audio, pp. 209-214, (Originally Published by: J. Audio Engrg. Soc., vol. 9, pp. 192-197, Jul. 1961).15"Efficient Representation of Spatial Audio Using Perceptual Parametrization", by Christof Faller etl al., IEEE Workshop on Applications of Signal Processing to Audio and Acoustics 2001, Oct. 21-24, 2001, New Paltz, New York, pp. W2001-01 to W2001-4.16"Final text for DIS 11172-1 (rev. 2): Information Technology-Coding of Moving Pictures and Associated Audio for Digital Storage Media-Part 1," ISO/IEC JTC 1/SC 29 N 147, Apr. 20, 1992, Section 3: Audio, XP-002083108, 2 pages.17"Final text for DIS 11172-1 (rev. 2): Information Technology-Coding of Moving Pictures and Associated Audio for Digital Storage Media—Part 1," ISO/IEC JTC 1/SC 29 N 147, Apr. 20, 1992, Section 3: Audio, XP-002083108, 2 pages.18"From Joint Stereo to Spatial Audio Coding-Recent Progress and Standardization," by Jurgen Herre, Proc. of the 7th Int. Conference on Digital Audio Effects (DAFx' 04), Oct. 5-8, 2004, Naples, Italy, XP002367849.19"From Joint Stereo to Spatial Audio Coding—Recent Progress and Standardization," by Jurgen Herre, Proc. of the 7th Int. Conference on Digital Audio Effects (DAFx' 04), Oct. 5-8, 2004, Naples, Italy, XP002367849.20"HILN-The MPEG-4 Parametric Audio Coding Tools" by Heiko Purnhagen and Nikolaus Meine, University of Hannover, Hannover, Germany, 4 pages.21"HILN—The MPEG-4 Parametric Audio Coding Tools" by Heiko Purnhagen and Nikolaus Meine, University of Hannover, Hannover, Germany, 4 pages.22"Improving Audio Codecs by Noise Substitution," by Donald Schulz, Journal of the Audio Engineering Society, vol. 44, No. 7/8, Jul./Aug. 1996, pp. 593-598, XP000733647.23"Information Technology-Coding of Audio-Visual Objects-Part 1: MPEG Surround (ISO/IEC JTC 1/SC 29/WG11 N7387)," Jul. 2005, International Organization for Standardization, Poznan, Poland, XP00237055, p. 46, lines 1,2.24"Information Technology—Coding of Audio-Visual Objects—Part 1: MPEG Surround (ISO/IEC JTC 1/SC 29/WG11 N7387)," Jul. 2005, International Organization for Standardization, Poznan, Poland, XP00237055, p. 46, lines 1,2.25"Low Complexity Parametric Stereo Coding", by Erik Schuijers et al., Audio Engineering Society 116th Convention Paper 6073, May 8-11, 2004, Berlin, Germany, pp. 1-11.26"MP3 Surround: Efficient and Compatible Coding of Multi-Channel Audio", by Juergen Herre et al., Audio Engineering Society 116th Convention Paper, May 8-11, 2004, Berlin, Germany, pp. 1-14.27"MPEG Audio Layer II: A Generic Coding Standard for Two and Multichannel Sound for DVB, DAB and Computer Multimedia," by G. Stoll, International Broadcasting Convention, Sep. 14-18, 1995, Germany, XP006528918, pp. 136-144.28"Multichannel Natural Music Recording Based on Psychoacoustic Principles", by Gunther Theile, Extended version of the paper presented at the AES 19th International Conference, May 2001, Oct. 2001, pp. 1-45.29"Parametric Audio Coding" by Bernd Edler and Heiko Purnhagen, University of Hannover, Hannover, Germany, pp. 1-4.30"Parametric Coding of Spatial Audio," by Christof Faller, Proc. of the 7th Int. Conference on Digital Audio Effects (DAFx' 04), Oct. 5-8, 2004, Naples, Itlay, XP002367850.31"Parametric Coding of Spatial Audio-Thesis No. 3062," by Christof Faller, These Presentee a La Faculte Informatique et Communications Institit De Systemes De Communication Section