KR20040103158A - Dolby prologic audio system - Google Patents

Abstract

PURPOSE: A dolby prologic audio signal output device is provided to output S/PDIF(Sony/Philips Digital Interface) sound on more than two video input modes using only one S/PDIF input terminal. CONSTITUTION: A dolby prologic audio signal output device includes a digital interface terminal to which an audio source is inputted, a digital selector(100), a decoder(200), a key input portion(500), and a controller(300). The digital selector transfers the input audio source to a corresponding decoder. The decoder stores decoder data corresponding to at least two video modes, selectively compresses and decodes the transferred audio source based on video modes and outputs the result as SOD(Serial Output Data). The key input portion generates a key signal for selecting an arbitrary video mode. The controller outputs the audio source by switching the audio source to decoder data corresponding to the video mode selected by the key input portion.

Description

Dolby Pro Logic Audio Signal Output Device {DOLBY PROLOGIC AUDIO SYSTEM}

The present invention relates to a technology for decoding and outputting a sound source in a Dolby Prologic audio device, and in particular, Dolby ProLogic Audio suitable for decoding and outputting at least two or more image mode sounds with one digital interface terminal. It relates to a signal output device.

In general, the pursuit of sound quality and sound field faithful to the original sound in an AV (audio-visual) device that plays music and movies is an eternal purpose in sound reproduction. Sound quality has already been greatly improved due to advances in digital signal recording and transmission technologies. In addition, in terms of sound field reproduction, reproduction by multi-channels seen in movie theaters has been pointed out as the answer.

Four-channel playback was proposed and released by each set maker in 1970 for general household use, but it disappeared from the market due to the troublesome arrangement and high price of four speakers.

The idea of creating a sound image in any direction around the listener using two front speakers has been around for a while. The principle was first published in 1963 by Dr. Schrader of the Bell Institute. The method using two speakers is realized by measuring the transmission characteristics of the listener's ears in an arbitrary direction and reproducing the aforementioned transmission characteristics by the two front speakers.

In the mid 70's, a product was introduced based on this principle of using two speakers to create sound in any direction around the listener. At the time, this product was made by analog technology, so complex reflections could not be realized, and thus could not achieve the required performance.

In the current technology, many standards have been proposed to overcome the problems of these functions, the most widely used among them, the Dolby AC-3 method is recognized for the excellent sound quality. For example, sound processing by the Dolby AC-3 system is performed in movie theaters. It encodes and records movie 5.1-channel soundtracks, also called Dolby Stereo, into tracks on film and plays them back.

The above-mentioned Dolby Surround is a multi-channel method originally made for reproduction in a movie theater. The theater is arranged to connect the front left and front right channels and the front center channel centered on the dialogue, the rear left and right channels and the surround channels to a plurality of speakers arranged on the wall. It is Dolby Surround (or Dolby Stereo) that stores this in the track of the film.

Software created for home use based on AC-3 recorded film has a soundtrack that is encoded as is, allowing playback on playback devices that support AC-3.

In addition, a system suitable for outputting the same after the playback is required. For this purpose, in order to play AC-3 encoded video or audio software at home, it is necessary to perform decoding processing and then install 6 or more speakers. After decoding, it should be output through each speaker.

Dolby's AC-3 surround described above is a multi-channel method originally created for cinema. Decode the encoded 5.1 channels by encoding audio signals in the form of 5.1-bit bitstreams, and output the decoded signals through the front left, front right, center and rear speakers and through multiple speakers on the left and right walls. This is Dolby's AC-3 surround (or Dolby AC-3 stereo).

However, since Dolby AC-3 stereo decodes only 5.1-encoded media into 5.1-channels and outputs them to multiple speakers, these Dolby AC-3 stereos are generally 2-channel-encoded signals such as video tapes, LDs, and satellites. Alternatively, a signal transmitted in stereo television broadcasting may not be decoded into 5.1 channels using Dolby AC-3 stereo.

To solve this problem, Dolby Pro Logic technology has emerged.

