This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2005-062654, filed Mar. 7, 2005, the entire contents of which are incorporated herein by reference.
1. Field
One embodiment of the invention relates to an optical disc playback apparatus and a control program therefor to play back a Digital Versatile Disk (DVD) and the like.
2. Description of the Related Art
Recently, an optical disc playback apparatus for playing back a Compact Disc (CD), DVD, and the like has become very popular. In this optical disc playback apparatus, since the data playback speed is generally lower than the data read speed of an optical disc, data is intermittently read from the optical disc. Conventionally, an optical disc drive is driven even while data is not being read from the optical disc, thus wasting power.
To cope with this problem, in order to reduce power consumption, it has been proposed to perform power saving control for the optical disc drive while not reading data from the optical disc.
It is disclosed by, for example, Jpn. Pat. Appln. KOKAI Publication No. 6-318359, upon reading a predetermined amount of data from the optical disc, power saving control such as stopping rotational drive is performed for the optical disc drive for a predetermined time. With this operation, power consumption can be reduced.
However, in the scheme disclosed in Jpn. Pat. Appln. KOKAI Publication No. 6-318359, when an address for reading data is designated, a predetermined amount of data is continuously read from the address. When this scheme is applied to a DVD or the like, data which is not used in playback processing, e.g., multiangle data or data pertaining to subtitles and audio data in an unselected language is also buffered. That is, memory efficiency decreases, access frequency to the optical disc drive increases, and power consumption also increases.
A general architecture that implements the various feature of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention.
Various embodiments according to the invention will be described hereinafter with reference to the accompanying drawings. In general, according to one embodiment of the invention, an optical disc playback apparatus which plays back an optical disc on which a plurality of data units to be played back are recorded, comprises a reading unit configured to read data from the optical disc by controlling an optical disc drive, and a temporary storage unit configured to temporarily store the data read by the reading unit, wherein the reading unit performs power saving control for the optical disc drive when an amount of the data stored in the temporary storage unit reaches a first predetermined amount, and reads the data for each of the data units on the basis of playback order information which is read from the optical disc and pertains to a playback order of the data units.
According to another embodiment of the present invention, an optical disc playback apparatus which plays back an optical disc, comprises a reading unit configured to read data from the optical disc by controlling an optical disc drive, and a temporary storage unit configured to temporarily store the data read by the reading unit, wherein the reading unit performs power saving control for the optical disc drive when an amount of the data stored in the temporary storage unit reaches a predetermined amount, and deletes, from the temporary storage unit, an unselected data pertaining to audio data or sub-picture data which is not selected in playback processing, of the data stored in the temporary storage unit.
According to an embodiment,
The disc drive unit 101 is a drive apparatus for reading the data from the optical disc 20. The disc drive unit 101 reads desired data by rotating the optical disc 20 and irradiating it with a laser beam.
Under the control of the navigation manager 103, the disc reading unit 102 obtains desired data from the optical disc 20 by controlling the disc drive unit 101. The data from the disc drive unit 101 is temporarily stored in the pre-read buffer 104. The disc reading unit 102 then deletes, from the pre-read buffer 104, data pertaining to the unselected audio and subtitle data of the data stored in the pre-read buffer 104, and stores the deleted data in the HDD 105. The navigation manager 103 interprets PGC information read from the optical disc 20, and designates the data to be read by the disc reading unit 102. Furthermore, the navigation manager 103 has audio information 103a pertaining to the selected audio data, sub-picture information 103b pertaining to the selected subtitle, and angle information 103c pertaining to the selected angle in playback processing. The navigation manager 103 designates, to the disc reading unit 102, the audio, subtitle, and angle data to be read and played back from the optical disc 20. More specifically, audio information 103a, sub-picture information 103b, and angle information 103c respectively correspond to an audio stream number, sub-picture number, and angle number of a system parameter (SPRM) held by the navigation manager 103.
In the pre-read buffer 104, the data read from the optical disc 20 is temporarily stored. In order to decrease an access frequency to the disc drive unit, the pre-read buffer 104 has a relatively large capacity of 100 Mbytes. As described above, the HDD 105 stores the data deleted from the pre-read buffer 104.
