JP2007080365A - Audio playback device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an audio reproducing apparatus capable of outputting an audio stream different from an audio stream output from a digital output terminal from an analog audio output terminal.
An audio playback device that does not have a DTS decoding function outputs an audio stream from one or a plurality of audio streams encoded by different encoding methods in accordance with an audio stream designation signal. The designation unit 1, the data conversion unit 2 that converts the output of the audio stream designation unit 1 into a bit stream of the IEC 61937 standard, the bit stream output terminal 3, and the designated audio when the audio stream designation signal designates other than the DTS stream When the audio stream designation signal designates the DTS stream, the alternative unit 4 that outputs an alternative decodable audio stream, the decoding unit 5 that decodes the output of the alternative unit 4, and the decoded data as analog data And an audio output terminal 7 for converting the sound into sound and reproducing the sound.
[Selection] Figure 1

Description

  The present invention relates to an audio playback device, and more particularly to an audio playback device to which a plurality of audio streams are input.

  In recent years, DVD discs, which are optical discs that record audio and video data digitally, have become widespread, and DVD disc playback devices that play back these are widely used as playback devices such as movie software and karaoke.

  A DVD disc can record up to eight audio streams, and can simultaneously record audio streams of a plurality of standard encoding methods such as Dolby Digital (AC-3), linear PCM, or MPEG. As an option, a DTS-encoded audio stream (DTS stream) can be recorded, and a DVD disc on which a high-quality DTS stream is recorded has been released. When reproducing the sound of a DVD disc in which a plurality of such audio streams are recorded, the user can select and reproduce any of the audio streams.

  However, since a very large amount of hardware is required to decode the DTS stream, a general DVD disk audio reproducing apparatus is not equipped with a DTS decoder. Therefore, in such a DVD disk audio reproducing apparatus, even if the user selects a DTS stream, the DTS stream input from the DVD disk is not decoded.

  However, in many cases, such a DVD disc audio reproducing apparatus is provided with a digital output terminal for outputting a DTS bit stream. Therefore, when a DTS stream is selected using such a DVD disk audio reproducing apparatus, the user connects the digital output terminal of the DVD disk audio reproducing apparatus to an AV amplifier with a built-in DTS decoder, and the AV amplifier side. The audio will be played back.

  However, in the case of using a normal DVD disk audio playback device, an analog audio output terminal for outputting analog audio after audio stream decoding is often simply connected to the TV. In the case of such a connection, there is a problem that no sound is output from the TV even if the DTS stream is selected by the audio reproducing apparatus of the DVD disk.

  Conventionally, as an optical disk reproducing apparatus that solves this problem, a method for forcibly selecting Dolby Digital (AC-3) and producing sound when a user selects a DTS stream has been proposed (for example, a patent) Reference 1).

However, with this method, since the output from the digital output terminal is also switched to the AC-3 stream, there is a problem that it is not possible to meet the needs of connecting the digital output terminal to the AV amplifier and enjoying the high sound quality of DTS. It was.
JP 2005-116152 A (page 16-17, FIG. 1)

  SUMMARY OF THE INVENTION An object of the present invention is to provide an audio reproducing apparatus that can output an audio stream different from an audio stream output from a digital output terminal from an analog audio output terminal.

  According to one aspect of the present invention, one audio stream is output from a DTS stream and one or more decodable audio streams encoded with different encoding schemes according to an input audio stream designation signal. An audio stream designating unit that performs data conversion unit that converts an audio stream output from the audio stream designating unit into a bit stream of a digital audio interface standard, and when the audio stream designating signal designates other than a DTS stream, the audio An alternative is to output the audio stream output from the stream specifying means as it is, and to output one audio stream in the decodable audio stream in place of the DTS stream when the audio stream specifying signal specifies a DTS stream Means, Audio reproduction apparatus is provided, characterized in that it comprises a decoding means for decoding the audio stream output from the serial alternatives.

  According to another aspect of the present invention, the selecting means for selecting a first audio stream and a second audio stream from a plurality of audio streams according to the input audio stream selection signal, and the first The data conversion means for converting the audio stream into a bit stream of the digital audio interface standard, the decoding means for decoding the second audio stream, and the type of the first audio stream and the second audio stream are displayed. There is provided an audio reproduction device comprising display signal generation means for generating a display signal for display on the display.

