MXPA06007036A - Method for recording information on a record medium,record medium containing information, and method and device for reading information from a record medium - Google Patents

Abstract

A method is described for recording an audiovisual information stream comprising a plurality of alternative parts (VS1;VS2;VS3) and at least one common part (AS1;AS2;GS1;GS2), wherein the alternative parts of the information stream are recorded in an interleaved manner. Each of the alternative information stream parts is divided into alternative information stream blocks (VSB1(i);VSB2(i);VSB3(i)). Each of the common information stream parts is divided into common information stream blocks (ASBI(i);ASB2(i);GSB1(i);GSB2(i)). The information stream is recorded as a succession of consecutive interleaved units (IU(i)), each interleaved unit comprising one corresponding block (ASB 1(i);ASB2(i);GSB1(i);GSB2(i)) of each of the common information stream parts (AS1;AS2;GS 1;GS2) and one corresponding block (VSBI(i);VSB2(i);VSB3(i)) of each of the alternative information stream parts (VS1;VS2;VS3), the common information stream blocks being separate from the alternative information stream blocks.

Description

METHOD FOR RECORDING INFORMATION IN A RECORDING MEDIA, RECORDING MEDIA CONTAINING INFORMATION, AND METHOD AND DEVICE FOR READING INFORMATION FROM A RECORDING MEDIA FIELD OF THE INVENTION The present invention relates in general to the field of recording information in a recording medium and, reciprocally, reading the information recorded from the recording medium. More particularly, the present invention relates to the field of optical recording, in which case the recording medium is typically an optical disc, but the essence of the present invention is not restricted to information recorded optically on a disc. Additionally, the present invention relates particularly to the field of recording an audio stream and / or a video stream, but the essence of the present invention is not restricted to such use. As will be elucidated below, the present invention is applicable in more cases in which an information flow has a plurality of alternative parts and one or more common parts. The optical discs and the disk drives have been developed according to different standards or formats, such as for example CD standard, DVD standard, etc. A relatively new standard is BD (Blue Ray Disk). Specifically, the present invention Ref .: 172215 relates to the field of BD-ROM recording and reading, and the invention will be explained hereinafter specifically for this example application, but it should be noted that it is not intended to restrict the scope of the invention to BD-ROM. BACKGROUND OF THE INVENTION As is commonly known, an optical storage disk comprises at least one track, either in the form of a continuous spiral or in the form of multiple concentric circles, of storage space where the information can be stored in the form of a data pattern. The optical discs can be of the read-only type, where the information is recorded during manufacturing, whose information can only be read by a user. The optical storage disk can also be of the rewritable type, where the information can be stored by a user. Since the technology of optical discs in general, the manner in which information can be stored on an optical disc, and the manner in which optical data can be read from an optical disc, is commonly known, it is not necessary to describe here this technology in greater detail. Optical discs have found widespread use as carriers of information, not only for storing computer data, but also for making audio and / or video recordings. Devices are available to allow a user to make their own recordings on recordable discs. Also, audio publishing companies or video publishing companies publish pre-recorded discs, which are read-only discs (ROMs); Playback devices are available to allow a user to play such discs. In such reproduction apparatuses, hereinafter simply indicated as a player, a disk unit component reads and decodes the data recorded on the disk, and a video stream and / or an audio stream is generated, suitable to be displayed on the disk. through a display device such as a television set, a monitor, a loudspeaker, etc. This is explained in the following example. A movie can contain several elements, indicated as follows: Moving Images, that is, real images of the movie, which will be shown on the TV screen. The content of moving images is stored in an elementary stream of video. Graphic images. Graphic images are overlapped on moving images as a picture-in-picture presentation. The graphic images are used to transmit subtitles. They may consist of background graphics (for exampleHE. , a still image) and some text. The content of the graphic images is stored in an elementary flow of graphics, in such a way that a user has the option to see the movie with or without graphics. Usually, the user is given the option of choosing a language, in which case different graphic images, associated with different languages, are provided. In such a case, the film is accompanied by a set of multiple graphic elementary streams, one for each language. Audio signals The audio signal of a movie consists of background audio with spoken text, and this combination is stored in an elementary stream of audio. Usually, a user is given the choice to choose a language, in which case the spoken text is different for different languages while the background audio is the same for all languages. In this case, the film is accompanied by a set of elementary audio streams, one for each language. A combination of multiple elementary streams (for example: motion movies + graphics + audio) can be transmitted in a transport stream. Each transport flow is stored as a separate file. Traditionally, an information carrier contains only one version of the movie. With the ongoing development of optical discs, especially the increase in data storage capacity, it has become possible for the information carrier to contain two or more versions of the movie, allowing a user to select which version to watch. For example, a user may wish to see the movie in its original version, but another user may wish to have subtitles. Still another user may prefer to listen to the spoken text in their own language. In accordance with the state of the art, especially the well-known DVD-VIDEO standard, several different versions of the elementary audio stream and the elementary stream of graphics are recorded in a transport stream, the packets of the elementary streams being multiplexed in the transport flow. Depending on the choice of a user, only one of several different versions of the elementary audio stream is selected to decode during playback, and only one of several different versions of the graphic elementary stream is selected for display during playback. Thus, it is for example possible that a film whose original language is English is published with optional spoken French text and optional spoken German text. In that case, there is a first elementary audio stream containing the original spoken text in English, a second elementary audio stream containing the spoken text in French (translation 1), and a third elementary audio stream containing the spoken text in German (translation 2).

