Reproducing apparatus and method, and recording mediumTechnical Field
The present invention relates to a reproducing apparatus and method, and more particularly, to a reproducing apparatus and method for reproducing a browsable contiguous display (browsable slideshow) to which still image data, such as sub-audio data, is independently added, and a recording medium therefor.
Background
Since moving picture data is large, it is necessary to compress picture data using spatio-temporal compression for easy transmission to encode. Generally, in order to be recorded on an information storage medium, video data is compressed and encoded under a Moving Picture Experts Group (MPEG) standard specified by the international organization for standardization (ISO) and the International Electrotechnical Commission (IEC), whereas audio data is compressed under the MPEG standard or converted into digital data using linear Pulse Code Modulation (PCM). Time information necessary for synchronizing the encoded video data and audio data with each other is incorporated into the system multiplexed data. In this case, MPEG2 is also frequently used when encoding data.
System multiplexing may be performed using packets. For example, as shown in fig. 1, when video data and audio data are multiplexed, the video data and the audio data are divided into bit stream packets of a predetermined length, additional information such as a header is included in the bit stream packets, and the video packets and the audio packets are mixed and transmitted using a time sharing technique. Thus, the start of a packet, i.e., the header, includes information indicating that the packet is a video packet or an audio packet.
Meanwhile, according to the MPEG standard, time information called a time stamp is used for synchronization between audio and video packets.
The time stamp is a time management stamp provided in an access unit for decoding processing required for data reproduction. That is, the time stamp is information that specifies when audio or video data must be decoded and reproduced in access units. There are two types of timestamps: presentation Time Stamp (PTS) and Decoding Time Stamp (DTS).
The PTS is time management information for data reproduction selected according to an employed MPEG encoding method, and when a System Time Clock (STC), for example, a reference synchronization signal generated in a reference decoder of an MPEG system is equal to the PTS, the relevant audio or video data is reproduced and output in access units.
The DTS is time management information for data decoding. Because the order in which the encoded video bitstream is transmitted is unique, the MPEG standard requires DTS. For example, since an I-frame picture and a P-frame picture are transmitted as an encoded bitstream before a B-frame picture, the order of decoding and reproducing the I-and P-frame pictures is different from the order of decoding and reproducing the B-frame pictures. If the PTS and the DTS are different, they are sequentially included in the packet data. If they are the same, only the PTS is included in the packet data.
Hereinafter, referring to fig. 2 to 6, a conventional MPEG encoding and decoding apparatus will be described.
Fig. 2 shows a conventional scalable encoding apparatus 200 used in MPEG encoding. Referring to fig. 2, a video encoder 210 receives and encodes digital video data, and an audio encoder 220 receives and encodes digital audio data.
The first packetizer 230 packetizes the encoded video data output from the video encoder 210 by dividing the video data in predetermined units, and generates a Packetized Elementary Stream (PES). The second packetizer 240 packetizes the encoded audio data output from the audio encoder 220 by dividing the audio data in predetermined units, and generates a PES.
Encoding time information such as PTS and DTS may be incorporated into the PES. Such encoding time information is used to synchronize the PES with other data. Specifically, the DTS indicates when a picture is decoded, and the PTS indicates when a picture is output. Generally, only PTS is included in audio data. In this case, the DTS is considered to be the same as the PTS. After including the PTS and DTS, audio data or video data is packetized in a payload data format.
The program stream multiplexer 250 multiplexes the video PES packetized by the first packetizer 230 into a Program Stream (PS). The transport stream multiplexer 260 multiplexes the audio PES packetized by the second packetizer 240 into a Transport Stream (TS). In multiplexing, each PES is divided into predetermined units, identification numbers are assigned to the predetermined units, and then the PES is multiplexed.
A Program Stream (PS) is generated optimally for an information storage medium and multiplexed in PS packet units. In the DVD-video standard, a PS packet unit of 2048 bytes is used for a representative application of a moving image storage medium.
