Patent Description:
Audio zoom is an audio operation where sound sources in one or more directions can be amplified compared to sound sources in other directions. This can be achieved using two or more microphones and beamforming.

<CIT> discloses (abstract) an electronic device including a camera, a plurality of microphones, at least one processor electrically coupled with the camera and the plurality of microphones. The at least one processor may acquire a video signal, based on a designated zoom level via the camera, acquire a plurality of audio signals respectively via the plurality of microphones while acquiring the video signal, identify a first signal characteristic of a first audio signal acquired via a first microphone and a second signal characteristic of a second audio signal acquired via a second microphone among the plurality of microphones, derive a control parameter for signal processing for the first audio signal and the second audio signal, based on the designated zoom level, the first signal characteristic, and the second signal characteristic, and perform audio signal processing including beamforming using the first audio signal and the second audio signal, based on the derived control parameter.

According to various, but not necessarily all, examples of the disclosure there is provided an apparatus comprising means for:.

The first direction may be within a region of interest and the second direction may be outside of the region of interest.

The amount of headroom provided may be controlled so as to enable audio zooming.

If the sound energy in the at least one second direction is not different to the sound energy by at least the threshold amount then the amount of headroom may be controlled to be large enough to enable amplification of the audio signal when audio zooming is selected.

If the sound energy in the at least one second direction is different to the sound energy by at least the threshold amount then the amount of headroom may be controlled to not be large enough to enable amplification of the audio signal when audio zooming is selected.

If the headroom provided is not large enough to enable amplification of the audio signal when audio zooming is selected the apparatus may be configured to enable audio zooming by attenuation of unwanted sound sources.

The means may be for detecting a change in whether or not the sound energy in the at least one first direction is higher than sound energy in the least one second direction by at least the threshold amount and adjusting the headroom provided based on the detected change.

The amount of headroom provided may be controlled by using automatic gain control.

The amount of headroom provided may be controlled by the compression used.

The sound energy may be measured as a sum of a beamformed signal.

The means may be for determining, for an audio signal, if sound energy in at least one first direction is higher than sound energy in at least one second direction by at least a threshold amount.

According to various, but not necessarily all, examples of the disclosure there is provided a method comprising:.

Examples of the disclosure relate to apparatus, methods and computer programs for enabling audio zooming. The audio zooming can enable sounds within a region of interest to be amplified compared to sounds outside of the region of interest. Audio zoom could be used together with a camera zoom. In such examples the region of interest could be the field of view of the camera or a section of the field of view of the camera. In order to enable effective audio zooming the amount of headroom provided in the audio signals can be controlled based on the types of processing that are to be used to implement the audio zooming. The types of processing that are used to implement the audio zooming can be determined by whether or not there are any loud sound sources outside of the region of interest.

<FIG> schematically shows an electronic device <NUM> according to examples of the disclosure. The electronic device <NUM> could be used to implement examples of the disclosure. The electronic device <NUM> comprises a processor <NUM>, a memory <NUM>, two or more microphones <NUM>, a data bus <NUM>, a wireless network module <NUM>, a transceiver <NUM> and a camera <NUM>. Only components that are referred to in the following description are shown in <FIG>. The electronic device <NUM> could comprise additional components that are not shown in <FIG>. For example, the electronic device <NUM> could comprise a user interface, a power source and/or any other suitable component.

The electronic device <NUM> can be a user electronic device <NUM>. In some examples the electronic device <NUM> could be a hand-held electronic device <NUM>. In some examples the electronic device <NUM> could be a communications device. The electronic device <NUM> could be a mobile telephone, a tablet computer or any other suitable type of electronic device <NUM>.

The processor <NUM> and the memory <NUM> can provide an apparatus such as a controller apparatus. An example processor <NUM> and memory <NUM> are shown in more detail in <FIG>.

The electronic device <NUM> comprises two or more microphones <NUM>. The microphones <NUM> can comprise any means that can be configured to capture sound and enable a microphone audio signal to be provided. The microphones <NUM> can comprise omnidirectional microphones. The microphone audio signals comprise an electrical signal that represents at least some of the sound field captured by the microphones <NUM>.

In the example shown in <FIG> the electronic device <NUM> comprises two or more microphones <NUM>. The microphones <NUM> can be provided at different positions within the electronic device <NUM> to enable spatial audio signals to be captured. In some examples the microphones <NUM> can be provided at different positions within the electronic device <NUM> so that the positions of one or more sound sources relative to the electronic device <NUM> can be determined based an audio signals captured by the microphones <NUM>.