Also, it is possible for example that a film be published with subtitles in English, French and German. In that case, there is a first elementary flow of graphics that contains the text in English, a second elementary flow of graphics that contains the text in French, and a third elementary flow of graphics that contains the text in German. The above applies already in the case of only one version of the moving images, that is, elementary video flow. However, it is also possible that the information carrier contains two or more alternative versions of the moving images, where the same scene is viewed from different angles. This will be indicated as a multi-angle movie. Since alternative versions of moving images are always related to the same scene, the audio and graphics can be the same or different for all alternative versions. In theory, it would be possible to multiplex the plurality of alternative video elementary streams in the transport streams. During playback, the entire transport stream would be read, and only the video stream, the audio stream, and the flow of selected graphics would be decoded. However, in view of the fact that the bit rate associated with an elementary video stream is already quite high (more than 20 Mbps), this approach would result in very high bit rates, quite high relative to the reading speed of the unit which is 54 Mbps for the BD-ROM drive. In accordance with the aforementioned DVD-VIDEO standard, this problem is avoided by generating a plurality of individual alternative transport streams associated with the alternative video elementary streams, ie each of the plurality of alternative video elementary streams is combined with the same set of multiple elementary audio streams and elementary graphics streams; during playback, only the single transport stream associated with the desired viewing angle is read, and only the audio stream and the flow of selected graphics are decoded. Therefore, information that is related to audio and graphics is recorded multiple. times (as many times as the number of alternative video elementary streams). A disadvantage of this approach is that, in case the audio and graphics information is the same for all the visual angles, the storage space is wasted. In principle, it would be possible to store each alternative transport stream as a continuous recording, in such a way that the different transport streams are physically recorded in different sections of the disc. This would be appropriate, if a user could only make a choice at the beginning of the reproduction. However, in a multi-angle video, a user is allowed to change from one angle of view to any other angle of view at any desired time. This involves, during playback, a jump from the current reading site in the current transport stream to the corresponding reading site in the transport stream of the user's choice. The required jump distance would be large to the extent that a very large video buffer was necessary to ensure continuous viewing. Also, the time between the entry of the user's choice (eg, one button press) and the response of the system by changing the presentation of one viewing angle to the other viewing angle would be relatively long, to the extent that the that the user would be expected, impatiently, to press the button again. In order to avoid these problems, the aforementioned DVD-VIDEO standard provides an interlaced recording of the different transport flows. More particularly, each transport flow is divided into relatively small transport flow pieces, indicated as angular blocks; The angular blocks of the different transport flows are interwoven in a flow. This is illustrated schematically in Figure 1, which shows the content of a portion of a track of a recording carrier (optical disc), for an illustrative example where a film is recorded at three different viewing angles. The recording bearer contains three different information streams TS1, TS2, TS3. Each information flow is divided into angular blocks AB1 (i), AB2 (i), AB3 (i), index i indicates the display order. A combination of three blocks AB1 (i), AB2 (i), AB3 (i) is indicated as an interlaced unit IU (i). Each angular block ABj (i) (j = l-3) contains a multiple of an elementary video stream VSj (i) and of multiple audio and graphic elementary streams ASj.k (i) and GSj, m (i). In the example shown, k = l-2 and m = l-3. In an interlaced unit IU (i), the three audio elementary streams ASj, k (i) of each angular block ABj (i) may be mutually identical, and the three graphic elementary flows GSj, m (i) of each angular block ABj (i) can be mutually identical. Suppose a user is watching version 2 of the movie, and has selected the second audio stream AS2, 2 and the third graphics stream GS2, 3 associated with the second version of the movie. With respect to the interleaved unit IU (i), a disk unit reads an angular block AB2 (i); at the end of this angular block, the disk unit jumps to the beginning of the next angular block AB2 (i + 1) of the same transport stream TS2 in the next interlaced unit IU (i + l). Therefore, the entire transport stream T2 is read from the