Source: https://patents.google.com/patent/US8340306B2/en
Timestamp: 2019-07-23 06:21:35
Document Index: 147615229

Matched Legal Cases: ['application No. 60', 'application No. 60', 'application No. 60', 'art 1', 'art 1', 'art 1', 'art 1', 'Application No. 05852198', 'Application No. 2007', 'Application No. 10', 'Application No. 2007']

US8340306B2 - Parametric coding of spatial audio with object-based side information - Google Patents
Parametric coding of spatial audio with object-based side information Download PDF
US8340306B2
US8340306B2 US11/667,747 US66774705A US8340306B2 US 8340306 B2 US8340306 B2 US 8340306B2 US 66774705 A US66774705 A US 66774705A US 8340306 B2 US8340306 B2 US 8340306B2
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US11/667,747
US20080130904A1 (en
2004-11-30 Priority to US63179804P priority Critical
2005-11-22 Priority to PCT/US2005/042772 priority patent/WO2006060279A1/en
2005-11-22 Priority to US11/667,747 priority patent/US8340306B2/en
2005-11-22 Application filed by Agere Systems LLC filed Critical Agere Systems LLC
2007-05-14 Assigned to AGERE SYSTEMS INC. reassignment AGERE SYSTEMS INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FALLER, CHRISTOF
2008-06-05 Publication of US20080130904A1 publication Critical patent/US20080130904A1/en
2012-11-15 Assigned to AGERE SYSTEMS LLC reassignment AGERE SYSTEMS LLC CERTIFICATE OF FORMATION/CERTIFICATE OF CONVERSION Assignors: AGERE SYSTEMS INC.
2012-12-25 Publication of US8340306B2 publication Critical patent/US8340306B2/en
A binaural cue coding scheme involving one or more object-based cue codes, wherein an object-based cue code directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of loudspeakers used to create the auditory scene. Examples of object-based cue codes include the angle of an auditory event, the width of the auditory event, the degree of envelopment of the auditory scene, and the directionality of the auditory scene.
This application claims the benefit of the filing date of U.S. provisional application No. 60/631,798, filed on Nov. 30, 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;
U.S. application Ser. No. 11/006,492, filed on Dec. 7, 2004;
U.S. application Ser. No. 11/006,482, filed on Dec. 7, 2004;
U.S. application Ser. No. 11/032,689, filed on Jan. 10, 2005; and
U.S. application Ser. No. 11/058,747, filed on Feb. 15, 2005, which itself claimed the benefit of the filing date of U.S. provisional application No. 60/631,917, filed on Nov. 30, 2004.
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:
F. Baumgarte and C. Faller, “Binaural Cue Coding—Part I: Psychoacoustic fundamentals and design principles,” IEEE Trans. on Speech and Audio Proc., vol. 11, no. 6, November 2003;
C. Faller and F. Baumgarte, “Binaural Cue Coding—Part II: Schemes and applications,” IEEE Trans. on Speech and Audio Proc., vol. 11, no. 6, November 2003; and
C. Faller, “Coding of spatial audio compatible with different playback formats,” Preprint 117th Conv. Aud. Eng. Soc., October 2004.
According to one embodiment, the present invention is a method, apparatus, and machine-readable medium for encoding audio channels. One or more cue codes are generated for two or more audio channels, wherein at least one cue code is an object-based cue code that directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of loudspeakers used to create the auditory scene, and the one or more cue codes are transmitted.
According to another embodiment, the present invention is an apparatus for encoding C input audio channels to generate E transmitted audio channel(s). The apparatus comprises a code estimator and a downmixer. The code estimator generates one or more cue codes for two or more audio channels, wherein at least one cue code is an object-based cue code that directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of loudspeakers used to create the auditory scene. The downmixer downmixes the C input channels to generate the E transmitted channel(s), where C>E≧1, wherein the apparatus transmits information about the cue codes to enable a decoder to perform synthesis processing during decoding of the E transmitted channel(s).
According to yet another embodiment, the present invention is a bitstream generated by encoding audio channels. One or more cue codes are generated for two or more audio channels, wherein at least one cue code is an object-based cue code that directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of loudspeakers used to create the auditory scene. The one or more cue codes and E transmitted audio channel(s) corresponding to the two or more audio channels, where E≧1, are encoded into the encoded audio bitstream.
According to another embodiment, the present invention is a method, apparatus, and machine-readable medium for decoding E transmitted audio channel(s) to generate C playback audio channels, where C>E≧1. Cue codes corresponding to the E transmitted channel(s) are received, wherein at least one cue code is an object-based cue code that directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of loudspeakers used to create the auditory scene. One or more of the E transmitted channel(s) are upmixed to generate one or more upmixed channels. One or more of the C playback channels are synthesized by applying the cue codes to the one or more upmixed channels.
