The present invention relates to a method and an apparatus for processing an audio signal, and more particularly, to a method and an apparatus for processing an audio signal that can process an audio signal received by a digital medium, a broadcast signal, and so on.
Generally, in a process of downmixing a plurality of objects into a mono or stereo signal, parameters are extracted from each object signal. Such parameters may be used in a decoder, and panning and gain of each object may be controlled by a user's choice (or selection).
In order to control each object signal, each source included in a downmix should be appropriately positioned and panned.
Furthermore, in order to ensure downward compatibility using a channel-oriented decoding method, an object information should be flexibly converted to a multi-channel parameter for upmixing.
An object of the present invention devised to solve the problem lies on providing a method and an apparatus for processing an audio signal that can control the gain and panning of an object without limitation.
Another object of the present invention devised to solve the problem lies on providing a method and an apparatus for processing an audio signal that can control the gain and panning of an object-based upon a user's choice (or selection).
A further object of the present invention devised to solve the problem lies on providing a method and an apparatus for processing an audio signal that does not generate distortion in sound quality, even when the gain of a vocal sound (or music) or background music has been adjusted within a large range.
The present invention has the following effects and advantages.
Firstly, the gain and panning of an object may be controlled.
Secondly, the gain and panning of an object may be controlled based upon a user's choice (or selection).
Thirdly, even when either one of a vocal sound (or music) and a background music is completely suppressed, a distortion in sound quality caused by gain adjustment may be prevented.
And, finally, when at least two independent objects, such as a vocal sound, exist (i.e., when a stereo channel or a plurality of voice signals exists), a distortion in sound quality caused by gain adjustment may be prevented.
The object of the present invention can be achieved by providing a method for processing an audio signal including receiving a downmix information having at least two independent objects and a background object downmixed therein; separating the downmix information into a first independent object and a temporary background object using a first enhanced object information; and extracting a second independent object from the temporary background object using a second enhanced object information.
According to the present invention, the independent object may correspond to an object-based signal, and the background object may correspond to a signal either including at least one channel-based signal or having at least one channel-based signal downmixed therein.
According to the present invention, the background object may include a left channel signal and a right channel signal.
According to the present invention, the first enhanced object information and the second enhanced object information may correspond to residual signals.
According to the present invention, the first enhanced object information and the second enhanced object information may be included in a side information bitstream, and a number of enhanced objects included in the side information bitstream and a number of independent objects included in the downmix information may be equal to one another.
According to the present invention, the separating the downmix information may be performed by a module generating (N+1) number of outputs using N number of inputs.
According to the present invention, the method may further include receiving an object information and a mix information; and generating a multi-channel information for adjusting gains of the first independent object and the second independent object using the object information and the mix information.
According to the present invention, the mix information may be generated based upon at least one of an object position information, an object gain information, and a playback configuration information.
According to the present invention, the extracting a second independent object may correspond to extracting a second temporary background object and a second independent object, and may further include extracting a third independent object from the second temporary background object using a second enhanced object information.
According to the present invention, another object of the present invention can be achieved by providing a recording medium capable of reading using a computer having a program stored therein, the program executing receiving a downmix information having at least two independent objects and a background object downmixed therein; separating the downmix information into a first independent object and a temporary background object using a first enhanced object information; and extracting a second independent object from the temporary background object using a second enhanced object information.
Another object of the present invention can be achieved by providing an apparatus for processing an audio signal including an information receiving unit receiving a downmix information having at least two independent objects and a background object downmixed therein; a first enhanced object information decoding unit separating the downmix into a first independent object and a temporary background object using a first enhanced object information; and a second enhanced object information decoding unit extracting a second independent object from the temporary background object using a second enhanced object information.
Another object of the present invention can be achieved by providing a method for processing an audio signal including generating a temporary background object and a first enhanced object information using a first independent object and a background object; generating a second enhanced object information using a second independent object and a temporary background object; and transmitting the first enhanced object information and the second enhanced object information.
Another object of the present invention can be achieved by providing an apparatus for processing an audio signal including a first enhanced object information generating unit generating a temporary background object and a first enhanced object information using a first independent object and a background object; a second enhanced object information generating unit generating a second enhanced object information using a second independent object and a temporary background object; and a multiplexer transmitting the first enhanced object information and the second enhanced object information.
Another object of the present invention can be achieved by providing a method for processing an audio signal including receiving a downmix information having an independent object and a background object downmixed therein; generating a first multi-channel information for controlling the independent object; and generating a second multi-channel information for controlling the background object using the downmix information and the first multi-channel information.
