HK1214711B - Method and apparatus for personalized audio virtualization - Google Patents

Description

Method and apparatus for personalized audio virtualization

Cross Reference to Related Applications

The present application claims priority from U.S. provisional application No. 61/731,958 filed on 30/11/2012, U.S. provisional application No. 61/749,746 filed on 7/1/2013, and U.S. provisional application No. 14/091,112 filed on 26/11/2013, which are incorporated by reference as if fully set forth.

Technical Field

The present application relates generally to methods and apparatus for personalized audio virtualization.

Background

In conventional audio reproduction, a consumer cannot reproduce spatial attributes of an original content producer or a device producer. Thus, the intent of the original content producer is lost and the consumer is left with an undesirable audio experience. It would thus be desirable to deliver to consumers a method and apparatus for delivering high quality audio production that conveys the original intent of the content producer.

Disclosure of Invention

A brief summary of various exemplary embodiments is presented. Certain simplifications and omissions may be made in the following summary, which is intended to highlight and introduce some aspects of the various exemplary embodiments, but not to limit the scope of the invention. A detailed description of preferred exemplary embodiments, sufficient to enable those of ordinary skill in the art to make and use the inventive concepts will follow in a later section.

Various exemplary embodiments relate to methods and apparatuses for performing personalized audio virtualization. The apparatus may include a speaker, an earphone (ear wrapped, ear attached, or in-ear), a microphone, a computer, a mobile device, a home theater receiver, a television, a blu-ray (BD) player, a Compact Disc (CD) player, a digital media player, and so forth. The apparatus may be configured to receive an audio signal, scale the audio signal, and perform convolution and reverberation on the scaled audio signal to produce a convolved audio signal. The apparatus may be configured to filter the convolved audio signal and process the filtered audio signal for output.

Various exemplary embodiments also relate to a method for use in an audio device, the method comprising: receiving digital audio content comprising at least one audio channel signal; receiving metadata affecting reproduction of the digital audio content, wherein the metadata includes an indoor measurement profile (profile) based on acoustic measurements of a predetermined room and a listener hearing profile based on a spectral response curve of a user's hearing ability; configuring at least one digital filter based on the received metadata; filtering the at least one audio channel with a corresponding at least one digital filter to produce a filtered audio signal; and outputting the filtered audio signal to the accessory device.

In some embodiments, the metadata further includes a playback device profile based on frequency response parameters of the playback device, and an accessory device profile based on frequency response parameters of the accessory device. In some embodiments, metadata multiplexed with digital audio content is received. In some embodiments, the metadata is received in the container file independently of the digital audio content. In some embodiments, the room measurement profile includes at least one set of Head Related Transfer Function (HRTF) filter coefficients, an early room response parameter, and a late reverberation parameter. In some embodiments, the early room response parameter and the late reverberation parameter configure the digital filter to produce a filtered audio signal having acoustic properties substantially similar to acoustic properties of the predetermined room. In some embodiments, the late reverberation parameter configures a parametric model of the late reverberation of the predetermined room.

Various exemplary embodiments also relate to an audio device, including: a receiver configured to receive digital audio content comprising at least one audio channel signal; and receiving metadata affecting reproduction of the digital audio content, wherein the metadata includes an indoor measurement profile based on acoustic measurements of the predetermined room and a listener hearing profile based on a spectral response curve of a user's hearing ability; a processor configured to configure at least one digital filter based on the received metadata, wherein the processor is configured to filter the at least one audio channel signal with the corresponding at least one digital filter to produce a filtered audio signal; and wherein the processor is configured to output the filtered audio signal to the accessory device.

In some embodiments, the metadata further includes a playback device profile based on frequency response parameters of the playback device, and an accessory device profile based on frequency response parameters of the accessory device. In some embodiments, metadata multiplexed with digital audio content is received. In some embodiments, the metadata is received in the container file independently of the digital audio content. In some embodiments, the room measurement profile includes at least one set of Head Related Transfer Function (HRTF) filter coefficients, an early room response parameter, and a late reverberation parameter. In some embodiments, the processor configures the digital filter with the early room response parameter and the late reverberation parameter to produce a filtered audio signal having acoustic properties substantially similar to acoustic properties of the predetermined room. In some embodiments, the processor utilizes the late reverberation parameter to configure a parametric model of the late reverberation of the predetermined room.

Various exemplary embodiments are also directed to a virtualized data format, comprising: a plurality of fields comprising a plurality of parameters, wherein the plurality of parameters are based on the following profile: an indoor measurement profile based on acoustic measurements of a predetermined room, a listener hearing profile based on a spectral response curve of a user's hearing ability, a playback device profile based on frequency response parameters of a playback device, and an accessory device profile based on frequency response parameters of an accessory device.

In some embodiments, at least one of the plurality of parameters is multiplexed with the digital audio content.

Various exemplary embodiments also relate to a method for use in an audio device, the method comprising: receiving digital audio content comprising at least one audio channel signal; receiving metadata affecting reproduction of the digital audio content, wherein the metadata includes an indoor measurement profile based on acoustic measurements of a predetermined room; configuring at least one digital filter based on the received metadata; filtering the at least one audio channel with a corresponding at least one digital filter to produce a filtered audio signal; and outputting the filtered audio signal to the accessory device.

In some embodiments, the metadata further includes a playback device profile based on frequency response parameters of the playback device, and an accessory device profile based on frequency response parameters of the accessory device. In some embodiments, metadata multiplexed with digital audio content is received. In some embodiments, the metadata is received in the container file independently of the digital audio content. In some embodiments, the room measurement profile includes at least one set of Head Related Transfer Function (HRTF) filter coefficients, an early room response parameter, and a late reverberation parameter. In some embodiments, the early room response parameter and the late reverberation parameter configure the digital filter to produce a filtered audio signal having acoustic properties substantially similar to acoustic properties of the predetermined room. In some embodiments, the late reverberation parameter configures a parametric model of the late reverberation of the predetermined room.

Various exemplary embodiments also relate to an audio device, including: a receiver configured to receive digital audio content comprising at least one audio channel signal; and receiving metadata affecting reproduction of the digital audio content, wherein the metadata includes an indoor measurement profile based on acoustic measurements of the predetermined room; a processor configured to configure at least one digital filter based on the received metadata, wherein the processor is configured to filter the at least one audio channel signal with the corresponding at least one digital filter to produce a filtered audio signal; and wherein the processor is configured to output the filtered audio signal to the accessory device.

