KR101108060B1 - A method and an apparatus for processing a signal - Google Patents

A method and an apparatus for processing a signal Download PDF

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KR101108060B1
KR101108060B1 KR1020090090515A KR20090090515A KR101108060B1 KR 101108060 B1 KR101108060 B1 KR 101108060B1 KR 1020090090515 A KR1020090090515 A KR 1020090090515A KR 20090090515 A KR20090090515 A KR 20090090515A KR 101108060 B1 KR101108060 B1 KR 101108060B1
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phase difference
channel
signal
inter
channels
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KR1020090090515A
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Korean (ko)
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KR20100035120A (en
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김동수
윤성용
이현국
임재현
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엘지전자 주식회사
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    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10LSPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
    • G10L19/00Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
    • G10L19/008Multichannel audio signal coding or decoding, i.e. using interchannel correlation to reduce redundancies, e.g. joint-stereo, intensity-coding, matrixing
    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10LSPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
    • G10L19/00Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
    • G10L19/02Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis using spectral analysis, e.g. transform vocoders or subband vocoders
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10Digital recording or reproducing
    • G11B20/12Formatting, e.g. arrangement of data block or words on the record carriers
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04SSTEREOPHONIC SYSTEMS 
    • H04S3/00Systems employing more than two channels, e.g. quadraphonic
    • H04S3/02Systems employing more than two channels, e.g. quadraphonic of the matrix type, i.e. in which input signals are combined algebraically, e.g. after having been phase shifted with respect to each other

Abstract

The present invention comprises the steps of: receiving a downmix signal generated from a multichannel signal and spatial information indicating attributes of the multichannel signal for upmixing the downmix signal; Obtaining an inter-channel phase difference coding flag indicating whether an inter-channel phase difference value is used in the spatial information from the header of the spatial information; Obtaining an inter-channel phase difference mode flag indicating whether the inter-channel phase difference value is used in the frame based on the inter-channel phase difference coding flag; Obtaining the inter-channel phase difference value from the parameter band of the frame based on the inter-channel phase difference mode flag; And generating the multi-channel signal by applying the phase difference value between the channels to the downmix signal.
According to the signal processing method and apparatus of the present invention, the inter-channel phase difference value and the inter-channel correlation value are restored by using the inter-channel phase difference value based on the inter-channel phase difference coding flag and the inter-channel phase difference mode flag. It can restore the hard feeling of space and clarify localization of sound image.
Inter-channel phase difference value, Inter-channel phase difference coding flag, Inter-channel phase difference mode flag, Phase shift flag

Description

Signal processing method and apparatus therefor {A METHOD AND AN APPARATUS FOR PROCESSING A SIGNAL}

The present invention uses a signal shifted the phase of the input signal, and the signal processing to improve the sound quality of the signal by using the phase difference value between the channel of the shifted signal of the phase, and to restore the input signal more completely A method and apparatus are disclosed.

In general, a signal may be coded using a decorrelator to generate a stereo signal from a mono signal.

In addition, the signal processing apparatus may code a signal using a level difference value between channels and a correlation value between channels.

When a speech signal is generated using a decorrelator, the decorator may not accurately reproduce a phase difference or a delay difference existing between channel signals.

In addition, when a signal is coded using a level difference value between channels and a correlation value between channels, it is difficult to perform accurate localization of a sound image because the phase difference between the input signals cannot be restored and reflected. There is a problem in that the spatial feeling of the signal cannot be restored.

The present invention was devised to solve the above problems, and by reconstructing and moving the phase of a decoded audio signal or a voice signal using a phase difference value and a phase shift flag between channels, a sound quality is improved and a signal close to the original sound. It is an object of the present invention to provide a method and apparatus for processing.

The present invention provides the following effects and advantages.

First, the signal processing method and apparatus of the present invention efficiently shift a phase of a decoded audio signal or a speech signal based on a phase shift flag to efficiently detect a phase difference or a delay difference that is difficult to be reproduced efficiently by a decorrelator during decoding. It has an effect that can be played back.

Second, the signal processing method and apparatus of the present invention restore the inter-channel level difference value and the inter-channel correlation value by using the inter-channel phase difference value based on the inter-channel phase difference coding flag and the inter-channel phase difference mode flag. This hard space can be restored and the localization of sound images can be clarified.

Third, the signal processing method and apparatus of the present invention decode the signal using the inter-channel phase difference value as necessary by receiving the inter-channel phase difference mode flag indicating whether or not the inter-channel phase difference value is used for each frame. can do.

Fourth, the signal processing method and apparatus of the present invention, by smoothing the phase difference value between the channels of the current parameter time slot using the phase difference value of the channel of the previous parameter time slot, the difference of the phase difference value between channels It has the effect of eliminating noise that may occur transiently.

Fifth, the signal processing method and apparatus of the present invention can increase coding efficiency and decode a signal close to the original sound by transmitting a phase difference value between channels only when certain conditions are satisfied.

Sixth, the signal processing method and apparatus of the present invention converts the phase difference value measured by the encoder into a level difference value between channels, thereby transmitting the existing signal processing apparatus that does not allow transmission of the phase difference value between channels. And even when using the method, the sense of space is improved and the localization of the sound image (localization) has the effect of restoring a signal close to the original sound (Backward compatibility).

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention, and do not represent all of the technical idea of the present invention, which can be replaced at the time of the present application It should be understood that there may be various equivalents and variations.

In particular, coding in the present invention should be understood as a concept including both encoding and decoding.

In addition, in the present specification, information is a term encompassing all values, parameters, coefficients, elements, and the like, and in some cases, meaning may be interpreted differently. The present invention is not limited to this. In the present specification, a stereo signal is described as an example of a signal, but is not limited thereto, and may be a multi-channel signal having three or more channels.

1 is a conceptual diagram illustrating a concept of a signal processing method according to an embodiment of the present invention, and illustrates a bitstream of spatial information. Referring to FIG. 1, spatial information may be divided into a header and a plurality of frames. In this case, the spatial information is information indicating the property of the multi-channel signal as an input signal, a level difference value between channels indicating a level difference between two channels among the plurality of channels, a correlation value between channels indicating a correlation between two channels, and between two channels. It may include a phase difference value between channels indicating a phase difference of. This may be used to upmix and reconstruct the downmix signal generated by downmixing the multichannel signal at the decoder.

The header of the spatial information includes an inter-channel phase difference coding flag (bsPhaseCoding) indicating whether there is a frame in which the inter-channel phase difference value is used in all frames. That is, the phase difference coding flag between channels may be included in the header to determine whether the channel difference value is used in every frame of spatial information. The meaning of the phase difference coding flag between channels is shown in Table 1 below.

bsPhaseCoding meaning One Indicates that IPD coding is applied to spatial information
That is, it indicates that the IPD value is used in at least one frame among the entire frames.
0 Indicates that IPD coding is not applied to spatial information
That is, it indicates that the IPD value is not used in the whole frame.

In addition, the spatial information includes an inter-channel phase difference mode flag (bsPhaseMode) indicating whether the inter-channel phase difference value is used in the frame for each frame. The inter-channel phase difference mode flag is included in the frame only when the inter-channel phase difference coding flag is 1, that is, the inter-channel phase difference coding flag indicates that IPD coding is used for spatial information. The specific meaning of the phase difference mode flag (bsPhaseMode) between channels is shown in Table 2 below.

bsPhaseMode meaning One Indicates the IPD value is used in the current frame 0 Indicates that the IPD value is not used in the current frame

Referring back to FIG. 1, when the inter-channel phase difference mode flag of Frame 2 is 1 (bsPhaseMode = 1), the inter-channel phase difference value IPD is included in frame 2 as a non-zero value. When the inter-channel phase difference mode flag of Frame 3 is 0 (bsPhaseMode = 0), the inter-channel phase difference value IPD in frame 3 has a value of 0.