The demultiplexer 106 demultiplexes the data received from the disc reading unit 102 into video data, audio data, and sub-picture data. The video decoder 107 decodes the video data received from the demultiplexer 106, the sub-picture decoder 108 decodes the sub-picture data pertaining to the subtitle data and the like received from the demultiplexer 106, and the audio decoder 109 decodes the audio data received from the demultiplexer 106.
The video renderer 110 synthesizes the data decoded by the video decoder 107 and sub-picture decoder 108, converts the synthesized data into a video signal, and displays the obtained signal on the LCD 111. The audio renderer 112 converts the audio data decoded by the audio decoder 109 into an audio signal, and then outputs the obtained signal to the loudspeaker 113.
As shown in
As shown in
That is, each PGCI 312 contains information pertaining to the cells in the PGC and the playback order of the cells. In playback processing, one PGC is selected. The navigation manager 103 interprets the PGCI 312 having the selected PGC, and causes the disc reading unit 102 to read data from the optical disc 20 in the playback order. With these operations, one program is played back.
Note that the cell 41 is a unit of a video object (VOB). The above-described VTS_01_1.VOB 227, VTS_01_2.VOB 228, and the like are each a set of one or more cells 41.
As shown in
The playback time of the VOBU 42 corresponds to that of the video data constructed by one or more picture groups (GOPs), and is set to fall within the range of 0.4 to 1.2 sec. One GOP is frame data which normally has a playback time of about 0.5 sec in the MPEG standard, and is compressed to play back approximately 15 images during this interval.
When the VOBU 42 contains video data, GOPs each having a V pack 44, SP pack 46, and A pack 45 are arranged to construct the video data stream. However, regardless of the number of GOPs, the VOBU 42 is defined with reference to the playback time of the GOP. As shown in
In the NV pack 43, the multiangle-compatible data is stored. More specifically, the data defines the relative address of the VOBU to be read next when a user switches or does not switch the angle.
The data pertaining to the video data is stored in the V pack 44, the audio data pertaining to audio data is stored in the A pack 45, and the data pertaining to sub-picture data corresponding to the subtitle is stored in the SP pack 46. When the currently played back contents are multilingual-compatible data, the A pack 45 and SP pack 46 corresponding to the respective languages exist in the VOBU 42. The language corresponding to the pack can be determined with reference to the pack header.
The process flow of the disc reading unit 102 when playing back the optical disc 20 will be described next.
First, the disc reading unit 102 controls the disc drive unit 101 to read the IFO file from the optical disc 20 (S601). Assume that the VTS_01_0_0.IFO 224 is read. Upon reading the VTS_10_0.IFO 224, the disc reading unit 102 transfers the VTS_01_0.IFO 224 to the navigation manager 103. The navigation manager 103 interprets the PGC to be played back, with reference to the VTS_01_0.IFO 224. Accordingly, a list of the playback order is made (S602).
Furthermore, under the control of the navigation manager 103, the disc reading unit 102 reads the data in the playback order of the cells 41 interpreted in step S602, and stores the read data in the pre-read buffer 104 (S603). In this embodiment, this process is performed for each VOBU 42.
When the read position matches the VOBU 42 pertaining to the default angle (NO in S701, YES in S703, and S704), the disc reading unit 102 reads the VOBU 42 at the read position (S705). The disc reading unit 102 also determines whether the read VOBU 42 is the last VOBU 42 to be played back in the cell 41 to which the VOBU 42 belongs (S706). If the VOBU 42 is not the last (NO in S706), the read position is updated to the VOBU 42 to be played back next of the selected angle (S707). The relative address to the VOBU 42 to be played back next can be determined on the basis of the NV pack 43.
If the VOBU 42 is the last VOBU 42 to be played back in the cell 41 to which the VOBU 42 belongs (YES in S706), the disc reading unit 102 updates the read position to the cell 41 to be played back next on the basis of the playback order analyzed in step S602 shown in
Referring back to
Subsequently, the disc reading unit 102 deletes, from the data stored in the pre-read buffer 104, the A pack 45 and SP pack 46 which respectively pertain to the unselected audio and subtitle data of the data stored in the pre-read buffer 104 (S605). As described above, with reference to the header of each pack, it can be determined whether the A pack 45 or SP pack 46 pertains to the selected language. More specifically, it can be determined whether the A pack 45 or SP pack 46 pertains to the selected language by comparing the audio stream number or sub-picture number in the header of the A pack 45 or SP pack 46, with the audio stream number serving as the audio information 103a or the sub-picture number serving as the sub-picture information 103b of the navigation manager 103. Note that the disc reading unit 102 separately stores, in the HDD 105, the data deleted from the pre-read buffer 104.
