JP2003101952A - Device for recording digital signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that a conventional recorder does not correspond, in a digital input, to video recording for a long time because the digital input is recorded at a TS rate and that image quality is deteriorated in an analog input because the digital input is once returned to analog input even though the recorder corresponds to the video recording for a long time. SOLUTION: A digital signal recorder is provided with a decoding means for decoding streams of input digital video and sound signals, an encoding means for encoding the digital video and sound signals obtained by the decoding means, a selecting means for selecting the stream obtained by the encoding means and an input stream, and a controlling means for controlling the selecting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device provided with a digital signal input device, for example, a recording device capable of recording a stream on a recording medium such as a magnetic disk.

[0002]

2. Description of the Related Art In recent years, the development of multimedia handling video and audio is remarkable, and video capable of storing or transferring data in accordance with the MPEG2 standard, which is a standard for compression of the video and audio signals, There are many audio devices on the market.

And, as represented by D-VHS,
One of them is a recording device for recording an MPEG2 transport stream (hereinafter, referred to as TS), which is a D-VH.
As an example of the use of S, as shown in FIG. 4, BS-STB
It is possible that the (set top box) 200 and the D-VHS 201 are connected by a 1394 cable 202.

IRD such as the above-mentioned BS-STB200
(Integrated Receiver-Deco
A receiver called “rder)” selects a transmission carrier with a tuner at the time of reception, selects one TS, and further extracts TS packets corresponding to a program (channel) selected by the user. Many models of IRD have extracted T
The S packet can be output to the outside via a digital I / F circuit (not shown) and is used for digital recording. That is, if the BS-STB 200 is capable of outputting TS packets via the 1394 cable 202, the BS-STB 200 receives the broadcast received by the BS-STB 200.
Stream recording is possible with the -VHS 201, and the signal flow in the D-VHS 201 at that time is shown in FIG.

In FIG. 5, the recording device 203 is a DV
The configuration of a recording unit for digital input of the HS 201 is shown, and a digital input terminal 101, a digital I / F circuit 102, a decoder circuit 103, and a TS processing circuit 10 are shown.
8, a recording circuit 109, an output processing circuit 112, and an output terminal 113.

T input from the digital input terminal 101
The S passes through the digital I / F circuit 102, is time-stamped by the TS processing circuit 108, and is stream-recorded on the recording medium 111 via the recording circuit 109. That is, the recording rate on the recording medium 111 is the rate input to the digital input terminal 101, that is, the rate of the broadcast TS. The stream output from the digital I / F circuit 102 is also given to the decoder circuit 103, and the video data and audio data decoded by the decoder circuit 103 are output processed by the output processing circuit 112 and output to the output terminal 113. And output as video and audio signals. This output corresponds to the output to the monitor, for example.

Here, the decoder circuit 103 is composed of a system decoder 114, a video decoder 115, and an audio decoder 116, as shown in FIG. The input TS is demultiplexed after the header information is analyzed by the system decoder 114, the video signal is output as video data after decoding by the video decoder 115, and the audio signal is output as audio data after decoding by the audio decoder 116. Is output.

The TS processing circuit 108 is a circuit for adding a time stamp for re-transmitting to the input stream at the same interval as at the input, and the TS processing circuit 108.
As shown in FIG. 9, a TS packet output from the
It becomes a byte.

The recording circuit 109 has an ECC (E
It is composed of a color correction code circuit, a modulation / demodulation circuit, and the like, and has a function of recording on the recording medium 111.

On the other hand, as shown in FIG. 6, the IRD is DV
Consider making an analog connection to the HS201. In FIG. 6, the BS-STB 204 is, for example, an IRD that does not have digital output means, and is connected to the D-VHS 201 via an analog I / F (not shown) in the BS-STB 204 and an analog cable 205. D at this time
The signal flow in -VHS 201 is shown in FIG.