The microphones <NUM> are coupled to the processor <NUM> and the memory <NUM> so that the microphone audio signals are provided to the processor <NUM> for processing. In the example of <FIG> the microphones <NUM> are coupled to the processor <NUM> and memory <NUM> via a data bus <NUM>. Other means for transferring signals between the microphones <NUM> and the processor <NUM> and memory <NUM> could be used in other examples of the disclosure.

The processing performed by the processor <NUM> can comprise enabling audio zooming, locating sound sources and/or any other suitable processing. The processing could comprise methods as shown in any of <FIG> and/or any other suitable processing.

The camera <NUM> can comprise any means that can enable images to be captured. The images could comprise video images, still images or any other suitable type of images. The images that are captured by the camera <NUM> can accompany the microphone audio signals from the two or more microphones <NUM>. The camera <NUM> can be controlled by the processor <NUM> to enable images to be captured.

In some examples of the disclosure the electronic device <NUM> can be used to capture audio signals to accompany images captured by the camera <NUM>. In such examples if a user zooms in on the camera <NUM> or on images captured by the camera this could also cause audio zooming. The audio zooming could amplify the sound sources that are within the images captured by the camera <NUM>. The sound sources that are within the images captured by the camera <NUM> can be determined based on the field of view of the camera <NUM>, the amount of zoom used by the camera <NUM> and the locations of the one or more sound sources. The effective amplification of the sound sources within the images captured by the camera can be achieved by amplifying the wanted sound sources and/or by attenuating unwanted sound sources.

In the example shown in <FIG> the electronic device <NUM> comprises a wireless network module <NUM> and a transceiver <NUM>. The wireless network module <NUM> and a transceiver <NUM> can be configured to enable data to be transmitted from the electronic device <NUM> and data to be transmitted to the electronic device <NUM>. The data that is transmitted from the electronic device <NUM> can comprise audio signals from the microphone <NUM>, processed audio signals, images from the camera <NUM> and or any other suitable data.

<FIG> shows an apparatus <NUM> comprising a processor <NUM> and a memory <NUM>. The apparatus <NUM> could be provided within the electronic device <NUM> as shown in <FIG>. The apparatus <NUM> could provide a control apparatus <NUM> for controlling the electronic device <NUM>.

The apparatus <NUM> illustrated in <FIG> can be a chip or a chip-set. The apparatus <NUM> comprises a processor <NUM> and a memory <NUM>. The processor <NUM> and memory <NUM> can be implemented as circuitry, in hardware, or can be a combination of hardware and software (including firmware).

In some examples the apparatus <NUM> can be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program <NUM> in a general-purpose or special-purpose processor <NUM> that can be stored on a computer readable storage medium (disk, memory etc.) to be executed by such a processor <NUM>.

The processor <NUM> can also comprise an output interface via which data and/or commands are output by the processor <NUM> and an input interface via which data and/or commands are input to the processor <NUM>.

The memory <NUM> is configured to store a computer program <NUM> comprising computer program instructions (computer program code <NUM>) that controls the operation of the apparatus <NUM> when loaded into the processor <NUM>. The computer program instructions, of the computer program <NUM>, provide the logic and routines that enable the apparatus <NUM> to perform the methods illustrated in <FIG> and <FIG>. The processor <NUM> by reading the memory <NUM> is able to load and execute the computer program <NUM>.

The apparatus <NUM> therefore comprises: at least one processor <NUM>; and at least one memory <NUM> including computer program code <NUM>, the at least one memory <NUM> and the computer program code <NUM> configured to, with the at least one processor <NUM>, cause the apparatus <NUM> at least to perform:.

As illustrated in <FIG> the computer program <NUM> can arrive at the apparatus <NUM> via any suitable delivery mechanism <NUM>. The delivery mechanism <NUM> can be, for example, a machine readable medium, a computer-readable medium, a non-transitory computer-readable storage medium, a computer program product, a memory device, a record medium such as a Compact Disc Read-Only Memory (CD-ROM) or a Digital Versatile Disc (DVD) or a solid-state memory, an article of manufacture that comprises or tangibly embodies the computer program <NUM>. The delivery mechanism can be a signal configured to reliably transfer the computer program <NUM>. The apparatus <NUM> can propagate or transmit the computer program <NUM> as a computer data signal. In some examples the computer program <NUM> can be transmitted to the apparatus <NUM> using a wireless protocol such as Bluetooth, Bluetooth Low Energy, Bluetooth Smart, 6LoWPan (IPv<NUM> over low power personal area networks) ZigBee, ANT+, near field communication (NFC), Radio frequency identification, wireless local area network (wireless LAN) or any other suitable protocol.

