JP2006106167A - Information processor and mobile phone terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately perform a task of audio reproduction processing while securing real time performance without increasing the cost nor the power consumption during multi-task execution including, for example, the task of audio reproduction processing and other tasks. <P>SOLUTION: During audio reproduction, a CPU 11 transfers audio data from a storage device 34 to a temporary RAM 33 and sets parameters of a reproduction direction, the number of successive frames to be reproduced, and the number of a multiple of a speed in a DSP 12. The DSP 12 controls the temporary RAM 33 divisionally as SIDEs (A) to (C) and temporary (A) and (B) and controls movements of a read pointer on the SIDEs (A) to (C) and copying of frame data read out of the SIDEs (A) to (C) to the temporary (A) and (B). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an information processing apparatus and a mobile phone terminal that are suitable for performing, for example, music playback on a mobile phone terminal, especially when performing special playback such as fast forward playback and fast reverse playback.

  In recent years, silicon audio players and portable audio players of the external memory insertion type have become widespread in the market, and accordingly, models equipped with a digital audio playback function are also released on mobile phone terminals.

  In the digital audio playback function of the mobile phone terminal, linear PCM is performed by an audio compression technique represented by so-called MPEG1-Layer 3 (Moving Picture Image Coding Experts Group 1-Layer 3) or so-called ATRAC3 (Adaptive Transform Accustic Coding 3). (Linear Pulse Code Modulation) A reproduction process that decompresses (decodes) data encoded with data is employed.

  In addition, the functions and specifications that are essential at the time of digital audio reproduction include “reproduction”, “stop”, “volume change”, “low frequency emphasis”, “reproduction time display”, and the like. In particular, the above "playback" includes special playback such as so-called "fast forward playback" and "fast reverse playback", and the special playback function is now indispensable as one of digital audio playback functions. Yes.

  Of the special playback functions, “fast-forward playback” is a function for performing audio playback at a constant speed generally higher than 1 × speed while the playback direction on the time axis is set to the forward direction. On the other hand, “fast reverse playback” is a function in which the playback direction on the time axis is reversed and audio playback is performed at a constant speed that is generally faster than 1 × speed. For example, in the case of “fast forward 7 × speed playback”, forward playback is performed at a constant speed of 7 × speed, and in the case of “fast reverse 7 × speed playback”, reverse playback is performed at a constant speed of 7 × speed.

  In addition, the special playback function is specifically a process for skip-playing frames of encoded audio bitstream data (hereinafter referred to as audio encoded data) by a predetermined number of frames in a desired playback direction. It is realized by.

  That is, for example, in the case of “fast forward 7 × speed playback”, after decoding one frame, it skips 6 frames in the forward direction (hereinafter referred to as frame skip) and decodes the next one frame. This is realized by repeating this process. Further, for example, in the case of “fast reverse 7 × speed playback”, after decoding one frame, skipping 6 frames in the reverse direction and repeating the process of decoding the next one frame are repeated.

  In the above example, in order to make the explanation easy to understand, the number of frames to be decoded at the time of special playback is set to one frame. 5 frames are continuously reproduced. Hereinafter, these continuously reproduced frames are referred to as continuously reproduced frames.

  In Japanese Patent Laid-Open No. 2002-8318 (Patent Document 1), the number of sectors per unit time of audio data to be reproduced is calculated from DVD audio management information, and fast-forward reproduction or fast reproduction is performed based on the calculated value. Calculate the number of playback sectors and jump sectors during reverse playback, and perform fast-forward playback and fast-rewind playback based on the calculation results to fast-forward playback of audio data with different audio attributes such as two or more transfer bit rates. In addition, an information reproducing apparatus and an information reproducing method applicable to fast reverse reproduction are disclosed.

  Japanese Patent Laid-Open No. 2002-199346 (Patent Document 2) discloses that the head block of a data block constituting a data format when stream data read from a randomly accessible medium is reproduced by a decoder. Disclosed is a digital recording / playback device that can realize a special playback function according to each operation of pause, fast forward, and rewind by moving the readout start point to enable setting the restart position of the playback operation. ing.

Japanese Patent Laid-Open No. 2002-8318 (FIG. 3) Japanese Patent Laid-Open No. 2002-199346 (FIG. 1)

  By the way, in the mobile phone terminals currently on the market, the digital audio playback processing as described above is actually divided into a control process by a CPU (Central Processing Unit) and a decoding process by a DSP (digital signal processor). Yes.

  That is, the CPU controls reading of the audio encoding data in units of frames from an internal or external storage medium storing the audio encoding data, while the DSP decodes the audio encoding data in units of frames. Play audio data of linear PCM. Hereinafter, audio encode data in units of frames will be simply referred to as frame data. Note that the DSP of an actual mobile phone terminal is mounted as a multimedia engine that performs not only audio reproduction processing but also video processing and the like.