In some embodiments, the metadata further includes a playback device profile based on frequency response parameters of the playback device, and an accessory device profile based on frequency response parameters of the accessory device. In some embodiments, metadata multiplexed with digital audio content is received. In some embodiments, the metadata is received in the container file independently of the digital audio content. In some embodiments, the room measurement profile includes at least one set of Head Related Transfer Function (HRTF) filter coefficients, an early room response parameter, and a late reverberation parameter. In some embodiments, the processor configures the digital filter with the early room response parameter and the late reverberation parameter to produce a filtered audio signal having acoustic properties substantially similar to acoustic properties of the predetermined room. In some embodiments, the processor utilizes the late reverberation parameter to configure a parametric model of the late reverberation of the predetermined room.

In some embodiments, the digital audio content includes a flag indicating that the audio channel signal contains pre-processed content. If the audio channel signal is pre-processed, the metadata may include information about how the audio signal was pre-processed.

In some embodiments, the metadata includes a flag indicating that the digital audio content contains at least one pre-processed audio channel signal. If the audio channel signal is pre-processed, the metadata may include information about how the audio signal was pre-processed.

Drawings

These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which:

fig. 1 is a diagram of an example speaker arrangement for a conventional 5.1 surround format;

FIG. 2 is a diagram illustrating an indoor acoustic measurement process;

FIG. 3A is a diagram of an example method for use in a virtualization system that applies virtualized data to process audio content that includes embedded virtualized data;

FIG. 3B is a diagram of an example method for use in a virtualization system that applies virtualized data to process audio content that does not include embedded virtualized data;

FIG. 4 is a diagram of an example virtualization system;

FIG. 5 is a block diagram illustrating an overview of a virtualization system;

FIGS. 6A and 6B are block diagrams illustrating a general overview of the operation of an embodiment of the virtualization system in FIG. 5; and is

FIG. 7 is a detailed flow diagram illustrating an example method described for use in a virtualization system.

Detailed Description

The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiments of the invention and is not intended to represent the only forms in which the present invention may be constructed or utilized. The description sets forth the functions and the sequence of steps for developing and operating the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention. It is further understood that the use of relational terms such as first and second, and the like, are used solely to distinguish one from another entity without necessarily requiring or implying any actual such relationship or order between such entities.

Acoustic waves are a type of pressure wave caused by the vibration of an object propagating through a compressible medium such as air. The acoustic waves periodically displace a substance in a medium (e.g., air), thereby oscillating the substance. The frequency of the acoustic wave describes the number of complete cycles in a time period and is expressed in hertz (Hz). Sound waves in the frequency range of 12Hz to 20,000Hz are audible to humans.

The present application relates to a method and apparatus for processing audio signals, i.e. signals representing physical sounds. These signals may be represented by digital electronic signals. In the discussion that follows, analog waveforms may be shown or discussed to illustrate concepts; it should be understood, however, that exemplary embodiments of the present invention may operate in the context of a time series of digital bytes or words that constitute a discrete approximation to an analog signal or (final) physical sound. The discrete digital signal may correspond to a digital representation of a periodically sampled audio waveform. As is known in the art, for uniform sampling, the waveform may be sampled at a rate at least sufficient to satisfy the Nyquist sampling theorem for the frequency of interest. For example, in an exemplary embodiment, a uniform sampling rate of about 44.1kHz may be used. A higher sampling rate such as 96kHz may alternatively be used. The quantization scheme and bit resolution may be selected to meet the requirements of a particular application according to principles known in the art. The techniques and apparatus of the present invention will generally be applied interdependently within multiple channels. For example, it may be used in the context of a "surround" audio system (having more than two channels).

As used herein, a "digital audio signal" or "audio signal" does not merely describe a mathematical abstraction, but rather represents information contained or carried by a physical medium capable of being detected by a machine or device. The term includes recorded or transmitted signals and should be understood to include transmission in any form of encoding, including Pulse Code Modulation (PCM), but not limited to PCM. The output or input, or even the intermediate audio signal, may be encoded or compressed by any of a variety of known methods, including MPEG, ATRAC, AC3, or DTS corporation proprietary methods, such as us patent 5,974,380; 5,978,762, respectively; and 6,487,535. As will be clear to those skilled in the art, some modification to the calculations may be required to accommodate this particular compression or encoding method.

The invention may be implemented in consumer electronics devices such as Digital Video Disc (DVD) or blu-ray disc (BD) players, Television (TV) tuners, Compact Disc (CD) players, handheld players, internet audio/video devices, game consoles, mobile phones, etc. The consumer electronic device includes a Central Processing Unit (CPU) or Digital Signal Processor (DSP), which may represent one or more conventional types of such processors, such as the IBM PowerPC, Intel Pentium (x86) processor, and so forth. Random Access Memory (RAM) temporarily stores the results of data processing operations performed by the CPU or DSP and is typically interconnected via dedicated memory channels. The consumer electronics device may also include a persistent storage device such as a hard drive that communicates with the CPU or DSP over an I/O bus. Other types of storage devices, such as tape drives, optical disk drives, etc., may also be connected. The graphics card is also connected to the CPU via a video bus and transmits signals representing display data to the display monitor. Peripheral data input devices such as a keyboard or mouse may be connected to the audio reproduction system through the USB port. The USB controller translates data and instructions to and from the CPU for peripheral devices connected to the USB port. Additional devices such as printers, microphones, speakers, etc. may be connected to the consumer electronic device.

Consumer electronic devices may utilize operating systems with Graphical User Interfaces (GUIs), such as WINDOWS from microsoft corporation of Redmond, Washington, MAC OS from apple corporation of Cupertino, CA, various mobile GUI versions designed for mobile operating systems such as Android, and the like. The consumer electronics device may execute one or more computer programs. Typically, the operating system and computer program are tangibly embodied in a computer-readable medium, such as one or more of fixed and/or removable data storage devices, including a hard disk drive. Both the operating system and the computer program can be loaded from the data storage device described above into RAM for execution by the CPU. The computer program may comprise instructions which, when read and executed by the CPU, cause it to perform steps to perform the steps or features of the present invention.

The invention may have many different configurations and architectures. Any such configuration or architecture may be readily substituted without departing from the scope of the present invention. Those skilled in the art will recognize that the sequences described above are most commonly used on computer readable media, however, there are other existing sequences that can be substituted without departing from the scope of the present invention.

Elements of one embodiment of the invention may be implemented by hardware, firmware, software, or any combination thereof. When implemented in hardware, the audio codec may be used on one audio signal processor or distributed among various processing components. When implemented as software, the elements of an embodiment of the present invention are essentially the code segments to perform the various tasks. The software may include the actual code to carry out the operations described in one embodiment of the invention, or code that emulates or simulates the operations. The program or code segments can be stored in a processor or machine accessible medium or transmitted by a transmission medium, by a computer data signal embodied in a carrier wave, or by a signal modulated by a carrier. A "processor-readable or accessible medium" or a "machine-readable or accessible medium" may include any medium that is configured to store, transmit, or transfer information.

