Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1998-06-26
2002-08-06
Chevalier, Robert (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000, C360S015000
Reexamination Certificate
active
06430356
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to an information recording and reproducing apparatus such as a video cassette tape recorder of a helical scan type, and more particularly to an information recording and reproducing apparatus in which an audio-visual digital signal and auxiliary information read out from a first recording medium is reproduced and the reproduced audio-visual digital signal and auxiliary information are recorded in a second recording medium for the dubbing of the audio-visual digital signal and auxiliary information.
2. Description of the Related Art
A video cassette tape recorder (VCR) of a helical scan type is conventionally known as a magnetic recording and reproducing apparatus. In this VCR, a visual signal and an audio signal are converted into an audio visual (AV) digital signal in which the visual signal and the audio signal are coded according to a moving picture experts group (MPEG), the AV digital signal is recorded in a cassette type magnetic tape through a rotational head while making a recording track inclined with respect to a moving direction (or a longitudinal direction) of the magnetic tape, and a control signal having a plurality of control pulses arranged in equal intervals is recorded in the magnetic tape through a fixed control head while making a control track extending along the moving direction of the magnetic tape. When the AV digital signal and the control signal are reproduced, the AV digital signal is readout from the inclined recording track of the magnetic tape through the rotational head, and the control signal is read out from the control track of the magnetic tape through the control head.
2.1. First Previously Proposed Art
In this VCR, the AV digital signal are recorded and reproduced by operating a known analog circuit. In this case, to record information indicating the leading position of the recorded AV digital signal, a duty ratio of a particular group of control pulses recorded in a particular position corresponding to the leading position of the recorded AV digital signal is changed from a first duty ratio to a second duty ratio. Therefore, when the particular group of control pulses recorded in the particular position at the second duty ratio is detected in the reproducing unit, the leading position of the recorded AV digital signal can be recognized, so that the AV digital signal can be immediately reproduced from its leading position.
2.2. Problems of First Previously Proposed Art to Be Solved by the Invention
However, when a digital signal recorded in a magnetic tape is reproduced in a reproducing VCR functioning as a reproducing unit and the reproduced digital signal is dubbed and recorded in another magnetic tape in a slave VCR functioning as a recording unit, because each of the VCRs has no digital interface, a particular group of control pulses (hereinafter, called an index signal) recorded in a control track at the second duty ratio cannot be transmitted to the slave VCR because the control pulses are an analog signal, or a private connection line for the transmission of the analog index signal is additionally required in addition to a main digital signal line for the AV digital signal. Therefore, in cases where the index signal cannot be transmitted to the slave VCR, the index signal cannot be recorded in the slave VCR. Also, in cases where the private connection line is additionally used, a connector is required for each VCR. As a result, a cost for manufacturing an information recording and reproducing apparatus composed of the reproducing VCR, the slave VCR and the main digital signal line is increased.
2.3. Second Previously Proposed Art
Also, an information recording and reproducing apparatus, in which a digital VCR for recording and reproducing a digital signal is arranged as a reproducing unit, an analog VCR with a digital interface for recording and reproducing an analog signal is arranged as a recording unit and a cable connecting the digital VCR and the analog VCR is arranged, is known. In this information recording and reproducing apparatus, an AV digital signal recorded in a first magnetic tape is reproduced in the digital VCR, the reproduced AV digital signal is transmitted to the analog VCR through the cable and the digital interface of the analog VCR, and the reproduced AV digital signal is recorded in a second magnetic tape by the analog VCR. In this case, the AV digital signal of the first magnetic tape is recorded in each of a plurality of recording tracks which are arranged in parallel to each other and are inclined with respect to a tape moving direction (or a longitudinal direction) of the first magnetic tape. As shown in
FIG. 1
, a format of each inclined track Ti is composed of a margin area A
1
, a first preamble area A
2
, a sub-code area A
3
for recording a sub-code signal, a first post-amble area A
4
, an inter-block gap (IBG) area A
5
, a second preamble area A
6
, a main data area A
7
for recording the AV digital signal, an error correcting code area A
8
, a second post-amble area A
9
, and a margin area A
10
, and each inclined track is composed of 356 synchronous blocks. The main data area A
7
is composed of 306 synchronous blocks. Each synchronous block is composed of a synchronous signal area of 2 bytes for the reproduction of the synchronous block, an address information area of 3 bytes, a header storing area of 3 bytes for recording various information, a data recording area of 96 bytes, and a parity area of 8 bytes for the error correction of the information of the synchronous block. The areas of each synchronous block are arranged in time-sequence, and each synchronous block is 112 bytes.
Therefore, when the digital VCR is operated, not only the AV digital signal recorded in the area A
7
is reproduced but also the sub-code signal recorded in the area A
3
is reproduced.
The sub-code signal indicates information data relating to the AV digital signal. For example, tape recording elapsed time data, recording date data, a program number corresponding to the AV digital signal and time data of a leading position (or a starting position) of the AV digital signal are included in the sub-code signal. Therefore, a change of information indicated by the sub-code signal is synchronized with the leading position of the AV digital signal.
2.4. Problems of Second Previously Proposed Art to Be Solved by the Invention
However, even though the AV digital signal and the sub-code signal reproduced in the digital VCR are received in the analog VCR through the digital interface of the analog VCR, because any recording unit for recording the sub-code signal is not arranged in the analog VCR, the AV digital signal and the sub-code signal recorded in the first magnetic tape cannot be dubbed in the second magnetic tape.
Also, in cases where any detecting unit for detecting the sub-code signal is not arranged in the analog VCR, even though a control signal generated in the analog VCR is recorded in the second magnetic tape, information indicated by the subcode signal cannot be transferred to the control signal. Therefore, it is difficult to immediately detect the leading position of the AV digital signal reproduced from the dubbed magnetic tape.
SUMMARY OF THE INVENTION
A first object of the present invention is to provide, with due consideration to the drawbacks of such a conventional information recording and reproducing apparatus, an information recording and reproducing apparatus in which a digital signal such as a digital AV signal and an analog identification signal such as an analog index signal recorded in a recording medium are recorded in another recording medium without using any private transmission line for the analog identification signal.
A second object of the present invention is to provide an information recording and reproducing apparatus and an information recording and reproducing method in which information of a sub-code signal recorded in a first recording medium with an AV digital signal are substantially recorde
Hara Mitsuhiko
Okauchi Takeshi
Chevalier Robert
Connolly Bove & Lodge & Hutz LLP
Victor Company of Japan Ltd.
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