disk; the corresponding video stream VS2, the selected audio stream AS2.2 and the selected graphics stream GS2.3 are decoded and displayed. A major disadvantage of this method of recording a prior art is that each elementary audio stream is recorded three times, and that each elementary stream of graphics is recorded three times (in the aforementioned example). This consumes storage space, and reduces the total playing time of the disc. An important objective of the present invention is to overcome or at least reduce at least one of these disadvantages. BRIEF DESCRIPTION OF THE INVENTION In accordance with an important aspect of the present invention, the video, graphics and audio information is stored as multiple transport flows, that is without completely mixing elementary streams. The graphics information and audio information that is related to an interlaced unit are stored in separate files, while the angle blocks only contain the video information of a visual angle. Therefore, in each interlaced unit, the graphics information is stored only once and the audio information is stored only once. During normal playback, the selected audio information is read and stored in an audio buffer and the selected graphics information is read and stored in a graphics buffer; then, the video information of the selected angular block, and the associated audio information is read from the disc-and the graphics information is read from the audio buffer and the graphics buffer, respectively. Therefore, less space is consumed, and the playing time of the disc is increased. As a result, it becomes possible to record more playing time (longer movies or more movies) on the same disc. In addition, it becomes possible to provide more versions of movies on the same disc (more subtitle languages and spoken text). In a variation of this mode, two or more of the audio streams may be multiplexed, and / or two or more of the graphics streams may be multiplexed. Advantageously, all audio streams and graphics streams can be multiplexed into a combined audio / graphics stream. During normal playback, this combined audio / graphics stream is read and stored in the audio buffer / combined graphics, the selected audio stream is decoded, and the selected graphics stream is decoded. This can be more efficient in time than having recorded audio streams and individual graphics, because a jump is avoided (between reading audio and reading graphics.) BRIEF DESCRIPTION OF THE FIGURES These and other aspects, characteristics and advantages of the present invention will be further explained by means of the following description with reference to the figures, in which the same reference numerals indicate the same or similar parts, and in which: Figure 1 schematically illustrates a portion of a track of a carrier of recording to illustrate interlaced recording of information of multiple angles in accordance with the state of the art; Figure 2 schematically shows an optical disk; 3A and 3B schematically illustrates a portion of a track of a recording carrier for illustrating interlace recording of multiple angle information in accordance with the present invention; Figure 4 is a block diagram schematically illustrating one embodiment of an audio / video playback system; Figure 5A is a timing diagram schematically illustrating the placement of an optical head as a function of time during normal playback; Fig. 5B is a timing diagram schematically illustrating the timing of the actions of a disk drive apparatus during normal playback; Fig. 6 is a timing diagram schematically illustrating the timing of the actions of a disk unit during in accordance with the present invention during a visual angle change. DETAILED DESCRIPTION OF THE INVENTION Figure 2 schematically illustrates an optical disc 2, more specifically a BD disc, as a preferred example of a recording carrier to which the present invention relates. The disk 2 has a track 3, which is shown as a track in the form of a continuous spiral but which alternatively may consist of a plurality of mutually concentric circular track portions. Track 3 contains a recording of a multi-angle film M with, in this example, three alternative versions of the moving images, two versions of the graphic images, and two versions of the audio signals. Figures 3A and 3B are each a diagram schematically illustrating a portion of the track 3. In the example of Figure 3A, the two versions of the graphics images and the two versions of the audio signals are recorded as elementary streams individual In the example of Figure 3B, the two versions of the graphics images and the two versions of the audio signals are recorded as a multiplexed audio / graphics stream. In one variation, the two versions of the graphics images can be recorded as multiplexed graphics stream and the. Two versions of audio signals can be recorded as a multiplexed audio stream. The multi-angle film is divided into a plurality of interlaced units IU (for its acronym in English). Each interlaced unit IU (i) corresponds to a predetermined amount of playing time. In the example of FIG. 3A, each interleaved unit