WO2012163451A2

WO2012163451A2 - Controlling multichannel signals

Info

Publication number: WO2012163451A2
Application number: PCT/EP2012/001732
Authority: WO
Inventors: Volker DROLLINGER
Original assignee: Drollinger Volker
Priority date: 2012-04-23
Filing date: 2012-04-23
Publication date: 2012-12-06
Also published as: WO2012163451A3

Abstract

The invention concerns a system capable of controlling multichannel signals which comprise a plurality of n channels. The system comprises a controller (11) with a processor (P), a first magnitude level (L1) and an associated first set of channel values (S1) comprising n channel values (S1_i), and a second magnitude level (L2) and an associated second set of channel values (S2) comprising n channel values (S2_i). The controller (11) is adapted to receive a third magnitude level (L3). The processor (P) is configured to determine a third set of channel values (S3) which is associated with the third magnitude level (L3) and which comprises n channel values (S3_i). The third set of channel values (S3) is determined by determining a channel value (S3_i) for each channel i = 1,..., n of the third set of channel values (S3) based on the corresponding channel value (S1_i) of the first set of channel values (S1), the corresponding channel value (S2_i) of the second set of channel values (S2), the first magnitude level (L1), the second magnitude level (L2), and the third magnitude level (L3). Moreover, the invention concerns a method for controlling multichannel signals and a data structure with computer-executable instructions for controlling multichannel signals.

Description

Controlling Multichannel Signals

The invention refers to a system, a method and a data structure for controlling multichannel signals.

Multichannel signals are present in various technical appUcations. For example, an audio signal (e.g. of hi-fi systems or musical instruments) can consist of different channels corresponding to different frequency ranges (or bandwidths) . High quality audio systems typically allow controlling and/or adjusting the values of each of said channels individually with help of equalizers. In this way a better sound can be achieved.

The overall volume of such an multichannel audio signal is typically controlled by a main volume control, meaning that the volume of all channels is controlled by a single volume control. In such a case, following problem could arise: for a given equalizer setting of the channels the sound is good at a low volume, but the sound is still not good or even worse at a high volume (e.g. due to undesired resonances). If, however, the equalizer setting of the channels would produce a good sound at the high volume, then it is possible that the sound is poor (e.g. flat) at said low volume.

The above mentioned type of problem could be avoided by adjusting the equalizer setting each time the volume is changed. In this way, an optimized sound could be achieved at any volume (e.g. minimum, low, middle, high, and maximum volume). Adjusting the equalizer setting each time the volume is changed, however, would be very cumbersome (and therefore, this is usually not done). Therefore, there is a need for a better way of controlling multichannel signals.

Another problem arises, when an audio system (e.g. amplifier and/or speakers) produces for different volumes non-linear responses at different frequencies. For instance, it could happen that at a low volume the response of low frequencies is lower than the response of high frequencies, and that at a high volume the response of low frequencies is higher than the response of high frequencies. Again, such a situation would require adjusting an equalizer setting each time the volume is changed in order to produce a good sound for the whole range of possible volumes.

Other examples for multichannel signals are video signals, where similar problems can arise. For example, the user of a computing device might prefer a rather warm tone for a light signal with a low brightness (intensity) and a colder (more brilliant) tone for a light signal with a high brightness (intensity). In order to have the desired tone for any particular brightness the user would have to recalibrate the (RGB) video signal each time the brightness (intensity) is changed. Recalibrating the (RGB) video signal each time the brightness (intensity) is changed, however, would be impractical. Again, there is a need for a better way of controlling multichannel signals.

A problem to be solved by the invention is to control multichannel signals in such a way that the quality of the multichannel signal is as high as possible. At the same time, the way of controlling multichannel signals should be as convenient as possible.

The above mentioned problem is solved by the system according to claim 1, the method according to claim 4, and the data structure according to claim 15. Additional embodiments of the invention are specified in the dependent claims.

A multichannel signal comprises a plurality of channels (e.g. 2, 3, 4, 5, 6, 7 or more than 7 channels). For example, an audio signal may comprise two channels, namely a "left" channel and a "right" channel. An example for a three-channel signal is an RGB video signal which comprises a "red" channel, a "green" channel and a "blue" channel. Further, the channels of a multichannel signal may represent frequencies or frequency ranges of an audio signal. There are plenty of additional examples for multichannel signals, where, for instance, the channels represent different light sources, different sound sources (e.g. speakers) different heating and/or cooling sources, or different mechanical and/or electrical parts of a device. In a multichannel signal each channel has assigned a channel value as is described in context with Fig. 6. When a multichannel signal is changed, this means that at least one (or more) of the channel values is changed.

A spectrum may be a continuous spectrum or a discrete spectrum. An example for a continuous spectrum is S(x) , where x can be any value of the whole range (or a value between a lower bound and an upper bound, respectively) of the spectrum S(x) . Thus, a continuous spectrum can be represented by an analytical function or a parametrization, respectively. An example for a discrete spectrum is Si with i = Ι, ., ., η, where n is the number of discrete values of the spectrum 5*. Hence, a discrete spectrum can be represented by a vector or a list, respectively.