  In particular, when performing special playback as described above, the CPU performs control for continuous playback frame reading and frame skipping, and sequentially reads frame data read by each control to the DSP via the main bus. Processing to transfer is performed.

  That is, the CPU when performing special playback has a higher load than normal playback, such as rearrangement and buffering of frame data according to the playback direction, the number of continuous playback frames, the number of frame skips, etc. Such processing must be performed.

  In addition, when special playback is being performed, the time interval on the audio playback processing is shortened compared to that at the time of 1 × playback, so that the bit stream data transfer rate per unit time increases. Therefore, the bus traffic of the main bus, which is the bit stream transfer path when executing the audio reproduction process, also increases.

  Further, for example, in the case where other processing (for example, protocol processing such as a call or mail transmission / reception) is performed simultaneously with the special playback processing, that is, when the special playback processing is executed by multitasking, for example, from the audio playback processing However, when the priority of the other processing is higher, it is necessary to reduce the processing load at the time of the special reproduction in order to guarantee the real time property of the audio reproduction.

  In other words, if the processing load during special playback cannot be reduced, the real-time performance of audio playback cannot be guaranteed. If the real-time property of audio reproduction cannot be guaranteed in this way, for example, sound interruption occurs, and desired double speed reproduction is not executed.

  As a method for solving such a problem, for example, there is a method of installing a high-performance CPU or increasing the operation clock of the CPU. However, in a system assuming a mobile terminal such as a mobile phone terminal, the cost is low. This is not desirable because it has a large impact such as an increase and a decrease in reproduction time due to an increase in power consumption.

  The present invention has been proposed in view of such a situation. For example, predetermined task processing related to audio playback processing and high priority task processing such as call protocol processing are mixedly executed. An object of the present invention is to provide an information processing apparatus and a mobile phone terminal capable of accurately executing a predetermined task process while guaranteeing real-time performance without increasing costs or increasing power consumption. To do.

  In the information processing apparatus according to the present invention, the task execution unit reads from the task execution unit capable of executing a plurality of task processes simultaneously and the stream data storage unit storing bit stream data composed of a plurality of frame data continuous in time order. A first buffer area for temporarily accumulating a predetermined number of frame data consecutive in time order, and a first buffer area for temporarily accumulating the frame data accumulated in the first buffer area A buffer means having two buffer areas, and a second buffer area by reading frame data from the first buffer area on the basis of parameters of the reproduction direction, the number of continuous reproduction frames and the double speed number set by the task execution means To the frame data sequentially read from the second buffer area. By providing an information reproduction processing means for performing information reproduction process, to solve the problems described above.

  In addition, the mobile phone terminal of the present invention includes at least a calling means for performing a wireless call, a task execution means capable of simultaneously executing a plurality of task processes including a task process related to a wireless call, and a plurality of continuous time orders. A first buffer area for temporarily storing a predetermined number of frame data consecutive in time order read by the task execution means from the stream data storage means storing bit stream data composed of frame data; A buffer means having a second buffer area in which the frame data accumulated in the first buffer area is copied and temporarily accumulated; a reproduction direction set by the task execution means, a continuous reproduction frame number, and a double speed Based on the number parameter, the frame data is read from the first buffer area and the second buffer area is read out. In addition to copying, by providing a corresponding information reproduction processing means for performing predetermined information reproduction processing to sequentially read out the frame data from the second buffer area, to solve the problems described above.

  Here, the information reproduction processing means determines the movement direction of the read pointer for reading the frame data from the first buffer area based on the reproduction direction parameter, and the first buffer based on the parameter of the number of continuously reproduced frames. The frame data continuously reproduced from the area is read and copied to the second buffer area, and the number of frame skips for skipping the frame data from the first buffer area is determined based on the parameters of the number of continuously reproduced frames and the double speed number. I have to.

  In other words, according to the present invention, the information reproduction processing unit performs frame information reading and copy buffer management with respect to the first and second buffer areas of the buffer unit together with predetermined information reproduction processing for the frame data. On the other hand, the task execution means only needs to read a predetermined number of frame data from the stream data storage means and perform task processing for setting the parameters of the playback direction, the number of continuous playback frames, and the double speed number. Less processing burden.

  In the present invention, since the information reproduction processing means manages the buffer means, for example, predetermined task processing related to audio reproduction processing and high priority task processing such as call protocol processing are executed as tasks. Even when the means execute at the same time, the load on the task execution means can be reduced, so that audio reproduction processing can be performed while guaranteeing real-time performance without increasing costs and increasing power consumption. It is possible to accurately execute related predetermined task processing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, a mobile phone terminal will be described as an embodiment of the present invention. Of course, the content described here is merely an example, and it goes without saying that the present invention is not limited to this example.