Accordingly, the inter-channel phase difference value may be obtained based on the inter-channel phase difference coding flag and the inter-channel phase difference mode flag, and applied to the downmix signal to upmix into a multi-channel signal.

2 is a block diagram illustrating a signal processing apparatus according to an embodiment of the present invention. Referring to FIG. 2, the signal processing apparatus 200 may include a downmixer 210, a spatial information generator 220, a multiplexer 230, a demultiplexer 240, an information acquirer 250, and an upmixer. The unit 260 is included.

The downmixer 210 may receive the multichannel signal and generate a downmix signal DMX. The multi-channel signal may be a signal having three or more channels, or may be a signal having a mono or stereo channel. The downmixing unit 210 may generate a downmix signal having a number of channels smaller than the number of channels of the multichannel signal by downmixing the multichannel signal.

As described above with reference to FIG. 1, the spatial information generator 220 generates spatial information information for upmixing the downmix signal in a decoder later, wherein the spatial information is a property of a multi-channel signal. Can be represented. As described above, the spatial information may include a level difference value between channels, a correlation value between channels, and a phase difference value between channels, but here, the phase difference value between channels is described with reference to the spatial information generator 220 of FIG. 2. This will be described in detail.

The spatial information generator 220 includes an IPD usage determiner 221, an IPD value measurer 222, an IPD code flag generator 223, and an IPD coded flag generator 224. The IPD utilization determining unit 221 may determine whether to include the inter-channel phase difference (IPD) value in the spatial information. In detail, the characteristics of the multi-channel signal, the inter-channel phase difference value, and the inter-channel level difference value It is possible to determine whether to include the phase difference value between channels based on the ratio of. For example, when the multi-channel signal is a voice signal, it may be determined to include a phase difference value between channels in the spatial information, which will be described later in detail.

The IPD value measuring unit 222 measures the phase difference between two channels from the multi-channel signal input to the spatial information generating unit 200 when the IPD use determining unit 221 determines to use the phase difference value between channels. do. The measured phase difference may be a phase and / or an angle, may be a time difference, or may be an index value corresponding to the angle or time difference. Phase and time difference in the signal (signal) has a close relationship, a detailed description thereof will be described later with reference to FIG.

The IPD mode flag generator 223 generates the phase difference mode flag bsPhaseMode described above with reference to FIG. 1. That is, it indicates whether a phase difference value between channels is used in a frame, and the frame may be a current frame including the phase difference value between channels. Therefore, the phase difference mode flag between channels may vary variably for each frame. In detail, when the inter-channel phase difference coding flag indicates that the inter-channel phase difference value is not used in all frames of the spatial information, the inter-channel phase difference mode flag may not be included in the frame. The phase difference mode flag between channels may have a value of 0 or 1. FIG.

The IPD coding flag generator 224 generates the phase difference coding flag bsPhaseCoding described above with reference to FIG. 1. That is, since the IPD coding flag indicating whether the IPD coding is used in the spatial information is generated, when the inter-channel phase difference value is used in at least one or more frames of the spatial information partitioned with reference to FIG. 1, the inter-channel phase difference coding flag Naturally, 1 is represented.

The information obtaining unit 230 receives the spatial information from the spatial information generating unit 220. The spatial information may include an inter-channel phase difference coding flag (bsPhaseCoding) and an inter-channel phase difference mode flag (bsPhaseMode) as well as an inter-channel phase difference (IPD) value. The information obtaining unit 230 includes an IPD coding flag obtaining unit 231, an IPD mode flag obtaining unit 232, and an IPD value obtaining unit 233, and the IPD coding flag obtaining unit 231 is configured from a header of spatial information. An inter-channel phase difference coding flag indicating whether an inter-channel phase difference value is used in at least one frame among all frames of spatial information is obtained. The meaning of the phase difference coding flag between channels is shown in Table 1 above.

The IPD mode flag acquirer 232 obtains an inter-channel phase difference mode flag (bsPhaseMode) indicating whether the inter-channel phase difference value is used in the frame based on the inter-channel phase difference coding flag. In detail, when the inter-channel phase difference coding flag indicates that the inter-channel phase difference value is used (bsPhaseCoding = 1), the IPD mode flag acquirer 232 may acquire the inter-channel phase difference mode flag.

The IPD value obtaining unit 233 may obtain a phase difference value between channels from the spatial information based on the phase difference mode flag between channels. The phase difference value between channels may exist for each parameter band. In the present specification, the parameter band indicates at least one or more subbands including the same phase difference value between channels, which will be described later with reference to FIGS. 7 and 8.

The upmixer 240 may generate a multi-channel signal by applying the phase difference value obtained from the information acquirer 230 to the downmix signal input from the downmixer 210. The upmixing refers to applying an upmixing matrix to generate a greater number of channel signals than the channels of the downmixing signal, and the upmixed signal refers to a signal to which the upmixing matrix is applied. Refers to. Thus, the multi-channel signal is a signal having a larger number of channels than the downmix signal. In addition, it may refer to a signal itself to which the upmixing matrix is applied, and may also be a QMF domain signal generated to have a plurality of channels by applying the upmixing matrix, or the final signal in which the QMF domain signal is converted into a signal in a time domain. It may be.

As described above, the signal processing apparatus and method of the present invention use the inter-channel phase difference value based on the inter-channel phase difference coding flag and the inter-channel phase difference mode flag, thereby providing the inter-channel level difference value and the inter-channel correlation value. It has the effect of restoring a sense of space that is difficult to restore and clarifying localization of sound images.

3 is a graph illustrating a relationship between phase and time in a signal. The left graph of FIG. 3 shows the signal on the phase-amplitude domain. The signal (a) is an input signal without phase change, and the signal (b) represents a signal whose phase is delayed by π / 2 than the signal (a).

Meanwhile, the graph on the right side of FIG. 3 shows signals on the time-amplitude domain, and shows signals (a) 'and (b)' corresponding to signals (a) and (b) on the left graph. That is, the signal (b), which is a signal whose phase is delayed by π / 2 than the signal (a), may be represented in the same manner as the signal (b) which is a signal input 3.3 ms later than the signal (a). As such, phase-times in a signal have a close relationship, and they have the same effect even when converted to corresponding values.

4 is a block diagram specifically illustrating an IPD value measuring unit and an IPD value obtaining unit of FIG. 2. The IPD value measurer 410 includes an IPD value measurer 411, an IPD quantizer 412, and a quantization mode flag generator 413. The IPD value measuring unit 411 measures phase difference information between channels from the input multichannel signal. As described above, the phase difference value between channels may be a phase angle, a time delay value, or an index value corresponding thereto.

The IPD quantizer 412 quantizes the phase difference value measured by the IPD value measurer 411. The IPD quantization unit 412 may further include a detailed structure for quantizing the phase difference value between channels according to the quantization interval in different ways. For example, the first quantizer (not shown) can quantize a phase difference value between channels using a minute quantization interval (fine gap), and the second quantizer (not shown) can have a sparse quantization interval (coarse spacing). It is possible to quantize the phase difference value between channels using.

  In addition, the quantization mode flag generator 413 may generate a quantization mode flag quant_mode_flag indicating a method of quantizing a phase difference value between channels. In detail, the quantization mode flag may indicate whether the phase difference value between channels is quantized using fine spacing or sparse spacing.

The inter-channel phase difference value obtaining unit (IPD value obtaining unit) 420 includes a quantization mode flag obtaining unit 421, a first inverse quantizing unit 422, a second inverse quantizing unit 423, and an inverse quantized IPD value obtaining unit. 424.