The computer program <NUM> comprises computer program instructions for causing an apparatus <NUM> to perform at least the following:.

The computer program instructions can be comprised in a computer program <NUM>, a non-transitory computer readable medium, a computer program product, a machine readable medium. In some but not necessarily all examples, the computer program instructions can be distributed over more than one computer program <NUM>.

Although the memory <NUM> is illustrated as a single component/circuitry it can be implemented as one or more separate components/circuitry some or all of which can be integrated/removable and/or can provide permanent/semi-permanent/ dynamic/cached storage.

Although the processor <NUM> is illustrated as a single component/circuitry it can be implemented as one or more separate components/circuitry some or all of which can be integrated/removable. The processor <NUM> can be a single core or multi-core processor.

References to "computer-readable storage medium", "computer program product", "tangibly embodied computer program" etc. or a "controller", "computer", "processor" etc. should be understood to encompass not only computers having different architectures such as single /multi- processor architectures and sequential (Von Neumann)/parallel architectures but also specialized circuits such as field-programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other processing circuitry.

As used in this application, the term "circuitry" can refer to one or more or all of the following:.

The blocks illustrated in <FIG> and <FIG> can represent steps in a method and/or sections of code in the computer program <NUM>. The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block can be varied. Furthermore, it can be possible for some blocks to be omitted.

<FIG> shows an example method according to examples of the disclosure. The method could be implemented using an apparatus <NUM> and/or electronic device <NUM> as described above or using any other suitable type of electronic device or apparatus.

At block <NUM> the method comprises determining, for an audio signal, if sound energy in at least one first direction is different to the sound energy in at least one second direction by at least a threshold amount. For example, the method can comprise determining if sound energy in at least one first direction is higher than the sound energy in at least one second direction by at least a threshold amount.

The first direction and the second direction can be selected so that the first direction is within a region of interest and the second direction is outside of the region of interest. For example, the first direction could be within the field of view of a camera and the second direction could be outside of the field of view of camera. The sound sources in the first direction could therefore be wanted sound sources that a user might want to listen to. For example, sound sources in the first direction could correspond to images captured by the camera <NUM>. The sound sources in the second direction could be unwanted sound sources that user might not want to listen to. For example, these could comprise sound sources that are not in the field of view of the camera <NUM>.

The first direction and the second direction can change depending upon the orientation of the camera <NUM>, the level of zoom used by the camera <NUM> and/or any other suitable factor.

At block <NUM> the method comprises controlling an amount of headroom provided based on whether or not sound energy in at least one first direction is different to the sound energy in at least one second direction by at least a threshold amount. For example, the amount of headroom provided can be controlled based on whether or not sound energy in at least one first direction is higher than the sound energy in at least one second direction by at least a threshold amount. Any suitable means can be used to measure the sound energy in the respective directions. In some examples the sound energy can be measured as a sum of a beamformed signal.

The amount of headroom provided can be controlled so as to enable audio zooming. The amount of headroom provided can be controlled so as to enable audio zooming while maximizing, or substantially maximising, signal levels.

If sound energy in the first direction is significantly higher than the sound energy in the second direction this indicates that the loudest sounds are wanted sounds. For example, the loudest sounds could come from sound sources that are within the field of view of the camera <NUM>.

If sound energy in the first direction is not significantly higher than the sound energy in the second direction this indicates that at least some of the loudest sounds could be unwanted sounds. For example, there could be some loud sound sources that are not located within the field of view of the camera <NUM>.

If the loudest sounds are wanted sounds then the audio zooming can be implemented by using amplification or other suitable processes. In order to allow for the amplification sufficient headroom has to be provided within the signal. Therefore, if the loudest sounds are wanted sounds then the amount of headroom can be controlled so that a large amount of headroom is provided. The large amount of headroom is large enough so as to enable amplification of the audio signal if audio zooming is selected. In some examples the headroom could be around 12dB. This amount of headroom can enable a clear change in the audio when the user selects audio zooming. This enables a user to clearly perceive that audio zooming has been used.