  According to the present invention, an audio stream different from the audio stream output from the digital output terminal can be output from the analog audio output terminal.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram illustrating an example of a configuration of an audio reproduction device according to Embodiment 1 of the present invention. The audio reproduction apparatus of the present embodiment has a standard AC-3 stream, linear PCM stream, or MPEG stream decoding function, but does not have an optional DTS stream decoding function.

  The audio reproducing apparatus of the present embodiment selects an audio stream specified by an audio stream specifying signal from a DTS stream and a standard specification audio stream, and outputs the audio stream specifying unit 1 and outputs from the specifying unit 1 A data conversion unit 2 that converts an audio stream into a bit stream of the IEC 61937 standard that is a digital audio interface standard, and a bit stream output terminal 3 that outputs the bit stream output from the data conversion unit 2 are provided.

  The data converter 2 includes a 1-frame extraction circuit 21 that extracts data frame by frame from the input audio stream, a preamble addition circuit 22 that adds preamble data immediately before the extracted 1-frame data, and an extracted 1-frame frame. A stuffing addition circuit 23 for adding stuffing data immediately after the data, and a conversion circuit 24 for converting the frame data to which the preamble data and the stuffing data are added into a bit stream of the IEC60958 standard.

  In addition, when the audio stream designation signal designates a standard specification audio stream, the audio reproduction apparatus of the present embodiment outputs the audio stream output from the audio stream designation unit 1, and the audio stream designation signal designates the DTS stream. When doing so, instead of the DTS stream, an alternative unit 4 that outputs one audio stream of standard audio streams, an audio decoding unit 5 that decodes the audio stream output from the alternative unit 4, and an audio decoding unit 5 The audio reproduction unit 6 that converts the data decoded by the above to analog data and reproduces analog audio, and the audio output terminal 7 that outputs the analog audio reproduced by the audio reproduction unit 6 are provided.

  The audio reproduction unit 6 includes a D / A converter 61 that converts the digital data decoded by the audio decoding unit 5 into analog data, and an amplifier circuit 62 that amplifies the output of the D / A converter 61.

  Here, for the DTS stream and the standard specification audio stream input to the audio stream specifying unit 1 and the alternative unit 4, for example, the data read from the recording medium 200 is demodulated by the demodulating unit 100, and the signal processing unit 110 performs error correction. And the audio stream separation unit 120 separates only the audio stream from the audio and video data.

  Next, the operation of the sound reproducing apparatus according to the present embodiment will be described.

  When the recording medium 200 is a DVD disc, a maximum of 8 audio streams are recorded. Therefore, the user inputs an audio stream designation signal and designates an audio stream to be reproduced.

  In accordance with the designation of the input audio stream designation signal, the audio stream designation unit 1 selects an audio stream desired by the user from the audio streams output from the audio stream separation unit 120 and outputs the selected audio stream to the data conversion unit 2 To do. The audio stream output from the data conversion unit 2 is converted into a bit stream of the IEC 61937 standard by the data conversion unit 2 and output from the bit stream output terminal 3.

  Therefore, when a DTS stream is designated by the audio stream designation signal, the DTS stream is output from the audio stream designation unit 1 and the DTS bit stream converted into the bit stream of the IEC 61937 standard by the data conversion unit 2 is a bit stream output terminal. 3 is output.

  Similarly, when a standard audio stream is designated by the audio stream designation signal, a bit stream obtained by converting the audio stream in accordance with the IEC 61937 standard is output from the bit stream output terminal 3.

  On the other hand, when the DTS stream is specified by the audio stream specifying signal, the alternative unit 4 replaces the DTS stream output from the audio stream specifying unit 1 with the standard from the audio streams output from the audio stream separating unit 120. An audio stream with specifications, for example, an AC-3 stream is selected and output to the audio decoding unit 5. The standardized audio stream output from the alternative unit 4 is decoded by the audio decoding unit 5, reproduced as analog audio by the audio reproduction unit 6, and output from the audio output terminal 7 as analog audio.

  That is, when a DTS stream is specified by an audio stream specifying signal, a standard specification audio stream, for example, an AC-3 stream, is decoded instead of the DTS stream, and analog audio is output from the audio output terminal 7.

  On the other hand, when the standard audio stream is specified by the audio stream specifying signal, the alternative unit 4 outputs the standard audio stream output from the audio stream specifying unit 1 to the audio decoding unit 5 as it is. Therefore, in this case, the analog audio reproduced by decoding the audio stream designated by the audio stream designation signal is output from the audio output terminal 7.