According to the present invention, the generating a second multi-channel information may include subtracting a signal having the first multi-channel information applied therein from the downmix information.
According to the present invention, the subtracting a signal from the downmix information may be performed within one of a time domain and a frequency domain.
According to the present invention, the subtracting a signal from the downmix information may be performed with respect to each channel, when a number of channel of the downmix information and a number of channels of the signal having the first multi-channel information applied therein is equal to one another.
According to the present invention, the method may further include generating an output channel from the downmix information using the first multi-channel information and the second multi-channel information.
According to the present invention, the method may further include receiving an enhanced object information; and separating the independent object and the background object from the downmix information using the enhanced object information.
According to the present invention, the method may further include receiving a mix information, and the generating a first multi-channel information and the generating a second multi-channel information may be performed based upon the mix information.
According to the present invention, the mix information may be generated based upon at least one of an object position information, an object gain information, and a playback configuration information.
According to the present invention, the downmix information may be received via a broadcast signal.
According to the present invention, the downmix information may be received on a digital medium.
According to the present invention, another object of the present invention can be achieved by providing a recording medium capable of reading using a computer having a program stored therein, the program executing receiving a downmix information having an independent object and a background object downmixed therein; generating a first multi-channel information for controlling the independent object; and generating a second multi-channel information for controlling the background object using the downmix information and the first multi-channel information.
Another object of the present invention can be achieved by providing an apparatus for processing an audio signal including an information receiving unit receiving a downmix information having an independent object and a background object downmixed therein; and a multi-channel generating unit generating a first multi-channel information for controlling the independent object, and generating a second multi-channel information for controlling the background object using the downmix information and the first multi-channel information.
Another object of the present invention can be achieved by providing a method for processing an audio signal including receiving a downmix information having at least one independent object and a background object downmixed therein; receiving an object information and a mix information; and extracting at least one independent object from the downmix information using the object information and the enhanced object information.
According to the present invention, the object information may correspond to information associated with the independent object and the background object.
According to the present invention, the object information may include at least one of a level information and a correlation information between the independent object and the background object.
According to the present invention, the enhanced object information may include a residual signal.
According to the present invention, the residual signal may be extracted during a process of grouping at least one object-based signal into an enhanced object.
According to the present invention, the independent object may correspond to an object-based signal, and the background object may correspond to a signal either including at least one channel-based signal or having at least one channel-based signal downmixed therein.
According to the present invention, the background object may include a left channel signal and a right channel signal.
According to the present invention, the downmix information may be received via a broadcast signal.
According to the present invention, the downmix information may be received on a digital medium.
According to the present invention, another object of the present invention can be achieved by providing a recording medium capable of reading using a computer having a program stored therein, the program executing receiving a downmix information having at least one independent object and a background object downmixed therein; receiving an object information and a mix information; and extracting at least one independent object from the downmix information using the object information and the enhanced object information.
A further object of the present invention can be achieved by providing an apparatus for processing an audio signal including an information receiving unit receiving a downmix information having at least one independent object and a background object downmixed therein and receiving an object information and a mix information; and an information generating unit extracting at least one independent object from the downmix using the object information and the enhanced object information.
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In addition, although the terms used in the present invention are selected from generally known and used terms, some of the terms mentioned in the description of the present invention have been selected by the applicant at his or her discretion, the detailed meanings of which are described in relevant parts of the description herein. Furthermore, it is required that the present invention is understood, not simply by the actual terms used but by the meaning of each term lying within. Also, the embodiments described in the description of the present invention and the structures illustrated in the drawings are merely exemplary of the most preferred embodiment of this invention. And, since the preferred embodiment in unable to wholly represent the technical spirit and scope of the present invention, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Most particularly, in the description of the present invention, information collectively refers to the terms values, parameters, coefficients, elements, and so on. And, in some cases the definition of the terms may be interpreted differently. However, the present invention will not be limited such definitions.
Especially, the term object is a concept including both an object-based signal and a channel-based signal. However, in some cases, the term object may only indicate the object-based signal.