If the loudest sounds are unwanted sounds then the audio zooming can be implemented by using attenuation of the unwanted sound sources or other suitable processes. The attenuation will not use headroom and so, if the loudest sounds are unwanted sounds then the headroom can be controlled so that a small amount of headroom is provided. The small amount of headroom might not be large enough to enable amplification of the audio signals when audio zooming is selected, however this could maximise, or substantially maximise, signal levels.

For example, the small amount of headroom could be much less than 12dB. Using the small amount of headroom can maximise the loudness of the audio signal.

In some examples the apparatus <NUM> can be configured to detect a change in whether or not the sound energy in the at least one first direction is higher than sound energy in the least one second direction by at least the threshold amount. For example, the apparatus <NUM> could detect if one or more of the sound sources has moved, or if the loudness of any of the sound sources has changed or any other suitable factor.

If a change in whether or not the sound energy in the at least one first direction is higher than sound energy in the least one second direction by at least the threshold amount is detected then the apparatus <NUM> can be configured to adjust the headroom provided based on the detected change. For example, if it is detected that the sound sources have changed so that the loudest sound source is now an unwanted sound source then the headroom can be decreased. Conversely if it is detected that the sound sources have changed so that the loudest sound source is now a wanted sound source then the headroom can be increased.

Any suitable means can be used to control the amount of headroom provided. In some examples the amount of headroom provided can be controlled by using automatic gain control. In some examples the amount of headroom provided can be controlled by using different types of compression.

<FIG> shows another example method that could be used in some examples of the disclosure. This method could be implemented using an electronic device <NUM> as shown in <FIG> and/or an apparatus <NUM> as shown in <FIG>.

The method comprises, at block <NUM>, analysing a sound signal to determine if sound energies in a first direction are larger than sound energies in a second direction. The first direction can comprise a region of interest and the second direction can comprise one or more directions outside of the region of interest. At block <NUM> it can be determined if the sound energies in the first direction are larger than the sound energies in the second direction by at least a threshold amount. The threshold amount can be determined by the processing that is to be used for the audio zooming or any other suitable factor.

If the sound energies in the first direction are larger than the sound energies in the second direction by at least the threshold amount then this indicates that the sound sources in the region of interest are the dominant sound sources. If this is the case then, at block <NUM> the method comprises controlling the amount of headroom provided in the audio file so as to leave a lot of headroom.

Leaving a lot of headroom can comprise leaving sufficient headroom to enable implementing audio zooming by using amplification. In some examples the headroom could be around 12dB.

Any suitable means can be used to control the amount of headroom that is provided. The amount of headroom provided can be controlled by controlling an algorithm such as automatic gain control and/or by using appropriate compression and/or by using any other suitable means.

At block <NUM> it is determined whether or not audio zoom is selected. A user of the electronic device <NUM> could select audio zoom by making an input using a user interface of the electronic device <NUM> or by any other suitable means. For instance, a user could be zooming images captured by the camera <NUM> which could also cause audio zooming.

If audio zoom is selected then, at block <NUM>, the audio zoom is implemented using a process that comprises amplification. The process can comprise amplification of the wanted sound sources. This amplification can make use of the headroom that is provided within the audio file.

If the sound energies in the first direction are not larger than the sound energies in the second direction by at least the threshold amount then this indicates that the sound sources in the region of interest are not the dominant sound sources. For instance, there could be some loud sound sources that are not in the region of interest or there could be a lot of background noise. If this is the case then, at block <NUM> the method comprises controlling the amount of headroom provided to leave little headroom in the audio file.

Leaving little headroom can comprise leaving insufficient headroom to enable implementing audio zooming by using amplification. Leaving little headroom can comprise leaving much less headroom compared to the cases when a lot of headroom is left. For, example the headroom provided could be much less than 12dB.

At block <NUM> it is determined whether or not audio zoom is selected. As described above a user of the electronic device <NUM> could select audio zoom by making an input using a user interface of the electronic device <NUM> or by any other suitable means. For instance, a user could be zooming images captured by the camera <NUM> which could also cause audio zooming.

If audio zoom is selected then, at block <NUM>, the audio zoom is implemented using attenuation. The attenuation does not need to make use of any headroom. The attenuation could comprise attenuating the unwanted sound sources. The attenuation could comprise attenuating the sound sources that are in the second direction.