IU (i) comprises: a first audio stream block ASBl (i) having a length corresponding to the predetermined amount of playback time, a second block of audio streams; audio ASB2 (i) having a length corresponding to the predetermined amount of playing time, a first block of graphics streams GSB1 (i) having a length corresponding to the predetermined amount of playing time, - a second block of graphics streams GSB2 (i) having a length corresponding to the predetermined amount of playback time, a first block of angular video streams VSB1 (i) having a length corresponding to the predetermined amount of playback time, a second block of angular video streams VSB2 (i) having a length corresponding to the predetermined amount of playing time, and a third block of video streams eo VSB3 (i) having a length corresponding to the predetermined amount of playing time. In the example of Figure 3B, each interleaved unit IU (i) comprises: - a block of multiplexed audio / graphics streams AGB (i); - a first block of angular video streams VSBl (i) having a length corresponding to the predetermined amount of playing time, a second block of angular video streams VSB2 (i) having a length corresponding to the amount of predetermined playing time, and a third block of angular video streams VSB3 (i) having a length corresponding to the predetermined amount of playing time. The block of multiplexed audio / graphics streams AGB (i) comprises: - a first block of elementary audio streams (not shown) having a length corresponding to the predetermined amount of playback time, - a second block of elementary streams audio (not shown) having a length corresponding to the predetermined amount of playing time, a first block of graphic elementary streams (not shown) having a length corresponding to the predetermined amount of playing time, a second block of graphic elementary flows (not shown) having a length corresponding to the predetermined amount of playing time. In the following, the invention will be explained in greater detail for the example of Figure 3A; modifications and adaptations for the example of Figure 3B will be clear to a person skilled in the art without it being necessary to mention here specifically those modifications and adaptations. Figure 4 is a block diagram schematically illustrating one embodiment of an audio / video playback system 1. The audio / video playback system 1 comprises a disk unit 10 and a display device 20, which comprises less a screen 21 for displaying images and at least one speaker 22 for generating sound. The disk unit 10 is capable of reading information from disk 2, whose disk contains information recorded in accordance with the invention. The disk unit 10 comprises a disk motor 4 for rotating the disk 2, and an optical head 5 for scanning the track 3 of the rotary disk 2. An actuator device 6 fixes the correct position of the optical head 5. A controller 30 controls the disk motor 4 and actuator device 6. Controller 30 has a first input 31 that receives an optical read signal SR from optical head 5. Controller 30 is designed to generate a control signal SC at a first output 32 to control the position of the optical head 5. The controller 30 is provided with a buffer for audio MA, a buffer for graphics MG, and a buffer for video MV. The controller 30 is further provided with a user control panel 11, which comprises input means controllable by the user, such as keys, switches, knobs, and the like, allowing a user to input a selection or command to the controller.; since such input means are known per se, they are not shown separately in Figure 4. Next, the operation of the disk unit 10 during normal playback will be explained with reference to Figure 5A, which is comparable with Figure 3 and illustrates the position of the optical head 5 as a function of time t (vertical axis), and with reference to Figure 5B, which is a timing diagram illustrating the timing of the actions of apparatus 1. Assume that a The user has made a selection to view the multi-angle film M with the second viewing angle, the first audio stream and the second graphics stream. With reference to Figure 5, which is a timing diagram illustrating the timing of the actions of the apparatus 1, the operation of the controller 10 during normal playback is as follows. Suppose that the reproduction has reached the intertwined unit IU (i). At time ti the controller 30 controls the optical head 5 to be positioned to read the first block of audio streams ASBl (i); this audio stream is stored in the audio buffer MA. At time t2, the controller 30 controls the optical head 5 so that it jumps to the initial location of the second block of graphics flows GSB2 (i), and at time t3, the reading of this second block of graphics flows starts GSB2 (i); this graphics stream is stored in the MG graphics buffer. At time t4, the controller 30 controls the optical head 5 so that it jumps to the initial location of the second block of angular video streams VSB2 (i), and at time t5, the reading of this second block of audio streams begins. angular videos VSB2 (i); this video stream is stored in the MV graphics buffer.