[Main components of mobile phone terminals]
In FIG. 1, the structure of the principal part of the mobile telephone terminal of this embodiment is shown.

  In FIG. 1, a general mobile phone terminal includes a radio signal transmission / reception circuit including an antenna and a high-frequency circuit, a speaker and a microphone, an accompanying amplifier, an analog / digital converter, a digital / analog converter, For example, an interface for connecting headphones, a display such as a liquid crystal and its drive circuit, an interface for connecting an external memory and an external device, and the like are not shown.

  In FIG. 1, hardware modules such as a CPU 11, a DSP 12, a temporary RAM 33, a storage device 34, a ROM 35, and an operation module 37, which are main components of the mobile phone terminal according to the present embodiment, are connected via a main bus. . The CPU 11, DSP 12, and temporary RAM 33 are provided in the baseband LSI 1 that performs baseband processing.

  The audio module 17 includes a digital / analog converter (DAC) device and amplifier (AMP) 18, a speaker interface (not shown), and the like, and outputs an audio signal from the DSP 12 to a speaker, headphones, or the like.

  The storage device 34 is a built-in or external storage medium. For example, a flash memory and its memory controller are mounted on the storage device 34. The audio encoding data in the present embodiment is stored in the storage device 34.

  The temporary RAM 33 is a memory for temporarily accumulating the audio encoded data read from the storage device 34 when the DSP 12 decodes the audio encoded data.

  The operation module 37 generates an operation signal when the user operates a numeric keypad, a power / end call key, an utterance key, other various keys, a jog dial, or the respective keys provided in a general mobile phone terminal. It consists of an operation signal generation circuit and the like.

  The CPU 11 is a control master, and controls the operation module 37 when playing back digital audio according to the embodiment of the present invention, in addition to control and calculation processing related to various functions in a general mobile phone terminal, control and calculation processing during execution of various applications. Control according to the playback request input from the user, for example, “playback” (including special playback such as “fast forward playback” and “fast reverse playback”), “stop”, “volume change”, “low range” In response to requests such as “emphasis” and “reproduction time display”, various task processes such as control of each module are executed.

  Further, the CPU 11 of the present embodiment transmits a command for setting each parameter of “playback direction”, “number of continuous playback frames”, and “double speed” to the DSP 12 during digital audio playback. When a response is returned from the DSP 12, a “reproduction start” command is transmitted to the DSP 12, or the desired audio encoded data is read from the storage device 34 via the main bus and transferred to the temporary RAM 33. .

  The DSP 12, in addition to various arithmetic processes related to the signal transmission / reception function in a general mobile phone terminal, as well as the function of executing the decoding process of the audio encoded data according to the embodiment of the present invention, the frame data stored in the temporary RAM 33 is sent to the CPU 11 It also has buffer management functions such as rearrangement processing and read processing according to the “reproduction direction”, “continuous reproduction frame number”, and “double speed number” set by.

  The linear PCM audio data obtained by the decoding process in the DSP 12 is sent to the audio module 17 via the audio serial interface (I / F).

  Furthermore, the DSP 12 of this embodiment also has a function of calculating a playback time by multiplying the decoded frame number by the playback time of one frame, and a function of sending the playback time information to the CPU 11.

  Note that the mobile phone terminal according to the present embodiment can also execute processes other than the above-described audio reproduction, for example, image drawing processing on a display, protocol processing, and the like by multitasking.

  The ROM 35 is a control / calculation program for the CPU 11 to control each part and perform various arithmetic processes, various initial setting values, a program for performing character input processing, dictionary data, and the telephone number of the mobile phone terminal. , Font data, a control program for digital audio playback according to the present embodiment, a table 36 indicating correspondence between audio special playback during multitask execution and other tasks as described later, and other mobile phone terminals. Programs for various applications, identification information (ID) of the mobile phone terminal, and the like are stored.

  The ROM 35 includes a rewritable ROM such as an EEPROM, and includes e-mail data, a telephone directory and e-mail address set by the user, downloaded photo data and ringtone data, the table 36, and other various users. It is also possible to update and save setting values and the like.

  Further, in FIG. 1, a path (a) and a path (b) in the figure indicate command transmission / reception paths between the CPU 11 and the DSP 12, and for example, “playback” is performed via these paths (a) and (b). Command for setting each parameter of “reproduction direction”, “number of continuous reproduction frames”, “number of double speeds”, “reproduction start” command, and response transmission / reception according to these commands.

  A path (c) in the figure indicates a transfer path of audio encoded data from the storage device 34 to the temporary RAM 33.

  Data transfer from the storage device 34 to the temporary RAM 33 via the path (c) is controlled by a memory controller (MEMC) of the CPU 11.

