An apparatus for and a method of storing a real time stream of digital information signals
The invention relates to an apparatus for recording a substantially real time stream of digital video information signals on a disc like record carrier, the stream of digital video information signals representing information arranged in a sequence of video frames, each video frame arranged in separate, consecutive data blocks transmitted in data packets, the data blocks comprising data blocks headers, the disc like record carrier having units of recording of a predetermined size larger than a size of the data packets, the apparatus comprising:
input means for receiving the stream of digital video information signals;
processing means for processing the stream of digital video information signals to obtain recordable information signals representing logical units of information;
writing means for writing the logical units of information into the units of recording on the disc like record carrier.
The invention further relates to an apparatus for reproducing a substantially real time stream of digital video information signals from a disc like record carrier, the stream of digital video information signals representing information arranged in a sequence of video frames, each video frame arranged in separate, consecutive data blocks, the disc like record carrier having units of recording of a predetermined size, the apparatus comprising:
input means for reading information signals representing logical units of information from the units of recording on the disc like record carrier, a size of each logical unit of information corresponding to the predetermined size of the unit of recording;
processing means for processing the information signals to obtain the stream of digital video information signals.
The invention also relates to a method of storing a substantially real time stream of digital video information signals on a disc like record carrier, the stream of digital video information signals representing information arranged in a sequence of video frames, each video frame arranged in separate, consecutive data blocks transmitted in data packets, the data blocks comprising data blocks headers, the disc like record carrier having units of recording of a predetermined size larger than a size of the data packets, the method comprising steps of:
receiving the stream of digital video information signals;
detecting the data packets in the stream of digital video information signals.
Further, the invention relates to a record carrier provided with the recordable information signals recorded on it by the apparatus for recording.
An embodiment of the apparatus for recording a substantially real time stream of digital video information signals described in the opening paragraph is known from the published international patent application WO 00/52693. It is capable of recording so-called MPEG Transport Streams on a disc like record carrier in a manner more efficient than in case of so-called Program Streams. Transport Streams contain data packets and corresponding time stamps representing a time of arrival of the data packets in a stream of video information signals. Transport Streams can be used for recording Standard Definition TV (SDTV) analog input signals (525/60 TV systems and 625/50 TV systems) and for recording SDTV digital input signals, like Digital Video (DV), or digital broadcast streams. Before recording, the analog signals are encoded by the MPEG encoder. In case of digital signals, they have to be first decoded before encoded again to an MPEG Transport Stream. This is disadvantageous in that some characteristic (auxiliary) data present in the digital signals may be lost while transcoding signals to the MPEG Transport Stream. It may also influence a quality of data. In particular, changing a format of original DV signals may make them not suitable for editing with dedicated software.
It is an object of the invention to overcome the above mentioned disadvantages and more generally to solve the problem of storing digital video information signals on a disc like record carrier.
This object is achieved, according to a first aspect of the invention, by an apparatus for recording of the type described in the opening paragraph, characterized in that the processing means are adapted to detect the data blocks in the data packets, to separate the data blocks from the data packets, to generate allocation information using information comprised in the data blocks headers and to allocate consecutive data blocks comprised in multiple data packets to consecutive logical units of information according to the allocation information, a size of each logical unit of information corresponding to the predetermined size of the unit of recording.
The apparatus according to the invention is advantageous in that it is capable of storing digital video information signals on a disc like record carrier in an efficient manner, which does not require transcoding to a different format—the original information such as auxiliary data is preserved.
In an embodiment of the apparatus for recording, the processing means are adapted to allocate a first data block representing a beginning of a video frame comprised in the sequence of video frames to a predefined location in a logical unit of information. This embodiment is advantageous in that it simplifies storage, retrieval and editing of the digital information signals. This is important specifically for cases in which the sequence of video frames undergoes editing operations, such as deletion of a part of the sequence.