TS is used in applications such as digital broadcasting where data loss cannot be avoided. The TS is multiplexed into TS packet units. The TS packet unit is fixed to 188 bytes long. Recently, the use of TS has increased when digital broadcast data is recorded on a recording medium. In the present invention, although TS is used for multiplexing, PS may also be used.
As described above, the TS is packetized data, such as video or audio data, divided in predetermined units, so that the data can be transmitted via satellite, cable, or Local Area Network (LAN). Here, the predetermined unit is 188 bytes long when using an MPEG-2 transport stream according to the ISO/IEC13818-1 standard, and 53 bytes long when using an Asynchronous Transfer Mode (ATM).
In digital broadcasting, packet data is transmitted at variable time intervals. The transmitted packet data is input into a buffer of a receiving apparatus having a decoder, decoded by the decoder and broadcasted, so that a user can view digital broadcasting. The packet data may be temporarily stored on the recording medium and reproduced at a desired time. In this case, when packet data is input to a decoder of the reproducing apparatus, a variable time interval at which the packet data is transmitted is important. This is because the transmitting end transmits packet data to the receiving end while adjusting a time interval between transmission of the packet data in consideration of the state of the buffer of the receiving apparatus having the decoder. If the variable time interval is not observed, the buffer of the receiving device overflows or underflows. Accordingly, information on the arrival time of each packet data transmitted to the recording apparatus is inserted in all packets, and the packet data is reproduced based on the information on the arrival time.
As described above, when packet data transmitted in the TS format is recorded on and reproduced from a recording medium, an Arrival Time Stamp (ATS) as information on the arrival time of the data is required for correct data reproduction.
In other words, the recording apparatus receives packet data transmitted at specific time intervals by the transmitting end and records it on the recording medium. In order to reproduce the recorded packet data, a counter is required to transmit the packet data to a decoder of the reproducing apparatus at the same time interval as a specific time interval used by the transmitting end. The counter operates in response to a system clock of 90KHz or 27MHz and includes a counter value into which packet data is inserted, the counter being an ATS obtained immediately at the time when the packet is input to the counter. In order to reproduce the recorded packet data, a time interval at which the packet data is transmitted to the buffer of the decoder is determined by a counter value included in the packet data. Such a counter is known as an Arrival Time Clock (ATC) counter. That is, an ATS is added to input packet data based on a counter value generated by an ATC counter, and the packet is output based on the ATS for data reproduction.
Fig. 3 illustrates a data structure of packet data including an ATS which specifies an arrival time of the packet data arriving at a receiving end, and a relationship between the ATS and a data output time when the packet data is reproduced. Referring to fig. 3, when packet data A, B, C, and D are received at arrival times 100, 110, 130, and 150, respectively, the recording apparatus generates an ATS indicating the arrival times 100, 110, 130, and 150 and inserts the ATS into packet data A, B, C, and D. For data reproduction, the packet data is output based on the ATS and reproduced. That is, packet data a is output at output time 100, packet data B is output at output time 110, packet data C is output at output time 130, and packet data D is output at output time 150.
Fig. 4 illustrates a data structure of packet data 400 including an ATS recorded on a recording medium. For convenience, fig. 4 illustrates packet data 400 including information according to the present invention, such as ATS 410, Decoding Time Stamps (DTS)420, Presentation Time Stamps (PTS)430, and audio/video (AV) data 440.
Fig. 5 illustrates a portion of a reproducing apparatus 500 that reproduces the packet data including the ATS shown in fig. 4. The recording apparatus 500 includes a disk drive unit 510, a buffer 520, a source depacketizer 530, and an ATC counter 540.
The disk drive 510 reads packet data including an ATS and transmits the packet data to the buffer 520.
The buffer 520 receives packet data including an ATS and transmits it to the source depacketizer 530.