In FIG. 7, the recording device 206 is a DV
The structure of the recording unit in the analog input of HS201 is shown, and the analog input terminal 207, the analog I / F circuit 208, the encoder circuit 106, and the TS processing circuit 1 are shown.
08 and a recording circuit 109.

Video or audio analog data input from the analog input terminal 207 is input to the encoder circuit 106 via the analog I / F circuit 208.
The encoder circuit 106 encodes the input data, the TS processing circuit 108 adds a desired time stamp, and then the recording medium 1 as a TS via the recording circuit 109.
11 is recorded.

Here, the encoder circuit 106 is shown in FIG.
As shown in FIG. 3, it is composed of a system encoder 117, a video encoder 118, and an audio encoder 119. The input video data or audio data is encoded by the video encoder 118 or the audio encoder 119, respectively, and after being multiplexed by the system encoder 117, a header is added and TS is added.
Is output as.

As described above, the existing D-VHS has an encoder circuit for digitally recording an analog input, and
It is common to mount a decoding circuit for performing analog output. Then, if it is an analog input, by encoding with rate limiting by the encoder circuit,
Long-term recording, which will be described later, is possible.

Therefore, the structure of the recording unit in the existing D-VHS is as shown in the recording device 209 shown in FIG. The recording device 209 is a combination of the recording devices 203 and 206 shown in FIGS. 5 and 7, and has a digital input terminal and an analog input terminal. That is, the digital input terminal 101, the digital I / F circuit 102, the decoder circuit 103, the analog input terminal 207, the analog I / F circuit 208, the encoder circuit 106, the selection circuit 107, and the TS processing circuit 108. Recording circuit 109
A controller circuit 110 and an output processing circuit 112
And an output terminal 113.

If the stream obtained from the digital input terminal is to be recorded, the TS input from the digital input terminal 101 passes through the digital I / F circuit 102 and is input to 107b in the selection circuit 107.

On the other hand, if video and audio input as analog signals are recorded, analog data of video or audio input from the analog input terminal 207 is passed through the analog I / F circuit 208 and the encoder circuit 106. Input to the selection circuit 10 and the output of the encoder circuit 106 is input to the selection circuit 10.
7 is input to 107a.

In the selection circuit 107, the controller circuit 1
Controlled by 10 and 107b for recording a digital input, 107b for recording an analog input.
a is selected, and its output is time-stamped by the TS processing circuit 108, and is sent to the recording medium 11 via the recording circuit 109.
1 is stream recorded.

By the way, the difference between the recording of the digital input and the recording of the analog input is that the deterioration of the image quality at the time of recording can be avoided because the digital input is not once converted into analog. Therefore, when a user records a digital broadcast such as a BS digital broadcast that has recently started, if a digital output means is added to the IRD, naturally, as shown in FIG.
-It will be connected to VHS.

[0020]

However, since the digital input is recorded at the broadcast TS rate as described above, there is a problem in that it is not compatible with long-time recording. Also, if it is an analog input, it is possible to record for a long time, but there is a problem that the image quality is deteriorated because it is once returned to analog in the IRD.

Here, the above-mentioned long-time recording is a recording means capable of recording for, for example, three times longer time by converting the bit rate as compared with the case of recording at the input bit rate.

The present invention has been made in view of the above problems, and when recording with high image quality and high sound quality, TS is recorded without conversion as before, and when it is desired to record for a long time, an analog input is used. The purpose is to record at a low bit rate by using an existing encoder circuit or decoder circuit without using it.

[0023]

In order to solve the above problems, the present invention takes the following means.

That is, the digital signal recording apparatus of the present invention is
Decoding means for decoding the input encoded digital signal, encoding means for re-encoding the decoded digital signal at a rate equal to or lower than the input encoded digital signal, and re-encoded And a selection means for selecting the input encoded digital signal.

Here, the analog signal input means, the input interface means for converting the input analog signal into a digital signal, the digital signal obtained by the input interface means and the digital signal obtained by the decoding means are selected. However, a second selecting means for inputting the selected output to the encoding means may be provided.

