JP2008300029A - Information reproducing method and information reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information reproducing method or the like in which special reproduction such as fast forwarding reproduction in which a load to be processed may be small and increment of required memory quantity is not performed, is achieved using compressed audio data recorded in an information recording medium. <P>SOLUTION: Disclosed is the method in which the compressed audio data are read out from an information recording medium in which the compressed audio data are recorded with a frame unit, extension processing is performed, and the data is reproduced. In the information reproducing method by which fast forwarding reproduction in which normal reproduction and skip-reading processing are repeated, is performed using the number of frames which is predetermined and fixed and is to be reproduced, and the number of frames which is predetermined and fixed and not to be reproduced when a user performs fast forwarding reproduction indication, after processing in which skip-reading of frames not to be reproduced is performed, reproduction processing of the frames to be reproduced is performed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an information reproducing method and an information reproducing apparatus that read out the compressed audio data from an information recording medium in which compressed audio data is recorded in units of frames and perform decompression processing. The present invention relates to an information reproduction method having a fast-forward reproduction function in which a frame area to be reproduced is alternately repeated.

  In recent years, a compression technique for compressing audio data for music to generate compressed audio data and decompressing the compressed audio data to restore the original audio data is becoming widespread. For example, the MP3 (MPEG Audio Layer-3) format is known as such a compression technique. The MP3 format is superior in that the data size can be greatly reduced compared to the original audio data.

  By the way, an information reproducing apparatus to which the above-described compression technology is applied has a configuration in which compressed audio data recorded on an information recording medium such as a CD or a flash memory is read and reproduced. In general, compressed audio data has a data structure divided into frames, and each frame includes header information and a compressed audio data body. When normal playback processing is performed in the information playback apparatus, the frames may be read out sequentially and played back in the read order. On the other hand, in the information reproducing apparatus, it is desirable that special reproduction processing can be realized in addition to the normal reproduction operation. Among them, fast-forward reproduction processing is typical. In this case, when fast-forward playback is performed while listening to music, it is very convenient for the user because an arbitrary position of the music can be determined. In order to realize such fast-forward playback, it is necessary to control the information playback apparatus to repeatedly perform an operation of skipping a plurality of frames after playing back a plurality of frames.

  The compression technique includes a fixed bit rate method in which the same bit rate is set for each frame and a variable bit rate in which a different bit rate is set for each frame. When fast forward playback as described above is realized, according to the fixed bit rate method, the relationship between time and data size is linear, and the frame size of each frame is uniform, so that the position of the subsequent frame can be determined in advance. Thus, it is possible to easily control to skip a plurality of frames. On the other hand, according to the variable bit rate method, since the frame size changes, it is necessary to determine the position of the subsequent frame by some method. As a general method, it is conceivable that position information such as an address is acquired in advance for each frame, stored in a memory as a map, and the above fast-forward reproduction is performed with reference to this map.

  However, it takes considerable processing time to create a map in advance over the entire information recording medium on which the compressed audio data is recorded. In addition, it is necessary to secure a memory having a sufficient storage capacity to hold the map. Therefore, in order to realize fast-forward playback corresponding to the compression technique of the variable bit rate method, there is a problem that a processing load increases and a necessary memory amount increases.

  Therefore, the present invention has been made in view of such problems, and it is possible to reduce the processing load when special audio playback such as fast-forward playback is performed by reading compressed audio data from an information recording medium, and the required amount of memory. It is an object of the present invention to provide an information reproducing method and an information reproducing apparatus that do not cause an increase in the amount of information.

  In order to solve the above-mentioned problem, the information reproducing method according to claim 1, wherein the compressed audio data is read out from an information recording medium in which the compressed audio data is recorded in units of frames and decompressed to reproduce the information. A fast-forward playback process for performing fast-forward playback using a predetermined number of frames to be played back and a predetermined number of non-playback frames when the user instructs fast-forward playback, From the time when the process of counting the number of non-reproduction target frames from the frame at the time of the fast-forward reproduction instruction and skipping frames without performing reproduction and the process of skipping frames corresponding to the number of non-reproduction target frames is completed. And a fast-forward playback process step that repeats playback processing for playing back frames for the number of playback target frames, and the fast-forward playback process step A reproduction target frame number obtaining step for obtaining the number of frames to be reproduced, a non-reproduction target frame number obtaining step for obtaining the number of non-reproduction target frames, and a frame header for obtaining a frame header of a frame to be processed An acquisition step; a frame header analysis step for analyzing the acquired frame header; a frame position determination step for determining a next frame head position based on a frame size obtained by the frame header analysis; and the frame position determination. A step of skipping a frame skipped to the head position of the next frame obtained in the process, and after performing the skipping process for the number of non-reproduction target frames, the number of the reproduction target frames A reproduction process is performed.

