JP2013125573A - Digital reproduction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calculate the exact total reproduction time of recording media in which storage is performed in a variable bit rate file format.SOLUTION: Reproduction of an optical disk 11 in which an audio digital signal in a variable bit rate file format, for example, an MP3 format is stored is instructed, a digital audio signal is generated, and file analysis information is simultaneously extracted. Whether the file analysis information is a variable bit rate is determined, and in the case of the variable bit rate, the total data size, reproduced data size, and reproduction lapse time of the digital audio signal are extracted, respectively. The corrected total reproduction time ((the reproduction lapse time)÷(the reproduced data size)×(the audio total data size)) is calculated based on the total size, the reproduced data size, and the reproduction lapse time of the digital audio signal to be displayed as the total reproduction time.

Description

  Embodiments described herein relate generally to a digital playback apparatus capable of reliably calculating the total playback time of a recording medium stored in a variable bit rate file format.

  Conventionally, VBR (Variable Bit Rate) is known as one of the techniques for encoding audio data by MP3 (MPEG-1 Audio Layer 3). The MP3 playback time is determined by comparing the playback progress time detected from the data being played back with the playback progress time currently being displayed and output, and based on the comparison result, the playback progress time detected at that time It is determined whether to display the value or to keep the time value of the reproduction progress time currently displayed on the display.

JP 2008-204551 A

  The total playback time when there is no conventional variable bit rate header information cannot obtain various information necessary for calculating the total playback time, so the playback progress time detected from the data being played back and the current display output Based on the result of comparison with the playback progress time, it is determined whether to display the time value of the playback progress time or to keep the time value of the playback progress time currently displayed on the display.

  However, there is still a large error from the actual total playback time in both cases of displaying the playback progress time value at the variable bit rate and displaying the playback progress time value currently displayed. When there is an error, the total playback time display will continue even if the total playback time of the display is exceeded, or conversely the playback will end before reaching the total playback time of the display. There was a problem.

  In this embodiment, a digital playback device is provided in which the total playback time of a digital audio signal stored in a variable bit rate file format is made closer to the actual time.

  According to the embodiment, a playback unit that plays back a digital audio signal in a variable bit rate format from a stored storage medium, a file analysis unit that extracts a total data size and a played back data size of the digital audio signal, and the digital A digital signal processing unit that performs decoding processing of the audio signal and extracts the elapsed playback time of the digital audio signal in the course of the decoding processing, and correction based on the playback elapsed time, the total data size, and the reproduced data size A control unit that calculates the total reproduction time by (reproduction elapsed time) / (reproduced data size) × (audio total data size); and a display unit that displays the corrected total reproduction time.

It is a circuit block diagram for demonstrating 1st Embodiment regarding a digital reproduction apparatus. It is explanatory drawing for demonstrating the conceptual data structure of the digital audio signal of a variable bit rate file. It is explanatory drawing for demonstrating the process of correction | amendment total reproduction time. It is explanatory drawing for demonstrating 2nd Embodiment regarding a digital reproduction apparatus. It is explanatory drawing for demonstrating 3rd Embodiment regarding a digital reproduction apparatus. It is explanatory drawing for demonstrating 4th Embodiment regarding a digital reproduction apparatus.

  Hereinafter, embodiments will be described in detail with reference to the drawings. In the drawings described below, components having the same function are denoted by the same reference numerals, and repeated description thereof is omitted.

(First embodiment)
FIG. 1 is a circuit configuration diagram for explaining a first embodiment relating to a digital playback device, and FIG. 2 is an explanatory diagram for explaining a conceptual data structure of a digital audio signal of a variable bit rate file. .

  The digital playback device 100 of FIG. 1 shows a circuit configuration diagram of an MP3 player. An optical disk 11 as a recording medium is an optical disk in which a digital audio signal having a data structure shown in FIG.

  During reproduction by operating the operation unit 10, the spindle motor 12 is rotated and driven to rotate at a constant linear velocity (CLV) or a constant angular velocity (CAV). The optical pickup 13 irradiates the optical disk 11 with laser and detects the reflected light. The reflected light detection signal is supplied to the RF amplifier 14. The RF amplifier 14 amplifies an RF signal corresponding to the data read by the optical pickup 13 and transmits the amplified RF signal to the file analysis unit 15. Further, the RF amplifier 14 separates the focus control signal and the tracking control signal from the RF signal, and sends these control signals to the servo control unit 20.

  The file analysis unit 15 analyzes the format of the RF signal transmitted from the RF amplifier 14 and supplies the analysis result to the control unit 17. Further, the file analysis unit 15 calculates the total playback time of the optical disk 11 before starting playback based on the total data size of the digital audio signal stored on the optical disk 11 and the average bit rate of the sampled digital audio signal. Further, the file analysis unit 15 calculates the reproduced data size from the difference between the read address of the current data and the audio head address.

  The digital signal processing unit 16 performs demodulation processing and error correction processing of the RF signal sent via the file analysis unit 15 and stores data obtained in the process of signal processing by the digital signal processing unit 16 in a RAM (not shown). Store in (Random Access Memory). Further, the control signal is separated from the digital signal, and the separated control signal is sent to the servo control unit 20 and the control unit 17.

  The digital signal processing unit 16 performs frame-by-frame decoding during the MP3 decoding process, and performs calculation processing of the elapsed playback time at the time of this frame decoding. The calculation of the elapsed playback time of the MP3 digital audio signal file can be obtained by calculating (data amount from the beginning of the file to the current playback position) / (bit rate).