In a further embodiment of the apparatus for recording, the processing means are adapted to allocate an integer number of the data blocks into a logical unit of information. This is advantageous in that it simplifies a structure of data comprised in a logical unit of information; all logical units may have the same structure.
It is advantageous, if the processing means are adapted to provide logical units of information with logical unit headers. The logical unit headers can be used for storing information concerning a structure of data comprised in the logical units.
A further embodiment of the apparatus for recording is characterized in that the processing means are adapted to provide the logical unit headers with copy protection information. This embodiment is advantageous in that the digital information signals stored on the record carrier can be protected against unauthorized copying.
In another embodiment of the apparatus for recording the processing means are adapted to remove data blocks headers from the data blocks and to provide the logical unit headers with address information for addressing the data blocks in the logical units of information. This makes it possible to simplify a structure of digital video information signals stored on the record carrier and to decrease a data rate.
According to a second aspect of the invention an apparatus for reproducing of the type described in the opening paragraph is provided, wherein the processing means are adapted to recover consecutive data blocks comprised in consecutive logical units of information and to form the sequence of video frames.
According to a third aspect of the invention a method of the type described in the opening paragraph is provided comprising steps of:
detecting the data blocks in the data packets;
separating the data blocks from the data packets;
generating allocation information using information comprised in the data blocks headers;
allocating consecutive data blocks comprised in multiple data packets to consecutive logical units of information according to the allocation information, a size of each logical unit of information corresponding to the predetermined size of the unit of recording.
According to a forth aspect of the invention a record carrier of the type described in the opening paragraph is provided, on which the recordable information signals are recorded by the method as described in relation to the third aspect of the invention.
These and other aspects of the invention will be further elucidated and described with reference to the drawings, in which:
The signals processing unit 100 is further adapted to process the stream of digital information signals representing information arranged in a sequence of video frames 10 as shown by an example in
The processing unit 100 can be adapted to allocate a first data block 20 representing a beginning of a video frame 21 comprised in the sequence of video frames 22 to a predefined location 23 in a logical unit 24, as illustrated in
The processing unit 100 can be further adapted to perform editing of the sequence of video frames by e.g. removing a part (some frames) of the sequence or dividing the sequence into plurality of sequences. Use of predefined locations 23 within a logical unit 24 for allocating the sequence of video frames guarantees that starting points of edited or new sequences are always known.
Predefined locations 23 may be defined depending on circumstances such as e.g. a format of the digital video information signals to be recorded.
The Digital Interface Format (DIF), for example, is widely used as the format for transmitting DV signals between different devices such as a digital camcorder and a video recorder. This format is defined in the publication “IEC 61883—Digital Interface for Consumer Electronic Audio/Video Equipment”. The stream of DV information signals represents a sequence of video data comprising video frames, wherein each video frame represents a complete video picture, audio information and additional data. In case of SDTV signals, one frame consists of 10 or 12 so-called DIF sequences, for NTSC or PAL system, respectively. Each DIF sequence contains 150 so-called DIF blocks of 80 bytes each. 144 DIF blocks (out of 150) comprise compressed video data (135 blocks) and audio data (9 blocks). The remaining six DIF blocks are devoted to sequence header (1 block), subcode (2 blocks) and video auxiliary (VAUX) data (3 blocks). VAUX data includes recording date and time, lens aperture, shutter speed, color balance and other video camera setting data.
Another embodiment of the apparatus for recording the stream of digital information signals according to the invention is realized by adapting the processing unit 100 to process a stream of digital video signals complying with the DIF standard.
The size of a video frame according to the DIF standard is 120000 bytes or 144000 bytes for NTSC or PAL system, respectively. The processing unit 100 can be adapted to use logical units of 2048 bytes and to allocate a first data block 20 representing a beginning of a video frame to a location which starts at a position being multiple of 64-bytes (for NTSC system) or 128-bytes (for PAL system) in a logical unit. It simplifies significantly localization of any video frame in the sequence of video data recorded on the record carrier. Also, it simplifies editing operations performed on the sequence and ensures that any sequence of video frames starts/ends at a position being multiple of 64-bytes (for NTSC system) or 128-bytes (for PAL system) in a logical unit.