Examples of a processor-readable medium include electronic circuits, semiconductor memory devices, Read Only Memory (ROM), flash memory, Erasable ROM (EROM), floppy disks, Compact Disk (CD) ROMs, optical disks, hard disks, fiber optic media, Radio Frequency (RF) links, and so forth. The computer data signal includes any signal that can propagate over a transmission medium such as electronic network channels, optical fibers, air, electromagnetic waves, RF links, etc. The code segments may be downloaded via computer networks such as the internet, intranet, etc. A machine accessible medium may be included in an article of manufacture. The machine-accessible medium may include data that, when accessed by a machine, may cause the machine to perform the operations described below. The term "data" herein refers to any type of information that may be encoded for machine-readable purposes. Thus, it may include programs, code, data, files, and the like.

All or a portion of embodiments of the present invention may be implemented by software. The software may have several modules coupled to each other. A software module may be coupled with another module to receive variables, parameters, arguments, pointers, etc. and/or to generate or pass results, updated variables, pointers, etc. The software modules may also be software drivers or interfaces that interact with the operating system running on the platform. The software modules may also be hardware drivers that configure, establish, initialize, send, and receive data to and from the hardware devices.

One embodiment of the invention may be described as a process which is usually depicted as a flowchart, a flow diagram, a structure diagram, or a block diagram. Although a block diagram may describe the operations as a sequential process, multiple operations may be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may terminate when its operations are complete. The processing may correspond to methods, procedures, and the like.

Particular embodiments of the present invention may utilize acoustic indoor measurements. The measurements may be made in a room containing the high fidelity audio equipment, such as, for example, a mixing room or listening room. The room may comprise a plurality of loudspeakers, and the loudspeakers may be arranged in a conventional loudspeaker layout, such as, for example, stereo, 5.1, 7.1, 11.1 or 22.2. Other speaker layouts or arrays may also be used, such as Wave Field Synthesis (WFS) arrays or other object-based rendering layouts.

Fig. 1 is a diagram of an example speaker arrangement 100 for a conventional 5.1 surround format. Speaker arrangement 100 may include a left front speaker 110, a right front speaker 120, a center front speaker 130, a left surround speaker 140, a right surround speaker 150, and a subwoofer 160. Although a mixing chamber with surround speakers is provided as an example, the measurements may be taken anywhere that one or more speakers are included.

Indoor acoustics

Fig. 2 is a diagram illustrating an indoor acoustic measurement process 200. In this example, the acoustic indoor measurements may be obtained by placing the measurement device in an optimal listening position (such as a chair of a producer). The measuring means may be a separate microphone, a binaural microphone placed in the dummy head or a binaural microphone placed in the test subject's ear. The measurement device may receive one or more test signals 210 from one or more speakers. The test signal may comprise a swept frequency signal or a chirp signal. Alternatively, or in addition, the test signal may be a noise sequence such as a Golay code or a maximum length sequence. As each speaker plays the test signal, the measurement device may record the audio signal 220 received at the listening position. From the recorded audio signals, an indoor measurement profile may be generated 230 for each speaker position and each microphone of the measurement device.

According to a particular embodiment, the measuring device may be rotatable. Additional test tones may be played with the measuring device rotated in various positions. The measurement information at various rotations may allow the system to support head tracking of the listener, as described below.

Additional indoor measurements may be made at other locations in the room, for example, for "out of sweet spot" monitoring. The "out of sweet spot" measurement may assist in determining the acoustic effect of the room under test for listeners not at the sweet spot.

In addition, according to particular embodiments, the frequency response of a particular playback earpiece may be obtained using a measurement device.

According to certain novel embodiments, each measured indoor measurement profile may be separated into a Head Related Transfer Function (HRTF), an early room response, and late reverberation. The HRTF can characterize how the measuring device receives sound from each loudspeaker without the acoustic influence of the room. The early room response may characterize early reflections after the sound from each speaker has been reflected by the surface of the room. Late reverberation can characterize the sound in the room after early reflections.

The HRTF may be represented by filter coefficients. The early room response and late reverberation may be represented by an acoustic model that reproduces the acoustics of the room, for example. The acoustic model may be determined in part by an early room response parameter and a late reverberation parameter. The acoustic model may be transmitted and/or stored as an indoor measurement profile.

According to certain novel embodiments, HRTF filter coefficients, early room response parameters, and/or late reverberation parameters may be used to process audio signals for playback through headphones. Alternatively, in another embodiment, a full indoor measurement profile may be used to process the audio signal. The audio signals may be processed such that the acoustics and speaker positions of the room under test are reproduced as the signals are played back through the headphones.

The early room response and late reverberation acoustic models may inaccurately reproduce room acoustics. Thus, according to certain novel embodiments, the acoustic models and/or parameters may be modified to apply virtual acoustic processing to the room or Equalization (EQ) to the speakers. The virtual acoustic measurements may include virtual absorption processes or virtual bass traps. The virtual absorption process may "attenuate" the room reverberation response or modify the sound reflected by certain surfaces. The virtual bass trap may remove some of the "tank resonance" of the room. EQ may be applied to modify the perceived frequency response of each speaker in the room.

The room measurement profile may include full room measurement profile data and/or HRTF filter coefficients, early room response parameters, and late reverberation parameters for one or more rooms and one or more listening positions within each room. The indoor measurement profile may also include other identification information, such as headphone frequency response information, headphone identification information, tested speaker placement information, playback mode information, measurement location information, measurement device information, and/or authorization/owner information.

According to certain novel embodiments, virtualization data may be stored as metadata that may be included in an audio content bitstream. The audio content may be channel-based or object-based. The virtualization data may include at least one of an indoor measurement profile, a playback device profile, an accessory device profile, and a listener hearing profile. The indoor measurement profile may include indoor response parameters and HRTFs. In some embodiments, the indoor measurement profile may not include HRTFs. The playback device profile may include frequency response parameters of the playback device and other playback device information. The playback device may be any device that converts audio data into a signal that can be rendered by a speaker, including headphones. The accessory device profile may include frequency response parameters of the accessory device (e.g., headset), as well as other accessory device information. The accessory device can be any device that converts audio signals from the playback device into audible sound. The playback device and the accessory device may be the same device in embodiments where the headphone/speaker includes the necessary DAC, amplifier, and virtual processor. The listener hearing profile may include listener hearing loss parameters, listener equalization preferences, and HRTFs.