As soon as, at time t6, the amount of data in the video buffer MV corresponds to at least one image, the display can be started. The controller 30 reads the video information from the video buffer MV, the graphics information from the graphics buffer MG, and the audio information of the audio buffer MA, and provides image and sound signals corresponding to the display device 20. When at time t7, the optical head 5 has reached the end of the second block of video streams VSB2 (i), the controller 30 controls the optical head so that it jumps to the starting place of the first audio stream block ASBl (i + l) of the next interlaced unit IU (i + l), and at time t8 the above described process is repeated for the next interlaced unit IU (i + l): the first block of audio streams ASB1 (i + 1) is read, the second block of graphics streams GSB2 (i + 1) is read, and then the optical head is placed to read the second block of angular video streams VSB2 (i + 1). In the time interval t7 (i) -t6 '(i + 1) required to jump to the start site of the first block of audio streams ASB1 (i + 1), the reading of this first block of audio streams ASB1 ( i + 1), the jump to the initial position of the second block of graphics flows GSB2 (i + 1), the reading of this second block of graphics flows GSB2 (i + 1), the jump to the starting position of the second block of angular video streams VSB2 (i + 1), and the reading of the first image of the second block of angular video streams VSB2 (i + 1), continues the visualization by reading information from the intermediate memories MA, MG , MV. It will be clear to a person skilled in the art that the above steps are continuous for the duration of the film. Suppose that, at some time tx during the time interval t5-t7 of the interleaved unit IU (i), the user provides a command to change the visual angle, more particularly a command to change to the third video stream VS3 (see Figures 5A and 6). Up to time t4 'of the next interleaved unit IU (i + l), the operation continues as described above, that is, the audio stream block ASBl (i + l) is read and stored, and the block of Graphics streams GSB2 (i + 1) is read and stored. Then, at time t4 ', the controller 30 controls the optical head 5 so that it jumps to the initial site of the third block of angular video streams VSB3 (i + 1), at time t5', the reading of this third one begins block of angular video streams VSB3 (i + 1); this video stream is stored in the MV video buffer. The visualization of this third block of angular video streams VSB3 (i + 1) starts at time t6 '. The time interval from the time tx of the user command to the time t6 'of the start of the display of the third video stream is indicated as the reaction time of the system. It is noted that, during normal reproduction, the transition from the current interlaced unit IU (i) to the next interlaced unit IU (i + l) always involves the jump in two stages. A first stage (t7-t8) carries the optical head 5 from the video information in the current interleaved unit IU (i) to the audio / graphics information in the next interlaced unit IU (i + l), while a second jump stage (t4'-t5 ') carries the optical head 5 from the audio / graphics information in the next interlaced unit IU (i + l) to the video information in the next interlaced unit IU (i + l). Therefore, the duration of each jump stage depends on the identity of the video stream that is being played, in the example discussed, the first jump stage involves jumping over a block of video streams, that is, the third block of video streams VSB3 (i), while the second jump stage involves jumping over a block of video streams, that is, the first block of video streams VSBl (i + l). The duration of the transition from the current interlaced unit to the next interlaced unit will be almost independent of the identity of the video stream that is being played, always involving a jump over two blocks of video streams, although it is noted that the time of jump as a function of the jump distance is not a linear function. In the case of a change in the visual angle, the duration of the transition from the current interlaced unit IU (i) to the next interlaced unit IU (i + 1) may be longer or shorter compared to normal reproduction. In the present example, if the user changes to the first visual angle, the second jump stage no longer includes a jump over some block of video streams. However, if the user changes to the third visual angle, the second jump involves a jump over two blocks of video streams VBl (i + l) and VB2 (i + 1). When the disk drive 10 is designed, the size of the MA, MG, MV buffers should be selected to accommodate the longest hop times that are expected, in relation to the block size, bit rate, etc. Or, on the contrary, when designing the recording / playback system, the size of the blocks should be selected in relation to the maximum buffer size, the bit rate, etc. Next, a numerical example will be given, based on a duration of a presentation (t6-t6 ') of 4 seconds for an interlaced unit. Assuming an audio bit rate of 384 kbps, 4 seconds of playback time corresponds to a size of almost 200 kB for the audio blocks, corresponding to approximately 3 ECC blocks, taking into account that, in the BD system, the size of an ECC block is 64 kByte. In the case of two selectable audio streams (for example, two languages), the size of the audio part of the interleaved units is almost 400 kB. The size of the MA audio buffer must be at least 200 kB. Assuming an audio bit rate of 192 kbps, 4 seconds of play time correspond to a size of almost 100 kB for graphics blocks. In the case of two selectable graphics streams (for example, two subtitles), the size of the graphics part of the interlaced units is almost 200 kB. The size of the MG graphics buffer must be at least 100 kB.