Once the audio zoom has been implemented the process returns, or if it is determined that audio zoom has not been selected then the method returns to block <NUM> and the audio signals are analysed to determine, for a different time period, whether or not the sound energies are louder in the first direction than the second direction. This can enable changes in the sound sources to be detected.

In examples of the disclosure, such as the method shown in <FIG>, the process that is to be used to implement the zoom is determined before the user has selected the audio zoom. That is, if at block <NUM>, a lot of headroom is left the audio zoom can be implemented using amplification or if, at block <NUM>, little head room is left then the audio zoom can be implemented using attenuation. This can enable any switch between the different types of processing to be implemented gradually. This can reduce artefacts caused when switching between the different types of processing.

<FIG> shows another example method that could be implemented using an electronic device <NUM> as shown in <FIG> and/or an apparatus <NUM> as shown in <FIG>.

In the example of <FIG> a plurality of microphones <NUM> capture a sound scene. Two microphones <NUM> are shown in <FIG> however, more than two microphones <NUM> could be provided in other examples of the disclosure.

The plurality of microphones <NUM> provide audio signals to an audio gain control (ACG) module <NUM> and also to a sound source location module <NUM>.

The sound source location module <NUM> can be configured to determine the location of one or more sound sources. The sound source location <NUM> module can determine whether sound sources are within a region of interest or outside of a region of interest. For example, the sound source location module can determine whether or not a sound source is within a field of view of a camera <NUM> or outside of a field of view of a camera <NUM>.

The sound source location module <NUM> can also be configured to determine the relative sound energies of the different sound sources and determine whether or not sound sources within the region of interest are significantly louder than sound sources outside of the region of interest. This provides an indication as to whether or not the dominant sound sources are wanted sound sources or unwanted sound sources.

The sound source location module <NUM> can also be configured to determine the amount of headroom that is to be provided. For instance, if it is determined that wanted sound sources are the dominant sound sources then a large amount of headroom can be provided. If it is determined that unwanted sound sources are the dominant sound sources then a small amount of headroom can be provided. The sound source location module <NUM> provides a control signal to the AGC module <NUM> indicating the amount of headroom that is to be provided within the audio file.

The ACG module <NUM> is configured to receive the audio signals from the microphones <NUM> and the input signal from the sound source location module <NUM> indicating the amount of headroom that is to be provided.

The ACG module <NUM> can be configured to control the level of the audio signals from the microphones <NUM>. The ACG module <NUM> can control the level of the audio signals so that they are set at a level which is comfortable for a user to listen to. The ACG module <NUM> can use the input signal from the sound source location module <NUM> to control the amount of headroom that is provided.

The signals from the ACG module <NUM> are provided to a spatial audio processing module <NUM>. The spatial audio processing module can process the audio signals to provide spatial audio output. The spatial audio output can comprise an output so that a user can perceive special effects of the audio when the spatial audio output is rendered and played back to a user.

Any suitable process can be used to generate the spatial audio output. The process for generating the spatial audio output can also comprise an audio zoom module <NUM> that can be configured to enable audio zooming. The audio zoom module <NUM> can indicate whether the audio zooming can be implemented by amplification of the wanted sound sources or by attenuation of the unwanted sound sources or by any other suitable process.

Once the spatial audio has been generated an output audio signal <NUM> is provided. The output audio signal <NUM> comprises the spatial audio signals. The headroom provided in the audio file comprising the output audio signal <NUM> is provided based on whether or not the dominant sound sources are wanted sound sources or unwanted sound sources and the processes used to implement the audio zooming.

<FIG> shows example sound sources <NUM>, <NUM> positioned relative to an electronic device <NUM>.

In the example of <FIG> the electronic device <NUM> has a region of interest <NUM>. The region of interest could be the field of view of a camera <NUM>, part of the field of view of the camera <NUM>, a region around a microphone being used for audio calls or any other suitable region.

In <FIG> two sound sources <NUM>, <NUM> are in the environment around the electronic device <NUM>. The first sound source <NUM> is positioned within the region of interest <NUM>. The first sound source <NUM> can therefore be a wanted sound source.