Further, the digital signal recording apparatus of the present invention is
Decoding means for decoding the input coded digital signal, bit rate conversion means for converting the bit rate of the decoded digital signal to a rate equal to or lower than the input coded digital signal, and the bit A selection unit for selecting the rate-converted digital signal and the input coded digital signal may be provided.

Here, it is preferable that the decoding means outputs a signal before being decoded into a baseband signal.

In addition, the analog signal input means, the input interface means for converting the input analog signal into a digital signal, the encoding means for encoding the digital signal obtained by the input interface means, and the selecting means, The encoded digital signal, the digital signal whose bit rate has been converted by the bit rate conversion means, and the input coded digital signal may be selected.

Further, transport stream generating means for adding time information to the output of the selecting means to generate a transport stream, and recording means for recording the transport stream obtained by the transport stream generating means on a recording medium. , May be provided.

It is preferable that the selection of the selecting means is switched depending on the remaining amount of the recording medium.

[0031]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a recording apparatus according to the present invention. It should be noted that components having the same functions as those of the conventional example will be described with the same reference numerals and detailed description thereof will be omitted.

In FIG. 1, the recording apparatus 100 includes a digital input terminal 101 to which TS is input and a digital I / F.
Circuit 102, decoder circuit 103, and selection circuit 105
, Encoder circuit 106, selection circuit 107, TS
A processing circuit 108, a recording circuit 109, a controller circuit 110, an analog I / F circuit 208, an output processing circuit 112, and an output terminal 113 are included.

T input from the digital input terminal 101
S is the selection circuit 10 via the digital I / F circuit 102.
It is output to 7, but there are two systems. The first is that the output of the digital I / F circuit 102 is directly fed to the selection circuit 107.
In the second case, when the output of the digital I / F circuit 102 is decoded by the decoder circuit 103, it is input to the encoder circuit 1 via the selection circuit 105.
In this case, the bit rate is limited by 06, re-encoding is performed, and the data is input to 107a in the selection circuit 107.

The former corresponds to the conventional recording method,
When recording without bitrate conversion,
The latter is a case of recording a stream whose bit rate has been converted by the selection circuit 105 newly provided in the present invention.

That is, at the time of long-time recording, the controller circuit 110 selects the 105b side of the selection circuit 105 and the 107a side of the selection circuit 107 so that the decoder circuit 103 performs decoding and then the encoder circuit 106. Record the re-encoded stream with the low bit rate.

Further, according to the embodiment of the present invention, it is possible to perform the exact recording. Perfect recording is, for example, when recording is started, recording is performed without bit rate conversion, and the remaining amount of the recording medium becomes small. In the state without bit rate conversion, it is determined that the remaining amount of recording medium becomes 0 during recording. At this time, it is a means for recording by reducing the bit rate.

Conventionally, when a tape such as a recording medium is used to implement the above-mentioned perfect recording in a model such as D-VHS for performing stream recording, there has been a problem that noise is generated when the bit rate is switched. However, since a large-capacity disk medium has appeared today and the above problem does not occur in recording on a disk, there is no problem in realizing perfect recording.

That is, at the time of bitter recording, the controller circuit 110 selects the 107b side of the selection circuit 107 at the beginning of recording to record the output of the digital I / F circuit 102 and the remaining amount of the recording medium becomes small. In case,
The controller circuit 110 selects the 105b side of the selection circuit 105 and the 107a side of the selection circuit 107 to record the re-encoded stream with the low bit rate limited as described above. Here, the determination of switching in the selection circuit 105 or the selection circuit 107 is made by a microcomputer (not shown) automatically calculating the remaining amount of the recording medium, or by the user selecting.