  Specifically, when the CPU 11 receives an empty request (frame empty request) of the temporary RAM 33 from the DSP 12, the CPU 11 reads the audio encoded data from the storage device 34 and transfers it to the temporary RAM 33 via the main bus.

  A path (d) in the figure indicates a path when frame data is transferred from the temporary RAM 33 to the work RAM in the DSP when the DSP 12 executes the decoding process of the audio encoded data.

  That is, in the present embodiment, the DSP 12 and the temporary RAM 33 are connected via the DSP memory bus, and the frame data is transferred through the DSP memory bus in the path (d).

[Control sequence during normal audio playback]
FIG. 2 shows a control sequence at the time of normal audio reproduction (forward normal speed reproduction) in the cellular phone terminal of this embodiment.

  In FIG. 2, when starting normal audio reproduction (forward normal speed reproduction), the CPU 11 first sets the “reproduction direction” to “forward direction” with respect to the DSP 12 as a process T1 through the path (a) in FIG. ”,“ Continuous playback frame number ”is set to“ 1 ”, and“ Double speed number ”is set to“ 1 ”.

  Although details will be described later, the DSP 12 performs buffering of the temporary RAM 33 based on these pieces of information when performing audio reproduction thereafter.

  Upon receiving these commands, the DSP 12 returns a response (response) to the CPU 11 through the path (b) in FIG. 1 as process T2.

  When receiving the response of the process T2 from the DSP 12, the CPU 11 sends a reproduction start command to the DSP 12 through the path (a) in FIG. 1 as the process T3.

  Receiving this reproduction start command, the DSP 12 returns a response through the path (b) in FIG. 1 as processing T4, and then issues a frame transmission request to the CPU 11 while referring to the data storage status of the buffer in the temporary RAM 33. To do.

  When receiving a frame transmission request from the DSP 12, the CPU 11 transfers frame data from the storage device 34 to the temporary RAM 33.

  At this time, if information indicating how many frames are stored in the cluster in the storage device 33 exists in the storage device 33, the CPU 11 also adds the information and transfers it to the temporary RAM 33.

  On the other hand, if there is no such information, the CPU 11 reads the frame data in units of clusters of the storage device 33 and transfers it to the temporary RAM 33.

  Then, the DSP 12 performs buffering of the temporary RAM 33 based on the “reproduction direction”, “number of continuous reproduction frames”, and “double speed number” set by the CPU 11 as described later, and passes the path (d) in FIG. Thus, the frame data to be reproduced is sequentially extracted from the temporary RAM 33 and decoded.

  The DSP 12 issues a frame empty request (frame transmission request) to the CPU 11 as processes T5, T6, and T7 each time the buffer of the temporary RAM 33 becomes empty during audio playback.

  The time interval at which the frame empty request is issued is an interval according to the number of frames stored in the buffer of the temporary RAM 33.

[Buffer management during normal audio playback]
Next, the buffer configuration of the temporary RAM 33 and the state of buffer management performed by the DSP 12 on the temporary RAM 33 during normal audio playback will be described with reference to FIG.

  The temporary RAM 33 includes, for example, SIDE (A), SIDE (B), and SIDE (C), which are buffers corresponding to three planes in which block data composed of a plurality of frame data is transferred from the storage device 34 and stored therein. For example, the buffer SIDE (A), SIDE (B), or SIDE (C) is stored with the frame data copied and stored, for example, two buffers for temporary (A) and temporary (B). ing.

  The buffer size of the SIDE (A), SIDE (B), and SIDE (C) is a size obtained by adding a block header to the cluster size of the storage device 34.

  If there is information on how many frames are stored in the cluster of the storage device 34, the information is stored in the block header. The DSP 12 monitors the buffers SIDE (A), SIDE (B), and SIDE (C) on these three surfaces, and issues a frame empty request to the CPU 11 every time one of the surfaces becomes empty.

  These three-sided buffers SIDE (A), SIDE (B), and SIDE (C) are cyclically used as SIDE (A) → SIDE (B) → SIDE (C) → SIDE (A). The

  The buffer sizes of temporary (A) and temporary (B) are defined by the maximum number of continuous playback frames × frame size. The frame size is, for example, the frame size of the maximum bit rate of the audio bit stream so as to be compatible with VBR (Variable Bit-Rate).

  When performing normal audio reproduction using the temporary RAM 33 having such a buffer configuration, the DSP 12 first copies the frame data stored in the SIDE (A) to the temporary (A). This copy of the frame data is repeated for the maximum number of temporary (A) continuous playback frames.

  Note that FIG. 3 shows an example in which the number of continuous playback frames is fixed to “4” during normal audio playback, and therefore, data for four frames is copied to temporary (A).