  According to the present embodiment, when a DTS bit stream is output from the bit stream output terminal, analog audio can be output from the analog audio terminal even if there is no DTS decoding function. It is possible to prevent the sound of a device such as a TV connected to the terminal from becoming silent. At this time, the DTS stream can be reproduced with high sound quality by connecting the bit stream output terminal to the AV amplifier.

  FIG. 2 is a block diagram illustrating an example of a configuration of an audio reproduction device according to Embodiment 2 of the present invention.

  The audio reproduction apparatus of this embodiment adds an encoding method detection unit 8 and a display signal generation unit 9 to the audio reproduction apparatus of Example 1 shown in FIG. A display signal for displaying each encoding method of the audio stream to be displayed is output. Therefore, in FIG. 2, blocks having the same functions as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof is omitted here.

  In the audio reproducing apparatus of the present embodiment, as in the audio reproducing apparatus of the first embodiment, when a DTS stream is designated by an audio stream designation signal, the DTS bit stream as designated is output from the bit stream output terminal 3. From the audio output terminal 7, an audio stream of a standard specification different from the designation is reproduced. In such a case, it is convenient for the user to know which audio stream is being played from the audio output terminal 7.

  Therefore, the audio reproduction device of this embodiment includes an encoding method detection unit 8 that detects the encoding methods of the audio streams output from the bit stream output terminal 3 and the audio output terminal 7, and an encoding method detection unit 8. And a display signal generation unit 9 that generates a display signal for displaying the encoding method detected in step S1 on a display device (not shown) such as an OSD (on-screen display).

  The encoding method detection unit 8 extracts the attribute information of the audio stream output from the bit stream output terminal 3 and the audio output terminal 7 from the signal processing unit 110 based on the specification of the audio stream specification signal, and describes the attribute information in the attribute information. The information of the encoding method being detected is detected.

  The display signal generation unit 9 generates a display signal that matches the display format of the external display device based on the information on the encoding method detected by the encoding method detection unit 8. The generated display signal is output to an external display device.

  FIG. 3 shows an example of a display displayed on an external display device by this display signal. Here, a display example is shown when a DTS stream is specified by an audio stream specifying signal, a DTS bit stream is output from the bit stream output terminal 3, and reproduced audio of an AC-3 stream is output from the audio output terminal 7. .

  As shown in FIG. 3, the display device indicates that the DTS bit stream is output to the bit stream output terminal 3 and the reproduction sound of the AC-3 stream is output to the audio output terminal 7.

  According to such a present Example, the user can know easily the encoding format of the audio | voice stream currently output to the bit stream output terminal and the audio | voice output terminal. In particular, it is useful because the encoding format of the audio stream reproduced at the audio output terminal when the DTS stream is specified by the audio stream specifying signal can be known.

  FIG. 4 is a block diagram illustrating an example of a configuration of an audio reproduction device according to Embodiment 3 of the present invention.

  The present embodiment is an audio reproduction device that can select audio streams to be output to a bit stream output terminal and an audio output terminal, and can simultaneously output different audio streams from the bit stream output terminal and the audio output terminal. . Since the structure of the main part of the present embodiment is the same as that of the sound reproduction apparatus of the first embodiment shown in FIG. 1, in FIG. 4, blocks having the same functions as those in FIG. Detailed description thereof is omitted here.

  The audio reproduction device according to this embodiment includes a selection unit 10 and a display signal generation unit 90.

  The selection unit 10 outputs an audio stream to be output to the data conversion unit 2 and an output to the audio decoding unit 5 from the audio streams output from the audio stream separation unit 120 based on an instruction from the input audio stream selection signal. Select the audio stream to be used.

  The audio stream output from the selection unit 10 is processed by the data conversion unit 2 and the audio decoding unit 5, respectively, and is output to the bit stream output terminal 3 and the audio output terminal 7.

  The display signal generation unit 90 displays the type of the audio stream output from the bit stream output terminal 3 and the audio output terminal 7 on an external display device (not shown) based on the instruction of the audio stream selection signal. Generate a display signal.

  Next, a usage method suitable for the sound reproducing apparatus of this embodiment will be described.

  In the case of a DVD disc containing a foreign movie, both an original audio stream such as English and a Japanese audio stream are generally recorded. When reproducing such a DVD disc, usually one of the languages is selected to reproduce the audio stream. However, for example, when a DVD disc is viewed by a large number of people, there may be a mixture of people who want to reproduce the original audio stream and people who want to reproduce the Japanese audio stream. In such a case, if the audio reproducing apparatus of the present embodiment is used, both audio streams can be reproduced simultaneously.