As described above, according to the first embodiment of the present invention, by using the existing decoder circuit and encoder circuit, the path for decoding the input digital signal, limiting the bit rate and re-encoding It is possible to record for a long time or exactly, and even when passing through a path for bit rate limiting and re-encoding, it does not return to an analog signal, so there is little deterioration in image quality.

Next, regarding the second embodiment of the present invention,
This will be described with reference to FIGS. 2 and 3. FIG. 2 is a block diagram showing an embodiment of the recording apparatus according to the present invention. It should be noted that those having the same functions as those of the conventional example or the first embodiment will be described with the same reference numerals, and detailed description thereof will be omitted.

In FIG. 2, the recording device 120 includes a digital input terminal 101 to which TS is input and a digital I / F.
The circuit 102, the decoder circuit 103 #, the bit rate conversion circuit 104, the encoder circuit 106, the selection circuit 107 #, the TS processing circuit 108, and the recording circuit 109.
, Controller circuit 110, and analog I / F circuit 2
08, an output processing circuit 112, and an output terminal 113.

T input from the digital input terminal 101
S is the selection circuit 10 via the digital I / F circuit 102.
It is output to 7 #, but there are two systems. The first is
The output of the digital I / F circuit 102 directly changes to the selection circuit 10
When input to 107 # b in 7 #, the second is
The output of the digital I / F circuit 102 is the decoder circuit 103.
After being decoded in #, the bit rate is converted in the bit rate conversion circuit 104, and 10 in the selection circuit 107 #.
7 # c is input.

The former corresponds to the conventional recording method,
When recording without bitrate conversion,
The latter is a case of recording a stream which has been bit rate converted by the bit rate conversion circuit 104 and the selection circuit 107 # newly provided in the present invention.

That is, during long-time recording, the controller circuit 110 selects the 107 # c side of the selection circuit 107 # so that the decoder circuit 103 # performs decoding and then the bit rate conversion circuit 104 reduces the bit rate. Record the stream. Further, even at the time of perfect recording, the controller circuit 110 causes the selection circuit 10 at the beginning of recording.
By selecting the 107 # b side of 7 #, the digital I
The output of the / F circuit 102 is recorded, and when the remaining amount of the recording medium is low, the controller circuit 110 selects the 107 # c side of the selection circuit 107 #, thereby reducing the bit rate as described above. To record.

Here, the output of the decoder circuit 103 #, which is output to the bit rate conversion circuit 104, is a stream in the intermediate stage of the decoding of the video decoder 115 # or the audio decoder 116 #, as shown in FIG. Before decoding to a baseband signal, eg DC
T (Discrete Cosine Transfer)
rm) The stream before processing corresponds. That is, in the long-time recording mode, the bit rate conversion circuit 10 outputs the stream before the DCT process output from the decoder circuit 103 #.
4, the bit rate conversion is performed, the TS processing circuit 108 adds a time stamp, and then the recording medium 1 passes through the recording circuit 109.
11 is recorded.

Thus, according to the second embodiment of the present invention, by utilizing the existing decoder circuit,
It is possible to perform bit rate conversion on the stream in the middle of decoding the input digital signal, and it is possible to record for a long period of time or exactly.

Further, as in the first embodiment, since the analog signal is not restored, the image quality is less deteriorated.

As the recording medium 111, the disk medium is more suitable than the tape medium as described above.
Because perfect recording switches between long-time recording mode (mode in which bit rate is lowered to enable long-time recording) and standard mode (mode without bit rate conversion) during recording, noise at the time of switching is Considering this, it is considered that a random access disk medium is suitable.

However, the recording medium targeted by the recording apparatus of the present invention is not limited to the disk medium. For example, it is a recording device that does not support the above-mentioned perfect recording but only long-time recording, and even if the recording device uses tape media unless the long-time recording mode and the standard mode are switched during recording. no problem.

[0050]

As described above, according to the present invention,
By using the existing decoder circuit and encoder circuit, it is possible to decode the input digital signal, limit the bit rate, and record the re-encoded stream.