FIG. 10( a) illustrates a listener perceiving a single, relatively focused auditory event (represented by the shaded circle) at a certain angle;
FIG. 10( b) illustrates a listener perceiving a single, more diffuse auditory event (represented by the shaded oval);
FIG. 11( a) illustrates another kind of perception, often referred to as listener envelopment, in which independent audio signals are applied to loudspeakers all around a listener such that the listener feels “enveloped” in the sound field;
FIG. 11( b) illustrates a listener being enveloped in a sound field, while perceiving an auditory event of a certain width at a certain angle;
FIGS. 12( a)-(c) illustrate three different auditory scenes and the values of their associated object-based BCC cues;
FIG. 13 graphically represents the orientations of the five loudspeakers of FIGS. 10-12;
FIG. 14 illustrates the angles and the scale factors for amplitude panning; and
FIG. 15 graphically represents the relationship between ICLD and the stereo event angle, according to the stereophonic law of sines.
Optional scaling/delay block 306 comprises a set 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)} y (k) of the downmixed signal in each subband is given by Equation (2) as follows:
[ p y ~ 1 ⁡ ( k ) p y ~ 1 ⁡ ( k ) ⋮ p y ~ E ⁡ ( k ) ] = D _ CE ⁡ [ p x ~ 1 ⁡ ( k ) P x ~ 2 ⁡ ( k ) ⋮ p x ~ C ⁡ ( k ) ] , ( 2 )
where D CE is derived by squaring each matrix element in the C-by-E downmixing matrix DCE and p{tilde over (x)} i (k) is the power of subband k of input channel i.
If the subbands are not independent, then the power values p{tilde over (y)} i (k) of the downmixed signal will be larger or smaller than that computed using Equation (2), due to signal amplifications or cancellations when signal components are in-phase or out-of-phase, respectively. To prevent this, the downmixing operation of Equation (1) is applied in subbands followed by the scaling operation of multipliers 310. The scaling factors ei(k) (1≧i≧E) can be derived using Equation (3) as follows:
e i ⁡ ( k ) = p y ~ i ⁡ ( k ) p y i ⁡ ( k ) , ( 3 )
where p{tilde over (y)} i (k) is the subband power as computed by Equation (2), and pŷ i (k) is power of the corresponding downmixed subband signal ŷi(k).
y ~ ⁡ ( k ) = e ⁡ ( k ) ⁢ ∑ c = 1 C ⁢ x ~ c ⁡ ( k ) . ( 4 )
the factor e(k) is given by Equation (5) as follows:
e ⁡ ( k ) = ∑ c = 1 C ⁢ p x ~ c ⁡ ( k ) p x ~ ⁡ ( k ) , ( 5 )
where p{tilde over (x)} c (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
∑ c = 1 C ⁢ ⁢ x ~ c ⁡ ( k ) .
[ s ~ 1 ⁡ ( k ) s ~ 2 ⁡ ( k ) ⋮ s ~ C ⁡ ( k ) ] = U EC ⁡ [ 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 subband.
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. De-correlation block 410 performs a de-correlation 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 de-correlation block 410 can be found in U.S. patent application Ser. No. 10/155,437, filed on May 24, 2002.
The synthesis of ICLD values may be less troublesome than the synthesis of ICTD and ICC values, since ICLD synthesis involves merely scaling of subband signals. Since ICLD cues are the most commonly used directional cues, it is usually more important that the ICLD values approximate those of the original audio signal. As such, ICLD data might be estimated between all channel pairs. The scaling factors ai(k) (1≧i≧C) for each subband are preferably chosen such that the subband power of each playback channel approximates the corresponding power of the original input audio channel.
Each inverse filter bank 412 converts a set of corresponding synthesized coefficients {circumflex over ({tilde over (x)}i(k) in the frequency domain into a frame of a corresponding digital, playback channel {tilde over (x)}i(n).
The following measures are used for ICTD, ICLD, and ICC for corresponding subband signals {tilde over (x)}1(k) and {tilde over (x)}2 (k) of two (e.g., stereo) audio channels:
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).
Δ ⁢ ⁢ L 12 ⁡ ( k ) = 10 ⁢ ⁢ log 10 ⁡ ( p x ~ 2 ⁡ ( k ) p x ~ 1 ⁡ ( k ) ) . ⁢ ICC ⁢ : ( 10 ) c 12 ⁡ ( k ) = max d ⁢  Φ 12 ⁡ ( d , k )  . ( 11 )
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 and ΔL1c(k) denote the ICTD and ICLD, respectively, between the reference channel 1 and channel c.
d c = { - 1 2 ⁢ ( max ⁢ 2 ≤ l ≤ C ⁢ τ 1 ⁢ l ⁡ ( k ) + min 2 ≤ l ≤ C ⁢ τ 1 ⁢ l ⁡ ( k ) ) , c = 1 τ 1 ⁢ ⁢ l ⁡ ( k ) + d 1 2 ≤ c ≤ C . ( 12 )
The delay for the reference channel, d1, is computed such that the maximum magnitude of the delays dc is minimized. The less the subband signals are modified, the less there is a danger for artifacts to occur. If the subband sampling rate does not provide high enough time-resolution for ICTD synthesis, delays can be imposed more precisely by using suitable all-pass filters.
