JPH10285698A - Video audio signal reproducing device and video audio signal reproduction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a sense of incongruity of movement of sound in left/right directions even when a video image device with a large screen by providing a pseudo stereophonic means and 1st and 2nd synthesis means. SOLUTION: A center channel signal is given to a pseudo stereophonic circuit 23, a pseudo left channel signal and a pseudo right channel signal are outputted. The pseudo left channel signal is synthesized with a left channel signal outputted from a multi-channel decoder circuit 31 at a mixing circuit 33 and a synthesis left channel signal is obtained. Similarly the pseudo right channel signal is synthesized with a right channel signal at a mixing circuit 34 and a synthesis right channel signal is obtained. A coefficient multiplier circuit 35 multiplies a coefficient with the pseudo left channel signal and the pseudo right channel signal outputted from the mixing circuits 33, 34 to provide an output of a signal with a level higher than the synthesis left channel signal and the synthesis right channel signal outputted from the mixing circuit 33 and 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video and audio signal reproducing apparatus and a video and audio signal reproducing method for reproducing an audio signal together with a video signal. The present invention relates to an apparatus and a video / audio signal reproducing method.

[0002]

2. Description of the Related Art In recent years, in order to enjoy a movie, a rental video, a laser disk, a satellite broadcast, or the like can be used in addition to a movie theater. In any case, the sound for movies uses an encoding system of Dolby Inc. in many cases.

[0003] Movie sound is decoded into a four-channel sound signal consisting of a left channel, a center channel, a right channel, and a surround channel by a dedicated decoder, and is reproduced by a four-channel reproduction system. The left channel, center channel, and right channel on the front side, the rear left channel and the rear right channel on the rear side of the listener, and the low-frequency subwoofer channel 0.1-channel sound signal. By decoding and reproducing by the 5.1-channel reproduction system, it is possible to enjoy sound with a sense of realism.

A device for reproducing a video signal and an audio signal in this way is called a video and audio signal reproducing device. FIG. 8 shows a system configuration diagram of the video and audio signal reproducing apparatus. Here, 5.1
An example of reproducing an audio signal of a channel will be described.
A video signal and multi-channel audio data are supplied from a DVD player 100 for reproducing a DVD (Digital Versatile Disk).

[0005] The video signal is output to a video device 102 such as a television or a projector through an AV amplifier 101 for surround reproduction and displayed as a video. In addition, a multi-channel decoder circuit (not shown) inside the surround reproduction AV amplifier 101 converts multi-channel audio data into an audio signal.

[0006] The acoustic signal is a 5.1 channel signal of a rear left channel, a rear right channel and a subwoofer channel, which are a left channel, a center channel, a right channel, and a surround channel, and is amplified by an AV amplifier device 101 for a surround playback device. And the left speaker 103 and the center speaker 1
04, right speaker 105, rear left speaker 10
6. Output from rear light speaker 107 and subwoofer speaker 108.

The left speaker 103, the center speaker 104, and the right speaker 105 are arranged in front of the listener, and the rear left speaker 106 and the rear right speaker 107 are arranged behind the listener. FIG. 9 shows an arrangement diagram of a speaker system arranged in front of a listener of a conventional audiovisual signal reproducing apparatus. The center channel signal emitted from the center speaker 104 plays a role of obtaining clarity and clear localization of the speech, and a left-channel playback sound and a right-channel playback sound emitted from the left speaker 103 and the right speaker 105 give a stereo feeling. Left speaker 106 and rear right speaker 1
The surround reproduction sound emitted from 07 plays a role to further enhance the sense of realism. Further, the low frequency band is emphasized by the subwoofer channel reproduced sound emitted from the subwoofer speaker 108.

[0008] Surround sounds that enhance the sense of presence include moving sounds, environmental sounds, and reverberant sounds. The moving sound is when the sound moves in the front and rear direction of the listener, the environmental sound is when the wind or street atmosphere is created, and the reverberation sound is the reflected sound of the sound emitted inside the building such as a hall or the direct sound. It is used when expressing a combined sound.