  When the DSP 12 completes the data copy for four frames in the temporary (A), the DSP 12 copies the data for one frame from the temporary (A) to the work RAM in the DSP 12 and performs the decoding process.

  In addition, during the decoding of the frame stored in the temporary (A), the DSP 12 copies the next 4 frame data of the 4 frame data copied to the temporary (A) to the temporary (B) as described above. The DSP 12 executes a buffering process that repeats the above-described copy operation in synchronization with the real-time process of the internal OS.

  Further, the DSP 12 executes switching from SIDE (A) to SIDE (B) when the frame in SIDE (A) becomes empty.

  When the block header is added to the block data, the DSP 12 determines whether it is empty or not based on the information of the block header, and when the number of stored frames becomes “0”, the DSP 12 Judge.

  On the other hand, when the block header is not added to the block data, the DSP 12 calculates the frame length from the bit rate information and the frame header information added to the frame, and the total size of the frame lengths in the cluster is the cluster size. When the value exceeds, the buffer surface is switched and a frame empty request is transmitted to the CPU 11.

  The DSP 12 cyclically performs the buffer surface switching process in the order of SIDE (A) → SIDE (B) → SIDE (C) → SIDE (A).

[Control sequence during special playback]
Next, FIG. 4 shows a control sequence when special playback is performed in the mobile phone terminal of the present embodiment.

  Here, in this embodiment, the control sequence for performing special playback is the same as the control sequence for normal playback described above, but the differences are the “playback direction” and “continuous playback” parameters at the start of playback. This is the setting of the “number of frames” and “double speed number” and the frame transmission request (frame empty request) issuance interval from the DSP 12 to the CPU 11.

  For example, in the case of “fast forward 5 × speed playback”, the CPU 11 indicates to the DSP 12 that “playback direction” is “forward”, “continuous playback frame number” is “arbitrary number”, and “double speed number” is “5”. Send a command with the setting parameter.

  Note that the “number of continuously reproduced frames” can be set to “2”, for example. Further, for example, in the case of “fast reverse 7 × speed playback”, the CPU 11 instructs the DSP 12 that “playback direction” is “reverse direction”, “continuous playback frame number” is “arbitrary number”, and “double speed number” is “ 7 ”is sent as a setting parameter command.

  Further, the frame transmission request (frame empty request) issuance interval depends on the set value of the double speed number. That is, when the transmission request issuance interval during normal reproduction is Msec (seconds), when N-times special reproduction is performed, the transmission request issuance interval during special reproduction is M / Nsec.

  As described above, according to the present embodiment, the control sequence and the processing flow for performing special reproduction are the same as the control sequence and processing flow for normal reproduction, and a single control sequence is used for both special reproduction and normal reproduction. Various reproductions can be executed in the processing flow.

  Further, according to the present embodiment, the CPU 11 only needs to transfer data from the storage device 34 to the temporary RAM 33, and the DSP 12 performs buffer management of the temporary RAM 33, frame skip processing, and the like for both special reproduction and normal reproduction. Therefore, the CPU 11 does not need to perform such buffer management or frame skip processing, and thus the processing load on the CPU 11 can be reduced.

[Buffer management during fast-forward playback]
Next, the buffer configuration of the temporary RAM 33 and the state of buffer management performed by the DSP 12 on the temporary RAM 33 during fast-forward playback will be described with reference to FIGS. 5 and 6 show an example in which “reproduction direction” is set to “forward direction”, “double speed number” is set to “5”, and “continuous reproduction frame number” is set to “2”.

  In the case of fast-forward playback, the difference from the normal playback described above is the frame skip processing and the setting of the number of frames stored in the temporary (A) and temporary (B).

  The frame skip process is a process of skipping a read pointer on a buffer of any one of SIDE (A), SIDE (B), and SIDE (C) (hereinafter referred to as SIDE (X)) by a predetermined number of frames.

  Here, how many frames the read pointer is skipped can be easily calculated from “double speed number” and “continuous playback frame number”. For example, “double speed number” is “n” and “continuous playback frame number” is “ In the case of “m”, “the number of frame skips x” can be obtained by calculation of x = (n × m) −m.

  That is, in the case of fast-forward playback, the DSP 12 obtains a “frame skip number” from the “double speed number” and “continuous playback frame number” set by the CPU 11, and in accordance with the “frame skip number”, SIDE (X The buffer management is performed so that the read pointer is skipped.

  In the case of the examples of FIGS. 5 and 6, the “reproduction direction” is “forward direction”, the “continuous reproduction frame number” is “2”, and the “double speed number” is “5”. Therefore, the DSP 12 moves the read pointer in the temporary RAM 33 to the 26th frame after the 25th frame, for example, and then skips forward for 8 frames to indicate the 35th frame. After that, it is moved to the 36th frame.