In order that the output subband signals have desired ICLDs ΔL12(k) between channel c and the reference channel 1, the gain factors ac should satisfy Equation (13) as follows:
a c a 1 = 10 Δ ⁢ ⁢ L 1 ⁢ c ⁡ ( k ) 20 . ( 13 )
Additionally, the output subbands are preferably normalized such that the sum of the power of all output channels is equal to the power of the input sum signal. Since the total original signal power in each subband is preserved in the sum signal, this normalization results in the absolute subband power for each output channel approximating the corresponding power of the original encoder input audio signal. Given these constraints, the scale factors ac are given by Equation (14) as follows:
a c = { 1 / 1 + ∑ i = 2 C ⁢ 10 Δ ⁢ ⁢ L 1 ⁢ i / 10 , c = 1 10 Δ ⁢ ⁢ L 1 ⁢ c / 20 ⁢ a 1 , otherwise . ( 14 )
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 more audio channels that are transmitted, the better the audio quality will be.
Object-Based BCC Cues
As described above, in a conventional C-to-E BCC scheme, the encoder derives statistical inter-channel difference parameters (e.g., ICTD, ICLD, and/or ICC cues) from C original channels. As represented in FIGS. 6 and 7A-B, these particular BCC cues are functions of the number and positions of the loudspeakers used to create the auditory spatial image. These BCC cues are referred to as “non-object-based” BCC cues, since they do not directly represent perceptual attributes of the auditory spatial image.
In addition to or instead of one or more of such non-object-based BCC cues, a BCC scheme may include one or more “object-based” BCC cues that directly represent attributes of the auditory spatial image inherent in multi-channel surround audio signals. As used in this specification, an object-based cue is a cue that directly represents a characteristic of an auditory scene, where the characteristic is independent of the number and positions of loudspeakers used to create that scene. The auditory scene itself will depend on the number and location of the speakers used to create it, but not the object-based BCC cues themselves.
Assume, for example, that (1) a first audio scene is generated using a first configuration of speakers and (2) a second audio scene is generated using a second configuration of speakers (e.g., having a different number and/or locations of speakers from the first configuration). Assume further that the first audio scene is identical to the second audio scene (at least from the perspective of a particular listener). In that case, non-object-based BCC cues (e.g., ICTDs, ICLDs, ICCs) for the first audio scene will be different from the non-object-based BCC cues for the second audio scene, but object-based BCC cues for both audio scenes will be the same, because those cues characterize the audio scenes directly (i.e., independent of the number and locations of speakers).
BCC schemes are often applied in the context of particular signal formats (e.g., 5-channel surround), where the number and locations of loudspeakers are specified by the signal format. In such applications, any non-object-based BCC cues will depend on the signal format, while any object-based BCC cues may be said to be independent of the signal format in that they are independent of the number and positions of loudspeakers associated with that signal format.
FIG. 10( a) illustrates a listener perceiving a single, relatively focused auditory event (represented by the shaded circle) at a certain angle. Such an auditory event can be generated by applying “amplitude panning” to the pair of loudspeakers enclosing the auditory event (i.e., loudspeakers 1 and 3 in FIG. 10( a)), where the same signal is sent to the two loudspeakers, but with possibly different strengths. The level difference (e.g., ICLD) determines where the auditory event appears between the loudspeaker pair. With this technique, an auditory event can be rendered at any direction by appropriate selection of the loudspeaker pair and ICLD value.
FIG. 10( b) illustrates a listener perceiving a single, more diffuse auditory event (represented by the shaded oval). Such an auditory event can be rendered at any direction using the same amplitude panning technique as described for FIG. 10( a). In addition, the similarity between the signal pair is reduced (e.g., using the ICC coherence parameter). For ICC=1, the auditory event is focused as in FIG. 10( a), and, as ICC decreases, the width of the auditory event increases as in FIG. 10( b).
FIG. 11( a) illustrates another kind of perception, often referred to as listener envelopment, in which independent audio signals are applied to loudspeakers all around a listener such that the listener feels “enveloped” in the sound field. This impression can be created by applying differently de-correlated versions of an audio signal to different loudspeakers.
FIG. 11( b) illustrates a listener being enveloped in a sound field, while perceiving an auditory event of a certain width at a certain angle. This auditory scene can be created by applying a signal to the loudspeaker pair enclosing the auditory event (i.e., loudspeakers 1 and 3 in FIG. 11( b)), while applying the same amount of independent (i.e., de-correlated) signals to all loudspeakers.
According to one embodiment of the present invention, the spatial aspect of audio signals is parameterized as a function of frequency (e.g., in subbands) and time, for scenarios such as those illustrated in FIG. 11( b). Rather than estimating and transmitting non-object-based BCC cues such as ICTD, ICLD, and ICC cues, this particular embodiment uses object-based parameters that more directly represent spatial aspects of the auditory scene, as the BCC cues. In particular, in each subband b at each time k, the angle α(b,k) of the auditory event, the width w(b,k) of the auditory event, and the degree of envelopment e(b,k) of the auditory scene are estimated and transmitted as BCC cues.
FIGS. 12( a)-(c) illustrate three different auditory scenes and the values of their associated object-based BCC cues. In the auditory scene of FIG. 12( c), there is no localized auditory event. As such, the width w(b,k) is zero and the angle α(b,k) is arbitrary.
FIGS. 10-12 illustrate one possible 5-channel surround configuration, in which the left loudspeaker (#1) is located 30° to the left of the center loudspeaker (#3), the right loudspeaker (#2) is located 30° to the right of the center loudspeaker, the left rear loudspeaker (#4) is located 110° to the left of the center loudspeaker, and the right rear loudspeaker (#5) is located 110° to the right of the center loudspeaker.