First, the quantization mode flag acquisition unit 421 obtains a quantization mode flag (quant_mode_flag) indicating a quantization scheme applied to a phase difference value between channels from spatial information received from an encoder. The meaning of the quantization mode flag is shown in Table 3 below.

quant_mode_flag meaning One Indicates that the phase difference value between channels is quantized using fine spacing. 0 Indicates that the phase difference between channels is quantized using sparse spacing

When the quantization flag is 0 (IPD_quant_flag = 0), the first inverse quantization unit 422 receives a phase difference value between channels and dequantizes the phase difference value between channels using a sparse interval. On the other hand, when the quantization flag is 1 (IPD_quant_flag = 1), the second inverse quantizer 423 receives the phase difference value between channels and inversely quantizes the phase difference value between channels by using a fine interval. Thereafter, the inverse quantized IPD value obtaining unit 424 may obtain a phase difference value between inverse quantized channels from the first inverse quantization unit 422 or the second inverse quantization unit 423.

5 illustrates a signal processing apparatus 500 that compensates for phase restoration of a multi-channel signal using a phase shift flag. The signal processing apparatus 500 may include a global-band IPD value determiner 510, a signal corrector 520, a downmixer 530, a spatial information generator 540, a spatial information acquirer 550, and upmixing. The unit 560 and the phase shifter 570 are included.

The global-band IPD value determiner 510 first receives a multi-channel signal. The multi-channel signal may be a signal in which phases of one or more channels are mismatched, or may be stereo signals, but may be signals having three or more channels. The global-band IPD value determiner 510 determines, from the multichannel signal, a phase shift flag indicating the degree of phase to be shifted to match the phase of the input multichannel signal.

The phase shift flag may be flag information indicating that a phase of the multi-channel signal has shifted, and not only the flag information but also information shifted in phase, a channel signal shifted in phase, a frequency band in which phase shift occurs, and a phase shift And may further include information related to phase shift, such as time information corresponding to.

First, when the phase shift flag indicates only flag information, the multi-channel signal may be shifted in phase using a fixed value. For example, when the multi-channel signal is a stereo signal, the phase of the right channel among the stereo signals is changed.

Figure 112009058765936-pat00001
Reduce or decrease the phase of the left channel
Figure 112009058765936-pat00002
Increase by to shift the phase so that the left and right channels are orthogonal to generate the multichannel signal,
Figure 112009058765936-pat00003
The multi-channel signal may be generated by shifting a phase such that the left and right channels are orthogonal, without being limited to the phase shift of.

In this case, the moving phase may be equally applied to all frequency bands of the multi-channel signal. In addition, the phase of at least one channel of the multi-channel signal

Figure 112009058765936-pat00004
The information that is deformed as much as possible, in detail, the information about the deformed phase or the phase moved to be orthogonal is not transmitted separately, but may use predetermined information later in the decoder, but is not limited thereto.

In this case, the amount of information transmission can be reduced as compared with the transmission of the phase difference value between channels in the plurality of parameter bands, and the problem of phase difference that can occur when applying the phase difference value between channels for each parameter band can be prevented. have.

Meanwhile, the phase shift flag may further include not only flag information but also detailed information related to phase shift. The detailed information may include phase shift information, information on a channel signal to which phase shifts, frequency band and time information on which phase shift occurs, and the like.

In addition, the phase shift flag may variably indicate the degree to which the phase of the multi-channel signal is shifted for each frame. When the phase shift flag includes only flag information, it may indicate whether the phase shift is performed for each frame. In addition, when the phase shift flag includes flag information and detailed information about a moving phase, the detailed information may variably indicate the degree of phase shift for each subband or parameter band, and for each fixed time range, for example. For example, the degree of movement of the phase in the corresponding time may be variably indicated, such as a frame or a time slot.

In addition, the phase shift flag may be used in parallel with the phase difference value between channels described with reference to FIGS. 1 to 4.

The signal correction unit 520 receives the phase shift flag and the multi-channel signal. The multi-channel signal may generate a multi-channel signal shifted in phase by modifying a phase of one or more channels using the phase shift flag. As described above, in the present specification, a method of correcting a phase of a multichannel signal and generating a phase shift flag associated with it in order to coincide the phase of a multichannel signal having a phase mismatch is described. It is also possible to deliberately shift the phases of at least one channel included in the multi-channel signals having the same phase to make out-phase signals and generate a phase shift flag associated therewith.

The downmixing unit 530 generates a downmix signal by downmixing the multi-channel signals having the phase shifted. The multi-channel signal is not limited to a stereo signal but may be a signal having three or more channels. When the multi-channel signal is a stereo signal, the downmix signal may be a mono signal, and when the multi-channel signal is a signal having three or more channels, the downmix signal is greater than the number of channels of the stereo signal or the multi-channel signal. It may be a signal with a small number of channels.

The spatial information generator 540 may receive the multi-channel signal whose phase is shifted, and generate spatial information indicating the property of the multi-channel signal. The spatial information is for upmixing the downmix signal into the multi-channel signal whose phase is shifted by a decoder, and may include level difference information between channels, a correlation value between channels, and a channel prediction coefficient. . Therefore, the spatial information generated by the spatial information generator 540 of the present invention may not be the same as the spatial information generated from the multi-channel signal whose phase is not shifted.

The bitstream generator (not shown) may generate one bitstream including the spatial information and the phase shift flag, and include one of the downmix signal, the spatial information and the phase shift flag. The bitstream may be generated.

The information acquisition unit 550 obtains the spatial information and the phase shift flag for upmixing a downmix signal from the bitstream.

The upmixing unit 560 performs the same configuration and function as the upmixing unit 240 of FIG. 2. The upmixed multichannel signal may be a signal that is upmixed by applying an upmixing matrix, a signal that is upmixed and generated on a QMF domain, or may be a signal finally outputted as a signal on a time domain. In addition, the signal upmixed by the upmixing unit 560 may be a multi-channel signal shifted in phase by the signal correction unit 520.

The phase shifter 570 receives a phase shift flag from the information acquirer 550 and a multi-channel signal whose phase is shifted from the upmixer 560. Thereafter, the phase shift flag is applied to the multi-channel signal having the phase shifted to restore the shifted phase of the multi-channel signal.

As described above, the phase shift flag may include only flag information indicating whether a phase of at least one or more channels of the multichannel signal is shifted, and may further include detailed information related to phase shift. When only the flag information is included, the phase shifter 570 determines whether to shift the phase of the upmixed multichannel signal based on the flag information, and uses the fixed value to determine the phase of at least one channel of the multichannel signal. Phase can be shifted. In this case, the fixed value uses a preset value at the decoder and may not be measured and transmitted by the encoder separately. For example, one or more channels of the multichannel signal may be

Figure 112009058765936-pat00005
Can be increased or decreased by At this time,
Figure 112009058765936-pat00006
May be equally applied to all frequency bands of the multi-channel signal. Also, since the phase shift flag may be determined for each frame, the phase shift flag may variably indicate the degree to which the phase of the multichannel signal is shifted or whether the phase is shifted for each frame.

FIG. 6 shows a signal processing apparatus 600 showing another embodiment of the present invention that compensates for phase restoration of a multi-channel signal using a phase shift flag. Referring to FIG. 6, the signal processing apparatus 600 includes a downmixer 610, a spatial information generator 620, a signal corrector 630, a global-band IPD value acquirer 640, and a phase shifter ( 650 and the upmixing unit 660.

The downmixing unit 610 downmixes the input multichannel signal to generate a downmix signal DMX. At this time, the multi-channel signal is a signal as it is input without phase shifting.

The spatial information generator 620 may generate spatial information indicating attributes of the input multichannel signal. The spatial information is different from the spatial information of FIG. 5 in that the spatial information is the same as the configuration and function of the spatial information of FIG. Meanwhile, the spatial information generator 620 includes a global-band IPD value determiner 621, and the global-band IPD value determiner 621 includes the global-band IPD value determiner and its configuration and function of FIG. 5. Since the same, detailed description thereof will be omitted.

The signal corrector 630 corrects the phase of at least one or more channels of the downmix signal output from the downmixer 610 based on the phase shift flag output from the global-band IPD value determiner 621 to adjust the phase. The modified downmix signal DMX 'may be generated.