Further, since it is possible to decode the input digital signal by using the existing decoder circuit and record the stream of which the bit rate has been reduced by the bit rate conversion circuit, it is possible to record the stream even when the digital signal is input. Time recording and even perfect recording are possible.

Further, even when the signal passes through a path for limiting the bit rate and re-encoding, it is not restored to an analog signal, so that image quality deterioration is small.

[Brief description of drawings]

FIG. 1 is a block diagram of a recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a recording device according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a decoder circuit.

FIG. 4 is a connection diagram in which BS-STB and D-VHS are connected by a 1394 cable.

FIG. 5 is a block diagram of a conventional digital input recording apparatus.

FIG. 6 is a connection diagram in which BS-STB and D-VHS are connected by an analog cable.

FIG. 7 is a block diagram of a conventional analog input recording apparatus.

FIG. 8 is a block diagram of a decoder circuit.

FIG. 9 is a TS packet with a time stamp added.

FIG. 10 is a block diagram of an encoder circuit.

FIG. 11 is a block diagram of a conventional recording apparatus.

[Explanation of symbols]

100 Recording apparatus according to the first embodiment of the present invention 101 Digital input terminal 102 Digital I / F circuit 103 decoder circuit 103 # decoder circuit 104 Bit rate conversion circuit 105 selection circuit 106 encoder circuit 107 selection circuit 108 TS processing circuit 109 recording circuit 110 controller circuit 111 recording medium 112 Output processing circuit 113 output terminals 114 system decoder 115 video decoder 115 # Video Decoder 116 audio decoder 116 # Audio Decoder 117 system encoder 118 video encoder 119 audio encoder 120 Recording Device in Second Embodiment of Present Invention 200 BS-STB 201 D-VHS 202 1394 cable 203 Conventional recording device for digital input 204 BS-STB 205 analog cable 206 Conventional recording device for analog input 207 Analog input terminal 208 analog I / F circuit 209 Conventional recording device

Continued front page    F-term (reference) 5C053 FA21 GB17 GB38 KA08 KA24                       KA26                 5D044 AB07 BC01 BC04 CC04 GK08                       GK10 GK12 GL19

Claims (7)

[Claims] 1. Decoding means for decoding an input encoded digital signal, and encoding means for re-encoding the decoded digital signal at a rate equal to or lower than the input encoded digital signal. A digital signal recording apparatus comprising: a selection unit that selects the re-encoded digital signal and the input encoded digital signal. 2. The digital signal recording apparatus according to claim 1, wherein the analog signal input means, the input interface means for converting the input analog signal into a digital signal, the digital signal obtained by the input interface means and the decoding A digital signal obtained by the means, and a second selection means for inputting the selected output to the encoding means. 3. Decoding means for decoding the input encoded digital signal, and bit rate conversion for converting the bit rate of the decoded digital signal to a rate equal to or lower than the input encoded digital signal. A digital signal recording apparatus, comprising: a means for selecting the digital signal whose bit rate has been converted and a selection means for selecting the input coded digital signal. 4. The digital signal recording device according to claim 3, wherein the decoding means outputs a signal before being decoded into a baseband signal. 5. The digital signal recording apparatus according to claim 3, wherein the analog signal input means, the input interface means for converting the input analog signal into a digital signal, and the digital signal obtained by the input interface means are encoded. And an encoding unit that selects the encoded digital signal, a digital signal whose bit rate is converted by the bit rate conversion unit, and the input encoded digital signal. Digital signal recorder. 6. The digital signal recording device according to claim 1, further comprising: a transport stream generation unit that adds time information to the output of the selection unit to generate a transport stream, and the transport stream generation unit. A digital signal recording device comprising: a recording unit configured to record the transport stream obtained by the stream generating unit on a recording medium. 7. The digital signal recording device according to claim 1, wherein the selection of the selecting unit is switched depending on the remaining amount of the recording medium.