FIG. 13 graphically represents the orientations of the five loudspeakers of FIGS. 10-12 as unit vectors si=(cos φi, sin φi)T, where the X-axis represents the orientation of the center loudspeaker, the Y-axis represents an orientation 90° to the left of the center loudspeaker, and φ1 are the loudspeaker angles relative to the X-axis.
At each time k, in each BCC subband b, the direction of the auditory event in the surround image can be estimated according to Equation (15) as follows:
α ⁡ ( b , k ) = ∠ ⁢ ∑ i = 1 5 ⁢ p i ⁡ ( b , k ) ⁢ s i , ( 15 )
where α(b,k) is the estimated angle of the auditory event with respect to the X-axis of FIG. 13, and pi(b,k) is the power or magnitude of surround channel i in subband b at time index k. If the magnitude is used, then Equation (15) corresponds to the particle velocity vector of the sound field in the sweet spot. The power has also often been used, especially for high frequencies, where sound intensities and head shadowing play a more important role.
The width w(b,k) of the auditory event can be estimated according to Equation (16) as follows:
w(b,k)=1−ICC(b,k), (16)
where ICC(b,k) is a coherence estimate between the signals for the two loudspeakers enclosing the direction defined by the angle α(b,k).
The degree of envelopment e(b,k) of the auditory scene estimates the total amount of de-correlated sound coming out of all loudspeakers. This measure can be computed as a coherence estimate between various channel pairs combined with some considerations as a function of the power pi(b,k). For example, e(b,k) could be a weighted average of coherence estimation obtained between different audio channel pairs, where the weighting is a function of the relative powers of the different audio channel pairs.
Another possible way of estimating the direction of the auditory event would be to select, at each time k and in each subband b, the two strongest channels and compute the level difference between these two channels. An amplitude panning law can then be used to compute the relative angle of the auditory event between the two selected loudspeakers. The relative angle between the two loudspeakers can then be converted to the absolute angle α(b,k).
In this alternative technique, the width w(b,k) of the auditory event can be estimated using Equation (16), where ICC(b,k) is the coherence estimate between the two strongest channels, and the degree of envelopment e(b,k) of the auditory scene can be estimated using Equation (17), as follows:
e ⁡ ( b , k ) = ∑ i ≠ i 1 , i ≠ i 2 C ⁢ p i ⁡ ( b , k ) ∑ i = 1 C ⁢ p i ⁡ ( b , k ) , ( 17 )
where C is the number of channels, and i1 and i2 are the indices of the two selected strongest channels.
Although a BCC scheme could transmit all three object-based parameters (i.e., α(b,k), w(b,k), and e(b,k)), an alternative BCC scheme might transmit fewer parameters, e.g., when very low bitrate is needed. For example, fairly good results can be obtained using only two parameters: direction α(b,k) and “directionality” d(b,k), where the directionality parameter combines w(b,k) and e(b,k) into one parameter based on a weighted average between w(b,k) and e(b,k).
The combination of w(b,k) and e(b,k) is motivated by the fact that the width of auditory events and degree of envelopment are somewhat related perceptions. Both are evoked by lateral independent sound. Thus, combination of w(b,k) and e(b,k) results in only a little less flexibility in terms of determining the attributes of the auditory spatial image. In one possible implementation, the weighting of w(b,k) and e(b,k) reflects the total signal power of the signals with which w(b,k) and e(b,k) have been computed. For example, the weight for w(b,k) can be chosen proportional to the power of the two channels that were selected for computation of w(b,k), and the weight for w(b,k) could be proportional to the power of all channels. Alternatively, α(b,k) and w(b,k) could be transmitted, where e(b,k) is determined heuristically at the decoder.
Decoder Processing
The decoder processing can be implemented by converting the object-based BCC cues into non-object-based BCC cues, such as level differences (ICLD) and coherence values (ICC), and then using those non-object-based BCC cues in a conventional BCC decoder.
For example, the angle α(b,k) of the auditory event can be used to determine the ICLD between the two loudspeaker channels enclosing the auditory event by applying an amplitude-panning law (or other possible frequency-dependent relation). When amplitude panning is applied, scale factors a1 and a2 may be estimated from the stereophonic law of sines given by Equation (18) as follows:
sin ⁢ ⁢ ϕ sin ⁢ ⁢ ϕ 0 = a 1 - a 2 a 1 + a 2 , ( 18 )
where φ0 is the magnitude of the half of the angle between the two loudspeakers, φ is the corresponding angle of the auditory event relative to the angle of the loudspeaker most close in the clockwise direction (if the angles are defined to increase in the counterclockwise direction), and the scale factors a1 and a2 are related to the level-difference cue ICLD, according to Equation (19) as follows:
ΔL 12(k)=20 log10(a 2 /a 1). (19)
FIG. 14 illustrates the angles φ0 and φ and the scale factors a1 and a2, where s(n) represents a mono signal that appears at angle φ when amplitude panning is applied based on the scale factors a1 and a2. FIG. 15 graphically represents the relationship between ICLD and the stereo event angle φ according to the stereophonic law of sines of Equation (18) for a standard stereo configuration with φ0=30°.
