Multimedia optical disc for storing audio data and sub-picture data in a plurality of channels as well as moving picture data and apparatus and method for reproducing the multimedia optical disc

(1) Field of the Invention

The present invention relates to a multimedia optical disc which stores multimedia data, and to an apparatus and a method for reproducing the multimedia optical disc, more specifically to an improvement in the reproduction of movie applications.

(2) Description of the Prior Art

Currently, laser discs and video CDs (Compact Discs) are known as optical media in which audio information and moving picture information are recorded to be reproduced by dedicated apparatuses.

Laser discs are optical discs with a diameter of about 30 cm storing about an hour of analog moving picture data. Laser discs have been used as media for storing movies or music video works. However, since laser discs are bulky and hard to carry or stock, other media which are more compact than the laser discs have been sought.

Video CDs have achieved the above purpose by enabling moving picture data to be recorded on CDs. The CDs have a diameter of 12 cm and at first were used to store only audio data. The video CDs adopt a digital data compression method called MPEG (Moving Picture Experts Group) which has a high compression rate. The resolution of video CDs is as low as 352×240 though they are compact in size.

The above laser discs and video CDs, on the other hand, have the following limitation on the voice and sub-pictures. That is, since audio information is recorded in a channel, it is impossible to deal with a plurality of languages. Furthermore, the sub-picture data is recorded as a part of moving picture data and it is impossible to deal with a plurality of languages. Therefore, Japanese, English, French, and Germany versions of voices and subtitles for the same moving picture data, for example, cannot be recorded in the above conventional discs.

Different versions of a movie, for example, a theater version, a no-cut version, and a TV on-air version are available. Conventionally, it was possible to record all these versions in a video CD only if the movie was short enough to record in the disc. However, this was not possible for general movie films having 1-2 hours of reproduction time.

A laser disc can store monoaural audio data (analog or digital) in four channels at maximum along with about one hour of analog moving picture data. Laser discs are mainly used for storing movie applications. However, general movies are often about two hours long and sometimes have different versions, namely, a theater version, a TV on-air version, other language versions (voices or subtitles), etc.

It is impossible for a laser disc to store all of such versions since the recording time of the analog moving picture data is limited to about one hour. Even if a laser disc stores audio data in channels along with a plurality kinds of very short moving picture data, the following problems occur:

(1) The plurality kinds of very short moving picture data overlap each other, generating a poor recording efficiency.
(2) If a plurality of subtitles are required, as many pieces of the same moving picture data as the plurality of subtitles must be created since the subtitle is inserted in the moving picture data.
(3) It is not possible for the user to change the current subtitle to another during a reproduction of moving picture data. To reproduce the desired subtitle, the user needs to reproduce a series of moving picture data including the desired subtitle from the beginning. That is, it is not possible for the user to change only the subtitle during a reproduction of moving picture data.
(4) If a plurality kinds of moving picture data have different numbers of audio channels for different languages and if a desired language is stored in a plurality of audio channels with different channel numbers, the user needs to change the audio channel number to maintain the desired language each time the user changes the moving picture data.

It is therefore an object of the present invention to provide a multimedia optical disc which may store a plurality pieces of video data, each of which is comprised of moving picture data and a plurality pieces of sub-data, such as audio data as voices and sub-picture data as subtitles, and with which the sub-data is managed easily even if different numbers of channels or different channels are assigned for the plurality pieces of video data, and to provide a disc reproduction apparatus and method for reproducing the multimedia optical disc.

The above object is achieved by a multimedia optical disc comprising: a data area for storing a plurality pieces of video data, wherein a piece of moving picture data and a plurality pieces of sub-data are interleaved in each of the plurality pieces of video data, wherein the plurality pieces of sub-data are reproduced selectively and synchronized with the piece of moving picture data, wherein the plurality pieces of sub-data are either of a plurality pieces of audio data and a plurality pieces of sub-picture data; and a management information area for storing a channel table in which a plurality of logical channel numbers are respectively related to a plurality of physical channel numbers for each of the plurality pieces of video data, wherein the plurality of logical channel numbers are shared by a certain numbers of pieces of video data, wherein the plurality of physical channel numbers are used to physically identify the plurality pieces of sub-data.

In the above multimedia optical disc, the data area may include a plurality of small areas over which a piece of video data is recorded, wherein each of the plurality of small areas includes: a first sub-area for storing moving picture data of a certain time period; and a plurality of second sub-areas for storing different pieces of sub-data, the different pieces of sub-data being reproduced simultaneously with the moving picture data of the first sub-area.