Thereafter, the global-band IPD value acquisition unit 640 obtains a phase shift flag, and the phase shifter 650 phases at least one or more channels of the corrected downmix signal MDX based on the phase shift flag. By restoring by moving, the downmix signal DMX can be restored. In this case, the downmix signal DMX whose phase is shifted by the phase shifter 650 may be the same as the signal DMX input to the signal correction unit 630.

The upmixer 660 may receive the downmix signal DMX from the spatial information and phase shifter 650 from the spatial information generator 620 and decode the multi-channel signal.

Meanwhile, the signal processing method and apparatus of the present invention perform various methods to remove noise that occurs transiently at a point where a phase difference value between channels changes. Reference will be made later.

First, FIG. 7 is a conceptual diagram illustrating a parameter time slot. The signal may be represented in the time-frequency domain. Referring to FIG. 7, a parameter set is applied to two timeslots (timeslot 2 and timeslot 4) of N timeslots of one frame. The entire frequency range of the signal is then divided into five parameter bands. Accordingly, the unit of the time axis may be a time slot, the unit of the frequency axis may be a parameter band (pb), and the parameter band may be a subband on at least one or more frequency domains including the same phase difference value between channels. Can be. In addition, a time slot defined to apply a phase difference value between channels so that a parameter set among time slots is applied is referred to as a parameter time slot.

8 is a schematic diagram illustrating a method of smoothing a phase difference value between channels according to another embodiment of the present invention. Referring to FIG. 8, a graph at the lower left is a graph showing a phase difference value between channels included in a second parameter band among parameter time slots. The inter-channel phase difference value applied to the parameter time slot [0] may be 10 °, and the inter-channel phase difference value applied to the parameter time slot [1] may be 60 °. The noise may occur unexpectedly at the point where the phase difference between the channels varies greatly. Accordingly, the signal processing method and apparatus of the present invention can remove noise by smoothing the inter-channel phase difference value applied to the current parameter time slot using the inter-channel phase difference value applied to the previous parameter time slot. Has an effect.

Referring back to FIG. 8, when the current parameter time slot is called a parameter time slot [1], the previous parameter time slot may be a parameter time slot [0]. As shown in the lower right graph of FIG. 8, the inter-channel phase difference value (60 °) applied to the current parameter time slot is smoothed using the inter-channel phase difference value (10 °) applied to the previous parameter time slot. Thus, the inter-channel phase difference value of the smoothed and modified current parameter time slot may have a value less than 60 °.

Then, by interpolating and / or copying the smoothed inter-channel phase difference values applied to the current and / or previous parameter time slot, a time slot for which a parameter set is not defined to apply, e.g., time slot 1 , Phase difference values applied to time slots 3, ..., and time slot N may be obtained.

9 is a block diagram illustrating a signal processing apparatus according to still another embodiment of the present invention of FIG. 8. The downmixing unit 910, the IPD usage determining unit 921, the IPD value measuring unit 922, the IPD mode flag generation unit 923, the IPD coding flag generation unit 924, and the IPD coding flag acquisition unit of FIG. 9 ( 931, the IPD mode flag acquirer 932, the IPD value acquirer 933, and the upmixer 940 include the downmixer 210, the IPD use determiner 221, and the IPD value measurer of FIG. 2. 222, the IPD mode flag generator 223, the IPD coding flag generator 224, the IPD coding flag acquirer 231, the IPD mode flag acquirer 232, the IPD value acquirer 233, and the upmixer Since 240 and its configuration and function are the same, a detailed description thereof will be omitted.

The information acquisition unit 930 may further include an IPD value smoothing unit 934. The IPD value smoothing unit 934 may modify the inter-channel phase difference value applied to the current parameter time slot by using the inter-channel phase difference value applied to the previous parameter time slot. As such, when the phase difference value between channels applied to the current parameter time slot has a large gap with the phase difference value between channels applied to the previous parameter time slot, there is an effect of preventing noise that may occur.

In addition, the IPD value smoothing unit 934 may generate a phase angle representing an angle between two channels among a plurality of channels from a phase difference value applied to a current parameter time slot, and transfer the phase angle to the previous angle. This can be modified using the phase angle of the parameter time slot. The modified phase angle is then output to the upmixing unit 640. The modified phase angle may be applied to the downmix signal by the upmixing unit 640 to generate a multi-channel signal.

Hereinafter, various embodiments of the present invention will be described to solve a problem that occurs when a signal is coded using a channel level difference and an inter channel correlation value instead of using a phase difference value between channels. Shall be.

10A and 10B are conceptual views illustrating a problem to be solved by a signal processing method and apparatus according to another embodiment of the present invention.

In many signal coding devices, in particular, PS used in EAAC +, HE AAC Plus, and USAC, which are standardized in 3GPP and MPEG, do not use the phase difference value between channels. I use it. This is because of the phase wrapping phenomenon that may occur when generating the phase difference value between channels and the degradation of sound quality that occurs when synthesizing the phase difference value between channels.

However, when coding a multi-channel signal without using a phase difference value between channels, a serious sound localization problem may occur. In other words, a problem may not occur in a signal coded mainly using a level difference value between channels, such as a signal recorded by placing two or more microphones adjacent to each other, but recording two or more microphones spaced apart from each other. If the decoded signal does not use the phase difference value between the channels, it is impossible to accurately correct the image when decoding the multi-channel signal.

FIG. 10A illustrates a result of decoding a stereo signal having only a phase difference value between channels without a phase difference value between channels. Referring to FIG. 10A, an original signal is a signal formed only with a phase difference value between channels (IPD = 30 °). However, when decoding using only the level difference value and the interchannel correlation value, there is no valid spatial information (IPD value), so that the sound image of the decoded signal (synthesis signal) is located at the center of the stereo signal regardless of the original signal. At this time, although the correlation value between the channels affects the sound positioning, accurate sound positioning is impossible without the phase difference value between the channels.

On the other hand, FIG. 10B shows the result of decoding a stereo signal having a phase difference value between channels and a level difference value between channels without a phase difference value between channels. Referring to FIG. 10B, a sound image position of a stereo signal is determined by a linear sum of an adjustment angle determined from an inter-channel phase difference value and an adjustment angle determined from an inter-channel level difference value. If the original stereo signal has an 8dB greater value than the right signal and is 0.5ms faster, as shown in Figure 10B, an 8dB level difference can shift the sound image 20 ° (-20 °) from center to left. In addition, a time difference of 0.5 ms (same as the phase difference value between channels of 10 °) has a characteristic of shifting a sound image by 10 ° (-10 °) to the left. Thus, the original stereo signal (original) is in the -30 ° position. However, if the signal is decoded without the phase difference value between channels, the sound image of the decoded signal is located at -20 °, so that accurate sound position is impossible.

Accordingly, the signal processing method and apparatus according to another embodiment of the present invention additionally provide various methods for solving the sound phase problem.

11 and 12 are block diagrams illustrating a signal processing method and apparatus according to another exemplary embodiment of the present invention.

First, the inter-channel phase difference information may be used only when a predetermined condition is satisfied based on the ratio of the inter-channel phase difference information and the inter-channel level difference value of the multi-channel signal. As shown in FIG. 11, the signal processing apparatus 1100 includes a downmixing unit 1110, a spatial information generating unit 1120, an information obtaining unit 1130, and an upmixing unit 1140.

The downmixing unit 1110 and the upmixing unit 1140 have the same configuration and function as the downmixing unit 210 and the upmixing unit 240 of FIG. 2. The spatial information generator 1120 includes an ILD value measurer 1121, an IPD value measurer 1122, an information determiner 1123, and an IPD flag generator 1124. The ILD value measuring unit 1121 and the IPD value measuring unit 1122 measure the inter-channel level difference value and the inter-channel phase difference value from the multi-channel signal. The inter-channel level difference value and the inter-channel phase difference value may be measured for each parameter band.