The ATC counter 540 is used when a data stream stored in a recording medium is transmitted to a decoder (not shown) at a time interval at which packet data is first transmitted from a receiving end. The ATC counter 540 operates to reset an ATS value obtained immediately when the first packet is input to the source depacketizer in the TS format as an initial value in response to a system clock of 90KHz or 27MHz, and continuously counts ATS of the input packets. When the ATS of the input packet is equal to the count value generated by the ATC counter 540, the ATS is removed from the input packet and the input packet is transmitted to the decoder.
In other words, the ATC counter 540 sets the ATS value of the first input packet transmitted to the source depacketizer 530 as an initial value and starts counting. Next, the source depacketizer 530 checks the ATS value of the next packet data of itself, removes the ATS from the packet data having an ATS value equal to the count value generated by the ATC counter 540, and transmits the packet data to the decoder.
For example, in the case of the packet data of fig. 3, since the value of the ATS of the first packet data is 100, the initial value of the ATC counter 540 is set to 100, and the ATC counter 540 continuously counts. The ATC is removed from the first packet data and the first packet data is transmitted to the decoder. Next, since the value of the ATS of the second packet data is 110, when the count value of the ATC counter 540 is 110, the source depacketizer 530 removes the ATS from the second packet data and transmits the second packet data to the decoder. This process is also applied to other packet data in a similar manner.
Fig. 6 is a block diagram of a conventional standard decoder 600 for data synchronization based on encoded time information such as PTS and DTS. Referring to fig. 6, the decoder 600 includes a demultiplexer 610, a video decoder 620, a System Time Clock (STC) counter 630, an audio decoder 640, and a graphic processor 650.
The demultiplexer 610 demultiplexes the multiplexed video packet data, audio packet data, and sub-picture packet data, and transmits the demultiplexed video packet data and audio packet data to the video decoder 620 and the audio decoder 640, respectively. The demultiplexed sprite may be subtitle data that is displayed to overlap with the video packet data. In fig. 6, a decoder that decodes sub-picture data is not shown.
The STC counter 630 operates at 90KHz or 27MHz, and controls the value of a packet obtained immediately when the packet is input to a buffer (not shown) of a decoder to be equal to the Program Clock Reference (PCR) value of the packet. The buffer temporarily stores packet data output from the demultiplexer 610 but not yet input to the video decoder 620. The PCR represents a program clock reference as a value for adjusting as an STC counter, a reference time value set by an MPEG decoding apparatus having video and audio decoders.
A process of decoding packet data including a DTS and a PTS will be described with reference to fig. 6. First, the demultiplexer 610 demultiplexes an input transport packet into original video packet data and audio packet data, and transmits the video packet data and the audio packet data to the video decoder 620 and the audio decoder 640, respectively.
Next, the STC counter 630 is set based on PCR information (not shown) contained in the packet data. The video packet data is input to the video decoder 620 through the set STC counter 630 at the DTS time and decoded by the video decoder 620. Since the audio packet data has only PTS values, the audio packet data is input to the audio decoder 640 at PTS times, decoded by the audio decoder 640 and output.
Next, the decoded video packet data output from the video decoder 620 is input to the graphic processor 650 through the STC counter 630 based on the PTS time, processed by the graphic processor 650, and output as video data.
As described above, by controlling the decoding and output of the audio and video packet data at the PTS time and the DTS time using the count value generated by the STC counter 630, the audio and video packet data can be synchronized with each other. That is, the audio and video packet data are decoded and synchronized to respond to the clock generated by the STC counter 630.
In general, there are two applications of still images. First, a continuous display in which still images are output at a predetermined time. That is, the user reproduces the still image using the reverse play in which the previous image is reproduced again or the forward play in which the reproduction of the previous image is skipped and the next image is reproduced. When the STC value is updated by a new value, the images can be sequentially reproduced again. If the audio data is included in the still image, the audio data is reproduced in synchronization with the newly updated still image. Accordingly, reproduction of the audio data is interrupted, and the audio data is reproduced again starting from a portion of the audio data corresponding to the new still image.