Both, a continuous spectrum and a discrete spectrum may be represented by a set of channels S. In case of a discrete spectrum each discrete spectrum value may be represented by a corresponding channel. A continuous spectrum may comprise a set of intervals (e.g. without gaps in between neighboring intervals), where each interval may be represented by a corresponding channel. If a continuous spectrum does not consist of intervals, the spectrum may be converted into an aforementioned continuous spectrum consisting of a set of intervals by partitioning the spectrum into intervals and thus, such a spectrum may be represented by a set of channels, too. Another possibility is to parameterize a continuous spectrum and to represent said spectrum by a set of channels, where each parameter (of the spectrum parametrization) corresponds to a channel. Therefore, discrete spectra and/or continuous spectra may be represented by sets of channels.

In the following description it is referred to sets of channels (5) and to sets of channel values (51, S2, 53, ...) where a spectrum is represented by a set of channels (e.g. "red" , "green" and "blue") and by the corresponding set of channel values (e.g. 0.5, 0.2 and 0.9). Another example is a sound spectrum, which is represented by a set of channels with frequency intervals (e.g. [50 Hz, 100 Hz], [100 Hz, 200 Hz], ...) and by a set of channel values with signal strengths or gains, respectively (e.g. 5 dB, 3 dB, ...). Furthermore, each channel of a set of channels has a corresponding channel value in a set of channel values, as is described in more detail in context with Fig. 6.

The overall signal strength of one set of channel values may be represented by one magnitude level. For instance, a magnitude level may be the average signal strength value of all channel values of an associated set of channel values, or a magnitude level may be a signal strength value of one particular channel of an associated set of channel values (e.g. the minimum or maximum signal strength value of the set of channel values).

Another possibility is to assign for a given set of channel values an arbitrary (or independent) value to the magnitude level. For instance, a first magnitude level for a first set of channel values is assigned with the value 1 (e.g. representing a low volume), and a second magnitude level for a second set of channel values is assigned with the value 10 (e.g. representing a high volume), where the scales of the magnitude levels and of the sets of channel values are different (e.g. the the channel values vary between -1 and 1).

If there are two sets of channel values 51 and 52, wherein 51 is associated with a first magnitude level LI and where 52 is associated with a second magnitude level L2, a third set of channel values 53 may be determined for an associated third magnitude level L3. The new set of channel values 53 may be obtained by interpolating (or extrapolating) between the sets of channel values 51 and 52 using magnitude levels LI, L2 and LS. It is noted that determining a set of channel values basically means determining the value (or parameter) of each channel of the set of channel values.

The sets of channel values 51, 52 and 53 each comprise n values, where n is the number of channels and the number of channel values, respectively. Therefore, the determination of the third set of channels may be performed for each channel in the following way:

where n is the number of channels of each set of channel values (51, 52 and 53). In Equation 1 each channel value 53* is determined based on the corresponding channel value 51 j and on the corresponding channel value 52j (51*, 52j and 53j have all the same index i). Further, the determination of each channel value 53j is based on the magnitude levels LI, L2 and LZ. It is pointed out that the magnitude levels LI, L2 and LZ do not carry indices and therefore, each magnitude level is the same for all channels.

In addition to Equation 1 the third set of channel values may be determined in one of the following ways: s^s'-^il-(¹-i i|)- ¹'^{+ £2}-(¹-jirn)-^s¾ "^*-¹--." ^(¾ or

( LZ— L\\ ( L — LZ\

1 - _L2__L1 )^■ Sit + LZ^■ 11 - _{L2 L1})^■ S2i with * = 1, ...,n (3)

In Equations 2 and 3 the third set of channel values 53 is proportional to one or a combination of the magnitude levels LI, L2 and LZ (meaning that in the third set of channel values 53 magnitude levels are reflected, too). Equations 2 and 3 lead to similar results. The results of Equations 2 and 3, however, are generally not exactly the same.

Equations 1 to 3 may be expressed in the following short way:

53i = LI -Fl-SU + L2-F2-S2i (4.2)

5¾ = LZ- Fl-SU + LZ-F2-S2i (4.3) where l = 1-(L3-L1)/(L2-L1) and F2 = 1- (L2 - LZ) / (L2 - LI) are dimensionless factors which each are functions of the magnitude levels LI, L2 and LZ. In case L and Si are quantities that should be combined by addition (e.g. logarithmic quantities), Equations 1 to 3 or Equations 4, respectively, may have the following form:

53i = Fl-SU + F2-S2i (5.1)

5¾ = F1- (L1 + SU) + F2- (L2 + S2i) (5.2)

5¾ = LZ + Fl-SU + F2-S2i (5.3) with the same dimensionless factors as above. Whereas in Equations 4.1 and 5.1 the channel values 53j depend only on the two dimensionless factors Fl and F2 (which axe not proportional to any magnitude level), in Equations 4.2, 4.3, 5.2 and 5.3 the channel values 53j depend additionaly on the magnitude level LI and L2, or LZ, respectively. This means that in case of Equations 4.2, 4.3, 5.2 and 5.3 at least one magnitude level is reflected (by addition and/or by multiplication) in the third set of channel values 53.