The information determiner 1123 calculates how much a sound phase is signaled using the measured level difference value between the channels and the phase difference value between the channels. By calculating whether the ratio is occupied, it is decided to use the phase difference value between channels only when the ratio of phase difference values between channels is higher. For example, if the measured phase difference value between channels corresponds to + 20 ° and the measured channel difference value corresponds to a value that can be + 10 ° phase shifted by 4 dB, the overall sound phase offset (20 ° + 10 ° = 30 °), the degree of contribution between the phase difference value between the channels and the level difference value between the channels may be 20/30 and 10/30, respectively. In this case, since the relative importance of the phase difference value between channels is great, the information determiner 1123 may determine to further use the phase difference value between channels.

The IPD flag generator 1124 may generate an inter-channel phase difference value flag indicating that the inter-channel phase difference value is used when the information determiner 1123 determines to further use the inter-channel phase difference value.

Meanwhile, the information acquisition unit 1130 may include an IPD flag acquisition unit 1131 and an IPD value acquisition unit 1132, and the IPD flag acquisition unit 1131 may acquire the phase difference value flag between channels to obtain spatial information. It is determined whether the phase difference value between channels is included in. If the inter-channel phase difference value flag is 1, the IPD value acquisition unit 1132 is activated to obtain the inter-channel phase difference value from the spatial information. Thereafter, the upmixer 1140 decodes the multi-channel signal by upmixing the downmix signal using spatial information including a phase difference value between channels, and compares the multi-channel signal with the case of not using the phase difference value between channels. Accurate sound positioning of the signal is possible. In addition, coding efficiency can be improved by transmitting a phase difference value between channels only when certain conditions are satisfied.

Second, the inter-channel phase difference value can be replaced by an equivalent inter-channel level difference value, and vice versa. At this time, the phase difference value between channels and the level difference between channels required for sound phase can vary according to frequency, so refer to the database defined for each frequency band.

FIG. 12 illustrates a signal processing apparatus 1200 in which a phase difference value between channels is changed to an equivalent level difference value between channels. The signal processing apparatus 1200 includes an ILD value measuring unit 1210, an IPD value measuring unit 1220, an information determining unit 1230, an IPD value converting unit 1240, and an ILD value correction unit 1250.

The ILD value measuring unit 1210, the IPD value measuring unit 1220, and the information determining unit 1230 may include the ILD value measuring unit 1121, the IPD value measuring unit 1122, and the information determining unit 1130 of FIG. 11. Since the configuration and function are the same, detailed description is omitted. When the information determiner 1130 determines to use the inter-channel phase difference value, the measured inter-channel phase difference value is input to the IPD value converter 1240.

The IPD value converter 1240 converts the inter-channel phase difference value measured in the corresponding frequency band into an equivalent inter-channel level difference value ILD 'using the database. Thereafter, the ILD value correction unit 1250 is corrected by adding the inter-channel level difference value ILD 'obtained by converting the inter-channel phase difference value to the inter-channel level difference value ILD input from the ILD value measuring unit 1210. Compute the level difference value (ILD '') between channels.

As such, when the channel-to-channel phase difference value is converted into an equivalent channel-to-channel level difference value, the existing channel that does not allow reception of the phase difference value such as the PS used in the HE AAC Plus or the USAC standard used in 3GPP and MPEG. By using the signal processing apparatus and the method of the phase difference between the channel can be decoded by reflecting the phase difference between the channel and the sound image enhancement.

Third, by applying the phase difference value between channels to at least one consecutive frame in common, it is possible to increase coding efficiency with accurate sound position. In the present specification, the inter-channel phase difference value used in several consecutive frames is referred to as a global frame IPD value. FIG. 13 is a diagram illustrating global frame IPD values according to another embodiment of the present invention. It is a conceptual diagram which shows the concept which a phase difference value is used. Referring to FIG. 13, numerals 0 to 13 each represent a frame, a shaded frame represents a frame using a phase difference value between channels, and a shaded frame represents a frame not using a phase difference value between channels. These may be determined based on the inter-channel phase difference mode flag (bsPhaseMode) described above.

As shown in FIG. 13, when only the frames 1 to 3 and the frames 8 to 12 use the inter-channel phase difference value, the inter-channel phase difference value is applied by calculating the representative value without transmitting the inter-channel phase difference value for each frame. The same applies to successive frames determined to be applied, and includes only the first frame of the successive frames, which includes a global frame-to-channel phase difference value, wherein each frame represents a global frame-channel phase difference value indicating whether or not to use a global frame-channel phase difference value. It may include a flag. The meaning of the phase difference flag between global frame channels is shown in Table 4 below.

Global_frame_IPD_flag meaning One Use phase difference value between global frame channels 0 Do not use phase difference between global frame channels

 For example, based on the phase difference flag between global frame channels, frame 0 does not use a phase difference value between global frame channels, and frame 1 uses a phase difference value between global frame channels. Accordingly, frame 1 includes a phase difference value between global frame channels, and the same global frame channel phase difference value may be applied to frames 1 to 3. Similarly, frame 8 includes a phase difference value between global frame channels, and the same global frame channel phase difference value may be applied to frames 8 to 12.

FIG. 14 illustrates a signal coding apparatus 1400 according to an exemplary embodiment of the present invention using the phase difference value between the global frame channels of FIG. 13. Referring to FIG. 14, the signal coding apparatus 1400 acquires a global frame IPD value receiver 1410, a global frame IPD value calculator 1420, a global frame IPD flag generator 1430, and a global frame IPD flag of a previous frame. The unit 1440 includes a global frame IPD value obtainer 1450 and an upmixer 1460.

The global frame IPD value receiving unit 1410 of the previous frame receives the phase difference value between the global frame channels of the previous frame. For example, if the current frame is the first frame including the phase difference value between the global frame channels, there will be no phase difference value between the global frame channels of the previous frame received. On the other hand, when the current frame is a second or more frame among consecutive frames including the phase difference value between the global frame channels, the phase difference value between the global frame channels may be received from the previous frame.

When the current frame is the first frame including the phase difference value between the global frame channels, that is, when the phase difference value between the global frame channels of the previous frame does not exist, the global frame IPD value calculator 1420 The phase difference value can be calculated. The phase difference value between channels of the global frame of the current frame may be an average of the phase difference value between channels of consecutive frames in which the phase difference value between channels is used.

The global frame IPD flag generator 1430 generates a global frame IPD flag (global_frame_IPD_flag) indicating whether a phase difference value IPD between global frame channels is used in the current frame.

Thereafter, the global frame IPD flag value obtaining unit 1440 obtains a phase difference value between global frame channels, and the global frame IPD value obtaining unit 1450 receives the previous frame output from the global frame IPD value receiving unit 1410 of the previous frame. The phase difference value between the global frame channels or the global frame channel difference value of the current frame output from the global frame IPD value calculator 1420 may be obtained. Preferably, the global frame IPD value obtaining unit 1450 obtains the phase difference value between the global frame channels of the previous frame when the current frame is the first frame among successive frames applying the phase difference value between the channels, In the case of a frame, a calculated phase difference value between global channels of the current frame may be obtained.

The upmixing unit 1460 generates a multi-channel signal by applying a phase difference value between global frame channels to the downmix signal.

Fourth, in order to adjust the decoded multichannel signal as close as possible to the spatial feeling of the multichannel signal input to the encoder, the inter-channel correlation value may be adjusted. Referring back to FIG. 10B, when a signal is decoded using a phase difference value between channels and a correlation value between channels, a problem arises in that a sense of space is exaggerated than an original signal. The sense of space refers to an effect in which a signal appears to exist in a wide space or a narrow space by ambient sound. In the present specification, the sense of exaggeration of space means that the original signal was recorded in a narrow recording room, but in a large auditorium when decoding. It sounds like it means.