Second is a browsable continuous display. In browsable continuous display, reproduction of audio data must not be interrupted even during reverse play and forward play. For example, files that are reproduced as if paging through an album are displayed continuously to view the included pictures. On the other hand, during reproduction of a browsable continuous display with background music, seamless reproduction of the background music is required for natural reproduction of still images even if the user selects and reproduces images before or after the current image.
Hereinafter, the problem of forward or reverse play of a browsable continuous display will be described with reference to fig. 7. Still images such as browsable continuous displays are divided into main stream data and sub audio data. Generally, mainstream data includes video data, audio data, and sub-picture data, but video data in a browsable continuous display application must be understood as still image data other than audio data. The sub audio data represents audio data that is additionally produced independently of the mainstream data and is reproduced as background music during reproduction of the still image data.
Referring to fig. 7, each still image and sub audio data is synchronized using PTS information, i.e., encoding time information. As data reproduction proceeds, an STC counter value of a decoder (not shown) is increased, and normal play is performed according to the increased STC counter value. However, when the user wants to perform reverse or forward play, the STC counter value is readjusted based on the target positions (e.g., 3000 and 20000) of the reverse or forward play. If the STC counter value is updated, the STC counter is reset to 10000 to restore the original still image and the original sub-audio, thereby causing a break in the sub-audio data, such as background music.
As described above, the conventional reproducing apparatus controls the video decoder and the audio decoder using the STC counter. Therefore, when the conventional reproducing apparatus is used to reproduce still images using an application such as a browsable continuous display, it is difficult to prevent an interruption in the reproduction of background music when the STC value is readjusted during reverse or forward play. In this case, the browsable continuous display may not be smoothly reproduced and may cause a strong harsh noise.
Disclosure of Invention
The present invention provides an apparatus and method for reproducing a browsable continuous display in which still image data such as sub audio data is additionally included even during forward or reverse play without interrupting reproduction of the sub audio data, i.e., background music, and a recording medium therefor.
According to an aspect of the present invention, there is provided a reproducing apparatus including: and a reproducing unit for reproducing the main stream data and the sub audio data independently added to the main stream data, wherein the reproducing unit includes a counter used in reproducing the sub audio data.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
In an aspect of the invention, the counter comprises a sub audio Arrival Time Clock (ATC) counter for depacketizing the sub audio data.
In another aspect of the present invention, the counter includes a sub audio System Time Clock (STC) counter for decoding the depacketized sub audio data.
In an aspect of the present invention, the mainstream data includes still image data.
According to another aspect of the present invention, there is provided a reproducing apparatus including: a mainstream reproducing unit for reproducing mainstream data including still image data using a clock for the mainstream data; and a sub audio reproducing unit for reproducing the sub audio data independently added to the main stream data using a clock for the sub audio data.
According to another aspect of the present invention, a main stream reproducing unit includes: the main stream depacketizer is used for depacketizing the main stream data; and a mainstream ATC counter providing a clock for depacketizing the mainstream data using the mainstream depacketizer. The sub audio reproducing unit includes: a sub audio depacketizer for depacketizing the sub audio data; and a sub-audio ATC counter providing a clock for depacketizing the sub-audio data using the sub-audio depacketizer.
According to another aspect of the present invention, a main stream reproducing unit includes: a main stream decoder for decoding the main stream data output from the main stream depacketizer; and a mainstream STC counter for providing a clock for use in decoding mainstream data using the mainstream decoder. The sub audio reproducing unit includes: a sub-audio decoder for decoding the sub-audio data output from the sub-audio depacketizer; and a sub-audio STC counter for providing a clock used for decoding the sub-audio data using the sub-audio decoder.
According to another aspect of the present invention, there is provided a reproducing method including reproducing sub audio data independently added to main stream data using a clock for reproducing the sub audio data.