  The information reproducing apparatus according to claim 3 is an information reproducing apparatus that reads out the compressed audio data from an information recording medium in which the compressed audio data is recorded in units of frames, performs reproduction, and reproduces the compressed audio data. A fast-forward playback process for performing fast-forward playback using a predetermined number of frames to be played back and a predetermined number of non-playback frames, and starting from the frame at the time of the fast-forward playback instruction. Counting the number of non-reproduction target frames, skipping frames without performing reproduction, and skipping frames for the number of non-reproduction targets. And fast-forward playback processing means for repeating playback processing, wherein the fast-forward playback processing means Frame number acquisition means for acquiring the number of frames to be reproduced, non-reproduction target frame number acquisition means for acquiring the number of non-reproduction target frames, frame header acquisition means for acquiring a frame header of a frame to be processed, and the acquired Frame header analyzing means for analyzing the frame header, frame position determining means for determining the next frame head position based on the frame size obtained by the frame header analysis, and the next obtained by the frame position determining means Processing means for skipping a frame skipped to the head position of the frame, and performing the playback processing for the number of playback target frames after performing the skip processing for the number of non-replay target frames. And

  Preferred embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing the overall configuration of a disc player as an information reproducing apparatus according to the present embodiment. The disc player shown in FIG. 1 reads and reproduces the compressed audio data recorded on the loaded disc 10, so that the spindle motor 11, the pickup 12, the RF amplifier 13, the driver 14, and the servo control unit 15. The digital signal processing unit 16, the buffer memory 17, the D / A converter 18, the CPU 19, the display unit 20, and the operation unit 21 are included.

  As the disk 10, for example, a CD as a reproduction-only information recording medium is used. Alternatively, a writable information recording medium may be used. The compressed audio data generated by compressing the original audio data is recorded on the disk 10, and the MP3 format is adopted as the compression format when generating the compressed audio data, for example. Note that the present invention can also be applied to an information recording medium other than a CD or a compression format other than the MP3 format.

  FIG. 2 shows the data structure of the disk 10. In this embodiment, it is assumed that compressed audio data is filed and one compressed audio file is assigned to one music piece. Each compressed audio file is divided into a plurality of frames. In the example of FIG. 2, the frame (N−1) starting from the head logical address LBA (N−1), the frame (N) starting from the head logical address LBA (N), and the head logical address LBA (N + 1). The start frame (N + 1) is shown. As described above, the compressed audio file has a predetermined number of frames arranged in a predetermined order, and each frame has a data structure including a frame header and a data body. In the frame header, various information related to the frame is recorded as header information, and for example, a bit rate, a sampling rate, a padding flag described later, and the like are recorded. Also, compressed audio data for a predetermined time of one piece of music is assigned to the data body of the frame.

  In this embodiment, it is assumed that a compression format based on a variable bit rate method such as MP3 as described above is used. Since this variable bit rate method sets a different bit rate for each frame, it is advantageous in terms of reproduction quality for the same data size and efficiency compared to a fixed bit rate method in which the same bit rate is set for each frame. It can compress well. In the case of the fixed bit rate method, the time and the data size have a uniform relationship, whereas in the variable bit rate method, the proportional relationship between the time and the data size does not hold. Therefore, when skipping frames (N−1) to (N + 1) in FIG. 2 during fast-forward playback processing in the disc player, the top logical addresses LBA (N−1) to LBA (N + 1) in FIG. 2 cannot be determined uniformly. It is necessary to determine the data amount of each frame according to the procedure described later.

  Next, in FIG. 1, a disc 10 mounted on a disc player is irradiated with laser light by a pickup 10 while being driven to rotate at a predetermined rotational speed by a spindle motor 11. In the pickup 12, an RF signal corresponding to the compressed audio data is generated based on the reflected light from the optical disk 10. The RF signal output from the pickup 12 is amplified with a predetermined gain by the RF amplifier 13 and then input to the digital signal processing unit 16 through the servo control unit 15. The servo control unit 15 servo-controls the spindle motor 11 via the driver 14 under the instruction of the CPU 19 and controls tracking servo and focus servo for the pickup 12 based on the RF signal.

  The digital signal processing unit 16 extracts a compressed audio file corresponding to the RF signal and performs various digital signal processing on each frame as a processing target. As processing corresponding to the above compression format, the digital signal processing unit 16 performs decompression processing on the compressed audio file, and restores and outputs the original audio data. The buffer memory 17 is connected to the digital signal processing unit 16, reads / writes only a predetermined number of frames of the compressed audio file to be processed by the digital signal processing unit 16 at an appropriate timing, and temporarily holds it. It is a storage means.