As described previously, the scale factors a1 and a2 are determined as a function of the direction of the auditory event. Since Equation (18) determines only the ratio a2/a1, there is one degree of freedom for the overall scaling of a1 and a2. This scaling also depends on other cues, e.g., w(b,k) and e(b,k).
The coherence cue ICC between the two loudspeaker channels enclosing the auditory event can be determined from the width parameter w(b,k) as ICC(b,k)=1−w(b,k). The power of each remaining channel i is computed as a function of the degree of envelopment parameter e(b,k), where larger values of e(b,k) imply more power given to the remaining channels. Since the total power is a constant (i.e., the total power is equal or proportional to the total power of the transmitted channels), the sum of power given to the two channels enclosing the auditory event direction plus the sum of power of all remaining channels (determined by e(b,k)) is constant. Thus, the higher the degree of envelopment e(b,k), the less power is relatively given to the localized sound, i.e., the smaller are a1 and a2 chosen (while the ratio a2/a1 is as determined from the direction of the auditory event).
One extreme case is when there is a maximum degree of envelopment. In this case, a1 and a2 are small, or even a1=a2=0. The other extreme is minimum degree of envelopment. In this case, a1 and a2 are chosen such that all signal power goes to these two channels, while the power of the remaining channels is zero. The signal that is given to the remaining channels is preferably an independent (de-correlated) signal in order to get the maximum effect of listener envelopment.
One characteristic of object-based BCC cues, such as α(b,k), w(b,k), and e(b,k), is that they are independent of the number and the positions of the loudspeakers. As such, these object-based BCC cues can be efficiently used to render an auditory scene for any number of loudspeakers at any positions.
BCC encoders and/or decoders may be used in conjunction with or incorporated into a variety of different applications or systems, including systems for television or electronic music distribution, movie theaters, broadcasting, streaming, and/or reception. These include systems for encoding/decoding transmissions via, for example, terrestrial, satellite, cable, interne, intranets, or physical media (e.g., compact discs, digital versatile discs, semiconductor chips, hard drives, memory cards, and the like). BCC encoders and/or decoders may also be employed in games and game systems, including, for example, interactive software products intended to interact with a user for entertainment (action, role play, strategy, adventure, simulations, racing, sports, arcade, card, and board games) and/or education that may be published for multiple machines, platforms, or media. Further, BCC encoders and/or decoders may be incorporated in audio recorders/players or CD-ROM/DVD systems. BCC encoders and/or decoders may also be incorporated into PC software applications that incorporate digital decoding (e.g., player, decoder) and software applications incorporating digital encoding capabilities (e.g., encoder, ripper, recoder, and jukebox).
generating one or more cue codes for two or more audio channels, wherein at least one cue code is an object-based cue code that directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of audio sources used to create the auditory scene; and
transmitting the one or more cue codes, wherein the at least one object-based cue code comprises one or more of:
(1) a first measure of an absolute angle of an auditory event in the auditory scene relative to a reference direction, wherein the first measure of the absolute angle of the auditory event is estimated by:
(i) generating a vector sum of relative power vectors for the audio channels; and
(ii) determining the first measure of the absolute angle of the auditory event based on the angle of the vector sum relative to the reference direction;
(2) a second measure of the absolute angle of the auditory event in the auditory scene relative to the reference direction, wherein the second measure of the absolute angle of the auditory event is estimated by:
(i) identifying the two strongest channels in the audio channels;
(ii) computing a level difference between the two strongest channels;
(iii) applying an amplitude panning law to compute a relative angle between the two strongest channels; and
(iv) converting the relative angle into the second measure of the absolute angle of the auditory event;
(3) a first measure of a width of the auditory event in the auditory scene, wherein the first measure of the width of the auditory event is estimated by:
(i) estimating the absolute angle of the auditory event;
(ii) identifying two audio channels enclosing the absolute angle;
(iii) estimating coherence between the two identified channels; and
(iv) calculating the first measure of the width of the auditory event based on the estimated coherence;
(4) a second measure of the width of the auditory event in the auditory scene, wherein the second measure of the width of the auditory event is estimated by:
(ii) estimating coherence between the two strongest channels; and
(iii) calculating the second measure of the width of the auditory event based on the estimated coherence;
(5) a first degree of envelopment of the auditory scene, wherein the first degree of envelopment is estimated as a weighted average of coherence estimates obtained between different audio channel pairs, where the weighting is a function of the relative powers of the different audio channel pairs;
(6) a second degree of envelopment of the auditory scene, wherein the second degree of envelopment is estimated as a ratio of (i) the sum of the powers of all but the two strongest audio channels and (ii) the sum of the powers of all of the audio channels; and
(7) directionality of the auditory scene, wherein the directionality is a weighted sum of the width of the auditory event and the degree of envelopment of the auditory scene.
2. The invention of claim 1, further comprising transmitting E transmitted audio channel(s) corresponding to the two or more audio channels, where E≧1.
the two or more audio channels comprise C input audio channels, where C>E; and
the C input channels are downmixed to generate the E transmitted channel(s).
4. The invention of claim 1, wherein the one or more cue codes are transmitted to enable a decoder to perform synthesis processing during decoding of E transmitted channel(s) based on the at least one object-based cue code, wherein the E transmitted audio channel(s) correspond to the two or more audio channels, where E≧1.