In an aspect of the invention, reproducing the sub audio data includes depacketizing the sub audio data using a clock of the depacketized sub audio data.
In an aspect of the present invention, reproducing the sub audio data includes decoding the sub audio data using a clock that decodes the depacketized sub audio data.
According to another aspect of the present invention, there is provided a reproducing method including: reproducing mainstream data including still image data using a clock for reproducing the mainstream data; and reproducing the sub audio data independently added to the main stream data using a clock for reproducing the sub audio data.
In an aspect of the present invention, reproducing the main stream data includes: depacketizing the mainstream data using a clock that depacketizes the mainstream data; and decoding the mainstream data using a clock that decodes the depacketized mainstream data.
In an aspect of the present invention, reproducing the sub audio data includes: depacketizing the sub-audio data using a clock of the depacketized sub-audio data; the sub audio data is decoded using a clock that decodes the depacketized sub audio data.
According to another aspect of the present invention, there is provided a computer-readable recording medium storing a program for executing a reproducing method, wherein the reproducing method includes reproducing sub audio data independently added to main stream data using a clock for reproducing the sub audio data.
According to another aspect of the present invention, there is provided a computer-readable recording medium storing a program for executing a reproducing method, wherein the reproducing method includes: reproducing mainstream data including still image data using a clock for reproducing the mainstream data; and reproducing the sub audio data independently added to the main stream data using a clock for reproducing the sub audio data.
Drawings
These and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 illustrates a conventional data structure of multiplexed packet data;
fig. 2 illustrates a conventional scalable encoding apparatus for MPEG encoding;
fig. 3 illustrates a conventional data structure of packet data including an Arrival Time Stamp (ATS) and a relationship between the ATS and a data output time when the packet data is reproduced;
fig. 4 illustrates a conventional data structure of packet data including time synchronization information;
fig. 5 illustrates a portion of a conventional reproducing apparatus that reproduces packet data including an ATS;
fig. 6 is a block diagram of a portion of a standard decoder included in a conventional reproducing apparatus;
fig. 7 illustrates a conventional method of resetting a System Time Clock (STC) when a browsable continuous display is reproduced;
fig. 8 is a schematic block diagram of a reproducing apparatus according to an embodiment of the present invention;
fig. 9 is a detailed block diagram of the reproducing apparatus of fig. 8;
fig. 10 is a detailed block diagram of the mainstream decoder shown in fig. 9; and
fig. 11 is a flowchart illustrating a method of reproducing still image data according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Hereinafter, the embodiments are described to explain the present invention by referring to the figures.
Fig. 8 is a block diagram illustrating a reproducing apparatus 800 according to an embodiment of the present invention. The reproducing apparatus 800 includes a main stream data reproducing unit 810 and a sub audio data reproducing unit 820.
The mainstream data reproducing unit 810 reproduces mainstream data using a clock, and includes a mainstream Arrival Time Clock (ATC) counter 905 and a mainstream System Time Clock (STC) counter 910.
The sub audio data reproducing unit 820 reproduces the sub audio data using a clock, and includes a sub audio ATC counter 906 and a sub audio STC counter 911.
The structure of the reproducing apparatus 800 will be described in detail with reference to fig. 9. As described above, the reproducing apparatus 800 reproduces the mainstream data using the clock for the mainstream data, and reproduces the sub audio data using the clock for the sub audio data. Therefore, even if the clock for the main stream data is adjusted, the clock for the sub audio data is not affected by the adjustment, thus realizing seamless reproduction of the sub audio data.
The structure of the reproducing apparatus 800 shown in fig. 8 will now be described with reference to fig. 9. The reproducing apparatus 900 includes: a disk drive unit 901, a main stream buffer 920, a sub audio buffer 903, a first source depacketizer 904, a main stream ATC counter 905, a sub audio ATC counter 906, a second source depacketizer 907, a demultiplexer 908, a main stream decoder 909, a main stream STC counter 910, a sub audio STC counter 911, a sub audio decoder 912, and a graphics processor 913.