The moving sound of the surround sound needs to be localized behind the listener and connected naturally when moving in the front-back direction. Further, it is desirable that the environmental sound and the reverberant sound are not localized in a specific place, but spread naturally throughout the room. Japanese Patent Application Laid-Open No. 8-168100 discloses an invention that expresses such a natural feeling of movement in surround reproduction.
In particular, we are considering improving the feeling of movement in the front-back direction.

[0010]

In a recent video / audio signal reproducing apparatus, the video apparatus 102 tends to be larger due to the progress of projectors and cathode ray tubes. In the conventional small-screen video device 102, when the character moves from the right end to the left end of the screen, for example, the line of the character moves along with the movement of the right, left, center, and left characters, and the character moves naturally and without discomfort Met.

However, in the large-screen video device 102, the left speaker 103 and the center speaker 1
04, or the sound between the center speaker 104 and the light speaker 105 is interrupted. For example, when a character moves from the right end to the left end, the position where the speech is heard and the position on the screen There was a disadvantage that the positions of the characters did not match and it was unnatural. The present invention
It is an object of the present invention to provide a video and audio signal reproducing apparatus and a video and audio signal reproducing method that eliminate the uncomfortable feeling of moving sound in the left and right directions even when a large-screen video device is used.

[0012]

According to a first aspect of the present invention, a video signal and an audio signal are input using an input signal of a right channel signal, a left channel signal, and a center channel signal. In a video and audio signal reproducing apparatus for reproducing, pseudo-stereo conversion means for converting the center channel signal to pseudo-stereo and outputting a pseudo left channel signal and a pseudo right channel signal,
First synthesizing means for synthesizing the pseudo left channel signal and the left channel signal output from the pseudo stereo conversion means and outputting as a synthesized left channel signal; and a pseudo right channel signal and light output from the pseudo stereo conversion means A second synthesizing unit for synthesizing the channel signal and outputting as a synthesized right channel signal; and a coefficient multiplying unit for adjusting an output level of the pseudo left channel signal and the pseudo right channel signal. .

According to a second aspect of the present invention, in the video and audio signal reproducing apparatus according to the first aspect, the input signal includes a monaural surround channel signal.

According to a third aspect of the present invention, in the video and audio signal reproducing apparatus of the first aspect, the input signal reproduces a stereo surround channel signal and a video and audio signal having a low frequency reproduction channel signal. It is characterized by the following.

According to a fourth aspect of the present invention, there is provided a video / audio signal reproducing method for reproducing an audio signal by using a video signal and an input signal of a right channel signal, a left channel signal, and a center channel signal. And outputs a pseudo left channel signal and a pseudo right channel signal, and outputs the synthesized left channel signal by synthesizing the pseudo left channel signal and the left channel signal output from the pseudo stereo conversion means. The pseudo right channel signal and the right channel signal output from the pseudo stereo conversion means are synthesized to output a synthesized right channel signal, and the output levels of the pseudo left channel signal and the pseudo right channel signal are adjusted. .

According to a fifth aspect of the present invention, in the video / audio signal reproducing method according to the fourth aspect, the input signal includes a monaural surround channel signal.

According to a sixth aspect of the present invention, in the video and audio signal reproducing method according to the fourth aspect, the input signal reproduces a video and audio signal having a stereo surround channel signal and a low frequency reproduction channel signal. It is characterized by the following.

[0018]

FIG. 1 is a system configuration diagram of a video and audio signal reproducing apparatus according to one embodiment of the present invention. FIG. 2 is a layout diagram of a speaker system arranged in front of a listener of the video and audio signal reproducing apparatus according to one embodiment of the present invention. FIG.
FIG. 1 is a block diagram of an audio signal conversion unit of a video and audio signal reproducing device according to one embodiment of the present invention. FIG. 4 is a block diagram of the pseudo stereo conversion means 32. FIG. 5 is a frequency spectrum diagram of the outputs A and B of the pseudo-stereo conversion circuit 32.
FIG. 6 is a block diagram of another example of the pseudo stereo conversion circuit. FIG. 7 is a flowchart of a video / audio signal reproducing method according to one embodiment of the present invention. Hereinafter, a description will be given with reference to FIGS.