The disc reading unit 102 also determines whether all the playback data pertaining to the currently played back PGC has been read (S606). If all the data has been read (YES in S606), the reading process ends.
If all the data has not been read (NO in S606), the disc reading unit 102 determines whether the pre-read buffer 104 has a free capacity (S607). If the pre-read buffer 104 has a free capacity (YES in S607), the data is further read at the read position updated in S707 or S708 shown in
If the pre-read buffer 104 has no free capacity (NO in S607), the disc reading unit 102 stops rotating the disc drive unit 101 (S608). After stopping rotation of the disc drive unit 101, the disc reading unit 102 determines whether the data amount in the pre-read buffer 104 has become equal to or smaller than a predetermined amount (S609). If this data amount is larger than the predetermined amount (NO in S609), the disc drive unit 101 is kept stopped (S609).
If the data amount in the pre-read buffer 104 is equal to or smaller than the predetermined amount (YES in S609), the disc reading unit 102 restarts rotating the disc drive unit 101 (S610), and the data is read from the optical disc 20 in the playback order of the PCGs generated in S602 (S603).
When the disc drive unit 101 starts reading the data from the optical disc 20 (time T0 in
When the pre-read buffer 104 has no free capacity (corresponding to time T1 in
When the data amount in the pre-read buffer 104 becomes equal to or smaller than a predetermined threshold value D1 (time T2 in
As described above, according to this embodiment, the pre-read buffer 104 has a relatively large capacity, and the rotational control performed by the disc drive unit 101 is temporarily stopped. Hence, power consumption for reading the data can be decreased. The PGCI 312 is read from the optical disc 20, and the data is read in the playback order of the PGCs in the PGCI 312. Hence, as compared with a case wherein a predetermined amount of data is obtained from, e.g., the designated read address, the amount of unnecessary data which is not used in playback processing can be reduced, thus increasing memory use efficiency.
For example, as shown in
Furthermore, the NV pack 43 is interpreted, and the VOBU 42 of the unselected angle is not read, thus increasing the memory use efficiency. Hence, the disc reading unit 102 decreases the access frequency to the disc drive unit 101, thus suppressing power consumption.
In this embodiment, the A pack 45 and SP pack 46 respectively pertaining to the unselected audio and subtitle data, and the data which is not supported by the video decoder 107, or audio decoder 109 are deleted from the pre-read buffer 104. After that, new data is read in the free area, thus increasing the memory use efficiency of the pre-read buffer 104.
Additionally, in this embodiment, the data deleted from the pre-read buffer 104 is stored in the HDD 105, and the stored data can be read from the HDD 105 when the user switches the audio and subtitle data. Hence, the access frequency to the disc drive unit 101 can also be decreased.
In this embodiment, the data is not read at once until the pre-read buffer 104 becomes full of data in step S603, but is read for each VOBU 42. While reading the data, a playback process is performed. When the data is read in a large unit, a large amount of data is read, which must then be deleted in steps S604 and S605 is read. However, in this embodiment, the data is read for each VOBU 42, thus suppressing this problem.
In this embodiment, when the pre-read buffer 104 becomes full of data, the rotation of the disc drive unit 101 is stopped to save power. However, as another method of saving power, for example, a method of stopping power supply to an optical pickup of the disc drive unit 101, stopping control of the optical pickup, stopping output of the laser beam, or their combination is also available.
In this embodiment, the process when the VTS_01_0.IFO 224 is read is described. However, the same process can be performed when the PGC is played back on the basis of the VIDEO_TS.IFO 221 serving as the management file pertaining to a menu.
In this embodiment, the case when the notebook PC 10 is used is described as an example. However, the optical disc playback apparatus may be a normal DVD player and the like.
While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Number | Date | Country | Kind |
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2005-062654 | Mar 2005 | JP | national |