The disk drive unit 901 reads packet data including an Arrival Time Stamp (ATS) from the recording medium 914, transmits mainstream packet data including still images from the packet data to the mainstream buffer 902, and transmits sub-audio packet data to the sub-audio buffer 903.
The first source depacketizer 904 receives mainstream packet data from the mainstream buffer 902, depacketizes the mainstream packet data, and transmits the depacketized mainstream data to the demultiplexer 908. More specifically, the first source depacketizer 904 transmits depacketized mainstream data, from which ATS is separated, to the demultiplexer 908 at predetermined time intervals based on ATS information added to mainstream packet data through the mainstream ATC counter 905.
The mainstream ATC counter 905 controls the first source depacketizer 904 to transmit the depacketized mainstream data to the demultiplexer 908 at predetermined time intervals. More specifically, the mainstream ATC counter 905 is initialized based on the ATS value of the first mainstream packet data input to the first source depacketizer 904 and starts counting at the same time. When the count value of the mainstream ATC counter 905 is equal to the value of the ATS of the second mainstream packet data input to the first source depacketizer 904, the first source depacketizer 904 depacketizes the second mainstream packet data and transmits the depacketized mainstream data to the demultiplexer 908.
The operations of the second source depacketizer 907 and the secondary audio ATC counter 906 are the same as the operations of the first source depacketizer 904 and the primary stream ATC counter 905, respectively.
The second source depacketizer 907 receives the sub-audio packet data from the sub-audio buffer 903, depacketizes the sub-audio packet data, and outputs the depacketized sub-audio data to the sub-audio decoder 912. More specifically, the second source depacketizer 907 outputs depacketized secondary audio data, from which ATS is separated, at predetermined time intervals based on the ATS information added to the secondary audio packet data through the secondary audio ATC counter 906.
The secondary audio ATC counter 906 controls the second source depacketizer 907 to output secondary audio packet data at predetermined time intervals. More specifically, the secondary audio ATC counter 906 is initialized based on the ATS value of the first secondary audio packet data input to the second source depacketizer 907, and at the same time, the secondary audio ATC counter 906 starts counting. When the count value of the sub-audio ATC counter 906 is equal to the value of the ATS added to the second sub-audio packet data input to the second source depacketizer 907, the second source depacketizer 907 depacketizes the second sub-audio packet data and outputs the depacketized sub-audio data. The depacketized sub-audio data output from the second source depacketizer 907 may be transmitted to a buffer (not shown).
The demultiplexer 908 demultiplexes the mainstream data of the demultiplexed packets containing Decoding Time Stamps (DTS) and Presentation Time Stamps (PTS), and transmits the demultiplexed data to the mainstream decoder 909. The demultiplexed mainstream data output from the demultiplexer 908 is buffered by a decoding buffer (not shown) before being input to the mainstream decoder 909.
Mainstream STC counter 910 operates at 90KHz or 27 MHz. The mainstream STC counter 910 is set based on Program Clock Reference (PCR) information (not shown) included in the packet data, and controls a value of the packet data obtained immediately at the time when the packet data is input to the decoding buffer based on a PCR value included in the packet data.
The set mainstream STC counter 910 controls the demultiplexed mainstream data to be input to the mainstream decoder 909 at the DTS time specified in the DTS information and decoded by the mainstream decoder 909.
The decoded mainstream data output from the mainstream decoder 909 is input to the graphics processor 913 at a PTS time specified in the PTS information. The decoded mainstream data is processed by the graphics processor 913 and output.
The operation of the mainstream STC counter 910 is similar to that of the mainstream ATC counter 905. That is, the mainstream STC counter 910 is initialized based on the PCR information and starts counting at the same time.