First of all, the object encoder 110 uses at least one object (objN) in order to generate an object information (OP). Herein, the object information (OP) corresponds to information related to object-based signals and may include object level information, object correlation information, and so on. Meanwhile, the object encoder 110 groups at least one object so as to generate a downmix. This process may be identical to a process of generating an enhanced object by having an enhanced object generating unit 122 group at least one object, which is to be described with reference to
The enhanced object encoder 120 uses at least one object (objN) in order to generate an enhanced object information (OP) and a downmix (DMX) (LL and RL). More specifically, at least one object-based signal is grouped so as to generate an enhanced object (EO), and a channel-based signal and an enhanced object (EO) are used in order to generate an enhanced object information (EOP). First of all, an enhanced object information (EOP) may correspond to energy information (including level information), residual signal, and so on, which will be described in detail later on with reference to
The multiplexer 130 multiplexes the object information (OP) generated by the object encoder 110 and the enhanced object information (EOP) generated by the enhanced object encoder 120, thereby generating a side information bitstream. Meanwhile, the side information bitstream may include spatial information (or spatial parameter) (SP) (not shown) corresponding to the channel-based signal. Herein, spatial information corresponds to information required for decoding channel-based signals, and spatial information may include channel level information, channel correlation information, and so on. However, the present invention will not be limited to this example.
The demultiplexer 210 of the decoder extracts an object information (OP) and an enhanced object information (EOP) from the side information bitstream. And, when the spatial information (SP) is included in the side information bitstream, the demultiplexer 210 extracts more spatial information (SP).
The information generating unit 220 uses the object information (OP) and enhanced object information (EOP) in order to generate multi-channel information (MI) and downmix processing information (DPI). In generating the multi-channel information (MI) and downmix processing information (DPI), downmix information (DMX) may be used, which will be described in detail later on with reference to
The downmix processing unit 230 uses the downmix processing information (DPI) in order to process the downmix (DMX). For example, the downmix (DMX) may be processed in order to adjust the gain or panning of the object.
The multi-channel decoder 240 receives the processed downmix and uses the multi-channel information (MI) to upmix a processed downmix signal, thereby generating a multi-channel signal.
Hereinafter, detailed structures of the enhanced object encoder 120 of the encoder 100 according to a variety of embodiments will be described with reference to
The enhanced object generating unit 122 groups at least one object (objN) in order to generate at least one enhanced object (EOL). Herein, the enhanced object (EOL) is grouped in order to provide high quality control. For example, the enhanced object (EOL) may be grouped in order to enable the enhanced object (EOL) over the background object to be completely suppressed independently (or vice versa, wherein only the enhanced object (EOL) is reproduced (or played-back), and wherein the background object is completely suppressed). Herein, the object (objN) that is to be the subject for grouping may be an object-based signal instead of a channel-based signal. And, the enhanced object (EO) may be generated by using a variety of methods, which are as follows: 1) one object may be used as one enhanced object (i.e., EO1=obj1), 2) at least two objects may be added so as to configure an enhanced object (i.e., EO2=obj1+obj2). Also, 3) a signal having a particular object excluded from the downmix may be used as the enhanced object (i.e., EO3=D−obj2), and a signal having at least two objects excluded from the downmix may be used as the enhanced object (i.e., EO4=D−obj1−obj2). The concept of the downmix (D) mentioned in methods 3) and 4) is different from that of the above-described downmix (DMX) (LL and RL), and may be referred to as a signal having only a downmixed object-based signal. Accordingly, the enhanced object (EO) may be generated by using at least one of the 4 methods described above.
The enhanced object information generating unit 124 uses the enhanced object (EO) so as to generate an enhanced object information (EOP). Herein, an enhanced object information (EOP) refers to an information on an enhanced object that may correspond to a) energy information (including level information) of an enhanced object, b) a relation between an enhanced object (EO) and a downmix (D) (e.g., mixing gain), c) enhanced object level information or enhanced object correlation information according to a high time resolution or high frequency resolution, d) prediction information or envelope information in a time domain with respect to an enhanced object (EO), and e) a bitstream having information of a time domain or spectrum domain with respect to an enhanced object such as a residual signal.
Meanwhile, if the enhanced object (EO) is generated as shown in the first and third examples (i.e., EO1=obj1 and EO3=D−obj2), in the above-described examples, the enhanced object information (EOP) may generate enhanced object information (EOP1 and EOP3) for each of the enhanced objects (EO1 and EO3) of the first and third examples, respectively. At this point, the enhanced object information (EOP1) according to the first example may correspond to information (or parameter) required for controlling the enhanced object (EO1) according to the first example. And, the enhanced object information (EOP3) according to the third example may be used to express (or represent) an instance in which only a particular object (obj2) is suppressed.