Dolby Pro Logic implements two-channel encoded signals into 5.1 front, left, center, and surround mono channels. In other words, this method decodes two-channel encoded signals into left and right signals of the front channel and mono signals of the center and surround and outputs them to the respective speakers.

Meanwhile, the audio decoder unit of the Dolby Pro Logic audio device includes a PCM (Pulse Coded Modulation) decoder, a Moving Pictures Experts Group (MPEG) decoder, and an AC-3 (Dolby Digital Audio Compression) decoder, respectively. For example, one of the PCM / MPEG / AC-3 decoders is selected according to the sound source source input through the S / PDIF (Sony / Philips Digital Interface) terminal to compress and decode the input sound source, and decoded sound source. Output as SOD (Serial Output Data).

However, conventionally, the sound for each image mode that can be accommodated by one S / PDIF terminal is limited to one sound.

That is, each decoder, e.g., an AC-3 decoder, selects one of a plurality of video modes (external input 1 to external input 4, component 1 to component 3) to decode the sound source source. If there is only one input terminal, there is a disadvantage in that sound can only be output in one mode.

This problem is similarly raised in the PCM decoder and the MPEG decoder.

The present invention has been implemented to overcome these disadvantages of the prior art, by setting the decoder data for each video mode in the form of a buffer in each decoder (PCM decoder, MPEG decoder, AC-3 decoder), and selects the input sound source source for each decoder selected An object of the present invention is to provide a Dolby Pro Logic audio signal output device configured to switch and decode each mode for each mode.

According to a preferred embodiment of the present invention for achieving the above object, a digital interface terminal to which the sound source is input, a decoder selector for switching the input sound source to the corresponding decoder and providing at least two video modes. A decoder unit having a decoder for storing decoder data and selectively compressing and decoding a sound source source switched in the decoder selector for each image mode to output SOD (Serial Output Data), and selecting an arbitrary image mode. It provides a Dolby Pro Logic audio signal output device including a key input unit for generating a key signal for the control unit, and a control unit for controlling the decoder unit to output a sound source by switching to decoder data corresponding to the video mode selected through the key input unit.

1 is a block diagram of a Dolby Pro Logic audio signal output device according to the present invention;

2A is a detailed configuration diagram of a PCM decoder in which decoder data for each video mode is implemented in a buffer form according to the present invention;

2b is a detailed configuration diagram of an MPEG decoder in which decoder data for each video mode is implemented in a buffer form according to the present invention;

2c is a detailed configuration diagram of an AC-3 decoder in which decoder data for each video mode is implemented in a buffer form according to the present invention;

3 is a flowchart of an audio signal output process performed in the Dolby Pro Logic audio signal output device of FIG. 1.

<Description of the code | symbol about the principal part of drawing>

100: decoder selection unit 200: decoder unit

202: Pulse Coded Modulation (PCM) Decoder

204: Moving Pictures Experts Group (MPEG) decoder

206: AC-3 (Dolby Digital Audio Compression) Decoder

300: control unit 400: memory unit

500: key input unit

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a schematic block diagram of a Dolby Pro Logic audio signal output device according to an embodiment of the present invention, the decoder selection unit 100, the decoder unit 200, the control unit 300, the memory unit 400, and the key input unit 500. ).

First, the decoder selector 100 switches a sound source source input through a digital interface terminal to a corresponding decoder and serves to provide the decoder 200. Here, the digital interface terminal may refer to, for example, a Sony / Philips Digital Interface (S / PDIF) terminal.

The decoder unit 200 includes a PCM decoder, an MPEG decoder, and an AC-3 decoder, respectively, and includes a PCM decoder 202, an MPEG decoder 204, and an AC-3 decoder according to a sound source input through an S / PDIF terminal. Select one of the 206 to compress and decode the input sound source source, and output the decoded sound source as SOD (Serial Output Data).

As shown in FIGS. 2A to 2C, the decoder 200 stores decoder data corresponding to at least two or more image modes, respectively, and the sound source (PCM or MPEG or the like) switched by the decoder selector 100. AC-3 sound source) is selectively compressed and decoded for each video mode.