It becomes clear (e.g. from Equation 1) that an actual interpolation can only be performed, if the magnitude levels LI and L2 are different from each other. In the case LI and L2 have been chosen (by accident) to be the same, for example, the averages 53j = · (5l_f + 52j) may be used instead.

If, for instance, the magnitude level L3 is equal to the magnitude level LI, the new set of channel values 53 is the same as 51 according to Equation 1. In such a case the interpolation may be simplified or even omitted, and less than the full set of input information (51, 52, LI, L2 and L3) may be needed in order to obtain 53. (In this example LI, LZ, and 51 would be sufficient in order to be able to determine 53.) An analogue situation arises if the magnitude levels LZ and L2 are equal. Moreover, if the channel values 51j and 52j with the same index i are equal, it follows from Equation 1 that 53j = 51j = 52* and therefore, in this case the interpolation may also be simplified or omitted, respectively.

It is noted that Equations 1 to 5 may be written in different ways, such that the resulting set of channel values 53 is identical. Further, other techniques may be used in order to obtain the third set of channel values 53, such as for instance, weighting techniques and/or averaging techniques.

A first embodiment of the invention concerns a system capable of controlling multichannel signals. A multichannel signal comprises a plurality of n channels, such as for instance, 2, 3, 4, 5, or more than 5 channels. The syatem comprises a controller with a processor, a first magnitude level LI and an associated first set of channel values 51 comprising n channel values 51 j, and a second magnitude level L2 and an associated second set of channel values 52 comprising n channel values 52j. The controller is adapted to receive a third magnitude level LZ. And the processor is configured to determine a third set of channel values 53 which is associated with the third magnitude level LZ. The third set of channel values 53 comprises n channel values 53*. For each channel i = 1, n a channel value 53j of the third set of channel values 53 is determined based on the channel value 5lj (with the same index i) of the first set of channel values 51, the channel value 52j (with the same index i) of the second set of channel values 52, said first magnitude level LI, said second magnitude level L2, and said third magnitude level L3.

The determination of each channel values of the third set of channel values 53 may be based on one or more corresponding channel values (with the same index i) of one or more additional sets of channel values (e.g. a fourth set of channel values 54) and on one or more additional magnitude levels (e.g. a fourth magnitude level LA) which are associated with the corresponding one or more additional sets of channel values.

Optionally, the system of the first embodiment comprises means for selecting one or more magnitude levels, wherein the one or more magnitude levels comprise (at least) the third magnitude level L3, and /or wherein the means for selecting one or more magnitude levels is capable of transmitting the one or more magnitude levels to the controller. The means for selecting one or more magnitude levels may be a user interface allowing a user to select and/or change the one or more magnitude levels. Alternatively, the means for selecting one or more magnitude levels is a (computing) device which is configured to automatically select and/or change the one or more magnitude levels.

As a further option the system of the first embodiment comprises means for receiving at least the third set of channel values 53 from the controller and/or for generating one or more output signals. An output signal may comprise n output signal values (¼. The output signal may be generated by determining an output signal value Oi for each channel i = 1, n based on the corresponding channel value 53* of the third set of channel values 53. Said generation of an output signal may comprise scaling each channel value 53j of the third set of channel values 53 and/or performing a digital to analog conversion for each channel value 53j of the third set of channel values 53. The one or more output signals may be audio signals and/or the one or more output signals may be video signals.

A second embodiment of the invention concerns a method for controlling multichannel signals. Multichannel signal are signals with a plurality of n channels (e.g. n > 2 channels). In a first step a first magnitude level LI and a first set of channel values 51 which is associated with the first magnitude level LI is received, where the first set of channel values 51 comprises one channel value 5lj for each channel i = l, ... , n. In a second step a second magnitude level L2 and a second set of channel values 52 which is associated with the second magnitude level L2 is received, where the second set of channel values 52 comprises one channel value 2* for each channel i = l, ..., n. In a third step a third magnitude level L3 is received. And in a fourth step a third set of channel values 53 which is associated with the third magnitude level L3 is determined. In said fourth step for each channel i = 1, ... , n a channel value 53j of the third set of channel values 53 is determined based on the corresponding channel value 5li of the first set of channel values 51, the corresponding channel value 52 j of the second set of channel values 52, the first magnitude level LI, the second magnitude level L2, and the third magnitude level L3.

In the second embodiment the steps of receiving a third magnitude level LZ and determining a third set of channel values 53 may be repeated (at least) a second time. Moreover, the first magnitude level LI, the first set of channel values 51, the second magnitude level L2, and the second set of channel values 52 may be updated (received) typically fewer times than the third magnitude level L3 and the third set of channel values 53 are updated (e.g. LI, L2, 51 and 52 are updated each time an audio device is set up at a new location, whereas L3 and 53 are updated each time the volume L3 of said audio device is changed). The method of the second embodiment may be performed employing the system of the first embodiment.