This problem occurs in a conventional signal processing method and apparatus that does not transmit a phase difference value between channels, but may also occur when a channel difference value is transmitted.

15 is a block diagram illustrating a signal processing apparatus 1500 according to another exemplary embodiment of the present invention for solving the above problem. The signal processing apparatus 1500 generates an ICC value measurer 1510, an IPD value measurer 1520, an ILD value measurer 1530, an information determiner 1540, an ICC value corrector 1550, and an IPD mode flag generation. The unit 1560 includes an IPD mode flag acquirer 1570, an IPD value acquirer 1580, an ICC value acquirer 1590, and an upmixer 1595. The ICC value measuring unit 1510, the IPD value measuring unit 1520, and the ILD value measuring unit 1530 may measure a correlation value, an inter-channel phase difference value, and an inter-channel level difference value, respectively, from the multi-channel signal. .

The information determiner 1540 and the IPD mode flag generator 1560 have the same structure and function as the information determiner 1123 and the IPD flag generator 1124 of FIG. 11. Also, the information determiner 1540 calculates how much of the measured inter-channel level difference and inter-channel phase difference value occupy the entire sound phase, and thus, the inter-channel phase only when the ratio of the inter-channel phase difference value is higher. The IPD mode flag generator 1560 generates an inter-channel phase difference mode flag indicating whether to use the channel-to-channel phase difference value.

When the information determiner 1540 determines that the phase difference value is used between the channels, the ICC value corrector 1550 may correct the inter-channel correlation value input from the ICC value measurer 1510. Preferably, in the parameter band including the phase difference value between channels, the measured inter-channel correlation value may not be used, and in order to solve the problem of exaggerated sense of space, the size of the value represented by the inter-channel correlation value may be modified. Can be.

Since the IPD flag acquisition unit 1570 and the IPD value acquisition unit 1580 have the same configurations and functions as the IPD flag acquisition unit 1131 and the IPD value acquisition unit 1132 of FIG. 11, detailed descriptions thereof will be omitted.

The ICC value obtaining unit 1590 receives the modified inter-channel correlation value from the ICC value correction unit 1550 when the inter-channel phase difference flag is used in the IPD flag obtaining unit 1570. .

The upmixer 1595 may generate a multi-channel signal by applying a phase difference value between channels and a corrected channel-to-channel correlation value to the received downmix signal. Therefore, in the signal processing method and apparatus using the phase difference value between channels, the sense of space may be exaggerated due to the correlation value between channels, thereby preventing the signal from being distorted.

Fifth, the phase difference value between channels can be used that the more important the signal having a simple sound source.

16 is a block diagram illustrating a signal processing apparatus 1600 according to another exemplary embodiment of the present invention. The signal processor 1600 may include an input signal classifier 1610, an IPD value obtainer 1620, an IPD flag generator 1630, an IPD flag acquirer 1640, an IPD value acquirer 1650, and an upmixer. 1660.

The input signal classifier 1610 determines whether the input signal is a signal including only a speech (if pure-speech signal), a music signal, or a mixed signal of a music signal and a voice signal. The input signal classifier 1610 may include a sound activity detector (SAD) or a speech and music classifier (SMC).

The IPD value measurer 1620 measures the phase difference value between channels only when the input signal classifier 1610 determines that the input signal is a signal including only a voice signal. Subsequently, the IPD flag generator 1630, the IPD flag acquirer 1640, the IPD value acquirer 1650, and the upmixer 1660 are the IPD flag generator 1124 and the IPD flag acquirer 1131 of FIG. 11. ), The configuration and function of the IPD value acquisition unit 1132 and the upmixing unit 1140 are the same, and thus a detailed description thereof will be omitted.

The music signal or the mixed signal in which the music signal is mixed with the audio signal includes various signals to some extent by using the level difference between channels and the correlation value between channels even if the phase difference value between channels is not used. Sound location is possible. However, in the case of a simple sound source such as a speech signal, since the importance of the phase difference value between channels is relatively high, accurate sound positioning is impossible without the phase difference value between channels. Therefore, when the input signal is a voice signal using the input signal classifying unit 1610, the phase difference value between channels can be used to more accurately decode a multi-channel signal having a negative stereotype.

17 illustrates a signal processing apparatus 1700 according to another embodiment of the present invention, which includes a multichannel encoder 1710, a bandwidth extension signal encoder 1720, an audio signal encoder 1730, and a voice signal. An encoder 1740, an audio signal decoder 1750, an audio signal decoder 1760, a bandwidth extension signal decoder 1770, and a multi-channel decoder 1780 are included.

First, in the multichannel encoder 1710, a downmix signal generated by downmixing a multichannel signal is referred to as a full band downmix signal, and a high frequency band signal is subsequently removed from the full band downmix signal, thereby lowering the low frequency band. A downmix signal in which only one exists is referred to as a low frequency band downmix signal.

The multichannel encoder 1710 receives a signal having a plurality of channels (hereinafter, referred to as a multichannel). Down-mixing the input multi-channel signal generates a full-band downmix signal, while generating spatial information corresponding to the multi-channel signal. The spatial information may include channel level difference information, channel prediction coefficients, inter-channel correlation values, and downmix gain information.

The multi-channel encoder 1710 according to an embodiment of the present invention determines whether to use a phase difference value between channels, measures a phase difference value between channels, and indicates whether to use a phase difference value between channels in a frame. Inter-channel phase difference mode information and inter-channel phase difference coding information indicating whether there is a frame using a phase difference value among channels among the entire frame may be generated and transmitted with the mix information, which is described with reference to FIGS. 1 to 4. As described above, a detailed description of this process will be omitted.

On the other hand, although not shown in the multi-channel encoder 1710 of the signal processing apparatus described with reference to FIGS. 1 to 4 or the signal processing apparatus according to another embodiment of the present invention described with reference to FIGS. It may include an encoding device.

The bandwidth extension signal encoding unit 1720 may receive the full band downmix signal and generate extension information corresponding to a signal of a high frequency band among the full band downmix signals. The extended information is information for restoring the low frequency band downmix signal from which the high frequency band is removed later to the full band downmix signal and transmitted together with the spatial information.

Further, the downmix signal is determined whether to be coded by an audio signal coding scheme or a voice signal coding scheme based on the characteristics of the signal, and generates mode information for determining the coding scheme (not shown). In this case, the audio coding scheme may use Modified Discrete Cosine Transform (MDCT), but the present invention is not limited thereto. The speech coding scheme may be in accordance with an adaptive multi-rate wide-band (AMR-WB) standard, but the present invention is not limited thereto.

The audio signal encoding unit 1730 encodes the low frequency band downmix signal from which the high frequency region is removed using the extension information input from the bandwidth extension signal encoding unit 1720 and the full band downmix signal according to an audio signal coding scheme.

The signal coded by the audio signal coding scheme may be an audio signal or a signal in which some audio signals are included in the audio signal. In addition, the audio signal encoder 1730 may be a frequency domain encoder.

The voice signal encoding unit 1740 encodes the low frequency band downmix signal from which the high frequency region is removed using the extension information and the full band downmix signal input from the bandwidth extension signal encoding unit 1720 according to the voice signal coding scheme.

The signal coded by the voice signal coding scheme may be a voice signal or a signal in which some audio signals are included in the voice signal. Also, the speech signal encoder 1740 may further use a linear prediction coding (LPC) method. When the input signal has high redundancy on the time axis, the input signal may be modeled by linear prediction that predicts the current signal from the past signal. In this case, the linear prediction coding method may increase coding efficiency. Meanwhile, the voice signal encoder 1740 may be a time domain encoder.

Thereafter, the audio signal decoding unit 1750 decodes the signal according to an audio signal coding scheme. The signal input to and decoded by the audio signal decoding unit 1750 may be an audio signal, or may be a signal including some voice signals in the audio signal. In addition, the audio signal decoding unit 1750 may include a frequency domain decoding unit and may use inverse modified discrete coefficients (IMDCT).