The second sound source <NUM> is positioned outside of the region of interest <NUM>. The second sound source <NUM> can therefore be an unwanted sound source. In this example the second sound source <NUM> is positioned toward the rear of the electronic device <NUM>. The second sound source <NUM> is provided on the opposite side of the electronic device <NUM> to the first sound source <NUM> and the region of interest <NUM>.

In the example of <FIG> both of the sound sources <NUM>, <NUM> are shown as the same size indicating that they have the same or similar loudness. In examples of the disclosure the electronic device <NUM> and/or an apparatus <NUM> within the electronic device <NUM> can be configured to compare the loudness of the sound sources <NUM>, <NUM> and determine whether or the wanted sound sources <NUM> are the dominant sound sources.

<FIG> also shows a plurality of beamformer patterns <NUM>. <NUM>, <NUM>. <NUM> that can be used by the electronic device <NUM>. The different beamformer patterns <NUM>. <NUM>, <NUM>. <NUM> that are available can be determined by the number of microphones <NUM> within the electronic device <NUM> and the relative position of those microphones <NUM>.

In some examples the beamformer patterns <NUM>. <NUM>, <NUM>. <NUM> can be used to determine the sound energy within a given direction and so provide an estimate of the locations of the sound sources <NUM>. The sound energy in a given direction can be measured by summing the energy of a beamformed signal where the look direction of the beamformer corresponds to the direction. Other methods for estimating the sound energy in a given direction can be used in other examples of the disclosure. For example, direction of arrival analysis of the sound signals or any other suitable processes can be used.

The different beamformer patterns <NUM>. <NUM>, <NUM>. <NUM> can be used to amplify or attenuate the sound sources <NUM>, <NUM> as appropriate. For example, different gains can be applied to the different beamformer patterns <NUM>. <NUM>, <NUM>. <NUM> based on the look directions of the beamformer patterns <NUM>. <NUM>, <NUM>. <NUM> and the positions of the wanted and unwanted sound sources <NUM>, <NUM>.

<FIG> show example sound sources <NUM>, <NUM> and signals <NUM>, <NUM>.

<FIG> shows the positions of the sound sources <NUM>, <NUM> relative to the electronic device <NUM>. In this example the first sound source <NUM> is located within the region of interest <NUM> and so is a wanted sound source. The second sound source <NUM> is located outside of the region of interest <NUM> and so is an unwanted sound source.

In the example of <FIG> the first sound source <NUM> and the second sound source <NUM> have the same, or substantially the same loudness. This means that the sound energy in the wanted direction is the same as, or approximately the same as, the sound energy in the unwanted direction. Therefore, when the methods shown in <FIG> are implemented, it will be determined that the sound energy in the first direction is not larger than the sound energy in the second direction by at least the threshold amount.

<FIG> shows the audio signals after ACG has been applied but before any zooming of the signals. This shows a first signal <NUM> corresponding to the first sound source <NUM> and a second signal <NUM> corresponding to the second sound source <NUM>. This shows that the first signal <NUM> and the second signal <NUM> have the same, or approximately the same, amplitudes.

In this example only a small amount of headroom is provided because the audio zooming can be implemented using attenuation of the unwanted sound source <NUM>. This maximizes, or substantially maximizes, the loudness of the audio signal <NUM>.

<FIG> shows the audio signals after zooming has been applied. In this example the zooming is applied by attenuating the unwanted sound source <NUM> relative to the wanted sound source <NUM>. In the example of <FIG> the first signal <NUM> has a larger amplitude than the second signal <NUM>. In the example of <FIG> the amplitude of the first signal <NUM> has not changed compared to the example of <FIG> however the amplitude of the second signal <NUM> has decreased. This effectively amplifies the wanted sound source <NUM> compared to the unwanted sound source <NUM>. This attenuation does not need to use very much headroom available but does provide for an audio difference that is clearly perceptible to a user.

<FIG> show another arrangement of example sound sources <NUM> and the corresponding signals.

<FIG> shows the positions of the sound source 603relative to the electronic device <NUM>. In this example only one sound source <NUM> is present. The sound source <NUM> is located within the region of interest <NUM> and so is a wanted sound source. In this example there are no unwanted sound sources. This means that the sound energy in the wanted direction is higher than the sound energy in the unwanted directions. In this example the sound source <NUM> is loud enough so that the sound energy in the wanted direction is higher than the sound energy in the unwanted directions by at least a threshold amount.

<FIG> shows the audio signals after ACG has been applied but before any zooming of the signals. This shows a first signal <NUM> corresponding to the sound source <NUM>.