A third embodiment of the invention concerns a data structure comprising computer- executable instructions for controlling multichannel signals. The data structure is, for instance a computer-readable medium (e.g. a compact disk, a floppy disk, or a hard disk), a file (for download) or data stream. Further, the controller of the first embodiment may comprise the data structure of the third embodiment and/or the processor of the first embodiment may employ the data structure of the third embodiment. Moreover, the data structure of the third embodiment may comprise instructions for performing one or more methods of the second embodiment.

Regarding any of the above mentioned embodiments, controlling a multichannel signal means determining a set of channel values for a selected magnitude level. Further, each channel value 53i of the third set of channel values 53 may be determined with the same algorithm as all the other values 3j of the third set of channel values 53. Moreover, each channel value 53j of the third set of channel values 53 may be determined by performing an interpolation and /or an extrapolation and/or a weighted averaging (method). Typically, the lower magnitude level of Ll and L2 is in the lowest quarter of the whole range of possible magnitude levels, and the higher magnitude level of Ll and L2 is in the highest quarter of the whole range of possible magnitude levels. For example, if the whole range is between 0 and 10, then the lower magnitude level (e.g. Ll) would typically be below 2.5 and the higher magnitude level (e.g. L2) would typically be above 7.5. It is possible, however, that the magnitude levels of Ll and L2 are closer to each other (e.g. Ll = 4 and L2 = 6). In the latter case, Equations 1 to 5 could be used, too, in order to determine the third set of channel values 53. If, however, Ll and L2 have (accidentally) been chosen to be the same, for example, the averages 53; = ^■ (SU + 52_») may be used instead of an interpolation technique.

Regarding any of the above mentioned embodiments, a channel value 53j of the third set of channel values 53 may be determined for each channel i = 1, n according to the equation 53j = Fl · 5lj + F2^■ 52j. Alternatively, a channel value 53j of the third set of channel values 53 may be determined for each channel i— 1, n according to one of the following equations: 53; = Ll -Fl -Sli+L2 F2-S2i , 53_» = Fl -(Ll+5li)-l-F2-(L2-|-5¼), 53_» = L3 · Fl · 51_» + L3 · F2^■ 52_» or 5¾ = L3 + Fl^■ SU + F2^■ 5¼. In all of the above mentioned equations 51* is the corresponding channel value of the first set of channel values 51, 52_» is the corresponding channel value of the second set of channel values 52, Ll is the first magnitude level, L2 is the second magnitude level, L3 is the third magnitude level, Fl and F2 are dimensionless factors. Each of the dimensionless factors depends the first magnitude level Ll, the second magnitude level L2 and the third magnitude level L3. In particular, the dimensionless factors may be defined as Fl = 1— (L3— L1)/(L2— Ll) and F2 = 1— (L2— L3)/(L2— Ll). It is noted that the dimensionless factors may be defined differently in such a way that the determination of a channel value 53, of the third set of channel values 53 leads to similar (or even identical) results.

Regarding any of the above mentioned embodiments, the multichannel signals may be sound signals and/or audio signals and/or light signal and/or video signals. Further, each set of channel values (e.g. 51, 52 and 53) may represent a characteristics of a frequency spectrum. For instance, each channel i = Ι, .,. , η represents a frequency or a frequency range of a frequency spectrum, and each channel value 53j of the third set of channel values 53 represents an amplitude (e.g. a volume, gain, or intensity) of said frequency spectrum. Said frequency spectrum may be a sound spectrum or a light spectrum.

Regarding any of the above mentioned embodiments, the multichannel signal may be an audio signal which is controlled with an equalizer (e.g. a digital equalizer) and a volume control, wherein the first set of channel values 51 and the second set of channel values 52 each corresponds to an equalizer setting, and wherein the first magnitude level LI, the second magnitude level L2 and the third magnitude level L3 each corresponds to a setting of the volume control. Further, the third set of channel values 53 may represent an equalizer setting (where each channel value 53i is determined according to, for instance, Equation 4.1 or 5.1). Alternatively, the third set of channel values 53 may represent an equalizer setting and the current setting of the volume control (where each channel value 53j is determined according to, for instance, Equation 4.2, 4.3, 5.2 or 5.3). Thus, when the setting of the volume control is changed the overall volume and the sound (corresponding to a particular equalizer setting which is determined automatically) of the audio signal are changed.

Further aspects of possible embodiments of the invention become clear from Figs. 1, 2, 3, 4, 5 and 6:

Fig. 1 shows a system which is capable of controlling multichannel signals.

Fig. 2 shows a flow chart of a method for controlling multichannel signals.

Fig. 3 shows a first example of a determined multichannel signal.

Fig. 4 shows a second example of a determined multichannel signal.

Fig. 5 shows a third example of a determined multichannel signal.

Fig. 6 shows an exemplary representation of a multichannel signal.