When the count value of the mainstream STC counter 910 is equal to the value of the DTS of the packet data, the mainstream decoder 909 decodes the demultiplexed mainstream data and transmits the decoded result to the graphic processor 913. In addition, when the count value of the mainstream STC counter 910 is equal to the value of the PTS contained in the packet data, the graphics processor 913 processes the received decoding result and outputs the processing result to a screen (not shown).
The operations of the sub-audio STC counter 911 and the sub-audio decoder 912 are similar to the operations of the mainstream STC counter 910 and the mainstream decoder 909.
The sub audio STC counter 911 operates at 90KHz or 27MHz, and controls the value of depacketized sub audio data input to a decoding buffer that temporarily stores data, based on a PCR value included in the packet data.
The set sub-audio STC counter 911 controls depacketized sub-audio data to be input to the sub-audio decoder 912 at a PTS time specified in the PTS information, and decoded by the sub-audio decoder 912.
The operation of the sub-audio STC counter 911 is similar to that of the main stream STC counter 910. That is, the sub-audio STC counter 911 is initialized based on the PCR information included in the packet data and starts counting at the same time.
The sub-audio decoder 912 decodes the depacketized sub-audio data when the count value of the sub-audio STC counter 911 is equal to the PTS value included in the packet data. The sub audio data is decoded and output to a screen without performing additional processing on the sub audio data.
Fig. 10 shows the main stream decoder 909 in fig. 9 in detail. The mainstream decoder 909 includes: an audio decoder 1 for decoding audio data; a sub picture decoder 2 for decoding sub picture data; and a video decoder 3 for decoding the video data. Mainstream data such as browsable continuous display of an application of still image data may include video data, i.e., still image data, and sub-picture data such as a subtitle, but the mainstream data does not include audio data. Therefore, the audio decoder 1 is not used in a browsable continuous display application.
The audio decoder 1, the sub-picture decoder 2, and the video decoder 3 decode audio data, sub-picture data, and video data, respectively, based on the count value of the mainstream STC counter 910 of fig. 9.
Fig. 11 is a flowchart illustrating a method of reproducing still picture data to which sub audio data is independently added according to an embodiment of the present invention. Referring to fig. 9 and 11, the disk drive unit 901 reads packet data from the recording medium 914 (operation 1100).
Mainstream data of the read packet data including the still image data is stored in the mainstream buffer 902, and sub-audio data of the read packet data is stored in the sub-audio buffer 903 (operation 1110).
Next, the first source depacketizer 904 depacketizes the mainstream data based on the count value of the mainstream ATC counter 905, and the second source depacketizer 907 depacketizes the sub-audio data based on the count value of the sub-audio ATC counter 906 (operation 1120).
Next, the demultiplexer 908 demultiplexes the main stream data depacketized by the first source depacketizer 904 (operation 1130).
Next, the mainstream decoder 909 decodes the demultiplexed mainstream data based on the count value of the mainstream STC counter 910, and the sub-audio decoder 912 decodes the depacketized sub-audio data based on the count value of the sub-audio STC counter 911 (operation 1140).
Next, the decoded main stream data and sub audio data are output (operation 1150).
The method of fig. 11 may be embodied as computer readable code in a computer readable medium. Here, the computer readable medium may be any recording apparatus capable of storing data read by a computer system, such as a Read Only Memory (ROM), a Random Access Memory (RAM), a Compact Disc (CD) -ROM, a magnetic tape, a floppy disk, an optical data storage device, and so on.
In addition, the computer readable medium may be a carrier wave that transmits data via the internet, for example. The computer-readable recording medium can be distributed over computer systems interconnected through a network, and the present invention can be stored and implemented as computer-readable code in the distributed system.
As described above, according to the present invention, using a clock for main stream data and a clock for sub audio data, still image data, such as a browsable continuous display to which sub audio data is independently added, can be reproduced more naturally, thereby preventing an interruption in reproduction of sub audio data, such as background music, even during forward or reverse play.
Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.