  Further, in the case of fast-forward playback, the “playback direction” is “forward” on the time axis, so either SIDE (X) to temporary (A) or temporary (B) (hereinafter referred to as temporary (X)). In the process of copying to the buffer (), the read pointer of the SIDE (X) is set to “forward direction”, and “m” frames of the “number of continuously reproduced frames” are copied to the temporary (X) buffer.

  When copying for “m” frames is completed, the read pointer is moved in the forward direction by “frame skip number ×” by “m” frames of “frame size” × “number of continuously reproduced frames”.

  That is, in the case of fast-forward playback, the DSP 12 performs frame copy for “number of continuously played frames” from SIDE (X) to temporary (X), and after the copy is completed, “frame size” in the forward direction for “number of frame skips”. X Buffer management is performed so that the read pointer is moved by the number of “continuous playback frames”.

  In the case of the example of FIGS. 5 and 6, since the “reproduction direction” is “forward direction”, the “number of continuous reproduction frames” is “2”, and the “double speed number” is “5”, the DSP 12 After the 25th and 26th frames of (A) are copied to temporary (A), the read pointer is skipped forward by 8 frames, and the 35th and 36th frames of SIDE (A) are temporarily stored (B). Will be copied.

  As described above, when frames are stored on both the temporary (A) and temporary (B) sides, the DSP 12 first reads one frame from the temporary (A) and copies it to the internal work RAM. The decoding process starts.

  After the start of the decoding process, the DSP 12 monitors whether one of the temporary (A) and temporary (B) is empty at every decoding cycle. As soon as it becomes empty, the “continuous playback frame” The process of copying “number” from the buffer of SIDE (X) is executed.

  When the SIDE (A), SIDE (B), and SIDE (C) buffers are empty, the DSP 12 performs monitoring after executing copying to the temporary (X), as in the normal playback described above. A frame empty request (frame transmission request) is issued to the CPU 11.

  5 and FIG. 6, the DSP 12 first reads and decodes the 25th frame of the temporary (A), and then moves the read pointer forward to move the 26th frame. Read and decode processing is performed, and then the 35th frame of temporary (B) is read and decoded, and then the read pointer is moved in the forward direction to read and decode the 36th frame.

  Further, the DSP 12 executes a process of copying from the buffer of the next SIDE (B) when either the temporary (A) or the temporary (B) becomes empty.

[Buffer management during fast reverse playback]
Next, the buffer configuration of the temporary RAM 33 and the state of buffer management performed by the DSP 12 on the temporary RAM 33 during fast reverse playback will be described with reference to FIGS.

  7 and 8 show an example in which “reproduction direction” is set to “reverse direction”, “double speed number” is set to “10”, and “continuous reproduction frame number” is set to “1”.

  In the case of fast reverse playback, since the “reproduction direction” is “reverse” on the time axis, the direction in which the read pointers of the three-sided buffers of SIDE (A), SIDE (B), and SIDE (C) advance is described above. This is set in the opposite direction to normal playback and fast forward playback. Other buffering processing and the like are the same as in the case of the fast-forward playback described above.

  That is, in the case of fast reverse playback, the DSP 12 obtains a “frame skip number” from the “double speed number” and the “continuous playback frame number” set by the CPU 11, and in accordance with the “frame skip number”, SIDE (X The buffer management is performed so that the read pointer is skipped in the reverse direction.

  7 and 8, the “reproduction direction” is “reverse direction”, the “number of continuous reproduction frames” is “1”, and the “double speed number” is “10”. Therefore, the DSP 12 copies the 36th frame of SIDE (A) to the temporary (A), for example, and then skips the read pointer by 9 frames in the reverse direction to make the 26th of SIDE (A). The frame is moved and the 26th frame is copied to the temporary (A).

  As described above, when frames are stored on both the temporary (A) and temporary (B) sides, the DSP 12 copies one frame to the internal work RAM and starts executing the decoding process for the frames. To do.

  7 and 8, the DSP 12 first reads and decodes the 36th frame of the temporary (B), and then moves the read pointer in the reverse direction to move the temporary (A The 26th frame is read and decoded.

  Further, when either the temporary (A) or the temporary (B) becomes empty, the DSP 12 executes a process of copying from the next SIDE (X) buffer to be read.

[DSP task schedule]
FIG. 9 shows a task timing chart in the DSP 12 during normal playback and special playback as described above.

  In FIG. 9, the period of task A indicates the period during which the DSP 12 is decoding the audio bitstream, and the period of task B is the SIDE (A), SIDE (B), SIDE of the temporary RAM 33 described above. (C), temporary (A), and temporary (B) buffering processes are shown.

  Further, T in FIG. 9 is a unit reproduction time of linear PCM audio data after decoding processing.