In Fig. 1 a system is illustrated which can be used to control multichannel signals. Controller 11 comprises a processor P and information which can be used by the processor P. The information comprises magnitude levels (e.g. LI, L2 and L3) and corresponding sets of channel values (e.g. 51, 52 and 53). Although only magnitude levels LI, L2 and L3, and sets of channel values 51, 52 and 53 axe shown, said information may comprise additional magnitude levels and/or additional sets of channel values and/or processor-executable instructions, for example.

Processor P may be configured to determine the third set of channel values 53 using LI, 51, L2, 52 and L3. Since said determination is based on LI, 51, L2, 52 and L3, this information has to be present before 53 can be determined. The third set of channel values 53 does not need to be present before said determination of 53. It is possible, however, that an old set of channel values 53 is present and said old set of channel values 53 is overwritten with a new set of channel values 53 (once the new set of channel values 53 has been determined). Typically, a new set of channel values 53 is determined each time the magnitude level L3 is updated.

Further, Fig. 1 shows means 12 for selecting one or more magnitude levels. In particular, the means 12 are suitable for selecting the magnitude level L3. Other magnitude levels (e.g. LI and L2) may either be selected by the same means 12 or may be selected by different means (similar to means 12). Means 12 may either be a user interface (e.g. a control or dial) or mans 12 may be a (computing) device that is configured to select magnitude levels automatically. Component 12 is capable of transmitting one or more magnitude levels to controller 11. Further, component 12 may comprise an analog to digital converter (e.g. in case digital signals are desired for further processing).

Once a new set of channel values 53 has been determined Controller 11 may transmit the new set of channel values 53 to component 13 which is configured to receive the new set of channel values 53. Further, component 13 may be configured to further process (e.g. scale up or down) the set of channel values 53. For example, component 13 may comprise a digital to analog converter (e.g. for generating an analog output signal). Moreover, component 13 may be configured to generate one or more output signals. Output signals may be (stereo) audio and/or video signals, for instance.

It is noted that the components 12 and/or 13 are optional. Further, components 11, 12 and 13 may be located in the same physical device. Moreover, each component may be located in a separate physical device. Other possibilities are that components 11 and 12 are located in the same physical device and that component 13 is located in a separate physical device, or that components 11 and 13 are located in the same physical device and that component 12 is located in a separate physical device. Moreover, components 12 and 13 may be located in the same physical device and controller 11 is located in a separate physical device. The latter combination may be used in cases where an existing system is upgraded (or extended) with a controller 11 such that the new system is better capable of controlling multichannel signals.

In Fig. 2 a flowchart of a method for controlling multichannel signals is illustrated. The method starts at step 20. In step 21 a first magnitude level LI and a first set of channel values 51 which is associated with the first magnitude level LI are received. Further, in step 22 a second magnitude level L2 and a second set of channel values 52 which is associated with the second magnitude level L2 are received. Furthermore, a third magnitude level L3 is received in step 23. Alternatively, steps 21, 22 and 23 may be carried out in a single step. Moreover, the magnitude levels LI, L2 and L3 and the sets of channel values 51 and 52 may be received in a different order.

Then, in step 24 a third set of channel values 53, which is associated with the third magnitude level L3 is determined. Determining 53 typically means that channel values 53j are determined for each channel i = l, ... , n. Said determination of the third set of channel values 53 is based on the magnitude levels LI, L2 and L3, and the sets of channel values 51 and 52. For example, the third set of channel values 53 is determined by performing an interpolation, extrapolation or weighted averaging (e.g. according to any of Equations 1 to 5). The representation of sets of channel values (e.g. 51, 52 and 53) is described in context with Fig. 6.

After step 24 the method is done. Alternatively, the method proceeds to step 25. At step 25 it is determined whether an update of the magnitude level L3 is accepted or not. If no update of L3 is accepted, the method proceeds to the end 26. If, however, an update of L3 is accepted, the method proceeds to step 23, where a new magnitude level L3 may be received. Alternatively, if an update of L3 is accepted, the method may wait for an update of L3 and then proceed to step 23. Such a situation is when a user updates the magnitude level L3 by changing the control of selector 12, for instance. If updates of LI and/or L2 and/or 51 and/or 52 are to be used for the determination of 53, then typically all method steps are repeated, but parts of steps 21, 22 and 23 may be omitted. An optional step (not shown) may be to check (e.g. after step 22) whether the magnitude levels LI and L2 are different from each other or not, and in case LI and L2 are not different from each other to repeat steps 21 and/or 22 (until magnitude levels LI and L2 are received that are actually different from each other).

For example, the above described method may be carried out by the processor P of controller 11, shown in Fig. 1. Further, the above described method may be carried out for any number of channels of a set of channel values (e.g. 2, 3, 4, 5 or more than 5). The number of channels is the same for each of the sets of channel values 51, S2 and 53.