In FIG. 1, a disc on which multi-channel audio data and video signals using the Dolby encoding method are recorded is reproduced by a DVD player 1, and the video signals and multi-channel audio data are reproduced by an AV amplifier 2 for surround reproduction. Supplied. The video signal is displayed as a video by a video device 3 such as a television or a projector through an AV amplifier 2 for surround reproduction.

The multi-channel audio data is converted to an audio signal in an audio converter in the AV amplifier 2 for surround reproduction, and is amplified by the amplifier.

The amplified sound signal is transmitted from a left speaker 4, a center left speaker 5, a center right speaker 6, and a right speaker 7 arranged in front of the listener to a rear left surround speaker arranged behind the listener. The reproduced sound is output from the speaker 8, the rear light speaker 9, and the subwoofer speaker 10, respectively. The arrangement of the speaker system disposed in front of the listener is such that the video device 3, the left speaker 4, the center left speaker 5, the center right speaker 6, and the right speaker 7 have a positional relationship as shown in FIG. To expand the sound field of the center signal.

Next, a description will be given of an audio converter of the video / audio signal reproducing apparatus according to the present embodiment. FIG. 2 shows an acoustic converter of the AV amplifier 2 for surround reproduction. The multi-channel audio data is input to the multi-channel decoder circuit 3
1 is converted into a 5.1 channel signal of a left channel signal, a center channel signal, a right channel signal, a rear left channel signal, a rear right channel signal, and a subwoofer channel signal, and becomes an acoustic signal.

In FIG. 3, of the 5.1-channel signals output from the multi-channel decoder circuit 31, the center channel signal is input to a pseudo-stereo conversion circuit 32 as pseudo-stereo conversion means.

FIG. 4 shows an example of a block diagram of the pseudo-stereo conversion circuit 32. The center channel signal delayed by the delay circuit 41 and the center channel signal are added by an adder 42 to generate a pseudo write channel signal output A.
And the center channel signal delayed from the center channel signal is subtracted by a subtractor 43 to generate a pseudo write channel signal output B. This principle is known as the Lorisen principle.

FIG. 5 is a frequency spectrum diagram of the outputs A and B of the pseudo-stereo circuit 32. Outputs A and B are
Since the peaks and valleys of the frequency characteristics are different, the correlation between the output A and the output B is reduced, so that a sense of spreading is obtained and a pseudo stereo effect is obtained.

FIG. 6 shows another example of the pseudo-stereo conversion circuit 32. Delay circuit 4 of pseudo-stereo circuit shown in FIG.
In place of 1, a phase shift circuit 61 is inserted. In this case, the output A and the output B have phases opposite to each other, and a sense of spreading is obtained by the effect of the opposite phases, and a pseudo stereo effect is obtained.

Further, as another pseudo-stereo circuit 32, a pseudo-stereo circuit for slightly raising or lowering the pitch of one of the two divided center channel signals, Pseudo stereo that gives a time delay only to one of the divided center channel signals
Pseudo-stereo circuit that adds different reverberation sounds to each of the two divided center channel signals, and a pseudo phase-shift circuit that inserts a phase shift circuit toward the two divided center channel signals. There is a stereo conversion circuit and the like, and the present invention can be implemented even if any pseudo stereo conversion circuit is used.

In FIG. 2, a pseudo left channel signal and a pseudo right channel signal are output from the pseudo stereo conversion circuit 32. The pseudo left channel signal output from the pseudo stereo conversion circuit 32 is
Is combined with the left channel signal output from the multi-channel decoder circuit 31 to form a combined left channel signal.

Similarly, the pseudo write channel signal is combined with the write channel signal in the mixing circuit 34 to become a combined light channel signal.

The coefficient multiplying circuit 35 multiplies the pseudo left channel signal and the pseudo right channel signal by a coefficient, and outputs a composite left channel signal output from the mixing circuits 33 and 34 and a signal having a higher level than the composite right channel signal. . The reason will be described later.