5. The invention of claim 1, wherein the at least one object-based cue code is estimated at different times and in different subbands.
6. The invention of claim 1, wherein the at least one object-based cue code comprises two or more of (1) the first measure of the absolute angle of the auditory event in the auditory scene relative to the reference direction; (2) the second measure of the absolute angle of the auditory event in the auditory scene relative to the reference direction; (3) the first measure of the width of the auditory event; (4) the second measure of the width of the auditory event; (5) the first degree of envelopment of the auditory scene; (6) the second degree of envelopment of the auditory scene; and (7) the directionality of the auditory scene.
7. The invention of claim 1, wherein the at least one object-based cue code comprises the first measure of the absolute angle of the auditory event in the auditory scene relative to the reference direction.
8. The invention of claim 1, wherein the at least one object-based cue code comprises the second measure of the absolute angle of the auditory event in the auditory scene.
9. The invention of claim 1, wherein the at least one object-based cue code comprises the first measure of the width of the auditory event in the auditory scene.
10. The invention of claim 1, wherein the at least one object-based cue code comprises the second measure of the width of the auditory event in the auditory scene.
11. The invention of claim 1, wherein the at least one object-based cue code comprises the first degree of envelopment of the auditory scene.
12. The invention of claim 1, wherein the at least one object-based cue code comprises the second degree of envelopment of the auditory scene.
13. The invention of claim 1, wherein the at least one object-based cue code comprises the directionality of the auditory scene.
14. The invention of claim 13, wherein the directionality is estimated by:
(i) estimating the width of the auditory event in the auditory scene;
(ii) estimating the degree of envelopment of the auditory scene; and
(iii) calculating the directionality as a weighted sum of the width and the degree of envelopment.
15. Apparatus for encoding audio channels, the apparatus comprising:
means for generating one or more cue codes for two or more audio channels, wherein at least one cue code is an object-based cue code that directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of audio sources used to create the auditory scene; and
means for transmitting the one or more cue codes, wherein the at least one object-based cue code comprises one or more of:
16. Apparatus for encoding C input audio channels to generate E transmitted audio channel(s), the apparatus comprising:
a code estimator adapted to generate one or more cue codes for two or more audio channels, wherein at least one cue code is an object-based cue code that directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of audio sources used to create the auditory scene; and
a downmixer adapted to downmix the C input channels to generate the E transmitted channel(s), where C>E≧1, wherein the apparatus is adapted to transmit information about the cue codes to enable a decoder to perform synthesis processing during decoding of the E transmitted channel(s), wherein the at least one object-based cue code comprises one or more of:
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 audio channels, the method comprising:
19. An encoded audio bitstream generated by encoding audio channels, wherein:
one or more cue codes are generated for two or more audio channels, wherein at least one cue code is an object-based cue code that directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of audio sources used to create the auditory scene; and
the one or more cue codes and E transmitted audio channel(s) corresponding to the two or more audio channels, where E≧1, are encoded into the encoded audio bitstream, wherein the at least one object-based cue code comprises one or more of:
20. A method for decoding E transmitted audio channel(s) to generate C playback audio channels, where C>E≧1, the method comprising:
receiving cue codes corresponding to the E transmitted channel(s), wherein at least one cue code is an object-based cue code that directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of audio sources used to create the auditory scene;
synthesizing one or more of the C playback channels by applying the cue codes to the one or more upmixed channels, wherein the at least one object-based cue code comprises one or more of:
21. The invention of claim 20, wherein at least two playback channels are synthesized by:
(i) converting the at least one object-based cue code into at least one non-object-based cue code based on position of two or more audio sources used to render the playback audio channels; and
(ii) applying the at least one non-object-based cue code to at least one upmixed channel to generate the at least two playback channels.
the at least one object-based cue code comprises two or more of (1) the first measure of the absolute angle of the auditory event in the auditory scene relative to the reference direction; (2) the second measure of the absolute angle of the auditory event in the auditory scene relative to the reference direction; (3) the first measure of the width of the auditory event; (4) the second measure of the width of the auditory event; (5) the first degree of envelopment of the auditory scene; (6) the second degree of envelopment of the auditory scene; and (7) the directionality of the auditory scene; and
the at least one non-object-based cue code comprises one or more of (1) an inter-channel correlation (ICC) code, an inter-channel level difference (ICLD) code, and an inter-channel time difference (ICTD) code.
23. The invention of claim 20, wherein the at least one object-based cue code comprises at least one of the first and second measures of the absolute angle of the auditory event in the auditory scene relative to the reference direction.
24. The invention of claim 20, wherein the at least one object-based cue code comprises at least one of the first and second measures of the width of the auditory event in the auditory scene.
25. The invention of claim 20, wherein the at least one object-based cue code comprises at least one of the first and second degrees of envelopment of the auditory scene.
26. The invention of claim 20, wherein the at least one object-based cue code comprises the directionality of the auditory scene.