Des Systems De Communication Ecole Polytechnique F�d�rale De Lausanne Pour L'Obtention Du Grade De Docteur Es Sciences, 2004, XP002343263, Laussane, Section 5.3, pp. 71-84.32"Parametric Coding of Spatial Audio—Thesis No. 3062," by Christof Faller, These Presentee a La Faculte Informatique et Communications Institit De Systemes De Communication Section Des Systems De Communication Ecole Polytechnique F�d�rale De Lausanne Pour L'Obtention Du Grade De Docteur Es Sciences, 2004, XP002343263, Laussane, Section 5.3, pp. 71-84.33"Parametric Coding of Spatial Audio-Thesis No. 3062," by Christof Faller, These Presentee a La Faculte Informatique et Communications Institit De Systemes De Communication Section Des Systems De Communication �cole Polytechnique F�d�rale De Lausanne Pour L'Obtention Du Grade De Docteur Es Sciences, 2004, XP002343263, Laussane, Section 5.3, pp. 71-84.34"Parametric Coding of Spatial Audio—Thesis No. 3062," by Christof Faller, These Presentee a La Faculte Informatique et Communications Institit De Systemes De Communication Section Des Systems De Communication �cole Polytechnique F�d�rale De Lausanne Pour L'Obtention Du Grade De Docteur Es Sciences, 2004, XP002343263, Laussane, Section 5.3, pp. 71-84.35"Responding to One of Two Simultaneous Message", by Walter Spieth et al., The Journal of the Acoustical Society of America, vol. 26, No. 3, May 1954, pp. 391-396.36"Spatial Audio Coding: Next-Generation Efficient and Compatible Coding of Multi-Channel Audio," by J. Herre et al., Audio Engineering Society Convention Paper Presented at the 117th Convention, Oct. 28-31, 2004, San Francisco, CA, XP-002343375, pp. 1-13.37"Surround Sound Past, Present, and Future" by Joseph Hull; Dolby Laboratories Inc.; 1999; 8 pages.38"Synthesized Stereo Combined with Acoustic Echo Cancellation for Desktop Conferencing", by Jacob Benesty et al., Bell Labs Technical Journal, Jul.-Sep. 1998, pp. 148-158.39"Text of ISO/IEC 14496-3:2002/PDAM 2 (Parametric coding for High Quality Audio)", by International Organisation for Standisation ISO/IEC JTCI/SC29/WG11 Coding of Moving Pictures and Audio, MPEG2002 N5381 Awaji Island, Dec. 2002, pp. 1-69.40"The Reference Model Architecture for MPEG Spatial Audio Coding," by Juergen Herre et al., Audio Engineering Society Convention Paper 6447, 118th Convention, May 28-31, 2005, Barcelona, Spain, pp. 1-13, XP009059973.41"The Role of Perceived Spatial Separation in the Unmasking of Speech", by Richard Freyman et al., J. Acoust. Soc., Am., vol. 106, No. 6, Dec. 1999, pp. 3578-3588.42Advisory Action; Mailed Jul. 21, 2011 for the corresponding U.S. Appl. No. 11/006,492.43Christof Faller, "Parametric Coding of Spatial Audio, These No. 3062," Presentee A La Faculte Informatique et Communications, Institut de Systemes de Communication, Ecole Polytechnique Federale de Lausanne, Lausanne, EPFL 2004.44Final Office Action received in U.S. Appl. No. 11/006,492, filed Dec. 7, 2004 dated Mar. 25, 2010.45Final Office Action; Mailed Apr. 27, 2011 for the corresponding U.S. Appl. No. 11/006,492.46Non-Final Office Action received in U.S. Appl. No. 11/006,492, filed Dec. 7, 2004 dated Jun. 18, 2010.47Non-Final Office Action received in U.S. Appl. No. 11/006,492, filed Dec. 7, 2004 dated Nov. 23, 2010.48Non-Final Office Action received in U.S. Appl. No. 11/006,492, filed Dec. 7, 2004 dated Sep. 14, 2009.49Notice of Allowance; Mailed Feb. 17, 2012 for corresponding U.S. Appl. No. 11/006,492.50Office Action for Japanese Patent Application No. 2007-537133 dated Feb. 16, 2010 received on Mar. 10, 2010.51Restriction Requirement received in U.S. Appl. No. 11/006,492, filed Dec. 7, 2004 dated Apr. 28, 2009.52van der Waal, R.G. et al., "Subband Coding of Stereographic Digital Audio Signals," Proc. of ICASSP '91, IEEE Computer Society, May 1991, pp. 3601-3604.