In this example a large amount of headroom is provided because the audio zooming can be implemented using amplification of the wanted sound source <NUM>. Therefore, the audio file needs to comprise sufficient headroom to enable the amplification.

<FIG> shows the audio signal <NUM> after zooming has been applied. In this example the zooming is applied by amplification. In the example of <FIG> the amplitude of the audio signal <NUM> has increased compared to the example of <FIG>. This significant change in the amplitude of the signals provides a clear change in audio that can be perceived by a user listening to the audio.

<FIG> shows the positions of the sound sources <NUM>, <NUM> relative to the electronic device <NUM>. In this example a first sound source <NUM> is located within the region of interest <NUM> and so is a wanted sound source. A second sound source <NUM> is located outside of the region of interest <NUM>. The second sound source <NUM> is therefore an unwanted sound source.

In the example of <FIG> the first sound source <NUM> is much louder than the second sound source <NUM>. This is shown by the second sound source <NUM> being much smaller than the first sound source <NUM>. In this case it will be determined that the sound energy in the first direction is larger than the sound energy in the second direction by at least the threshold amount.

<FIG> shows the audio signals after ACG has been applied but before any zooming of the signals. This shows a first signal <NUM> corresponding to the first sound source <NUM> and a second signal <NUM> corresponding to the second sound source <NUM>. This shows that the first signal <NUM> has a larger amplitude than the second signal <NUM>.

<FIG> shows the audio signals after zooming has been applied. In this example the zooming is applied by amplification. In the example of <FIG> the amplitude of the audio signal <NUM> has increased compared to the example of <FIG>. In this example the overall level can also be increased. This significant change in the amplitude of the signals provides a clear change in audio that can be perceived by a user listening to the audio.

Variations to the above described examples can be used in implementations of the disclosure. For instance, in some examples processes other than ACG can be used to control the loudness of the audio signals and the amount of headroom provided. For instance, in some examples compression of the audio signal can be used to control the loudness of the audio signals and the amount of headroom provided.

The compression can comprise using different compression curves. The compression can be used with a gain factor so that the more compression is sued the more the audio signal can be amplified without clipping. In some examples the compression could comprise multiband compression which could comprise using different compression in different frequency bands.

The compression curve that is used can be dependent upon whether or not audio zooming is selected.

The audio zooming might be more effective in some frequency bands than others. In such examples multiband compression could be used and the compression curve might only be dependent upon whether or not audio zooming is selected for the frequencies that are affected by the audio zooming.

The different compressions curves can be used to control the amount of headroom and may also be used to adjust the amount of headroom that is needed. The different compression curves could be used together with ACG and/or any other suitable processes.

Also in the above described examples the headroom is controlled to provide either a lot of headroom or a small amount of headroom. In some examples the headroom provided could be in between these two extremes. For example, if it is determined that the relative sound energies in a sound environment are changing then the amount of headroom provided could be changed to take this into account. The amount of headroom provided could be changed gradually to avoid a sudden switch between the two extremes. Therefore, for a time period over which the gradual change is taking place, the headroom provided could be in between the maximum and minimum amounts.

Therefore, examples of the disclosure control the amount of headroom provided based on whether dominants sounds are unwanted sounds or wanted sounds. This can enable audio zooming to be used while using the headroom available within the audio file to maximizing, or substantially maximizing, the loudness of the audio signals. The examples of the disclosure reduce audio clipping by ensuring that there is always sufficient headroom available for audio zooming.

The term 'a' or 'the' is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising a/the Y indicates that X may comprise only one Y or may comprise more than one Y unless the context clearly indicates the contrary. If it is intended to use 'a' or 'the' with an exclusive meaning then it will be made clear in the context. In some circumstances the use of 'at least one' or 'one or more' may be used to emphasis an inclusive meaning but the absence of these terms should not be taken to infer any exclusive meaning.

Claim 1:
An apparatus (<NUM>) comprising means for:
determining (<NUM>), for an audio signal, if sound energy in at least one first direction is different to sound energy in at least one second direction by at least a threshold amount; and
controlling (<NUM>), before an audio zoom function is selected, an amount of headroom provided in the audio signal so as to enable audio zooming at a later time when the zoom function is selected, based on whether or not sound energy in at least one first direction is different to the sound energy in at least one second direction by at least a threshold amount.