The virtualization data may be embedded or multiplexed in a file header of the audio content, or may be embedded or multiplexed in any other portion of the audio file or frame. The virtualization data may also be repeated in multiple frames of the audio bitstream. Alternatively or in addition, the virtualization data may be changed over time over several frames or may be stored in a virtualization data file separate from the audio content. The virtualization data may be transmitted to the virtualization system with the audio content or the virtualization data may be transmitted separately from the audio content.

FIG. 3A is an illustration of an example method 300 for use in a virtualization system that applies virtualized data to process audio content that includes embedded or multiplexed virtualized data. Once the virtualization system receives the audio content 310, the virtualization system may determine 320 that the virtualization data is multiplexed with the audio content. The virtualization system may separate 330 the virtualization data from the audio content and parse 340 the virtualization data. The virtualized data and/or audio content may be communicated to the virtualization system via a wired and/or wireless connection.

FIG. 3B is an illustration of an example method 350 for use in a virtualization system that applies virtualized data to process audio content that does not include embedded or multiplexed virtualized data. In this example, the virtualization system may receive audio content 360 and separately receive virtualization data 370. The virtualization system may then parse 380 the virtualized data. In this example, the virtualization data can be received before receiving the audio content, after receiving the audio content, or during receipt of the audio content.

According to certain novel embodiments, virtualized data may have a unique identifier, such as, for example, an MD5 checksum or other hash function. The virtualization system may receive a unique identifier independent of the virtualization data. The virtualization system may poll a remote server containing the unique identifier and virtualization data, or the unique identifier may be transmitted directly to the virtualization system. The unique identifier may be transmitted to the virtualization system intermittently (e.g., in frames designated as random access points). The virtualization system may compare the unique identifier to a unique identifier of previously received virtualization data. If the unique identifier matches previously received virtualization data, the virtualization system may use the previously received virtualization data.

If the virtualization data includes a full indoor measurement profile, the virtualization system may process the audio content by performing a direct convolution of the audio content with the indoor measurement profile. If the virtualization data includes HRTF filter coefficients, an early room response parameter, and a late reverberation parameter, the virtualization system can create an acoustic model of the room and process the audio content using the acoustic model and HRTFs. In this example, the early room response parameter and the late reverberation parameter may be convolved with the audio content.

Alternatively, the virtualization system may use a combination of direct convolution and acoustic modeling to compensate for perceptually relevant indoor measurement profiles that may be lost due to the use of the reverberation algorithm contained by the virtual system. For example, the early room response parameters may be convolved with the audio content, while the late reverberation parameters may be modeled. In this example, the late reverberation parameters may be modeled without convolution filtering. This example may be employed in situations where implementation resources do not allow full indoor measurement parameters to be convolved. In this example, the raw measured reverberation tail may be replaced with an artificial reverberation tail that is used as part of the room measurement profile. The parameters of the reverberation may be chosen such that the perceptual properties of the original reverberation tail are reproduced as close as possible. These parameters may be specified as part of an indoor measurement profile.

Further, according to particular embodiments, the virtualization system may track the position of the listener's head. Based on the listener's head position, the virtualization system may alter the HRTFs and/or indoor measurement profiles to better correspond to similar listening positions in the room under test.

The virtualization system may process the audio content at and/or prior to playback. The processing of the audio content may be distributed. For example, the audio content may be pre-processed with certain virtualization data, and the virtualization system may further process the audio content to correct for hearing loss of the listener. The process may be performed in a user's playback device such as, for example, an MP3 player, a mobile phone, a computer, a headset, an AV receiver, or any other device capable of processing audio content. Alternatively, in some embodiments, the processing may be performed prior to being stored in the user's local device or prior to being transmitted to the user's local device. For example, audio content may be pre-processed at a server of the content owner and then transferred to the user device as a spatialized headphone mix.

For example, the virtualization system may render audio content as a binaural signal with surround virtualization and may be part of the virtualization system. The virtualization system may be constructed in a manner that allows the content producer to pre-process the audio. The process may generate optimized audio tracks designed to enhance device playback in a manner specified by the content producer. The virtualization system may include one or more processors configured to maintain desired attributes of the original mixed surround sound tracks and provide the listener with the sound experience that the studio originally provided.

Any room and speaker configuration intended for pre-processing content may be measured and stored in a virtualized file format. Since the model may assume that preprocessing will not be performed in real-time, the pre-encoded content model may provide the ability to simulate any space with a full indoor measurement profile. The virtualized file format may include information about how the signal was preprocessed in the case where the signal was preprocessed. For example, the virtualization file format may include full or partial information related to an indoor measurement profile, an accessory device profile, a playback device profile, and/or a listener hearing profile.

The result of the pre-processing by the virtualization system may be a bitstream that can be decoded using any decoder. The bitstream may include a flag indicating whether audio has been pre-processed with virtualization data. If the bitstream is played back using a legacy decoder that does not recognize the flag, the content can still be played using the virtualization system, however, headphone EQ cannot be included in the process. Headphone EQ can include an equalization filter that approximately normalizes the frequency response of a particular headphone.

The playback device or the accessory device may contain a virtualization system configured to render audio signals that have been pre-processed with virtualization data. When the playback device or accessory device receives the audio signal, it may look for a consumer device logo in the bitstream. In this example, the consumer device identification may be a headset device identification. If the headphone flag is set, the binaural room and reverberation processing block may be bypassed and only headphone EQ processing may be applied. Spatial processing may be applied to those signals for which the headphone flag is not set.

The audio content may be processed in a mixing room, allowing the audio producer to monitor the spatialized headphone mix heard by the end user. When the processed or pre-processed audio content is played back through headphones, for example, the audio content sounds similar to the audio played back through speakers in the listening environment being tested.

Processing content at runtime

When the virtualized data is intended for real-time use, a runtime data format may be used. The runtime data format may include a simplified indoor measurement profile that may be executed quickly and/or with less processor load. This is in contrast to indoor measurement profiles that would be used with pre-processed audio, where execution speed and processor load are less important. The runtime data format may be a representation of the indoor measurement profile with one or more shortened convolution filters that are better suited to the processing limitations of the playback device and/or accessory device. The virtualization system may compensate for perceptually relevant indoor measurement profiles that may be lost due to the use of reverberation algorithms included in the virtualization system.

If the audio source stream is not pre-processed with virtual data, the runtime data format may be obtained from a "preset" file that may be stored locally. The runtime data format may include indoor measurement profiles measured by the customer and/or indoor measurement profiles from different sources (e.g., remote servers).