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS8386267 *Mar 18, 2009Feb 26, 2013Panasonic CorporationStereo signal encoding device, stereo signal decoding device and methods for themUS8908874 *Feb 7, 2011Dec 9, 2014Dts, Inc.Spatial audio encoding and reproductionUS20110004466 *Mar 18, 2009Jan 6, 2011Panasonic CorporationStereo signal encoding device, stereo signal decoding device and methods for themUS20120057715 *Feb 7, 2011Mar 8, 2012Johnston James DSpatial audio encoding and reproduction* Cited by examinerClassifications U.S. Classification381/23, 381/18, 700/94, 704/501International ClassificationH04R5/00Cooperative ClassificationG10L19/008, H04S3/02European ClassificationH04S3/02, G10L19/008Legal EventsDateCodeEventDescriptionSep 4, 2009ASAssignmentOwner name: AGERE SYSTEMS INC., PENNSYLVANIAFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ALLAMANCHE, ERIC;DISCH, SASCHA;FALLER, CHRISTOF;AND OTHERS;REEL/FRAME:023193/0638;SIGNING DATES FROM 20050117 TO 20050201Owner name: FRAUNHOFER-GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ALLAMANCHE, ERIC;DISCH, SASCHA;FALLER, CHRISTOF;AND OTHERS;REEL/FRAME:023193/0638;SIGNING DATES FROM 20050117 TO 20050201Owner name: AGERE SYSTEMS INC., PENNSYLVANIAFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ALLAMANCHE, ERIC;DISCH, SASCHA;FALLER, CHRISTOF;AND OTHERS;SIGNING DATES FROM 20050117 TO 20050201;REEL/FRAME:023193/0638Owner name: FRAUNHOFER-GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ALLAMANCHE, ERIC;DISCH, SASCHA;FALLER, CHRISTOF;AND OTHERS;SIGNING DATES FROM 20050117 TO 20050201;REEL/FRAME:023193/0638May 8, 2014ASAssignmentOwner name: DEUTSCHE BANK AG NEW YORK BRANCH, AS COLLATERAL AGFree format text: PATENT SECURITY AGREEMENT;ASSIGNORS:LSI CORPORATION;AGERE SYSTEMS LLC;REEL/FRAME:032856/0031Effective date: 20140506Apr 3, 2015ASAssignmentOwner name: AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTDFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:AGERE SYSTEMS LLC;REEL/FRAME:035365/0634Effective date: 20140804Jan 28, 2016FPAYFee paymentYear of fee payment: 4Feb 2, 2016ASAssignmentOwner name: AGERE SYSTEMS LLC, PENNSYLVANIAFree format text: TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENT RIGHTS (RELEASES RF 032856-0031);ASSIGNOR:DEUTSCHE BANK AG NEW YORK BRANCH, AS COLLATERAL AGENT;REEL/FRAME:037684/0039Effective date: 20160201Owner name: LSI CORPORATION, CALIFORNIAFree format text: TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENT RIGHTS (RELEASES RF 032856-0031);ASSIGNOR:DEUTSCHE BANK AG NEW YORK BRANCH, AS COLLATERAL AGENT;REEL/FRAME:037684/0039Effective date: 20160201Feb 11, 2016ASAssignmentOwner name: BANK OF AMERICA, N.A., AS COLLATERAL AGENT, NORTHFree format text: PATENT SECURITY AGREEMENT;ASSIGNOR:AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD.;REEL/FRAME:037808/0001Effective date: 20160201RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services