Assuming an average video bit rate of 24 Mbps, 4 seconds of playback time correspond to a size of 12 MB for the video blocks, corresponding to approximately 200 ECC blocks. In the case of three selectable video streams (three visual angles), the size of the video portion of the interlaced units is 36 mB. The total length of the interlaced units is approximately 36.6 MB, corresponding to approximately 580 ECC blocks. During normal playback, assuming that the reading takes place at 54 Mbps, the duration time of the actions of the disk unit 10 is illustrated in the following table. Table 1 The overall duration time of these actions is approximately 2,185 seconds, substantially less than 4 seconds of playback time, so that the unit can be quiet for just under 2 seconds. In this example, it is possible to use interlaced units with a duration of 2.5 seconds, corresponding to 5 GOP; this decrease in reaction time also decreases the size of the buffer. In the case of a change in the viewing angle, in the most disadvantageous circumstances (current angle = VS1, new angle = VS3), the duration time of the actions of the disk unit 10 is illustrated in the following table. Table 2 The overall duration of these actions between the end of the reading of the current video block (t7) and the end of the next block of videos (tT) is now approximately 2,245 seconds, slightly more than during normal playback, but still Substantially less than 4 seconds of playback time, so that the unit can be quiet for less than 2 seconds. It should be clear to one skilled in the art that the present invention is not limited to the exemplary embodiments discussed above, but that various variations and modifications are possible within the protective scope of the invention as defined in the claims. For example, according to the above, with reference to Figure 3A, the audio blocks are shown as written before the graphics blocks, but the order can be reversed. In addition, the audio stream is an example of a common information flow of a first type, and the graphics stream is an example of a common information flow of a second type. Therefore, in the example discussed, the information flow comprises two different types of common information flows. However, the present invention is not limited to this number of common information flow types. This number can be less than two; For example, a movie may be free of graphics. On the other hand, that number can be three or more. Furthermore, in the example discussed, the selectable number of information flows of the first type (two audio streams) is equal to the number of information streams of the second selectable type (two graphics streams). However, more generally, the number of selectable information flows may differ from type to type; such a number can even be equal to one. Furthermore, in the above, the present invention has been explained for a situation in which the video blocks must be read and fully visualized before the jump to a next interlaced unit can be made. In a related invention of the present inventor, a system is proposed where this limitation does not apply, such that a leap can be made to a next interlaced unit before the current video block ends. It should be clear that this can be easily applied in combination with the present invention. In the above, the present invention has been explained with reference to block diagrams, which illustrate functional blocks of the device according to the present invention. It should be understood that one or more of these functional blocks can be implemented in hardware, wherein the function of such functional block is carried out by individual hardware components, but it is also possible that one or more of these functional blocks are implemented in software, in such a way that the function of such functional block is effected by means of one or more program lines of a computer program or a programmable device such as a microprocessor, a microcontroller, etc. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (19)

2. Having described the invention as above, the content of the following claims is claimed as property: 1. A method for recording a flow of information in a recording medium, the information flow comprising a plurality of alternative streams and at least one common part , characterized in that the alternative flows of the information flow are recorded in an interlaced form; where each of the alternative information flows is divided into blocks of alternative information flows; wherein each of the parts of common information flows is divided into blocks of common information flows; and wherein the information flow is recorded as a succession of consecutive interleaved units, each interleaved unit comprises a corresponding block of each of the common information flow parts and a corresponding block of each of the alternative information flows, being separate the common information flow blocks of the alternative information flow blocks. The method according to claim 1, characterized in that two or more of the blocks of common information flows of an interleaved unit are combined in a separate multiplexed block of the blocks of alternative information flows.