A first example of controlling a multichannel signal is shown in Fig. 3. In this particular example, a first characteristics 31 of a first set of channel values 51 is associated with a magnitude level LI = 2 (not shown) , and a second characteristics 32 of a second set of channel values 52 is associated with a magnitude level L2 = 10 (not shown). Starting from the aforementioned information any third set of channel values 53 can be determined for a given third magnitude level LZ (not shown). In this example, the third set of channel values 53 is determined for the magnitude level LZ = 5.5 according to Equation 1. The resulting third set of channel values LZ has the characteristics 33. It is noted that, for instance, the magnitude levels LI = 4, L2 = 20 and LZ = 11 would result in exactly the same characteristics 33.

The example, illustrated in Fig. 3, may be used to control a multichannel signal of an equalizer (of an audio system) , for instance, where the sets of channel values 51, 52 and 53 each consist of 10 channels. Each set of channel values may correspond to a frequency spectrum with 10 adjacent frequency ranges which may add up to a continuous overall frequency spectrum (e.g. in the range of 20 Hz to 20 kHz) . In the example of Fig. 3, the number of channels is exemplary. In general, the number of channels may be higher or lower than 10.

The third set of channel values 53 (with characteristics 33) may be determined with the system and/or with the method which are described in context with Figs. 1 and 2, respectively. In this particular example, Equation 1 is used to determine each cannel value of the set of channel values 53 with characteristics 33.

If, however, the magnitude level LZ would be chosen closer to the magnitude level LI than in the example illustrated in Fig. 3 then the characteristics 33 would be closer (closer in magnitude and closer in shape) to the characteristics 31 (using the same algorithm). Similarly, if the magnitude level L3 would be chosen closer to the magnitude level L2 (than in the example illustrated in Fig. 3 and using the same algorithm) then the magnitude and shape of characteristics 33 would be closer to the magnitude and shape of the characteristics 32. Further, if the the magnitude level L3 was selected to be the average L3 = ^■ (L1+L2) of LI and L2, then each channel value of 53 would be the average of the corresponding channel values of SI and 52, namely 53j = (Sli+S2i) with i = 1, 2, 10 in case of 10 channels. Furthermore, the characteristics 33 and 31 would be identical for L3 = L\, and the characteristics 33 and 32 would be identical for L3 = L2. (The latter three cases can be verified by replacing L3 with ^■ (LI + L2), LI or L2 in Equation 1.)

A second example of controlling a multichannel signal is shown in Fig. 4. Each set of channel values comprises three channel values labeled with a, b and c. These three channel values could correspond to "low" , "mid" and "high" channels of an audio signal, for example. In another example, these three channels could correspond to "red" , "green" and "blue" channels of a video signal. The values 41 represent the first set of channel values 51, the values 42 represent the second set of channel values 52, and the values 43 represent the third set of channel values 53. In this particular example of Fig. 4, the third set of channel values is determined based on the first set of channel values 51, the second set of channel values 53 and the three magnitude levels LI, L2 and L3 according to Equation 1 with the level choices LI = 0.1, L2 = 0.9, and L3 = 0.5 (not shown).

It is noted, however, that the choices LI = c · 0.1, L2 — c · 0.9, and L3 = c · 0.5, where c is any constant number that is not equal to zero, would have led to an identical result. Further, it is noted that the magnitude level L3 does not have to be in between magnitude levels LI and L2, but magnitude level L3 could also be below magnitude level LI or above magnitude level L2, respectively. In the latter case the values 43 would be below values 41 or above values 42, respectively. Moreover, the closer magnitude level L3 would be to magnitude level LI, the closer (in shape and in magnitude) values 43 would be to values 41. And the closer magnitude level L3 would be to magnitude level L2, the closer (in shape and in magnitude) values 43 would be to values 42.

If, for example, in Fig. 4 a video signal is represented (the three channels corresponding to "red" , "green" and "blue" of the video signal) then the color of the video signal corresponds to the first set of channel values 51 (with RGB values 41) if the magnitude levels LI and LZ are equal. In this case the intensity (magnitude) of the video signal would be relatively low. If then the magnitude level LZ is increased, the intensity of the video signal is increased, too, and the color becomes closer to the color corresponding to the values 42 of the second set of channel values 52. If the magnitude level LZ eventually is the same as the magnitude level L2, the video signal would have the same intensity and color as is defined by the second set of channel values 52 which is associated with the second magnitude level L2.

In the example of Fig. 4 the value 43a (of 53) is determined based on the magnitude levels LI, L2 and LZ, and based on the values 41a (of 51) and 42a (of 52). Correspondingly, the value 436 (of 53) is determined based on the magnitude levels LI, L2 and LZ, and based on the values 416 (of 51) and 426 (of 52) , and the value 43c (of 53) is determined based on the magnitude levels LI , L2 and LZ, and based on the values 41c (of 51) and 42c (of 52). Thus, each channel 53j of the set of channel values 53 is determined based on the magnitude levels LI , L2 and LZ, and based on the corresponding channel values 5li and S2i of the sets of channel values 51 and 52, respectively, for all channels i = 1, ..., n, where n is the number of channels.