  The D / A converter 18 converts the audio data output from the digital signal processing unit 16 into an analog signal, generates an L channel audio output and an R channel audio output corresponding to stereo audio, and outputs them externally.

  The CPU 19 controls the overall operation of the disc player shown in FIG. The CPU 19 sends control signals to the servo control unit 15 and the digital signal processing unit 16, respectively, to control execution of normal playback processing, and to control execution of fast-forward playback processing as special playback as described later. Further, a display unit 20 for displaying predetermined information and an operation unit 21 including a key unit for a user to instruct the operation of the disc player are connected to the CPU 19.

  Next, fast-forward playback processing performed by the disc player according to the present embodiment will be described with reference to FIGS. Here, a fast-forward playback process in the case where playback and search of the disk 10 are repeated intermittently at regular time intervals in order to search for a music piece existing at a predetermined position on the disk 10 will be described. That is, fast-forward playback is realized by repeating the operation of normally reading S consecutive frames after reading M consecutive frames from the disk 10. The continuous M frames correspond to non-reproduction target frame regions, and the continuous S frames correspond to reproduction target frame regions.

  FIG. 3 is a flowchart for explaining the entire fast-forward playback process. The process shown in FIG. 3 is started, for example, when the user performs a predetermined key operation on the operation unit 21 during reproduction of the disk 10. As shown in FIG. 3, first, when the target frame located at the head of the S reproduction target frames is being searched, the target frame number is determined (step S11). Specifically, the target frame number may be determined by adding the number M of frames to be skipped to the current frame number to be normally reproduced. In the compression method such as MP3, since the frame number is not recorded in the frame header shown in FIG. 2, it is necessary for the CPU 19 to always count and manage the frame number.

  Next, a high-speed search for the target frame is performed (step S12). As a result, the M frames preceding the target frame are skipped. Here, FIG. 4 is a flowchart showing specific processing of the high-speed search for the target frame in step S12.

  In FIG. 4, it is assumed that the current frame number is acquired as described above and the top logical address LBA (C) of the current frame is determined at the time when the high-speed search for the target frame is started. On the other hand, if the variable bit rate method is used as described above and it is assumed that an address map is not created, the start logical address LBA (T) of the target frame cannot be determined at this time, and the following processing is performed. Is.

  As shown in FIG. 4, first, the frame header of the current frame is read (step S21). Then, the contents of the read frame header are analyzed to calculate the frame size of the current frame (step S22). Specifically, the frame size of the current frame is obtained from the data size of the frame header itself and the data size of the data body obtained based on the bit rate, sampling rate, and padding flag recorded as header information in the frame header. Can do.

  Next, the top logical address of the subsequent frame adjacent to the current frame is obtained (step S23). That is, the frame size of the current frame calculated in step S22 may be added to the first logical address LBA (C) of the acquired current frame. Note that the top logical address LBA (C) of the current frame is updated with the value obtained in step S23 and used for the next processing.

  Next, in order to advance the search by one frame, 1 is added to the current frame number (step S24). Then, the new current frame number is compared with the target frame number, and it is determined whether or not they match (step S25). As a result, when the current frame number and the target frame number do not match (step S25; NO), it is one of M frames to skip, so the process returns to step S21 and the same processing is repeated. As a result, the transition from the current frame to the subsequent frame is performed. On the other hand, if the current frame number and the target frame number match (step S25; YES), it is determined that M frames have been skipped at this point, so the processing of FIG. Note that the head logical address LBA (T) of the target frame is determined to be the head logical address LBA (C) of the current frame at this time.

  Next, as shown in FIG. 3, following step S12 shown in the flowchart of FIG. 4, a normal reproduction operation is performed on the subsequent S frames with the target frame as a base point (step S13). Then, when the reproduction of S frames is completed, it is determined whether or not the fast-forward reproduction currently being executed is terminated (step S14). For example, this is a case where the user instructs the end of fast-forward playback by performing a predetermined key operation on the operation unit 21.

  As a result of the determination in step S14, when the fast-forward reproduction is to be ended (step S14; YES), the fast-forward reproduction process in FIGS. 3 and 4 is finished. On the other hand, when the fast forward reproduction is continued (step S14; NO), the process returns to step S11 and the same processing is repeated. In this way, while repeatedly executing the processing of steps S11 to S14, skipping of consecutive M frames and normal reproduction of consecutive S frames are alternately performed. At this time, when only skipping M frames, only the frame header is read out, so that it can be executed in a very short time compared to the time required for normal reproduction of S frames. In addition, it is possible to reproduce fast-forwarding in which reproduction and search are alternately performed at regular time intervals. Therefore, since the fast-forwarding state is realized while outputting the reproduction sound at high speed, the user can easily determine the desired start position.