The enhanced object information generating unit 124 may include one or more enhanced object information generators 124-1, . . . , 124-L. More specifically, the enhanced object information generating unit 124 may include a first enhanced object information generator 124-1 generating an enhanced object information (EOP1) corresponding to one enhanced object (EO1), and may also include a second enhanced object information generator 124-2 generating an enhanced object information (EOP2) corresponding to at least two enhanced objects (EO1 and EO2). Meanwhile, Lth enhanced object information generator 124-L generating an enhanced object information (EOPL) using not only the enhanced object (EO1) but also the output of the second enhanced object information generator 124-2 may be included. Each of the enhanced object information generators 124-1, . . . , 124-L may be operated by a module generating N number of outputs by using (N+1) number of inputs. For example, each of the enhanced object information generators 124-1, . . . , 124-L may be operated by a module generating 2 outputs by using 3 inputs. Hereinafter, a variety of embodiments of the enhanced object information generators 124-1, . . . , 124-L will be described in detail with reference to
The multiplexer 126 multiplexes at least one enhanced object information (EOP1, . . . EOPL) (and enhanced enhanced object (EEOP)) generated from the enhanced object information generating unit 124.
First of all, referring to
Meanwhile, the stereo vocal signals (Vocal1L, Vocal1R, Vocal2L, Vocal2R) corresponding to object-based signals may include a left channel signal (Vocal1L) and a right channel signal (Vocal1R) corresponding to a vocal sound (Vocal1) of singer 1, and a left channel signal (Vocal2L) and a right channel signal (Vocal2R) corresponding to a vocal sound (Vocal2) of singer 2. Meanwhile, although in this example it is illustrated in the stereo object signal, it is apparent that a multi-channel object signal (Vocal1L, Vocal1R, Vocal1Ls, Vocal1Rs, Vocal1c, Vocal1LFE) may be received and be grouped as a single enhanced object (Vocal).
As described above, since a single enhanced object (Vocal) is generated, the enhanced object information generating unit 124A includes only a first enhanced object information generator 124A-1 corresponding to the single enhanced object (Vocal). The first enhanced object information generator 124A-1 uses the enhanced object (Vocal) and channel-based signal (L and R) so as to generate a first residual signal (res1) as an enhanced object information (EOP1) and a temporary background object (L1 and R1). The temporary background object (L1 and R1) corresponds to a signal having a channel-based signal, i.e., a background object (L and R) added to the enhanced object (Vocal). Therefore, in the third example, wherein only a single enhanced object information generator exists, the temporary background object (L1 and R1) may correspond to a final downmix signal (L1 and R1).
Referring to
The first enhanced object generator 124B-1 uses a background signal (channel-based signal (L and R)) and a first enhanced object signal (Vocal1) so as to generate a first enhanced object information (res1) and a temporary background object (L1 and R1).
The second enhanced object generator 124B-2 not only uses a second enhanced object signal (Vocal2) but also uses a first temporary background object (L1 and R1), so as to generate a second enhanced object information (rest) and a background object (L2 and R2) as the final downmix (L1 and R1). In the second example shown in
Referring to
Referring to
Referring to
DDMX=DMX−EOL [Equation 1]
The enhanced enhanced object information (EEOP) does not correspond to information between the downmix (DMX: LL and RL) and the enhanced object (EOL) but corresponds to information between the signal (DDMX) defined in Equation 1 and the enhanced object (EOL). When the enhanced object (EOL) is subtracted from the downmix (DMX), a quantizing noise may be generated with respect to the enhanced object. Such quantizing noise may be cancelled by using an object information (OP), thereby enhancing the sound quality. (This process will be described in detail later on with reference to
By being provided with the above-described parts, the encoder 100 of the apparatus for processing an audio signal according to the embodiment of the present invention generates a downmix and a side information bitstream.
Referring to (d) of
The decoder 200 of the apparatus for processing an audio signal according to the embodiment of the present invention receives the side information bitstream and downmix, which are generated as describe above, so as to perform decoding.
First of all, the enhanced object information decoding unit 224 uses the object information (OP) and enhanced object information (EOP) that are received from the demultiplexer 210 in order to extract an enhanced object (EO), thereby outputting the background object (L and R). The structure of the enhanced object information decoding unit 224 will be described in detail with reference to
Referring to
Similarly, the Lth enhanced object information decoder 224-L uses an Lth enhanced object information (EOP1) in order to generate a background parameter (BP) for separating an (L−1)th temporary background object (L and R) into an Lth enhanced object (EO1) and a background object (L and R).
Meanwhile, the first enhanced object information decoder 224-1 to the Lth enhanced object information decoder 224-L may be represented by a module generating (N+1) number of outputs by using N number of inputs (e.g., generating 3 outputs by using 2 inputs).