The synthesized left channel signal is output from the left speaker 4, the pseudo left channel signal is output from the center left speaker 5, the pseudo right channel signal is output from the center right speaker 6, the synthesized right channel signal is output from the right speaker 7, and the surround sound is output. A channel signal is converted from a surround sound rear left speaker 8 and a rear right speaker 9 and a subwoofer channel signal for a low frequency signal is converted from a subwoofer speaker 10 into a reproduced sound and output.

As a result, a pseudo stereo reproduction sound of the center channel signal is output from each of the left speaker 4, the center left speaker 5, the center right speaker 6, and the right speaker 7 in the front section, and the center speaker is output from all the front section speakers. Since the channel playback sound is output, even if the playback sound moves between the right channel playback sound and the center channel playback sound, or between the left channel playback sound and the center channel playback sound, the playback sound suddenly changes between the channels. The sense of discomfort that the user feels has moved is eliminated.

The level of the signal input to the center left speaker 5 and the center right speaker 6 is higher than the level of the signal input to the left speaker 4 and the right speaker 7. As a result, adjustment is performed to return the localization of the sound image to the center, and an appropriate localization of the sound image can be obtained.

As a general property of localization of a sound image, an acoustic signal having a frequency of 700 Hz to 1 kHz diffracts the listener's head and reaches both ears. As an important factor, since the diffraction of an acoustic signal having a frequency of 2 kHz or more is cut off by the listener's head, the signal level difference between the left and right ears is an important factor, and from 1 kHz to 2 kHz, the delay amount and The difference between the amount of phase shift and the signal level is an important factor.

That is, the localization of the acoustic signal component having a frequency of 2 kHz or less can be controlled by the delay amount and the phase shift amount.
Further, the localization of the sound signal component of 1 kHz or more can be controlled by the signal level difference.

Hereinafter, it is assumed that only the pseudo stereo reproduction sound of the center channel signal is output from the left speaker 4, the center left speaker 5, the center right speaker 6, and the right speaker 7 in the front section. When the signal level of the center channel signal is low, there is no difference between the signal levels of the synthesized left channel reproduced sound, the pseudo left channel reproduced sound, the pseudo right channel signal, and the synthesized right channel signal. It feels like is output.

As the signal level of the center channel signal is increased, the pseudo left channel reproduced sound and the pseudo right channel reproduced sound become larger than the synthesized left channel reproduced sound and the synthesized right channel reproduced sound, and the difference between the signal levels becomes larger. Therefore, the user feels as if the localization of the sound image has moved toward the center. This has the effect that the uncomfortable feeling of movement in the left-right direction is eliminated as compared with the case where the center channel signal is simply reproduced in pseudo stereo.

The coefficient multiplying circuit 35 is provided between the input terminals of the center left speaker 45 and the center right speaker 6 and the pseudo-stereo circuit 32, but is provided between the pseudo-stereo means 32 and the mixing circuits 33 and 34. The present invention can be implemented even if the signal levels of the signals input to the mixing circuits 33 and 34 are reduced.

FIG. 7 is a flowchart of a video / audio signal reproducing method according to an embodiment of the present invention. This processing can be performed by hardware, and a DSP (Digita
l Signal Processor) or the like.

In FIG. 7, the left channel signal and the right channel signal are referred to as a left / right signal,
Notation of the flowchart has been simplified. Step s1 indicates the start of the program.

In step s2, the multi-channel audio data is input to the multi-channel decoder circuit, and the left channel signal, the center channel signal,
The audio signal is converted into a 5.1 channel signal of a right channel signal, a rear left channel signal for surround, a rear right channel signal, and a subwoofer channel signal for a low frequency signal.

In step s3, of the 5.1-channel sound signals, the center channel signal is pseudo-stereo-converted and output as a pseudo left channel signal and a pseudo right channel signal, respectively. In step s4,
The pseudo left channel signal and the left channel signal are synthesized, and the pseudo right channel signal and the right channel signal are synthesized to generate a synthesized left channel signal and a synthesized right channel signal.

In step s5, the pseudo left channel signal and the pseudo right channel signal are set to have higher signal levels as compared with the signal levels of the composite left channel signal and the composite right channel signal. In step s6, a combined right channel signal, a combined left channel signal,
A pseudo left channel signal and a pseudo right channel signal are output. Then, it jumps to the head of step s2 and repeats the same operation.