  As can be seen from FIG. 9, according to the present embodiment, even when a task for special reproduction is being executed, there is sufficient time margin, so that real-time performance of audio reproduction can be ensured.

[Special regeneration control according to bus traffic]
Further, according to the present embodiment, when performing fast reverse playback or fast forward playback by the buffer management by the DSP 12 as described above, by arbitrarily changing the “number of continuous playback frames” and “number of frame skips”, The number of double speeds can be changed flexibly. For example, it is possible to perform playback at 6 × speed at first, and change to 20 × speed playback after a few seconds without any sequence change.

  For this reason, in the present embodiment, for example, the system bus is changed by changing the “number of continuous playback frames” and “number of frame skips” during special playback according to the processing load during multitask execution. It is also possible to achieve optimal special playback according to traffic.

  That is, for example, in the present embodiment, by changing the “number of continuous playback frames” and “number of frame skips” during the special playback according to the priority of other tasks executed simultaneously with the task of the special playback processing, In addition, it is possible to guarantee real-time audio reproduction without interfering with the processing of tasks with high priority.

  Here, in the present embodiment, as one specific example, correspondence information between the “number of continuous playback frames” and “number of frame skips” for audio special playback and the priority of other tasks executed in multitasking is shown. , Prepared in the table 36 of the ROM 35, and when executing multitasking, the “continuous playback frame number” and “frame skip number” corresponding to the priority of the other task being executed are referred to from the table 36 and obtained. In addition, special playback is performed at a multiple of the number of continuous playback frames and the number of frame skips.

  Of course, this is only an example, and the actual bus traffic is measured without using a table, and the optimum values of “the number of consecutively played frames” and “the number of frame skips” are calculated according to the measured values. Also good.

[Summary]
As described above, according to the present embodiment, it is possible to reduce the processing load on the CPU 11 side by performing frame skip processing and buffer management during special playback in the DSP 12.

  Further, according to the present embodiment, the bit stream transfer processing in the CPU 11 at the time of special playback can be made the same as that at the time of normal playback, the processing flow can be unified, and the CPU 11 can transfer from the storage device 34 to the temporary RAM 33. Since it is only necessary to perform data transfer and parameter setting such as “reproduction direction”, “number of continuous reproduction frames”, and “number of double speeds”, the processing load on the CPU 11 side can be reduced.

  In addition, according to the present embodiment, the “number of continuous playback frames” and the “number of frame skips” at the time of special playback can be set flexibly. For example, the system bus traffic, the priority of other tasks at the time of multitask execution, etc. Accordingly, it is possible to realize optimum special reproduction.

  Furthermore, according to the present embodiment, since the frame skip processing is executed by the DSP 12, the DSP 12 can calculate the playback time during the audio playback from the number of frame skips.

  That is, the DSP 12 can obtain the audio playback time during special playback by multiplying the number of skipped frames by the playback time per frame. As a result, the CPU 11 does not have to perform the audio playback time calculation process, and the processing load on the CPU 11 can be reduced.

  Note that the audio playback time information obtained by this calculation is displayed on, for example, a display, etc., so that the user can know the audio playback time during special playback, that is, the progress of audio playback.

  In addition, according to the present embodiment, special reproduction of not only so-called CBR (Constant Bit-Rate) audio bitstream data but also VBR (Variable Bit-Rate) and ABR (Average Bit-Rate) audio bitstream data is performed. Even when it is performed, it can be dealt with by changing the size of each buffer surface in the temporary RAM 33, for example.

  In the present embodiment, the three-side buffer configuration of SIDE (A), SIDE (B), and SIDE (C) has been described as an example. However, if the temporary RAM 33 has sufficient resources, more buffer planes are provided. By securing it, it becomes possible to reduce the bit stream transfer amount per unit time, and it is possible to further guarantee the real-time property at the time of audio reproduction.

  The above description of the embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made according to the design or the like as long as the technical idea according to the present invention is not deviated.

  The present embodiment is not limited to a mobile phone terminal, and can be applied to various information processing apparatuses in which audio reproduction processing and other information processing with higher priority may be mixed. Thus, the desired special reproduction can be performed.

  In addition, in the above-described embodiment, audio reproduction is taken as an example, but the present invention can also be applied to special reproduction at the time of video reproduction, for example.