The runtime data format may also be embedded or multiplexed as metadata in the stream. In this example, the runtime metadata is parsed and sent to a real-time algorithm running on the device. This feature may be useful in gaming applications because providing an indoor measurement profile in this manner may allow a content provider to define virtual indoor acoustics that should be used when processing audio in real time for a particular game. In this example, the relevant indoor measurement profile may be delivered to one or more external devices, such as game peripherals, by transcoding a multi-channel soundtrack of a game into a multi-channel stream with an embedded indoor measurement profile that may be used on the external device.

According to certain novel embodiments, the virtualization system may use data measured within the current room using similar virtualization data and post-processing techniques described above to render the acoustic effects of the local listening environment through headphones.

If the virtualization data includes measurements of multiple rooms, the virtualization system may select which room's acoustic effects should be used to process the audio content. The user may prefer audio content that is processed with an indoor measurement profile that is most similar to the acoustic effect of the current room. The virtualization system may utilize one or more tests to determine some measure of the acoustic effectiveness of the current room. For example, the user may capture their hands in the current room. The clap may be recorded by the virtualization system and then processed to determine the acoustic parameters of the room. Alternatively or in addition, the virtualization system may analyze other environmental sounds such as speech.

Once the virtualization system has determined the acoustic parameters of the current room, the virtualization system may select and/or change the acoustic effect of the room under test. According to a particular embodiment, the virtualization system may select the room under test with the most similar acoustic effect as the current room. The virtualization system may determine the most similar room under test by correlating the acoustic parameters of the current room with the acoustic parameters of the room under test. For example, the acoustic parameters of a clap in the current room may be associated with the acoustic parameters of a real or simulated clap in the room under test.

Alternatively or additionally, according to particular embodiments, the virtualization system may change the acoustic model of the room under test to be more similar to the current room. For example, the virtualization system may filter or time scale the early response of the room under test to more closely resemble the early response of the current room. The virtualization system may also use the early response of the current room. The virtualization system may also use the reverberation parameters of the current room in the late reverberation model of the room under test.

When the processed audio content is played through the headphones, the processed audio content may approximate the timbre of the speaker under test and the acoustic characteristics of the room under test. However, the listener may be accustomed to the timbre of the headphones, and the timbre differences between the unprocessed or "downmixed" headphone signal and the acoustic characteristics of the speaker and the room under test may be significant for the listener. Thus, according to certain novel embodiments, the virtualization system neutralizes timbre differences for certain input channels and/or input channel pairs while preserving the spatial properties of the speakers in the room under test. The virtualization system can neutralize the timbre differences by applying an equalization that produces an overall timbre signature that more closely approximates the timbre of the original headphone signal that the listener is accustomed to hearing. The equalization may be based on the frequency response of the particular playback headphone and/or the acoustic model and HRTF of the room under test.

Depending on the particular embodiment, the listener may choose between different equalization profiles. For example, a listener may select an indoor measurement profile that approximates the exact tone and spatial attributes of the original work as played in the room under test. Or the listener may select an accessory device profile that neutralizes timbre differences while preserving the spatial attributes of the original work. Or the listener may select from a combination of these or other equalization profiles.

According to another particular embodiment, the listener and/or the virtualization system may additionally select between different HRTF profiles if the listener's particular HRTF is not known. The listener may select the HRTF profile through listening tests or the virtualization system may select the HRTF profile through other means. The listening test may include different sets of HRTFs and allow the listener to select a set of HRTFs with preferred locations for the test sound. The HRTFs used in the original indoor measurement profile may be replaced and a selected set of HRTFs may be merged such that the acoustic properties of the original measurement space are preserved.

Listener auditory profiles

FIG. 4 is a diagram of an example virtualization system 400. Virtualization system 400 can include one or more local playback devices 410 of a user, one or more accessory devices 420, and a server 430. Server 430 may be a local server or a remote server. The server 430 may include one or more indoor measurement profiles 435. One or more indoor measurement profiles 435 may be included in the unique listener account 440. The user may be associated with a unique listener account 440 of the virtualization system 400. The playback device 410 can communicate with the server 430 via a wired or wireless interface 415, and can communicate with the accessory device 420 via a wired or wireless interface 425. The listener account 440 may include information about the user, such as one or more listener hearing profiles 450, one or more playback device profiles 460, and one or more accessory device profiles 470. The one or more indoor measurement profiles 435 and the one or more profiles from the listener account 440 may be transmitted to the playback device 410 and/or the accessory device 420 for use and storage. The one or more indoor measurement profiles 435 and the one or more profiles from the listener account 440 may be transmitted as embedded metadata in the audio signal, or they may be transmitted separately from the audio signal.

The listener hearing profile 450 may be generated based on the results of the listener hearing test. The listener hearing test may be performed using a user's playback device, such as a smart phone, computer, personal audio player, MP3 player, a/V receiver, television, or any other device capable of playing audio and receiving user input. Alternatively, the listener hearing test may be performed on a separate system that may upload the hearing test results to the server 430 for later use with the user's playback device 410. According to particular embodiments, the listener hearing test may occur after the user is associated with the unique listener account 440. Alternatively, the listener hearing test may occur before the user is associated with the unique listener account 440, and then may be associated with the listener account 440 at some time after the test is completed.

According to particular embodiments, the virtualization system 400 may obtain information about the playback device 410, the accessory device 420, and the room measurement profile 435 to be used with the listener hearing test. This information may be obtained before, simultaneously with, or after the listener hearing test. The playback device 410 may send the playback device identification number to the server 430. Based on the playback device identification number, the server 430 may look up the make/model of the playback device 410, the audio characteristics (such as frequency response) of the playback device 410, the maximum and minimum volume levels, and/or the indoor measurement profile 435. Alternatively, the playback device 410 may send the make/model of the playback device and/or the audio characteristics of the playback device 410 directly to the server 430. Based on the make/model of the playback device 410, the audio characteristics of the playback device 410, and/or the indoor measurement profile 435, the server 430 may generate a playback device profile 460 for that particular playback device 410.

In addition, the playback device 410 can send information about the accessory device 420 connected to the playback device 410. The accessory device 420 may be an earphone, a headphone, an integrated speaker, a stand-alone speaker, or any other device capable of reproducing audio. The playback device 410 can identify the accessory device 420 through user input or automatically identify the accessory device 420 by detecting the make/model of the accessory device 420. The user input of the accessory device 420 may include a user selection of a particular make/model of the accessory device 420, or a user selection of a general category of accessory device, such as in-ear headphones, over-the-ear headphones, earbuds, on-ear headphones, built-in speakers, or external speakers. The playback device 410 can then send the accessory device identification number to the server 430. Based on the accessory device identification number, the server 430 can look up the make/model of the accessory device 420, audio characteristics of the accessory device 420, such as frequency response, harmonic distortion, maximum and minimum volume levels, and/or the indoor measurement profile 435. Alternatively, the playback device 410 can send the make/model of the accessory device 420 and/or the audio characteristics of the accessory device 420 directly to the server 430. Based on the make/model of the accessory device 420, the audio characteristics of the accessory device 420, and/or the indoor measurement profile 435, the server 430 can generate an accessory device profile 470 for that particular accessory device 420.