That is, the PCM decoder 202 of FIG. 2A corresponds to the Hex value of a plurality of image modes (external input 1, external input 2, external input 3, external input 4, component 1, component 2, component 3). PCM decoder data is configured in the form of a buffer, and in the MPEG decoder 204 of FIG. 2B, MPEG decoder data corresponding to the nucleus values of a plurality of video modes is configured in the form of a buffer.

Similarly, in the AC-3 decoder 206, as shown in FIG. 2C, AC-3 decoder data corresponding to the nucleus values of the plurality of video modes is formed in the form of a buffer.

Meanwhile, the controller 300 switches the decoder data corresponding to the image mode selected through the key input unit 500 for generating a key signal for selecting an image mode to output a corresponding sound source. To control the MPEG decoder 204 and the AC-3 decoder 206, respectively.

The control unit 300 is connected to a memory unit 400 in which the image mode setting data of each decoder 202, 204, and 206 is recorded, for example, an E ² PROM. The image mode selection values input through the input unit 500 may be compared.

Hereinafter, an audio signal output process performed in the Dolby Pro Logic audio signal output device according to the present invention will be described in more detail with reference to the flowchart of FIG. 3.

As shown in FIG. 3, in steps S300 and S302, the key input unit 500 determines whether a predetermined image input mode, for example, an external input 1 mode, is selected.

As a result of the determination in step S302, when the predetermined image input mode is selected, the controller 300 proceeds to step S304 and checks the digital interface ID through the digital interface terminal. That is, it is checked whether the sound source source currently input is PCM, MPEG, or AC-3.

If the sound source is PCM, the controller 300 proceeds to step S306 to check each decoder data stored in the PCM decoder 202.

In step S308, the controller 300 determines whether the decoder data stored in the PCM decoder 202 and the image mode setting data stored in the memory 400 match, respectively, and if so, proceeds to step S312.

Therefore, in step S312, the PCM sound source source is decoded and output in the mode selected through the PCM decoder-1 shown in FIG. 2A, that is, the external input 1 mode.

Likewise, the sound source may be decoded and output in the corresponding video mode through the PCM decoder-2, 3, 4, 5, 6, and 7.

On the other hand, when the determination result in step S308 does not match the values (PCM decoder data and video mode input setting data) previously assigned to the memory unit 400 and the PCM and video mode values currently set, Proceed to (S310) and let the RCA output. Here, RCA means Scart input <R-L> sound.

In this process, a technique of outputting a sound source for each of a plurality of image input modes through the PCM decoder 202 has been described. However, the same technique may be applied to the MPEG decoder 204 and the AC-3 decoder 206. Overlapping descriptions will be omitted.

According to the present invention, it is possible to listen to S / PDIF sound in at least two video input modes through one S / PDIF input terminal, thereby increasing user satisfaction and lowering production cost through improved internal design of the audio decoder. It can be effective.

As mentioned above, although this invention was concretely demonstrated based on the Example, this invention is not limited to this Example, Of course, various changes are possible within the range which does not deviate from the summary.

Claims (3)

A digital interface terminal to which a sound source is input, A decoder selector configured to switch the input sound source source to a corresponding decoder; Decoder unit having a decoder for storing at least two decoder data corresponding to at least two video modes, and selectively compressing and decoding the sound source source switched in the decoder selector for each video mode to output as SOD (Serial Output Data) Wow, A key input unit for generating a key signal for selecting an arbitrary video mode; A control unit which controls the decoder to output the sound source by switching to decoder data corresponding to the image mode selected through the key input unit Dolby Prologic (Dolby Prologic) audio signal output device comprising a. The method of claim 1, The decoder unit, A PCM decoder for decoding a PCM (Pulse Code Modulation) sound source, MPEG decoder for decoding MPEG (Moving Pictures Experts Group) sound source, AC-3 decoder for decoding AC-3 (Dolby Digital Audio Compression) sound sources Dolby Pro Logic audio signal output device, characterized in that consisting of. The method of claim 1, The image mode selected through the key input unit may be any one of an external input 1, an external input 2, an external input 3, an external input 4, a component 1, a component 2, and a component 3 mode. Signal output device.