3. 3. The method according to claim 1, characterized in that the information flow comprises a plurality of selectable common flows; and wherein, in each interleaved unit, a plurality of selectable blocks is recorded, each selectable block corresponds to a respective one of a plurality of selectable common flows.
4. The method according to claim 1, characterized in that the information flow is an audiovisual stream comprising a plurality of alternative moving images, one or more common audio streams, and optionally one or more common graphics streams.
5. The method according to claim 4, characterized in that the audio-visual stream comprises user-selectable audio streams, user-selectable graphics streams, and user selectable video streams; and where, in each interlaced unit, audio blocks are recorded, and graphics blocks and video blocks are recorded.
6. 6. The method according to claim 1, characterized in that the recording medium is an optical disk.
7. 7. A recording medium, preferably an optical disk, containing a flow of information comprising a plurality of alternative flows to be processed selectively and at least one common flow to be processed simultaneously with the selected alternate flow, such records being recorded flows in that medium in an interlaced way; characterized in that; a track of the recording medium contains a succession of consecutive interleaved units, each interlaced unit comprising a corresponding block of each of the parts of common information flows and a corresponding block of each of the parts of alternative information flows, being separated the common information blocks of the alternative information flow blocks.
8. 8. A recording medium according to claim 7, characterized in that two or more of the blocks of common information flows of the interleaved unit are combined in a multiplexed block separated from the blocks of alternative information flows.
9. 9. A recording medium according to claim 7, characterized in that the information flow is an audiovisual stream comprising a plurality of alternative moving images, one or more common audio streams, and optionally one or more common graphics streams. .
10. 10. A recording medium according to claim 9, characterized in that the audiovisual stream comprises user-selectable audio streams, graphics streams selectable by the user, and user selectable video streams.; and wherein each interlaced unit comprises audio blocks and blocks of graphics and video blocks.
11. A method for reading a recording medium according to claim 7, characterized by comprising the steps of: a) selecting at least one common information flow; b) select one of the alternative information flows; c) reading the block of information flows common to the at least one selected common information flow associated with an interlaced unit. d) storing the information of the common block read in a buffer memory; e) reading the block of alternative information flows of the selected flow of the alternative information flows associated with an interlaced unit; f) simultaneously processing the block of alternative information flows in combination with the block of common information flows of the buffer.
12. The method according to claim 11, characterized in that the steps (c) - (f) are repeated for each next interlaced unit.
13. The method according to claim 11, wherein the information flow recorded in the recording medium comprises a plurality of selectable common flows of different type; and wherein each interlaced unit comprises a plurality of selectable blocks; each corresponding to a respective one of the plurality of selectable common flows; characterized in that the method comprises the steps of: a) for each common flow type, selecting one of a plurality of selectable common flows; b) select one of the alternative information flows; c) for a first type of common flow, read the selected common flow block associated with an interlaced unit; d) storing the information of this block in a buffer of a first type; d2) repeat steps (c) - (d) for all types of remaining common flows; e) reading the block of alternative information flows of the selected flow of the alternative information flows associated with the interleaved unit; f) simultaneously processing the block of alternative information flows in combination with all the blocks of common information flows of the buffers.
14. A unit for reading a recording medium according to claim 7, characterized in that it is adapted to execute the method according to claim 11.
15. The unit according to claim 14, characterized in that it comprises: reading means to read the recorded medium; an actuator for positioning the reading means with respect to the track of the recording medium; - a controller for controlling the actuator, the controller has an input that receives a read signal from the reading means; the controller is provided with at least one buffer to store the blocks of at least one of the common information flows.
16. 16. The unit according to claim 14, adapted to execute the method according to claim 13, characterized in that the controller is provided with a plurality of buffers of different type, for storing the blocks of the selected common information flows. of different types.
17. 17. The unit according to claim 14, characterized in that it additionally comprises a buffer for storing information of the alternative information flow selected.
18. The unit according to claim 14, characterized in that it additionally comprises a user input means to allow a user to enter a selection of an alternative information flow and a selection of at least one common information flow.
19. 19. An audio / video playback system, characterized in that it comprises a disk unit according to any of claims 14-18, the system further comprises a display device comprising at least one screen for displaying images and at least one speaker to generate sound.