The listener hearing test may be performed using the user's playback device 410 and an accessory device 420 connected to the playback device 410. The listener hearing test may determine the user's hearing characteristics, such as a minimum loudness threshold, a maximum loudness threshold, an equal loudness curve, and HRTFs, and the virtualization system may use the user's hearing characteristics in rendering the headphone output. In addition, the listener hearing test may determine the user's equalization preferences, such as preferred volumes for bass, mid-range, and treble frequencies. The listener hearing test may be performed by the playback device 410 playing a series of tones through the accessory device 420. The series of tones may be played at various frequencies and loudness levels. The user may then input to the playback device 410 whether they are able to hear the tones, and the minimum loudness level of the tones that the user hears. Based on the user's input, the user's auditory characteristics may be determined for the particular playback device 410 and accessory device 420 used for the test. The playback device 410 may transmit the results of the listener hearing test to the server 430. The listener hearing test results may include specific hearing characteristics of the user, or raw user input data generated during the listener hearing test. Further, the listener hearing test results may include equalization preferences for a particular playback device 410 and output speakers used during the test. The indoor measurement profile 435, the accessory device profile 470, and/or the playback device profile 460 can be updated based on the listener hearing test results.

After the server 430 obtains the hearing test results, the playback device profile 460, and the accessory device profile 470, the server 430 may generate the listener hearing profile 450. The listener auditory profile 450 can be generated by removing audio characteristics of the playback device 410 and the accessory device 420 according to the results of the auditory test. In this manner, a listener auditory profile 450 can be generated that is independent of the playback device 410 and the accessory device 420.

In some embodiments, the components of virtualization system 400 may reside on servers 430 in a cloud computing environment. The cloud computing environment may deliver computing resources as a service over a network between server 430 and any registered playback devices.

Once the listener hearing profiles 450 have been generated for the user, the server 430 may transmit the listener hearing profiles 450 to each of the playback devices 410 registered with the system. In this manner, each of the playback devices 410 may store a listener profile 780 that is synchronized with the current listener hearing profile 450 on the server 430. This may allow a user to experience a rich personalized playback experience on the user's arbitrarily registered playback device. Regardless of which of the user's registered devices is used as the playback device 410, the listener profile 480 contained on the playback device 410 may optimize the playback experience for the listener on that device.

Once the user requests audio content from the system and attempts playback of the content, the playback device 410 being used to playback the content may check to determine if the user has a valid playback session. A valid playback session may mean that the user is logged into the system and the system knows the identity of the user and the type of playback device being used. Additionally, this may also mean that a copy of the listener profile 480 may be included on the playback device 410. If there is no valid session, the playback device 410 can communicate with the server 430 and authenticate the session to the system using the user identification, the playback device identification, and any available accessory device information.

The virtualization system 400 can change the playback device profile 460 and the accessory device profile 470 (if any) based on the listener auditory profile 450. In other words, using the listener auditory profile 450 as a reference for how the user wishes to hear the audio content, the system may configure the playback device profile 460 and the accessory device profile 470 of any connected accessory device as close as possible to achieve the reference. This information may be transmitted from the server 430 to the playback device 410 prior to playback of the audio content and stored at the playback device 410.

Playback of the audio content can then begin on the playback device 410 based on the listener auditory profile 450, the playback device profile 460, and the accessory device profile 470. At various intervals, the server 430 may query the playback device 410 for any state changes, such as accessory device changes when a new headset is connected. Alternatively, the playback device 410 may notify the virtualization system 400 that a state change has occurred. Or it may be that the user has updated his preferences or has re-conducted the listener hearing test. Whenever one of these changes occurs, the update module of the system may provide all or some of the following to the playback device: 1) an updated listener profile; 2) a playback device profile for a playback device currently being used; and 3) an attachment device profile for any attachments being used in connection with playback.

It should be noted that the configuration file may be stored by the virtualization system in the event that the configuration file is needed in the future. The configuration file may be stored by any component of the virtualization system even if the playback device is no longer in use or the accessory device is disconnected from the playback device. In some embodiments, the virtualization system may also track the number of times a user uses a playback device or an accessory device. This may allow the virtualization system to provide customized recommendations to the user based on previous playback device and accessory device usage.

In some embodiments, the virtualization system may be notified of which playback devices and accessory devices are being used. In some examples, the virtualization system may be notified without user input of which playback devices and accessory devices are being used. There may be several options for implementing the notification, for example using Radio Frequency Identification (RFID) and plug and play technology. Thus, even if the user makes a mistake as to which playback device or accessory device is being used, the virtualization system can determine the correct playback device profile and accessory device profile to use.

In some embodiments, the listener profile may be associated with the user without using a listener hearing test. This may be done by mining a database of listener hearing tests that have been previously conducted and associating them with the identity of the user who completed the test. Based on the system's knowledge of the user, the system may assign a listener profile from the database that most closely matches the user's characteristics (such as age, gender, height, weight, etc.).

Embodiments of the virtualization system may allow entities such as Original Equipment Manufacturers (OEMs) to change the factory settings of playback devices. Specifically, the OEM may perform tuning of the audio characteristics of the playback device at the factory. The ability to adjust these factory settings is often limited or non-existent. Using a virtualization system, OEMs may make changes to playback device profiles to reflect desired changes in factory settings. The updated playback device profile may be transferred from the server to the playback device and permanently stored thereon.

If multiple registered users are using a single playback device and accessory device (such as listening to speakers together in a room), the virtualization system may determine optimal playback settings for the multiple users. For example, the system may average the listener profiles of multiple users.

FIG. 5 is a block diagram illustrating an overview of an example virtualization system 500. It should be noted that FIG. 5 is one of many ways in which embodiments of virtualization system 500 can be implemented. Referring to fig. 5, an example virtualization system 500 can include a remote server 505 that can be included within a cloud computing environment 510. Cloud computing environment 510 may be a distributed environment that distributes hardware and software resources among various devices. Several components of the virtualization system 500 may be distributed in the cloud computing environment 510 and in communication with the remote server 505. In alternative embodiments, at least one or more of the following components may be included on the remote server 505.