27. Apparatus for decoding E transmitted audio channel(s) to generate C playback audio channels, where C>E≧1, the apparatus comprising:
means for receiving cue codes corresponding to the E transmitted channel(s), wherein at least one cue code is an object-based cue code that directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of audio sources used to create the auditory scene;
means for synthesizing one or more of the C playback channels by applying the cue codes to the one or more upmixed channels, wherein the at least one object-based cue code comprises one or more of:
28. Apparatus for decoding E transmitted audio channel(s) to generate C playback audio channels, where C>E≧1, the apparatus comprising:
a receiver adapted to receive cue codes corresponding to the E transmitted channel(s), wherein at least one cue code is an object-based cue code that directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of audio sources used to create the auditory scene;
an upmixer adapted to upmix one or more of the E transmitted channel(s) to generate one or more upmixed channels; and
a synthesizer adapted to synthesize one or more of the C playback channels by applying the cue codes to the one or more upmixed channels, wherein the at least one object-based cue code comprises one or more of:
30. 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 decoding E transmitted audio channel(s) to generate C playback audio channels, where C>E≧1, the method comprising:
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TW (1) TWI427621B (en)
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US20090089479A1 (en) * 2007-10-01 2009-04-02 Samsung Electronics Co., Ltd. Method of managing memory, and method and apparatus for decoding multi-channel data
US20120230512A1 (en) * 2009-11-30 2012-09-13 Nokia Corporation Audio Zooming Process within an Audio Scene
US9818412B2 (en) 2013-05-24 2017-11-14 Dolby International Ab Methods for audio encoding and decoding, corresponding computer-readable media and corresponding audio encoder and decoder
KR100682915B1 (en) * 2005-01-13 2007-02-15 삼성전자주식회사 Method and apparatus for encoding and decoding multi-channel signals
US20070223740A1 (en) * 2006-02-14 2007-09-27 Reams Robert W Audio spatial environment engine using a single fine structure
CN101617360B (en) 2006-09-29 2012-08-22 韩国电子通信研究院 Apparatus and method for coding and decoding multi-object audio signal with various channel
US8130966B2 (en) * 2006-10-31 2012-03-06 Anthony Grimani Method for performance measurement and optimization of sound systems using a sliding band integration curve
WO2008082276A1 (en) 2007-01-05 2008-07-10 Lg Electronics Inc. A method and an apparatus for processing an audio signal
EP2154911A1 (en) * 2008-08-13 2010-02-17 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. An apparatus for determining a spatial output multi-channel audio signal
CN107071688A (en) * 2009-06-23 2017-08-18 诺基亚技术有限公司 Method and device for processing audio signals
TW347623B (en) 1995-08-31 1998-12-11 Nippon Steel Corp Digital data encoding device and method therefor
US5860060A (en) 1997-05-02 1999-01-12 Texas Instruments Incorporated Method for left/right channel self-alignment
TW360859B (en) 1996-09-24 1999-06-11 Sony Corp Vector quantization method and speech encoding method and apparatus
WO1999052326A1 (en) 1998-04-07 1999-10-14 Ray Milton Dolby Low bit-rate spatial coding method and system
CA2326495A1 (en) 1999-12-03 2001-06-03 Lucent Technologies Inc. Technique for parametric coding of a signal containing information
US20010031054A1 (en) 1999-12-07 2001-10-18 Anthony Grimani Automatic life audio signal derivation system
US20010031055A1 (en) 1999-12-24 2001-10-18 Aarts Ronaldus Maria Multichannel audio signal processing device
WO2002029808A2 (en) 2000-10-04 2002-04-11 University Of Miami Auxiliary channel masking in an audio signal
TW517223B (en) 2000-10-26 2003-01-11 Mitsubishi Electric Corp Voice coding method and device
TW521261B (en) 1999-06-18 2003-02-21 Sony Corp Speech encoding method and apparatus, input signal verifying method, speech decoding method and apparatus and program furnishing medium
WO2004036548A1 (en) 2002-10-14 2004-04-29 Thomson Licensing S.A. Method for coding and decoding the wideness of a sound source in an audio scene
US6782366B1 (en) 2000-05-15 2004-08-24 Lsi Logic Corporation Method for independent dynamic range control
US20070094012A1 (en) 2005-10-24 2007-04-26 Pang Hee S Removing time delays in signal paths
TW507194B (en) * 2000-05-24 2002-10-21 Nat Science Council Variable-rate residual-transform vocoders using auditory perception approximation
TW544654B (en) * 2001-07-06 2003-08-01 Shyue-Yun Wan Method of eliminating noise on sound storage and regeneration system
CN1321423C (en) * 2003-03-03 2007-06-13 三菱重工业株式会社 Cask, composition for neutron shielding body, and method of manufacturing the neutron shielding body
2005-11-22 EP EP05852198.0A patent/EP1817767B1/en active Active
2005-11-22 WO PCT/US2005/042772 patent/WO2006060279A1/en active Application Filing
2005-11-22 JP JP2007544408A patent/JP5106115B2/en active Active
2005-11-22 US US11/667,747 patent/US8340306B2/en not_active Expired - Fee Related
2005-11-22 KR KR1020077015056A patent/KR101215868B1/en active IP Right Grant
2005-11-28 TW TW94141787A patent/TWI427621B/en active
US7181019B2 (en) 2003-02-11 2007-02-20 Koninklijke Philips Electronics N. V. Audio coding
"Advances in Parametric Coding for High-Quality Audio," by Erik Schuijers et al., Audio Engineering Society Convention Paper 5852, 114th Convention, Amsterdam, The Netherlands, Mar. 22-25, 2003, pp. 1-11.