Yet another embodiment of the apparatus for recording the stream of digital video information signals can be realized by adapting the processing unit 100 to allocate an integer number of the data blocks into a logical unit. This is a way to ensure, for example, that each data block is comprised in only one logical unit or, in other words, no data block extends from one to another logical unit. This is illustrated by an example of a logical unit shown in
The processing unit 100 can be adapted to “fill” the remaining bytes (in this particular example, 48 bytes) with zeros or to use those bytes for carrying additional information. For example, a logical unit 30 can be provided with a logical unit header 32, which may contain a specific information concerning digital video information signals. More specifically, the header 32 may comprise copy protection information, e.g. in a form of 2-bits flag, which can be used to prevent unauthorized copying of data stored on the record carrier.
Further, the processing unit 100 can be modified to provide logical unit headers 32 with address information, e.g. for addressing contents of logical units. For example, in case of DIF blocks, 3-bytes block headers (ID in
DIF frames have fixed structure and size of 120000 bytes (NTSC frames) or 144000 bytes (PAL frames). The processing unit 100 can be adapted to make use of this feature and to allocate DIF blocks comprised a sequence of DIP frames in a manner that reduces data rate. For example, the processing unit 100 can allocate data blocks into so-called aligned units, each comprising three consecutive logical units of 2048 bytes.
The specific structure of logical units 14, 24, 30, 40, as described in reference to operations performed by different embodiments of the apparatus for recording the stream of digital video information signals, define a format of storing the digital video information signals on the record carrier 3.
The apparatus can be further provided with an input unit 330 for receiving commands from a user. In case of digital information signals representing video data, such commands can be in a form of different playback commands.
The signals processing unit 300 is further adapted to recover consecutive data blocks 12 comprised in consecutive logical units 14 and to form a sequence of video frames 10 as shown by an example in
The processing unit 300 can be adapted to be capable of recovering a first data block 20 representing a beginning of a video frame 21 comprised in the sequence of video frames 22, starting at a predefined location 23 in a logical unit 24, as illustrated in
Predefined locations 23 may be defined depending on circumstances such as e.g. a format of the digital information signals to be reproduced.
Another embodiment of the apparatus for reproducing the stream of digital information signals according to the invention is realized by adapting the processing unit 300 to process a stream of digital video signals complying with the DIF standard, as was explained in reference to
The processing unit 300 can be adapted to use logical units of 2048 bytes and to recover a first data block 20 representing a beginning of a video frame from a location which starts at a position being multiple of 64-bytes (for NTSC system) or 128-bytes (for PAL system) in a logical unit. It simplifies significantly localization of any video frame in the sequence of video data recorded on the record carrier. Also, it simplifies editing operations performed on the sequence and ensures that any sequence of video frames starts/ends at a position being multiple of 64-bytes (for NTSC system) or 128-bytes (for PAL system) in a logical unit.
Yet another embodiment of the apparatus for reproducing the stream of digital information signals can be realized by adapting the processing unit 300 to recover an integer number of the data blocks from a logical unit. This is illustrated by an example of a logical unit shown in
The processing unit 300 can be adapted to recover additional information from the remaining bytes (in this particular example, 48 bytes). For example, a logical unit 30 can be provided with a logical unit header 32, which may contain a specific information concerning digital information signals. More specifically, the header 32 may comprise copy protection information 33, e.g. in a form of 2-bits flag, which can be used to prevent unauthorized reproduction or copying of data stored on the record carrier.
Further, the processing unit 300 can be modified to recover logical unit headers 32 with address information, e.g. for addressing contents of logical units.