The voice signal decoding unit 1760 decodes the signal according to a voice signal coding scheme. The signal decoded by the voice signal decoding unit 1760 may be a voice signal or a signal in which some audio signals are included in the voice signal. Also, the speech signal decoding unit 1760 may include a time domain decoding unit and may further use a linear prediction coding (LPC) method.

The bandwidth extension decoding unit 1770 receives a low frequency band downmix signal and extension information, which is a signal decoded by the audio signal decoding unit 1750 or a signal decoded by the voice signal decoding unit 1760, and is removed during encoding. A signal corresponding to the generated full-band downmix signal is recovered.

The full band downmix signal may be generated using all of the low frequency band downmix signal and the extension information, and may be generated using a part of the low frequency band downmix signal.

The multi-channel decoding unit 1780 receives the full-band downmix signal, the spatial information, the inter-channel phase difference value, the inter-channel phase difference mode flag, and the inter-channel phase difference coding flag, and applies the information to the full-band downmix signal. By generating a multi-channel signal, a detailed description of this process has been described in detail with reference to Figures 1 to 4 will be omitted.

As described above, the signal processing method and apparatus of the present invention generate a multi-channel signal using the phase difference value between channels, thereby effectively reproducing a phase difference or delay difference that is difficult for the multi-channel decoder to reproduce.

18 is a schematic diagram of a product in which an IPD coding flag obtaining unit 1841, an IPD mode flag obtaining unit 1842, an IPD value obtaining unit 1843, and an upmixing unit 1844 are implemented according to an embodiment of the present invention. 19 illustrates an IPD coding flag obtainer 1841, an IPD mode flag acquirer 1882, an IPD value acquirer 1843, and an upmixer 1844, according to an exemplary embodiment. Is a diagram showing the relationship between the finished products.

Referring to FIG. 18, the wired / wireless communication unit 1810 receives a bitstream through a wired / wireless communication scheme. Specifically, the wired / wireless communication unit 1810 may include at least one of a wired communication unit 1811, an infrared communication unit 1812, a Bluetooth unit 1813, and a wireless LAN communication unit 1814.

The user authentication unit 1820 performs user authentication by inputting user information, and includes one or more of a fingerprint recognition unit 1821, an iris recognition unit 1822, a face recognition unit 1823, and a voice recognition unit 1824. The fingerprint, iris information, facial contour information, and voice information may be input, converted into user information, and the user authentication may be performed by determining whether the user information matches the existing registered user data. .

The input unit 1830 is an input device for a user to input various types of commands, and may include one or more of a keypad unit 1831, a touch pad unit 1832, and a remote controller unit 1833. It is not limited.

The signal decoding unit 1840 includes an IPD coding flag obtaining unit 1841, an IPD mode flag obtaining unit 1842, an IPD value obtaining unit 1843, and an upmixing unit 1844, which have the same names as those of FIG. 2. Since the unit and its configuration and function are the same, detailed description thereof will be omitted.

The controller 1850 receives input signals from the input devices, and controls all processes of the signal decoding unit 1840 and the output unit 1860. As described above, a user input from the input unit 1830 is input to the control unit 1850, for example, phase shift of an output signal, input / output of metadata, operation on / off of a signal decoding unit, and the like. In this case, it is used to decode the signal.

The output unit 1860 is a component that outputs an output signal generated by the signal decoding unit 1840 and the like, and may include a signal output unit 1861 and a display unit 1862. When the output signal is an audio signal, the output signal is output through the signal output unit 1861, and when the output signal is a video signal, the output signal is output through the display unit 1862. In addition, when metadata is input to the input unit 1830, the metadata is displayed on the screen through the display unit 1862.

FIG. 19 illustrates a relationship between a terminal and a server corresponding to the product illustrated in FIG. 18. Referring to FIG. 19A, the first terminal 1910 and the second terminal 1920 each of the terminals through the wired / wireless communication unit. It can be seen that the data to the bitstream can communicate in both directions. The data or bitstream communicating through the wired / wireless communication unit may be in the form of the bitstream of FIG. 1 of the present invention, the phase shift flag of the present invention described with reference to FIGS. 5 to 16, a phase difference value between global frame channels, and the like. It may be data including. Referring to FIG. 19B, it can be seen that the server 1930 and the first terminal 1940 may also perform wired / wireless communication with each other.

20 is a multi-channel decoding unit including an IPD coding flag acquirer 2041, an IPD mode flag acquirer 2042, an IPD value obtainer 2043, and an upmixer 2044 according to an embodiment of the present invention. FIG. Is a diagram illustrating a schematic configuration of an implemented broadcast signal decoding apparatus 2000. Referring to FIG.

Referring to FIG. 20, the demultiplexer 2020 receives data related to TV broadcasting from the tuner 2010. Received data are separated at demultiplexer 2020 and decoded via data decoder 2030. Meanwhile, data separated from the demultiplexer 2020 may be stored in a storage medium 2050 such as an HDD.

  Data separated by the demultiplexer 2020 is input to a signal decoding unit 2040 including a multi-channel decoding unit 2041 and a video decoding unit 2042 to decode the audio signal and the video signal. The signal decoding unit 2040 includes an IPD coding flag obtaining unit 2041, an IPD mode flag obtaining unit 2042, an IPD value obtaining unit 2043, and an upmixing unit 2044 according to an embodiment of the present invention. Since the configuration and function are the same as the units of the same name in FIG. 2, detailed description thereof will be omitted. The signal decoding unit 2040 decodes a signal using the received phase difference value between channels, and when the video signal is input, decodes the video signal and outputs it. When the metadata is generated, the signal decoding unit 2040 outputs it in text form. .

When the video signal is decoded, the output unit 2070 displays the output metadata on the screen when the output video signal and the metadata are generated. In addition, the output unit 2070 includes a speaker unit (not shown) and the speaker included in the output unit 2070 to output a multi-channel signal decoded using the phase difference value between channels output from the signal decoding unit 2040. Output through wealth. In addition, the data decoded by the signal decoding unit 2040 may be stored in a storage medium 2050 such as an HDD.

The signal decoding apparatus 2000 may further include an application manager 2060 that may receive information from a user and control the received data. The application manager 2060 includes a user interface manager 2061 and a service manager 2062. The user interface manager 2061 controls an interface for receiving information from a user. For example, the font of the text displayed on the output unit 2070, the brightness of the screen, the menu configuration, and the like can be controlled. Meanwhile, when the signal decoder 2040 and the output unit 2070 decode and output the broadcast signal, the service manager 2062 may control the received broadcast signal using information input from the user. For example, a broadcast channel setting, an alarm function setting, an adult authentication function, and the like may be provided. The data output from the application manager 2060 may be transmitted to the output unit 2070 as well as the signal decoding unit 2040 and may be used.

As such, since the signal processing apparatus of the present invention is included in an actual product, the inter-channel phase difference value is used as compared with the conventional technology using a multi-channel signal upmixed using only the inter-channel level difference value and the inter-channel correlation value. As a result, the sound quality is improved and the multiple channel signal close to the original input signal can be heard.

The decoding / encoding method to which the present invention is applied may be stored in a computer-readable recording medium that is produced as a program for execution on a computer, and the computer-readable recording medium may also have multimedia data having a data structure according to the present invention. Can be stored in. The computer readable recording medium includes all kinds of storage devices in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission via the Internet) . In addition, the bit stream generated by the encoding method may be stored in a computer-readable recording medium or transmitted using a wired / wireless communication network.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

The present invention can be applied to encode and decode a signal.

1 is a conceptual diagram illustrating the concept of a signal processing method according to an embodiment of the present invention.

2 is a block diagram illustrating a signal processing apparatus according to an embodiment of the present invention.

3 is a graph illustrating a relationship between phase and time in a signal.