"Binaural Cue Coding Applied to Stereo and Multi-Channel Audio Compression," by Christof Faller et al., Audio Engineering Society 112th Covention, Munich, Germany, vol. 112, No. 5574, May 10 2002, pp. 1-9.
"Binaural Cue Coding-Part I: Psychoacoustic Fundamentals and Design Principles", by Frank Baumgarte et al., IEEE Transactions on Speech and Audio Processing, vol. 11, No. 6, Nov. 2003, pp. 509-519.
"Binaural Cue Coding—Part I: Psychoacoustic Fundamentals and Design Principles", by Frank Baumgarte et al., IEEE Transactions on Speech and Audio Processing, vol. 11, No. 6, Nov. 2003, pp. 509-519.
"Binaural Cue Coding-Part II: Schemes and Applications", by Christof Faller et al., IEEE Transactions on Speech and Audio Processing, vol. 11, No. 6, Nov. 2003, pp. 520-531, XP-002338415.
"Binaural Cue Coding—Part II: Schemes and Applications", by Christof Faller et al., IEEE Transactions on Speech and Audio Processing, vol. 11, No. 6, Nov. 2003, pp. 520-531, XP-002338415.
"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.
"Efficient Representation of Spatial Audio Using Perceptual Parametrization",, by Christof Faller et 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.
"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.
"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.
"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.
"HILN-The MPEG-4 Parametric Audio Coding Tools" by Heiko Purnhagen and Nikolaus Meine, University of Hannover, Hannover, Germany, 4 pages.
"HILN—The MPEG-4 Parametric Audio Coding Tools" by Heiko Purnhagen and Nikolaus Meine, University of Hannover, Hannover, Germany, 4 pages.
"Imroving 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.
"Information Technology-Coding of Audio-Visual Objects-Part 1: MPEG Surround (ISO/IEC JTC 1/SC 29/WG11 N7387)," Jul. 2005, International Organizational for Standardization, Poznan, Poland, XP002370055, p. 46.
"Information Technology—Coding of Audio-Visual Objects—Part 1: MPEG Surround (ISO/IEC JTC 1/SC 29/WG11 N7387)," Jul. 2005, International Organizational for Standardization, Poznan, Poland, XP002370055, p. 46.
"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, XP-002350798.
"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 Fédérale De Lausanne Pour L'Obtention Du Grade De Docteur Es Sciences, 2004, XP002343263, Laussane, Section 5.3, pp. 71-84.
"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 Fédérale De Lausanne Pour L'Obtention Du Grade De Docteur Es Sciences, 2004, XP002343263, Laussane, Section 5.3, pp. 71-84.
"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.
"Text of ISO/IEC 14496-3:2002/PDAM 2 (Parametric coding for High Quality Audio)" by International Organisation for Standardisation ISO/IEC JTC1/SC29/WG11 Coding of Moving Pictures and Audio, MPEG2002 N5381 Awaji Island, Dec. 2002, pp. 1-69.
"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.
Christof 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.
European Examination Report; Mailed May 4, 2011 for the corresponding European Application No. 05852198.0.
Examination Office Letter; Mailed Sep. 5, 2011 for corresponding Japanese Application No. 2007-544408.
Notice of Preliminary Rejection; Mailed Feb. 28, 2012 for corresponding Korean Application No. 10-2007-7015056.
Notification of Transmittal of The International Search Report and The Written Opinion of the International Searching Authority; Mailed Apr. 25, 2006 for the corresponding PCT/US2005/42772.
Office Action for Japanese Patent Application No. 2007-537133 dated Feb. 16, 2010 received on Mar. 10, 2010.
van 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.
US8989401B2 (en) * 2009-11-30 2015-03-24 Nokia Corporation Audio zooming process within an audio scene
WO2015071148A1 (en) 2013-11-14 2015-05-21 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Method and device for compressing and decompressing sound field data of an area
KR101215868B1 (en) 2012-12-31
US20080130904A1 (en) 2008-06-05
TWI427621B (en) 2014-02-21
WO2006060279A1 (en) 2006-06-08
EP1817767A1 (en) 2007-08-15
JP2008522244A (en) 2008-06-26
JP5106115B2 (en) 2012-12-26
EP1817767B1 (en) 2015-11-11
TW200636677A (en) 2006-10-16
KR20070086851A (en) 2007-08-27
KR101120909B1 (en) 2012-02-27 Apparatus and method for multi-channel parameter transformation and computer readable recording medium therefor
JP5511136B2 (en) 2014-06-04 Apparatus and method for device and method, and a multi-channel synthesis to generate the multi-channel synthesizer control signal
ES2306076T3 (en) 2008-11-01 Apparatus and method for constructing a multi-channel signal output or for generating a downmix signal.
CN101390443B (en) 2010-12-01 Audio encoding and decoding
RU2604342C2 (en) 2016-12-10 Device and method of generating output audio signals using object-oriented metadata
JP5189979B2 (en) 2013-04-24 Control of spatial audio coding parameters as a function of auditory events
JP5311597B2 (en) 2013-10-09 Multi-channel encoder
US8798275B2 (en) 2014-08-05 Signal synthesizing
US7974713B2 (en) 2011-07-05 Temporal and spatial shaping of multi-channel audio signals
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