The processing unit 300 can be adapted to recover data blocks from so-called aligned units, each comprising three consecutive logical units of 2048 bytes as was explained in reference to
In an embodiment of the method of storing the stream of digital video information signals, step 406 is modified so a first data block 20 representing a beginning of a video frame 21 comprised in the sequence of video frames 22 is allocated to a predefined location 23 in a logical unit 24, as illustrated in
In another embodiment of the method of storing the stream of digital video information signals, all steps are modified to process a stream of digital video signals complying with the DIF standard as referred to previously in the description.
Yet another embodiment of the method of storing the stream of digital video information signals can be realized by modifying step 406 so an integer number of the data blocks are allocated to a logical unit, as was explained in reference to
Step 406 can be modified to provide a logical unit 30 with a logical unit header 32, which may contain a specific information concerning digital video information signals. More specifically, the header 32 may comprise copy protection information 33, e.g. in a form of 2-bits flag, which can be used to prevent unauthorized copying of data stored on the record carrier.
Furthermore, step 406 can be modified to include sub-steps of removing data blocks headers and providing logical unit headers 32 with address information, e.g. for addressing contents of logical units. For example, in case of DIF blocks, 3-bytes block headers (ID in
In another embodiment of the method of storing the stream of digital video information signals, step 406 is modified to allocate data blocks in a manner as was described in reference to
Whilst the invention has been described with reference to preferred embodiments thereof, it is to be understood that these are not limitative examples. Thus, various modifications may become apparent to those skilled in the art, without departing from the scope of the invention, as defined by the claims. Further, the invention lies in each and every novel feature or combination of features described above. It is noted, that the invention may be implemented by means of a general purpose processor executing a computer program or by dedicated hardware or by a combination of both, and that in this document the word “comprising” does not exclude the presence of other elements or steps than those listed and the word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements, that any reference signs do not limit the scope of the claims, that “means” may be represented by a single item or a plurality and that several “means” may be represented by the same item of hardware.
Number | Date | Country | Kind |
---|---|---|---|
03100667 | Mar 2003 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/IB2004/050241 | 3/12/2004 | WO | 00 | 9/14/2005 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2004/084213 | 9/30/2004 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
5758054 | Katz et al. | May 1998 | A |
6131161 | Linnartz | Oct 2000 | A |
6580462 | Inoue et al. | Jun 2003 | B2 |
6609176 | Mizuno | Aug 2003 | B1 |
6826181 | Higashida et al. | Nov 2004 | B1 |
6886068 | Tomita | Apr 2005 | B2 |
7194548 | Matsumi et al. | Mar 2007 | B1 |
20010007568 | Morris | Jul 2001 | A1 |
20010036355 | Kelly et al. | Nov 2001 | A1 |
20020131508 | Otaka et al. | Sep 2002 | A1 |
Number | Date | Country |
---|---|---|
1228221 | Sep 1999 | CN |
2001285800 | Oct 2001 | JP |
WO0052693 | Sep 2000 | WO |
Entry |
---|
IEC 61883—Digital Interface for Consumer Electroic Audio /Video Equipment (Parts 1-7). |
“Proposed SMPTE standard for television-data structure for DV-based audio data and compressed video-25 and 50 MS/S” SMPTE Journal, SMPTE, Inc. Scarsdale New York, US, vol. 108, No. 5, May 1999, pp. 308-330, XP000831859, ISSN:0036-1682, the whole document. |
IEC 61883—Digital Interface for Consumer Electroic Audio/Video Equipment (Parts 1-7), Jan. 2003. |
“Proposed SMPTE standard for television-data structure for DV-based audio data and compressed video-25 and 50 MS/S” SMPTE Journal, SMPTE, Inc. Scarsdale, May 1999 New York, US, vol. 108, No. 5, May 1999, pp. 308-330, XP000831859, ISSN:0036-1682, the whole document. |
Number | Date | Country | |
---|---|---|---|
20070041716 A1 | Feb 2007 | US |