Multiplex communications – Communication techniques for information carried in plural... – Combining or distributing information via time channels
Reexamination Certificate
1998-11-06
2003-04-29
Vincent, David (Department: 2732)
Multiplex communications
Communication techniques for information carried in plural...
Combining or distributing information via time channels
C375S240000, C386S349000
Reexamination Certificate
active
06556590
ABSTRACT:
BACKGROUND OF THE INVENTION
The Invention relates to a recording arrangement for recording an information signal in tracks on a record carrier, the recording arrangement comprising
an input terminal for receiving the information signal,
channel encoding means for channel encoding the information signal so as to obtain a channel signal suitable for recording in a track on said record carrier,
writing means for writing the channel signal in the track, the channel signal comprising subsequent or a succession of signal blocks, each signal block comprising a first block section which comprises a synchronization signal and a second block section which comprises a number of channel bytes, to a record carrier obtained with the recording arrangement, and to a reproducing arrangement for reproducing the information signal from the record carrier.
A recording arrangement as given in the opening paragraph is known from EP-A 492, 704, document (
1
) in the list of references that can be found at the end of this application.
The known arrangement is a recording arrangement of the helical scan type, such as used in a digital VCR (DVCR) and records an information signal comprising a digital audio signal and a digital video signal in audio signal recording sectors and video signal recording sectors respectively in subsequent tracks, where, when recording a track, the video signal recording sector in a track comes first and is followed by the audio signal recording sector. The order in which the sectors occur in a track can however also be in the reverse order. Further, other sectors may be included in a track, such as a clock run-in area located at the beginning of a track, so as to enable a locking-in of the internal system clock on the signals read from the track, and preamble and postamble areas that are located between the various sectors and function as an edit gap. Reference is made in this respect to the earlier filed European patent applications No. 93.202.950, reference (
2
) in the list of references, and No. 93.201.263, reference (
3
) in the list of references.
The prior art reference documents relate to proposals for the realization of a new digital video cassette (DVC) recorder standard, which enables the recording and reproduction of digital video and digital audio on/from a longitudinal magnetic record carrier such as magnetic tape. This new digital video recorder standard will lead to new digital video recorders/reproducers of the so-called DVC type.
BRIEF SUMMARY OF THE INVENTION
The invention aims at providing a recording arrangement which is capable of recording other types of information signals in the known tape format as defined in the preamble. The recording arrangement in accordance with the invention is characterized in that the information signal is an MPEG information signal in accordance with an MPEG format, the MPEG information signal comprising subsequent or a succession of transport packets, that the channel encoding means are adapted to store each time information included in x transport packets of the MPEG information signal in the second block section of a group of y signal blocks of the channel signal, that the second block section of at least the first signal block of the group of y signal blocks comprise a third block section for storing identification information identifying the signal clock as being the first signal block of the group of y signal blocks, and that x and y are integers such that x∃1 and y∃1. More specifically, the recording arrangement in accordance with the opening paragraph is characterized in that the information signal is an MPEG information signal in accordance with an MPEG format, the MPEG information signal comprising subsequent transport packets, that the channel encoding means are adapted to store each time information included in x transport packets of the MPEG information signal in the second block sections of a group of y signal blocks of the channel signal, that the second block sections of the signal blocks comprise a third block section for storing sequence number information relating to a sequence number of the signal blocks, and that x and y are integers such that x∃1and y∃1.
The invention is based on the following recognition. The draft Grand Alliance HDTV System Specification dated Feb. 22, 1994, document (
4
) in the list of references, more specifically chapters V and VI of the specification, comprises a description of a transport system for transmitting an MPEG information signal, which includes a data compressed digital video signal and a corresponding data compressed digital audio signal, for broadcasting purposes or for transmission via a cable network. The MPEG information signal is in the form of transport packets having either an equal length or a variable length in time. In both cases, however, a transport packet comprises 199 bytes of information, the first byte of which being a synchronization byte.
A transmission such an MPEG information signal in the form of a recording on a reproduction from a record carrier, such as a magnetic record carrier as a tape, require special measures to be taken in order to realize such kind of transmission via the known tape format. More specifically, the invention relates to storing the transport packets in the signal blocks of the known tape format.
Generally, it can be said that, when storing the information included in a number of x transport packets of the MPEG information signal in a number of y signal blocks, some unoccupied space remains available in the y signal blocks for the storage of additional information, which additional information relates to the specific application of recording and reproducing the MPEG information signal on/from the record carrier. In a specific example of the DVC format, the second block sections of five signal blocks. Now, 11 bytes (=5×77−2×187) remain available in the five signal blocks. Those 11 bytes can be divided over the second block sections of the five signal blocks in various ways so as to obtain the third block sections. One such way is that the first two bytes of all second block sections are available as third block sections and that the last byte available can be considered as a third block section to indicate the boundary between the information of the two transport packets as stored in the five signal blocks.
In the above example, identification information identifying the signal block as being the first signal block of the group of y signal blocks can be stored in a third block section of the first signal block in a group of y signal blocks. Or, sequence number information (sequence numbers) relating to the sequence of the signal blocks can be stored in the third block sections. This sequence number can also be identified as a continuity counter. The measures proposed result in a number of advantages.
The advantage of using identification information identifying a signal block as being the first signal block in a group of y signal blocks, is that the beginning of a group can be detected, which simplifies the read-out of the data during reproduction.
One advantage using sequence numbers is that, when reproducing the signal blocks, it can be decided upon retrieval of the sequence numbers, whether a signal block has been missed because of reproductions errors or not, so that an error correction or concealment can be carried out. Another advantage is that one may shuffle the information to be stored in the signal blocks upon recording. Upon retrieval of the sequence numbers it is possible to realize a corresponding deshuffling in response to the sequence numbers retrieved so as to obtain the original data stream.
Further, having sequence numbers included in the third block sections of the signal blocks makes it possible to repeat signal blocks in the case that a transport packet of the MPEG data stream stored in those signal blocks requires a higher protection against errors that can occur during the recording and a subsequent reproduction process.
The recording arrangement as gi
Saeijs Ronald W. J. .J.
Sato Takashi
Shah Imran A.
Belk Michael E.
Koninklijke Philips Electronics , N.V.
Vincent David
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