In the embodiment of the present invention, a description has been given of a video / audio signal reproducing apparatus of a surround system having 5.1 channel signals. The present invention is also applicable to a surround-sound video / audio reproducing apparatus having the same configuration of the front section.

[0045]

According to the video and audio signal reproducing apparatus and the video and audio signal reproducing method of the present invention, even if a character moves from the right end to the left end, the position where the dialogue is heard and the position on the screen are displayed on a large screen device. Can be provided, in which the positions of the characters coincide with each other and the movement in the left-right direction feels natural.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a video and audio signal reproducing device according to an embodiment of the present invention.

FIG. 2 is a layout diagram of a speaker system arranged in front of a listener of the video and audio signal reproducing apparatus of the present invention.

FIG. 3 is a block diagram of an audio signal converter of the audio video signal reproducing apparatus according to one embodiment of the present invention;

FIG. 4 is a block diagram of a pseudo stereo conversion circuit.

FIG. 5 is a frequency spectrum diagram showing amplitude characteristics of outputs A and B of the pseudo-stereo conversion circuit.

FIG. 6 is a block diagram of another example of the pseudo-stereo conversion circuit.

FIG. 7 is a flowchart of a video and audio signal reproducing method according to an embodiment of the present invention.

FIG. 8 is a system configuration diagram of a conventional video / audio signal reproducing apparatus.

FIG. 9 is a layout diagram of a speaker system arranged in front of a listener of a conventional video and audio signal reproducing apparatus.

[Explanation of symbols]

 1 ··· DVD player 2 ··· AV amplifier for surround reproduction 3 ··· Video device 4 ··· Left speaker 5 ··· Center left speaker 6 ··· Center right speaker 7 ··· ..Right speakers 8 ... rear left speakers 9 ... rear right speakers 10 ... subwoofer speakers 31 ... multi-channel decoder circuits 32 ... pseudo stereo circuits 33 ... mixing circuits 34 ... ..Mixing circuit 35 Coefficient multiplying circuit 41 Delay circuit 42 Adder 43 Adder 61 Phase shift circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04S 5/02 H04S 5/02 E 7/00 7/00 F

Claims (6)

[Claims] An audio / video signal reproducing apparatus for reproducing an audio signal using an input signal of a video signal, a right channel signal, a left channel signal and a center channel signal. Pseudo-stereo converting means for outputting a signal and a pseudo right channel signal; first synthesizing means for synthesizing the pseudo left channel signal and the left channel signal output from the pseudo stereo converting means and outputting as a synthesized left channel signal A second synthesizing unit that synthesizes the pseudo right channel signal and the right channel signal output from the pseudo stereo conversion unit and outputs the synthesized right channel signal, and an output level of the pseudo left channel signal and the pseudo right channel signal Power to adjust A video and audio signal reproducing apparatus, comprising: 2. The video and audio signal reproducing device according to claim 1, wherein the input signal includes a monaural surround channel signal. 3. The video / audio signal reproducing apparatus according to claim 1, wherein said input signal reproduces a video / audio signal having a stereo surround channel signal and a low frequency reproduction channel signal. Playback device. 4. A video / audio signal reproducing method for reproducing an audio signal by using a video signal and an input signal of a right channel signal, a left channel signal, and a center channel signal. A pseudo left channel signal and a pseudo left channel signal, and outputs a synthesized left channel signal by combining the pseudo left channel signal and the left channel signal output from the pseudo stereo conversion means. A video / audio signal reproducing method, comprising: combining a pseudo right channel signal and a right channel signal to output a synthesized right channel signal; and adjusting output levels of the pseudo left channel signal and the pseudo right channel signal. 5. The video / audio signal reproducing method according to claim 4, wherein said input signal comprises a monaural surround channel signal. 6. The video / audio signal reproducing method according to claim 4, wherein said input signal reproduces a video / audio signal having a stereo surround channel signal and a low frequency reproduction channel signal. Playback method.