In particular, the virtualization system 500 can include a registration module 515 in communication with a remote server 505 over a first network link 517. The registration module 515 may facilitate registering users, devices, and other information (such as a playback environment) with the virtualization system 500. The update module 520 may communicate with the remote server 505 over a second communication link 522. The update module 520 may receive updates of user and device status and send queries to determine user and device status. If the update module 520 becomes aware of the state or a change in state, any necessary configuration files may be updated. The virtualization system 500 can include audio content 525 in communication with the remote server 505 over a third communication link 527. The audio content 525 may be selected by the user and transmitted by the remote server 505.

The listener hearing test 530 to be performed by the user on the device may be stored in the cloud computing environment 510 and may communicate with the remote server 505 over a fourth communication link 532. In some embodiments, the listener hearing test 530 may be a plurality of different tests. As mentioned above, the user may conduct the listener hearing test 530 on the device, and the results may be uploaded to the remote server 505, where the virtualization system 500 may generate the listener profile 535. The listener profile 535 may be device independent, meaning that the same audio content played on different playback devices may sound almost the same. Listener profiles 535 for each registered user may be stored in cloud computing environment 510 and may communicate with remote server 505 via a fifth communication link 537.

Based on the listener profile 535 of a particular registered user, the virtualization system 500 can generate a playback device profile 540, which playback device profile 540 can be based on the type of device the user is using to play back any audio content 525. In some embodiments, the playback device profile 540 may be a plurality of profiles stored for a plurality of different playback devices. The playback device profile 540 may communicate with the remote server 505 over a sixth communication link 542. Additionally, the virtualization system 500 can generate an accessory device profile 545 for any type of accessory device that a user is using. In some embodiments, the accessory device profile 545 can be multiple profiles stored for a variety of different accessory devices. The accessory device profile 545 may communicate with the remote server 505 over a seventh communication link 547.

Virtualization system 500 can include an indoor measurement profile 548 that can communicate with remote server 505 over an eighth communication link 549. It should be noted that one or more of communication links 517, 522, 527, 532, 537, 542, 547, and/or 549 discussed above may be shared.

Embodiments of the virtualization system 500 can also include a playback device 550 for playing back audio content 525 in a playback environment 555. The playback environment 555 can be almost anywhere that audio content 525 can be enjoyed, such as a room, car, or building. The user may conduct the listener hearing test 530 on the device and the results may be sent to the remote server 505 for processing by the virtualization system 500. In some embodiments of the virtualization system 500, a user may use the application 560 to conduct the listener hearing test 530. In fig. 5, the application 560 is shown on the playback device 550 to ease description of the virtualization system 500, but it should be noted that the device on which the listener hearing test 530 is conducted may not necessarily be the same device as the playback device 550. The virtualization system 500 may generate the listener profile 535 from the results of the listener hearing test 530 and transmit the listener profile 535 to all registered devices associated with the user.

Playback of the audio content 525 to the listener 565 may occur in a playback environment 555. In the exemplary embodiment shown in fig. 5, a 5.1 speaker configuration is shown in the playback environment 555. It will be appreciated that any of a variety of audio configurations may be used in a playback environment, including headphones. As shown in fig. 5, the 5.1 speaker configuration may include a center speaker 570, a front right speaker 575, a front left speaker 580, a rear right speaker 585, a rear left speaker 590, and a subwoofer 595. The playback device 550 may communicate with the remote server 505 over an eighth communication link 597.

Fig. 6A and 6B are block diagrams illustrating a general overview of the operation of an embodiment of a virtualization system 500. For example, the first playback device 600 may be used to perform the listener hearing test 530. In some embodiments, the first playback device 600 may include an application 560 for assisting in conducting the listener hearing test 530. Once the user completes the listener hearing test 530, the listener hearing test results 605 may be sent to the remote server 505. Further, the first playback device 600 may send the first playback device information 610, accessory device information 615 (such as the type of speaker or headphones connected to the first playback device 600), and a user identification to the remote server 505.

The second playback device 625 may be used to play back the audio content 525 for the listener 565. Again, although the first playback device 600 and the second playback device 625 are shown as separate devices, in some embodiments they may be the same device. Prior to playback, the second playback device 625 can send information such as user identification 620, second playback device information 630, accessory device information 635, and playback environment information 640 to the remote server 505. The virtualization system 500 on the remote server 505 may process this information from the second playback device 625 and transmit the information back to the second playback device 625. The information transmitted back to the second playback device 625 can be profile information such as a listener profile 535, a second playback device profile 645, an accessory device profile 650, and a playback environment profile 655. Using one or more of these profiles 535, 645, 650, or 655, the second playback device 625 can play back the audio content 525 to a listener 565.

The second playback device 625 may be any of a number of different types of playback devices with network connectivity. By way of example and not limitation, the second playback device 625 may be an MP3 device 660, a television 665, a computing device 670, an a/V receiver 675, or an embedded device such as a smart phone 680. Using embodiments of virtualization system 500, listeners 565 can listen to the same audio content and have substantially similar audio experiences using different types of playback devices, accessory devices, and in various playback environments.

FIG. 7 is a flow diagram of an example method for use in a virtualization system. The method may begin by associating a user with a unique listener account 700. This information may be stored in cloud computing environment 510. Additionally, each of the user's playback devices may be registered with the virtualization system 500 and stored 710 in the cloud computing environment 510.

As described above, the user may execute 720 the listener hearing test 530 on the first playback device 600. Additionally, information regarding the first playback device 600 and any accessory devices used with the first playback device 600 may be transmitted 740 to the remote server 505. Using this information, embodiments of virtualization system 500 can generate 750 a listener profile 535 for the user on remote server 505.

The user may select 760 audio content 525 to be played back on the second playback device 625 in the playback environment 555. The second playback device 625 can transmit 770 information about the second playback device 625 (such as a model number), information about any accessory devices (such as a brand and/or type), and information about the playback environment 555 (such as indoor characteristics and speaker placement) to the remote server 505. In some embodiments, the device may only need to register with the virtualization system 500 once and may be given a device identification after registration. Further interaction with virtualization system 500 may require a device to provide its device identification.

The remote server 505 may then transmit 780 the listener profile 535, the second playback device profile 645, the accessory device profile 650, and the playback environment profile 655 to the second playback device 625. In some embodiments, any one or any combination of these profiles may be transmitted. In some embodiments, certain profiles may not apply, and in other embodiments, the profiles may be stored locally on the second playback device 625. Using these profiles, the user may play 790 the audio content 525 on the second playback device 625. Playback of the audio content 525 can be personalized for user listening preferences based on the listener profile 535 and other profiles such as the second playback device profile 645, the accessory device profile 650, and the playback environment profile 655.