A third example of controlling a multichannel signal is shown in Fig. 5. Diagram 51 is an illustration of the first set of channel values 51, and diagram 52 is an illustration of the second set of channel values 52. In this example, the third set of channel values, shown in diagram 53, is determined for the magnitude levels LI— 1.0, L2 = 9.0 and LZ = 6.5 according to Equation 2. The number of channels is n = 7 in this particular case. In contrast to the examples of Figs. 3 and 4 the scale of the third set of channel values 53 (diagram 53) is different form the scales of the first and second sets of channels 51 and 52 (diagrams 51 and 52). Employing Equation 2 allows to determine a third set of channel values 53 which reflects (in each channel value 53j with i = 1, ... , n) the magnitude of the magnitude levels LI and L2. It is noted that determining the third set of channel values 53 using Equation 3 would lead to a similar result. In the latter case, however, the third set of channel values 53 would reflect the magnitude of the third magnitude level LZ (in each channel value 53i with i = 1 , ... , n). In Fig. 5 the diagrams 51 and 52 may each represent an equalizer setting. Said equalizer settings are defined at the corresponding settings of a volume control (e.g. magnitude levels LI and L2). Both diagrams 51 and 52 have a scale from zero to one, whereas diagram 53 has a scale between zero and ten. The scale of diagram 53 is different (in the particular case of Fig. 5) because the third set of channel values 53 represents an equalizer setting and a setting of the volume control (e.g. a weighted average of the magnitude levels LI and L2).

In Fig. 6 it is illustrated how a multichannel signal (with three different characteristics) may be represented by one set of channels 5 and (in this particular case) three sets of channel values 51, 52 and 53. As is illustrated in Fig. 6, the number of channels and the number of channel values, respectively, is n for each set. In Fig. 6, individual channel numbers are indicated by the subindices i = 1, 2, ..., n. Depending on the particular application n is 2, 3, 4, 5 or more than 5. For one particular application, however, n is the same number for all sets 5, 51, 52 and 53. Hence, each channel of 5 has one corresponding channel value (5lj, 52j and 53i) in each set of channel values 51, 52 and 53. It is noted, that the number of sets of channel values may be more than three.

For example, a light/video signal may be represented with RGB values. Thus the set of channels has three channels, namely the "red" , "green" and "blue" channels. Therefore, a corresponding set of channel values has three channel values (e.g. 0.7, 0.4 and 0.9). In the latter example, each set of channel values corresponds to a particular color. Correspondingly, a sound/audio signal may be represented by a set of channels 5, where each channel represents a frequency range, and where a set of channel values comprises values that may represent gains and/or volumes.

In the present invention a multichannel signal is controlled by determimng a third set of channel values 53. As is described in context with Equation 1 the third set of channel values 53 is determined based on a first set of channel values 51, a second set of channel values 52 and three magnitude levels LI, L2 and L3. In other words, multichannel signals are controlled by determining sets of channel values. When a multichannel signal is controlled (or manipulated) the number of channels n and/or the channels themselves remain the same during the whole procedure. Thus, for the aforementioned determination of 53 the set of channels 5 is not used directly. There axe various examples of applications, where the above described system and method for controlling multichannel signals may be employed in audio (or sound) systems. Such applications are, for instance, surround sound systems, headphones, telephones, car hi-fi systems, home entertainment systems, audio systems for conference rooms, computing systems, music equipment, musical instruments, and audio recording systems.

Examples of the above mentioned system and method of controlling multichannel signals in applications which are related to video (or fight) signals are video systems with different fight sources (e.g. theaters, show and/or meeting rooms, cinemas, cars, illumination systems for buildings or parks) and video systems (e.g. involving RGB signals), such as monitors, displays, color fight sources, beamers and cameras.

Even though the invention has mainly been discussed in context with audio and video signals, there axe other applications possible, too, such as for instance temperature regulating systems or electro-mechanical systems comprising a plurality of parts moved by actuators, where each actuator may correspond to one channel of a set of channels.

A typical use case is an audio system comprising an equalizer (for controlling sets of channel values) and a volume control (for selecting magnitude levels) , where a user would like to optimize the sound at different volume levels. Employing the system and/or method for controlling multichannel signals the user starts to optimize the sound of the audio system by adjusting the equalizer channel values 51 at a low volume LI. Then the user of the audio system optimizes the sound by adjusting the equalizer channel values 52 at a high volume L2. After these two steps the user can select any volume L3, and then the channel values 53 are automatically adjusted (by an audio system according to the invention) based on LI, 51, L2, 52 and L3. The channel values 53 may represent equalizer channel values (where each channel value 53* is determined according to, for instance, Equation 4.1 or 5.1). Further, the channel values 53 may represent equalizer channel values and the selected volume (where each channel value 53j is determined according to, for instance, Equation 4.2, 4.3, 5.2 or 5.3). Automatically adjusting the channel values 53 each time the volume L3 is updated results in a better sound (e.g. almost free of nonfinearity effects and/or undesired resonances) at any selected volume L3. Therefore, the quality of the sound is as high as possible for any selected volume while the way of controlling and optimizing the sound is as convenient as possible.