  As described above, by performing the fast forward reproduction process according to the procedure described with reference to FIGS. 3 and 4, it is not necessary to create a map for determining the frame arrangement in advance. That is, since the frame size is not constant in the variable bit rate method, in order to specify the position of the frame to be skipped during special playback, a map in which the head logical address is sequentially described by reading the frame header of each frame of the compressed audio file in advance is specified. It becomes effective to memorize. However, as the amount of data increases, it takes a considerable amount of time to create a map, which hinders rapid processing. Further, when the amount of data increases, it becomes necessary to secure a sufficient amount of memory for storing the map, which causes an increase in cost. In the present embodiment, map creation is not required even in fast-forward playback when the variable bit rate method is adopted, processing can be started quickly, and the amount of memory can be reduced (the processing load is reduced). Small and does not require a large amount of memory).

  In this embodiment, the case where fast-forward playback is performed as one type of special playback in the disc player has been described. However, the present invention is not limited to this, and special playback in which a frame area to be played back and a frame area to be played back is mixed. The present invention can be widely applied when performing the above.

1 is a block diagram showing an overall configuration of a disc player as an information reproducing apparatus according to an embodiment. It is a figure which shows the data structure of the disc based on this embodiment. It is a flowchart explaining the whole fast-forward playback process in the disc player. It is a flowchart which shows the specific process of the high-speed search of the target frame in step S2 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Disk 11 ... Spindle motor 12 ... Pickup 13 ... RF amplifier 14 ... Driver 15 ... Servo control part 16 ... Digital signal processing part 17 ... Buffer memory 18 ... D / A converter 19 ... CPU
20 ... Display unit 21 ... Operation unit

Claims (4)

In an information reproduction method of reading out the compressed audio data from an information recording medium in which compressed audio data is recorded in units of frames, and performing decompression processing to reproduce the compressed audio data,
When the user gives a fast-forward playback instruction,
A predetermined number of frames to be played and
Using a predetermined number of non-playback frames,
A fast-forward playback process for performing fast-forward playback,
Count the number of non-reproduction frames from the frame at the time of the fast forward reproduction instruction,
A fast-forward playback process that repeats a process of skipping frames without playback and a playback process of playing back the frames for the number of frames to be played back after the process of skipping the frames for the number of non-playback frames is completed. Having a process,
The fast forward reproduction processing step includes
A step of obtaining the number of frames to be reproduced to obtain the number of frames to be reproduced;
A non-reproduction target frame number acquisition step of acquiring the non-reproduction target frame number;
A frame header acquisition step of acquiring a frame header of a frame to be processed;
A frame header analysis step of analyzing the acquired frame header;
Based on the frame size obtained by the frame header analysis, a frame position determination step for determining the next frame head position;
A processing step of skipping a frame skipped to the head position of the next frame obtained by the frame position determination step;
Including
After performing the skip processing for the number of non-reproduction target frames,
An information reproduction method comprising performing the reproduction processing for the number of reproduction target frames. The information reproduction method according to claim 1,
The information reproducing method, wherein the data body is recorded on the information recording medium as compressed audio data based on a variable bit rate method in which a different bit rate is set for each frame. In an information reproducing apparatus that reads out the compressed audio data from an information recording medium in which compressed audio data is recorded in units of frames, performs reproduction processing, and reproduces the compressed audio data.
When the user gives a fast-forward playback instruction,
A predetermined number of frames to be played and
Using a predetermined number of non-playback frames,
A fast-forward playback process for performing fast-forward playback,
Count the number of non-reproduction frames from the frame at the time of the fast forward reproduction instruction,
A fast-forward playback process that repeats a process of skipping frames without playback and a playback process of playing back the frames for the number of frames to be played back after the process of skipping the frames for the number of non-playback frames is completed. Having means,
The fast-forward reproduction processing means includes
Playback target frame number acquisition means for acquiring the playback target frame number;
Non-reproduction target frame number acquisition means for acquiring the non-reproduction target frame number;
Frame header acquisition means for acquiring a frame header of a frame to be processed;
Frame header analysis means for analyzing the acquired frame header;
Frame position determining means for determining the next frame head position based on the frame size obtained by the frame header analysis;
Processing means for skipping a frame skipped to the head position of the next frame obtained by the frame position determining means;
Including
After performing the skip processing for the number of non-reproduction target frames,
An information reproducing apparatus that performs the reproduction processing for the number of frames to be reproduced. The information reproducing apparatus according to claim 3, wherein
The information reproducing apparatus, wherein the data body is recorded on the information recording medium as compressed audio data based on a variable bit rate method in which a different bit rate is set for each frame.

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