Meanwhile, in order to generate the above-described background parameter (BP), the enhanced object information decoding unit 224 may not only use the enhanced object information (EOP) but also use the object information (OP). Hereinafter, the objects of using the object information (OP) and the associated advantages will now be described in detail.
One of the objects of the present invention is to discard (or remove) an enhanced object (EO) from a downmix (DMX). Herein, depending upon a method of encoding the downmix and a method of encoding the enhanced object information, a quantizing noise may be included in the corresponding output. In this case, since the quantizing noise is associated with an original signal, more specifically, by using the object information (OP), which corresponds to information on an object prior to being grouped into an enhanced object, the sound quality may be additionally enhanced. For example, when the first object corresponds to a vocal object, the first object information (OP1) includes information associated with the time, frequency, and space of the vocal sound. An output having a vocal sound subtracted from the downmix (DMX) corresponds to the equation shown below. Herein, when the first object information (OP1) is used on the output having the vocal sound removed therefrom so as to suppress the vocal sound, this output performs additional suppression on the quantizing noise that remains within the section where the vocal sound was initially present.
Output=DMX−EO1′ [Equation 2]
(Herein, DMX indicates an input downmix signal, and EO1′ represents an encoded/decoded first enhanced object within a codec.)
Therefore, by applying an enhanced object information (EOP) and an object information (OP) with respect to a specific object, the performance of the present invention may be additionally enhanced, and the application of such enhanced object information (EOP) and object information (OP) may either be sequential or be simultaneous. Meanwhile, the object information (OP) may correspond to information on an enhanced object (independent object) and background object.
Referring back to
Referring to
Referring back to
Herein, a mix information (MXI) corresponds to information generated based upon an object position information, an object gain information, a playback configuration information, and so on. Herein, the object position information refers to information inputted by the user in order to control the position or panning of each object. The object gain information refers to information inputted by the user in order to control the gain of each object. The playback configuration information refers to information including a number of speakers, positions of the speakers, ambient information (virtual positions of the speakers), and so on. Herein, the playback configuration information may be received from the user, may be pre-stored within the system, or may be received from another apparatus (or device).
In order to generate the multi-channel information (MI), the multi-channel information generating unit 226 may use the independent parameter (IP) received from the object information decoding unit 222 and/or the background parameter (BP) received from the enhanced object information decoding unit 224. First of all, a first multi-channel information (MI1) for controlling the enhanced object (independent object) is generated in accordance with the mix information (MXI). For example, if the user inputted control information in order to completely suppress the enhanced object, such as a vocal signal, a first multi-channel information for controlling the enhanced object from the downmix (DMX) is generated in accordance with the mix information (MXI) having the above-mentioned control information applied thereto.
After generating the first multi-channel information (MI1) for controlling the independent object, as described above, a second multi-channel information (MI2) for controlling the background object is generated by using the first multi-channel information (MI1) and the spatial parameter (SP) transmitted from the demultiplexer 210. More specifically, as shown in the following equation, the second multi-channel information (MI2) may be generated by subtracting a signal (i.e., enhanced object (EO)) to which the first multi-channel information (MI1) is applied from the downmix (DMX).
BO=DMX−EOL [Equation 3]
(Herein, BO represents a background object signal, DMX signifies a downmix signal, and EOL represents an Lth enhanced object.)
Herein, the process of subtracting an enhanced object from a downmix may be performed either on a time domain or on a frequency domain. Furthermore, the process of subtracting the enhanced object may be performed with respect to each channel, when a number of channels of the downmix (DMX) and a number of channels of the signal to which the first multi-channel information is applied (i.e., a number of enhanced objects) are equal to one another.
Then, a multi-channel information (MI) including a first multi-channel information (MI1) and a second multi-channel information (MI2) is generated and transmitted to the multi-channel decoder 240.
The multi-channel decoder 240 receives the processed downmix and, then, uses the multi-channel information (MI) to upmix the processed downmix signal, thereby generating a multi-channel signal.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
The present invention may be applied in encoding and decoding an audio signal.
Number | Date | Country | Kind |
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10-2008-0024245 | Mar 2008 | EP | regional |
10-2008-0024247 | Mar 2008 | EP | regional |
10-2008-0024248 | Mar 2008 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/KR08/01493 | 3/17/2008 | WO | 00 | 11/25/2009 |
Number | Date | Country | |
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60895314 | Mar 2007 | US |