Claims

1. A system capable of controlling multichannel signals, wherein a multichannel signal comprises a plurality of n channels, the system comprising: a controller (11) comprising a processor (P) , a first magnitude level (LI) and an associated first set of channel values (51) comprising n channel values (5lj) , and a second magnitude level (L2) and an associated second set of channel values (52) comprising n channel values (52j); wherein the controller (11) is adapted to receive a third magnitude level (£3); and wherein the processor (P) is configured to determine a third set of channel values (53) which is associated with the third magnitude level (L3), where the third set of channel values (53) comprises n channel values (53i) , and where for each channel i = 1, n a channel value (53j) of the third set of channel values (53) is determined based on the corresponding channel value (5li) of the first set of channel values (51) , the corresponding channel value (52j) of the second set of channel values (52) , the first magnitude level (LI), the second magnitude level (L2) , and the third magnitude level (L3).

2. The system according to claim 1 further comprising: means (12) for selecting one or more magnitude levels, wherein the one or more magnitude levels comprise the third magnitude level (L3), and/or wherein the means (12) for selecting one or more magnitude levels is capable of transmitting the one or more magnitude levels to the controller (11).

3. The system according to claim 1 or 2 further comprising: means (13) for receiving at least the third set of channel values (53) from the controller (11) and for generating one or more output signals.

4. A method for controlling multichannel signals, wherein a multichannel signal comprises a plurality of n channels, the method comprising: receiving (21) a first magnitude level (Ll) and a first set of channel values (51) which is associated with the first magnitude level (Ll) , wherein the first set of channel values (51) comprises one channel value (SI*) for each channel i = 1, ..., n; receiving (22) a second magnitude level (L2) and a second set of channel values (52) which is associated with the second magnitude level (L2) , wherein the second set of channel values (52) comprises one channel value (52j) for each channel i = 1 , ... , n; receiving (23) a third magnitude level (L3); and determining (24) a third set of channel values (53) which is associated with the third magnitude level (LZ) , wherein for each channel i = 1, ... , n a channel value (53*) of the third set of channel values (53) is determined based on the corresponding channel value (51 j) of the first set of channel values (51) , the corresponding channel value (52j) of the second set of channel values (52), the first magnitude level (Ll), the second magnitude level (L2) , and the third magnitude level (L3).

5. The method according to claim 4, wherein the steps of receiving (23) a third magnitude level (LZ) and determining (24) a third set of channel values (53) are performed at least two times, and/or wherein the first magnitude level (Ll) , the first set of channel values (51), the second magnitude level (L2) , and the second set of channel values (52) are updated fewer times than the third magnitude level (LZ) and the third set of channel values (53) are updated.

6. The system/method according to any of claims 1 to 5, wherein each channel value (53i) of the third set of channel values (53) is determined by performing at least one of: interpolation, extrapolation, and weighted averaging.

7. The system/method according to any of claims 1 to 6, wherein for each channel i = 1, ..., n the channel value (53;) of the third set of channel values (53) is determined according to

where 51; is the corresponding channel value of the first set of channel values ( 1), where 52; is the corresponding channel value of the second set of channel values (52), and where Fl and F2 are dimensionless factors.

8. The system/method according to any of claims 1 to 6, wherein for each channel i = l, ..., n the channel value (53;) of the third set of channel values (53) is determined according to

53; = LI■ Fl · 51; + L2^■ F2^■ 52;

or 53; = Fl · (LI + 51;) + F2 · (L2 + 52;)

or 53; = L3 · Fl · 51; + L3^■ F2 · 52;

or 53; = L3 + Fl · 51; + F2 · 52;

where 51; is the corresponding channel value of the first set of channel values (51), where 52; is the corresponding channel value of the second set of channel values (52), where LI is the first magnitude level, where L2 is the second magnitude level, where L3 is the third magnitude level, and where Fl and F2 are dimensionless factors.

9. The system/method according to claims 7 or 8, wherein each of the dimensionless factors (Fl, F2) is a function of the first magnitude level (LI) , the second magnitude level (L2) and the third magnitude level (LZ) .

10. The system/method according to any of claims 1 to 9, wherein the multichannel signals are one or more of the following: sound signals, audio signals, hght signals and/or video signals.

11. The system/method according to any of claims 1 to 10, wherein each channel i = l, ... , n represents a frequency or a frequency range of a frequency spectrum, and wherein each channel value (53j) of the third set of channel values (S3) represents an amplitude of said frequency spectrum.

12. The system/method according to any of claims 1 to 11, wherein the multichannel signal is an audio signal which is controlled by an equalizer and a volume control, wherein the first set of channel values (51) and the second set of channel values (52) each corresponds to an equalizer setting, and wherein the first magnitude level (LI), the second magnitude level (L2) and the third magnitude level (L3) each corresponds to a setting of the volume control.

13. The system/method according to claim 12, wherein the third set of channel values (53) represents an equalizer setting.

14. The system/method according to claim 12, wherein the third set of channel values (53) represents an equalizer setting and a current setting of the volume control.

15. A data structure comprising computer-executable instructions for performing one or more methods according to any of claims 4 to 14.