The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

Claims (30)

1. A method for use in an audio device, the method comprising:

receiving, by an audio device, digital audio content comprising at least one audio channel signal;

transmitting information identifying the audio device to a server;

receiving metadata associated with the audio device from the server that affects reproduction of the digital audio content, wherein the metadata includes an indoor measurement profile based on acoustic measurements of a predetermined room and a listener hearing profile based on a spectral response curve of a user's hearing ability;

configuring at least one digital filter based on the received metadata;

filtering the at least one audio channel with a corresponding at least one digital filter to produce a filtered audio signal; and

the filtered audio signal is output to an accessory device coupled to the audio device to reproduce the digital audio content.

2. The method of claim 1, wherein the metadata further comprises a playback device profile based on frequency response parameters of the playback device and an accessory device profile based on frequency response parameters of the accessory device.

3. The method of claim 1, wherein the metadata multiplexed with the digital audio content is received.

4. The method of claim 1, wherein the metadata is received in the container file independently of the digital audio content.

5. The method of claim 1, wherein the room measurement profile includes at least one set of Head Related Transfer Function (HRTF) filter coefficients, an early room response parameter, and a late reverberation parameter.

6. The method of claim 5, wherein the early room response parameter and the late reverberation parameter configure the digital filter to produce a filtered audio signal having acoustic properties substantially similar to acoustic properties of the predetermined room.

7. The method of claim 6, wherein the late reverberation parameter configures a parametric model of the late reverberation of the predetermined room.

8. An audio device, comprising:

a receiver configured to

Receiving digital audio content comprising at least one audio channel signal;

transmitting information identifying the audio device to a server;

receiving, from a server, metadata associated with an audio device that affects reproduction of digital audio content, wherein the metadata includes an indoor measurement profile based on acoustic measurements of a predetermined room and a listener hearing profile based on a spectral response curve of a user's hearing ability;

a processor configured to configure at least one digital filter based on the received metadata, wherein the processor is configured to filter the at least one audio channel signal with the corresponding at least one digital filter to produce a filtered audio signal; and is

Wherein the processor is configured to output the filtered audio signal to an accessory device coupled to the audio device to reproduce the digital audio content.

9. The audio device of claim 8, wherein the metadata further comprises a playback device profile based on frequency response parameters of the playback device and an accessory device profile based on frequency response parameters of the accessory device.

10. The audio device of claim 8, wherein the metadata multiplexed with the digital audio content is received.

11. The audio device of claim 8, wherein the metadata is received in the container file independently of the digital audio content.

12. The audio device of claim 8, wherein the room measurement profile includes at least one set of Head Related Transfer Function (HRTF) filter coefficients, an early room response parameter, and a late reverberation parameter.

13. The audio device of claim 12, wherein the processor configures the digital filter with the early room response parameter and the late reverberation parameter to produce a filtered audio signal having acoustic properties substantially similar to acoustic properties of the predetermined room.

14. The audio device of claim 13, wherein the processor utilizes the late reverberation parameter to configure a parametric model of the late reverberation of the predetermined room.

15. A method for audio virtualization, comprising:

receiving, at a server, a result of a user listening test;

receiving information about at least one playback device associated with a user and at least one accessory device coupled to the playback device;

storing the received test results and information in a virtualization profile associated with the user, the virtualization profile comprising a plurality of parameters for an indoor measurement profile based on acoustic measurements of a predetermined room, a listener hearing profile based on a spectral response curve of the user's hearing ability, a playback device profile based on frequency response parameters of the playback device, and an accessory device profile based on frequency response parameters of the accessory device;

receiving a request for a virtualization profile from a playback device associated with a user; and

the requested virtualization profile is sent to the playback device.

16. The method of claim 15, wherein at least one of the plurality of parameters is multiplexed with digital audio content.

17. A method for use in an audio device, the method comprising:

receiving, by an audio device, digital audio content comprising at least one audio channel signal;

transmitting information identifying the audio device to a server;

receiving metadata associated with the audio device from the server that affects reproduction of the digital audio content, wherein the metadata includes an indoor measurement profile based on acoustic measurements of the predetermined room;

configuring at least one digital filter based on the received metadata;

filtering the at least one audio channel with a corresponding at least one digital filter to produce a filtered audio signal; and

the filtered audio signal is output to an accessory device coupled to the audio device to reproduce the digital audio content.

18. The method of claim 17, wherein the metadata further comprises a playback device profile based on frequency response parameters of the playback device and an accessory device profile based on frequency response parameters of the accessory device.

19. The method of claim 17, wherein the metadata multiplexed with the digital audio content is received.

20. The method of claim 17, wherein the metadata is received in the container file independently of the digital audio content.

21. The method of claim 17, wherein the room measurement profile includes at least one set of Head Related Transfer Function (HRTF) filter coefficients, an early room response parameter, and a late reverberation parameter.

22. The method of claim 21, wherein the early room response parameter and the late reverberation parameter configure the digital filter to produce a filtered audio signal having acoustic properties substantially similar to acoustic properties of the predetermined room.

23. The method of claim 22, wherein the late reverberation parameter configures a parametric model of the late reverberation of the predetermined room.

24. An audio device, comprising:

a receiver configured to

Receiving digital audio content comprising at least one audio channel signal; and

transmitting information identifying the audio device to a server;

receiving metadata associated with the audio device from the server that affects reproduction of the digital audio content, wherein the metadata includes an indoor measurement profile based on acoustic measurements of the predetermined room;

a processor configured to configure at least one digital filter based on the received metadata, wherein the processor is configured to filter the at least one audio channel signal with the corresponding at least one digital filter to produce a filtered audio signal; and is

Wherein the processor is configured to output the filtered audio signal to an accessory device coupled to the audio device to reproduce the digital audio content.

25. The audio device of claim 24, wherein the metadata further includes a playback device profile based on frequency response parameters of the playback device and an accessory device profile based on frequency response parameters of the accessory device.

26. The audio device of claim 24, wherein the metadata multiplexed with the digital audio content is received.

27. The audio device of claim 24, wherein the metadata is received in the container file independently of the digital audio content.

28. The audio device of claim 24, wherein the room measurement profile includes at least one set of Head Related Transfer Function (HRTF) filter coefficients, an early room response parameter, and a late reverberation parameter.

29. The audio device of claim 28, wherein the processor configures the digital filter with the early room response parameter and the late reverberation parameter to produce a filtered audio signal having acoustic properties substantially similar to acoustic properties of the predetermined room.

30. The audio device of claim 29, wherein the processor utilizes the late reverberation parameter to configure a parametric model of the late reverberation of the predetermined room.