It is a block circuit diagram which shows the structure of the principal part concerning this invention among the internal structures of the mobile telephone terminal of this invention embodiment. 6 is a time flowchart used for explaining a control sequence when normal audio playback is executed in the mobile phone terminal of the present embodiment. FIG. 4 is a schematic buffer configuration diagram for explaining a buffer configuration of a temporary RAM of the mobile phone terminal according to the present embodiment and a state of buffer management performed by the DSP for the temporary RAM during normal audio playback. 6 is a time flowchart used for explaining a control sequence when audio special reproduction is executed in the mobile phone terminal of the present embodiment. FIG. 4 is a schematic buffer configuration diagram for explaining a buffer configuration of a temporary RAM of the mobile phone terminal according to the present embodiment and a state of buffer management performed by the DSP for the temporary RAM during audio fast-forward playback. In the mobile phone terminal of this embodiment, it is a figure used for description of the specific flow of the buffering which DSP performs with respect to temporary RAM at the time of audio | voice fast-forward reproduction | regeneration. FIG. 4 is a schematic buffer configuration diagram for explaining a buffer configuration of a temporary RAM of the mobile phone terminal according to the present embodiment and a state of buffer management performed by the DSP for the temporary RAM during audio fast-reverse playback. In the mobile phone terminal of this embodiment, it is a figure used for description of the specific flow of the buffering which DSP performs with respect to temporary RAM at the time of audio | voice rewind reproduction | regeneration. 5 is a task timing chart in the DSP during normal playback and special playback in the mobile phone terminal of the present embodiment.

Explanation of symbols

  1 baseband LSI, 11 CPU, 12 DSP, 17 audio module, 18 digital / analog converter and headphone amplifier, 33 temporary RAM, 34 storage device, 35 ROM, 36 table, 37 operation module

Claims (7)

Task execution means capable of executing multiple task processes simultaneously;
For temporarily accumulating a predetermined number of frame data consecutive in time order read by the task execution means from the stream data storage means storing bit stream data composed of a plurality of frame data continuous in time order Buffer means having a first buffer area and a second buffer area in which the frame data accumulated in the first buffer area is copied and temporarily accumulated;
Based on the playback direction, continuous playback frame number and double speed number parameters set by the task execution means, the frame data is read from the first buffer area of the buffer means and copied to the second buffer area, and An information processing apparatus comprising: information reproduction processing means for performing predetermined information reproduction processing on frame data sequentially read from the second buffer area. The information processing apparatus according to claim 1,
The information reproduction processing means is
Based on the playback direction parameter set by the task execution means, determine the moving direction of the read pointer for reading frame data from the first buffer area of the buffer means,
Based on the parameter of the number of continuously reproduced frames set by the task executing means, the frame data to be continuously reproduced is read from the first buffer area of the buffer means and copied to the second buffer area,
An information processing apparatus for determining a frame skip number for skipping frame data from the first buffer area of the buffer means based on the parameters of the continuous reproduction frame number and the double speed number set by the task execution means . The information processing apparatus according to claim 1,
In response to a frame transmission request from the information reproduction processing means, the task execution means reads out the predetermined number of frame data from the stream data storage means, accumulates the frame data in the first buffer area of the buffer means,
The information reproduction processing means monitors the first buffer area of the buffer means, and sends the frame transmission request to the task execution means when the first buffer area becomes empty. An information processing apparatus, wherein the second buffer area is monitored, and when the second buffer area becomes empty, the frame data is read from the first buffer area and copied to the second buffer area. The information processing apparatus according to claim 1,
The first buffer area of the buffer means has a plurality of buffer surfaces for storing a plurality of predetermined number of frame data,
The second buffer area of the buffer means has a plurality of buffer surfaces for storing at least the frame data by the maximum value of the number of continuously reproduced frames,
The information reproduction processing means cyclically uses a plurality of buffer surfaces of the first buffer area, and cyclically uses a plurality of buffer surfaces of the second buffer area. . An information processing apparatus according to claim 4,
The information reproduction processing means determines the size of the first buffer area and the second buffer area of the buffer means based on the reproduction direction, the number of continuous reproduction frames and the double speed parameter set by the task execution means. An information processing apparatus characterized by varying at least one of the number of buffer surfaces. The information processing apparatus according to claim 1,
The task execution means is executed simultaneously with a task process for reading the predetermined number of frame data from the stream data storage means and a task process for setting parameters of the reproduction direction, the number of continuous reproduction frames, and the double speed number, An information processing apparatus characterized in that the setting of the parameters of the number of continuous playback frames and the number of times of speed is changed based on the type of task processing or the processing load. A calling means for making at least a wireless call;
Task execution means capable of simultaneously executing a plurality of task processes including a task process related to a wireless call;
For temporarily accumulating a predetermined number of frame data consecutive in time order read by the task execution means from the stream data storage means storing bit stream data composed of a plurality of frame data continuous in time order Buffer means having a first buffer area and a second buffer area in which the frame data accumulated in the first buffer area is copied and temporarily accumulated;
Based on the playback direction, continuous playback frame number and double speed number parameters set by the task execution means, the frame data is read from the first buffer area of the buffer means and copied to the second buffer area, and An information reproduction processing means for performing predetermined information reproduction processing on frame data sequentially read from the second buffer area.

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