4 is a block diagram specifically illustrating an IPD value measuring unit and an IPD value obtaining unit of FIG. 2.

5 is a block diagram illustrating a signal processing apparatus according to another embodiment of the present invention.

6 is a block diagram illustrating a signal processing apparatus according to another embodiment of the present invention.

7 is a conceptual diagram illustrating a conventional parameter time slot.

8 is a schematic diagram illustrating a method of smoothing a phase difference value between channels according to another embodiment of the present invention.

9 is a block diagram illustrating a signal processing apparatus according to still another embodiment of the present invention of FIG. 8.

10A and 10B are conceptual views illustrating a problem to be solved by a signal processing method and apparatus according to another embodiment of the present invention.

11 and 12 are block diagrams illustrating a signal processing apparatus according to another embodiment of the present invention.

FIG. 13 is a conceptual diagram illustrating a concept of using a global frame IPD according to another embodiment of the present invention.

14 is a block diagram illustrating a signal processing apparatus according to another embodiment of the present invention.

15 to 17 are block diagrams illustrating a signal processing apparatus according to another embodiment of the present invention.

FIG. 18 illustrates a schematic configuration of a product in which an IPD coding flag acquirer, an IPD mode flag acquirer, an IPD value acquirer, and an upmixer are implemented according to another embodiment of the present invention.

19A and 19B illustrate relationships between products in which an IPD coding flag acquirer, an IPD mode flag acquirer, an IPD value acquirer, and an upmixer are implemented according to another embodiment of the present invention.

20 illustrates a schematic configuration of a broadcast signal decoding apparatus implemented with an IPD coding flag acquirer, an IPD mode flag acquirer, an IPD value acquirer, and an upmixer according to another embodiment of the present invention.

Claims (15)

  1. Receiving a downmix signal generated from a multichannel signal and spatial information indicating an attribute of the multichannel signal to upmix the downmix signal;
    Obtaining an inter-channel phase difference coding flag indicating whether an inter-channel phase difference value is used in the spatial information from the header of the spatial information;
    Obtaining an inter-channel phase difference mode flag indicating whether the inter-channel phase difference value is used in the frame, based on the inter-channel phase difference coding flag;
    Obtaining the inter-channel phase difference value from the parameter band of the frame based on the inter-channel phase difference mode flag; And
    Generating the multi-channel signal by applying the phase difference value between the channels to the downmix signal,
    The spatial information is partitioned into the header and the plurality of frames,
    The phase difference value between the channels represents a phase difference between two channels of the multichannel signal.
    And wherein said parameter band is a subband on at least one frequency domain containing said phase difference value between channels.
  2. The method of claim 1,
    And quantizing the channel-to-channel phase difference value by determining a degree of quantization according to a quantization mode flag.
  3. The method of claim 2,
    The quantization mode flag is determined by the quantization interval, characterized in that the signal processing method.
  4. The method of claim 1,
    The phase difference value between channels is received when the ratio between the channel level difference value and the phase difference value between the channels representing the level difference between two channels of the multi-channel signal included in the downmix signal is greater than or equal to a predetermined value. A signal processing method.
  5. The method of claim 1,
    And the phase difference value between the channels is compatible with the level difference value between the channels in the frame.
  6. The method of claim 1,
    And the phase difference value between channels corresponds to a level difference value between channels indicating a level difference between two channels of the multichannel signal included in the downmix signal.
  7. The method of claim 1,
    Further receiving a global frame channel-to-channel phase difference flag indicating whether the channel-to-channel phase difference value is a global channel-to-channel phase difference value used in several consecutive frames;
    The generating of the multi-channel signal may include applying the phase difference value between the global frame channels to successive frames of the downmix signal based on the phase difference flag between the global channels. Treatment method.
  8. The method of claim 1,
    If the phase difference value between the channels of a specific subband is a predetermined value or more,
    Obtaining an inter-channel correlation value representing correlation information between two channels of the multi-channel signal included in the downmix signal from the spatial information, wherein the inter-channel correlation value is based on the phase difference value between the channels; Signal processing method characterized in that the adjusted.
  9. The method of claim 1,
    The phase difference value between the channels is obtained when the downmix signal is a voice signal.
  10. A signal receiving unit receiving a downmix signal generated from a multichannel signal and spatial information indicating an attribute of the multichannel signal to upmix the downmix signal;
    An inter-channel phase difference coding flag acquisition unit for acquiring an inter-channel phase difference coding flag indicating whether a channel-to-channel phase difference value is used in the spatial information from the header of the spatial information;
    An inter-channel phase difference mode flag acquisition unit for acquiring an inter-channel phase difference mode flag indicating whether the inter-channel phase difference value is used in the frame based on the inter-channel phase difference coding flag;
    An inter-channel phase difference value obtaining unit obtaining the inter-channel phase difference value for each parameter band based on the inter-channel phase difference mode flag; And
    An upmixing unit generating a multi-channel signal by applying the phase difference value between the channels to the downmix signal;
    The spatial information is partitioned into the header and the plurality of frames, the phase difference value between channels indicates a phase between two channels of the multichannel signal, and the parameter band includes at least a phase difference value between the channels. And a subband on at least one frequency domain.
  11. The method of claim 10, wherein the phase difference value acquisition unit between channels,
    A quantization mode flag obtaining unit for obtaining a quantization mode flag indicating a method of inversely quantizing the phase difference value between channels;
    A first inverse quantizer for inversely quantizing the phase difference value between the channels based on the sparse interval based on the quantization mode flag;
    A second inverse quantizer for inversely quantizing the phase difference value between channels based on the quantization mode flag using a fine interval; And
    And an inverse quantized inter-channel phase difference value obtaining unit obtaining the inverse quantized inter-channel phase difference value.
  12. The method of claim 10, wherein the phase difference value between channels is used.
    The apparatus may further include an inter-channel correlation value obtaining unit configured to receive an inter-channel correlation value indicating a correlation between two channels of the multi-channel signal included in the downmix signal.
    And the correlation value between the channels is adjusted based on the phase difference value between the channels.
  13. 11. The method of claim 10,
    A global frame IPD flag acquisition unit configured to receive a global frame channel phase difference flag indicating whether the phase difference value between channels is a phase difference value between global frame channels used in several frames in succession; And
    And a global frame IPD obtaining unit obtaining a global frame IPD value applied to successive frames of the downmix signal based on the phase difference flag between the global frame channels.
  14. Downmixing the plurality of channel signals to generate a downmix signal; And
    Generating spatial information for indicating a property of the multichannel signal and upmixing the downmix signal;
    Generating the spatial information,
    Measuring phase difference information between channels indicating a phase difference between two channels of the multichannel signal;
    Generating an inter-channel phase difference mode flag of the frame indicating that the inter-channel phase difference value is used in the frame;
    Generating an inter-channel phase difference coding flag indicating whether the inter-channel phase difference value is used in the spatial information; And
    And including the inter-channel phase difference value and the inter-channel phase difference mode flag in the frame of the spatial information, and including the inter-channel phase difference coding flag in the header of the spatial information. Way.
  15. A downmixing unit for downmixing a plurality of channel signals to generate a downmix signal; And
    A spatial information generator to indicate the property of the multi-channel signal and to generate spatial information for upmixing the downmix signal;
    The spatial information generation unit,
    A phase difference value measuring unit measuring channel difference information indicating phase difference between two channels of the multi-channel signal;
    An inter-channel phase difference mode flag generator configured to generate an inter-channel phase difference mode flag of the frame indicating that the inter-channel phase difference value is used in the frame; And
    An inter-channel phase difference coding flag generator for generating an inter-channel phase difference coding flag indicating whether the inter-channel phase difference value is used in the spatial information;
    And the phase difference value flag between the channel and the phase difference mode flag between the channels are included in the frame of the spatial information, and the phase difference coding flag between the channels is included in the header of the spatial information.
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