  For example, if the selection unit 10 is instructed to output the original language audio stream to the data conversion unit 2 and output the Japanese audio stream to the audio decoding unit 5 using the audio stream selection signal, to the bit stream output terminal 3. The original bit stream is output, and Japanese analog audio is output to the audio output terminal 7. Therefore, if the bit stream output terminal 3 is connected to the AV amplifier, and the audio output terminal 7 is connected to the TV for playback, the audio of the original language is output from the AV amplifier and the Japanese audio is output from the TV. .

  That is, the original language voice and the Japanese language voice can be reproduced at the same time, and a person who wants to reproduce each voice can be satisfied at the same time.

  At this time, by outputting the display signal generated by the display signal generation unit 90 to an external display device, the type of the audio stream output to the bit stream output terminal 3 and the audio output terminal 7 is set to the external display device. Can be displayed.

  FIG. 5 shows an example of display displayed on an external display device by this display signal. Here, it is shown that an English bit stream is output to the bit stream output terminal 3 and a Japanese audio stream is output to the audio output terminal 7.

  According to this embodiment, different audio streams can be simultaneously output to the bit stream output terminal and the audio output terminal, and the respective audio streams can be reproduced simultaneously. Thereby, for example, the content can be enjoyed simultaneously in a foreign language and Japanese.

  In the description of each embodiment described above, an example of a reproduction target has been described as a recording medium on which a plurality of audio streams are recorded. However, the reproduction target is not limited to this, and for example, a plurality of audio Broadcast content in which streams are transmitted at the same time may be targeted for reproduction.

  Further, the sound reproducing device of each of the above embodiments may be realized as a semiconductor device mounted on an integrated circuit. At that time, the entire audio reproduction device may be an integrated circuit, or a portion excluding an audio reproduction unit including an analog circuit may be an integrated circuit.

1 is a block diagram showing an example of the configuration of a sound reproduction device according to Embodiment 1 of the present invention. The block diagram which shows the example of a structure of the audio | voice reproduction apparatus which concerns on Example 2 of this invention. The figure which shows the example of the display by the display signal output from the audio | voice reproduction apparatus which concerns on Example 2 of this invention. The block diagram which shows the example of a structure of the audio | voice reproduction apparatus which concerns on Example 3 of this invention. The figure which shows the example of the display by the display signal output from the audio | voice reproduction apparatus which concerns on Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Audio stream designation | designated part 2 Data conversion part 3 Bit stream output terminal 4 Alternative part 5 Audio | voice decoding part 6 Audio | voice reproduction | regeneration part 7 Audio | voice output terminal 8 Coding system detection part 9, 90 Display signal generation part 10 Selection part 21 1 frame extraction circuit 22 Preamble addition circuit 23 Stuffing addition circuit 24 Conversion circuit 61 D / A converter 62 Amplification circuit

Claims (5)

Audio stream designating means for outputting one audio stream from among the DTS stream and one or more decodable audio streams encoded by different encoding methods according to the inputted audio stream designating signal;
Data conversion means for converting the audio stream output from the audio stream specifying means into a bit stream of a digital audio interface standard;
When the audio stream designating signal designates other than the DTS stream, the audio stream output from the audio stream designating means is output as it is, and when the audio stream designating signal designates the DTS stream, the DTS stream is replaced with the DTS stream. An alternative means for outputting one of the decodable audio streams;
An audio reproducing apparatus comprising: decoding means for decoding the audio stream output from the alternative means. Detecting means for detecting the encoding method of the audio stream output from the bit stream output terminal and the encoding method of the audio stream output from the audio output terminal;
The audio reproduction device according to claim 1, further comprising display signal generation means for generating a display signal for displaying the encoding method detected by the detection means on a display device.   3. The audio reproduction device according to claim 1, wherein the plurality of decodable audio streams include at least one of an AC-3 stream, a linear PCM stream, and an MPEG stream. Selecting means for selecting a first audio stream and a second audio stream from a plurality of audio streams in accordance with an input audio stream selection signal;
Data conversion means for converting the first audio stream into a digital audio interface standard bit stream;
Decoding means for decoding the second audio stream;
An audio reproducing apparatus comprising: a display signal generating unit configured to generate a display signal for displaying a type of the first audio stream and the second audio stream on a display device.   5. The sound reproducing apparatus according to claim 1, further comprising sound reproducing means for converting the data decoded by the decoding means into analog data and reproducing analog sound.

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