  The digital audio signal demodulated by the digital signal processing unit 16 is supplied to the D / A converter 18, converted into an analog audio signal, and supplied to the audio output unit 19. The audio output unit 19 includes an audio signal generation unit, an amplification circuit unit, and a speaker (not shown), and performs audio output.

  The servo control unit 20 executes servo control such as focus servo control and tracking servo control based on the focus error signal and tracking error signal generated by the RF amplifier 14. That is, a focus drive signal and a tracking drive signal are generated according to a focus error signal and a tracking error signal, and a biaxial mechanism holding the objective lens in the optical pickup 13 is driven by the biaxial driver 21 to perform focus servo control, Perform tracking servo control. The servo control unit 20 also controls movement of the optical pickup 13 in the disk radial direction by a thread mechanism (not shown).

  In addition, the servo control unit 20 generates a spindle servo signal based on, for example, rotation speed error information obtained from the digital signal processing unit 16, and controls the rotation driving of the spindle motor 12 by the spindle driver 22. Servo control of rotation or CAV rotation is performed.

  The control unit 17 includes a microcomputer having a CPU (Central Processing Unit), a memory area, an interface unit, and the like, and performs overall control of the playback apparatus 100 and various arithmetic processes based on an operation program.

  In addition, the control unit 17 calculates a corrected total playback time for correcting that the total playback time of the optical disc 11 calculated by the file analysis unit 15 before the start of playback is different from the actual total playback time. The corrected total reproduction time is calculated by the following equation based on the total data size of the digital audio signal calculated by the file analysis unit 15, the reproduced data size, and the reproduction elapsed time calculated by the digital signal processing unit 16.

Here, the corrected total playback time is the total playback time of the optical disc 11 calculated based on the total data size of the digital audio signal stored on the disc at the start of playback of the optical disc 11 and the average bit rate of the sampled digital audio signal. On the other hand, it is the total playback time recalculated by the following equation during playback.

  The control unit 17 outputs the calculated corrected total reproduction time to the reproduction time display unit 23. The corrected total playback time represents the total time corrected for the playback elapsed time, and is calculated, for example, at regular intervals. The reproduction time display unit 23 displays the calculated corrected total reproduction time.

  The playback time display unit 23 may display the elapsed time from the audio head address, or may display the playback time counted up according to the playback of the digital audio signal. These elapsed time and playback time may be displayed separately or simultaneously.

  Thus, the corrected total playback time becomes closer to the actual total playback time as time elapses. In other words, the accuracy of the total playback time can be improved as playback approaches the end of the file.

  Next, the corrected total reproduction time will be further described with reference to FIGS. FIG. 2 is an explanatory diagram of a conceptual data structure of a digital audio signal of a variable bit rate file, and FIG. 3 is an explanatory diagram for explaining processing of a corrected total reproduction time.

  When the operation unit 10 is operated to instruct the reproduction of the optical disk 11, the digital audio signal from the RF amplifier 14 is output and supplied to the file analysis unit 15, where the reproduction information signal is analyzed, and the control unit as file analysis information is analyzed. 17 is supplied. In step S1, the control unit 17 first determines whether the digital audio signal has a variable bit rate.

  In the case of the variable bit rate, the file analysis unit 15 extracts the total data size of the digital audio signal, the reproduced data size, and the reproduction elapsed time by the digital signal processing unit 16 (S2 to S4), and proceeds to step S5.

  In step S5, based on the total data size, reproduced data size, and elapsed playback time of the digital audio signal extracted in steps S2 to S4, (reproduced elapsed time) / (reproduced data size) × (total audio data size) To calculate the corrected total playback time.

  The control unit 17 outputs the calculation result of the corrected total reproduction time, and displays the total reproduction time from the reproduction time display unit 23 in step S6. Note that the processing of steps S2 to S6 is executed, for example, every second.

  In step S7, the control unit 17 controls the digital signal processing unit 16, outputs the digital audio signal to the D / A converter 18, converts the digital audio signal into an analog audio signal, and outputs the audio from the audio output unit 19.

  The corrected total playback time calculated by the algorithm of this embodiment can improve the accuracy as the playback approaches the end of the file. Further, since the extreme correction is a control to suppress, it is possible to provide the user with a playback time display, a playback progress bar display, and the like that suppress a sense of discomfort.

(Second Embodiment)
FIG. 4 is an explanatory diagram for explaining a second embodiment related to the digital playback device.

  In this embodiment, in order to increase the reliability of the calculated corrected total playback time, the update is started after the playback elapsed time reaches the set time of the total playback time calculated by the file analysis unit 15 before the playback starts. It is what you do.

  That is, when the pre-processing of step S5 for calculating the corrected total reproduction time in the flowchart shown in FIG. 3 reaches, for example, 1/2 hour or more of the total reproduction time calculated before the start of reproduction, the process of step S4 is performed. Step S401 is added.

  In this case, the result of extracting the elapsed playback time, which is a factor for calculating the corrected total playback time, for the first time when the total playback time calculated before the start of playback reaches, for example, ½ hour or more is calculated. It will be displayed as playback time. Thus, the display is performed in a state where the accuracy of the corrected total reproduction time is improved, and the reliability of the displayed total reproduction time display can be improved.

  In this embodiment, the total playback time is displayed when the total playback time reaches, for example, ½ hour or more. For this reason, the closer the playback is to the end of the file, the closer the display of the total playback time becomes to the actual total playback time.

(Third embodiment)
FIG. 5 is an explanatory diagram for explaining a third embodiment relating to a digital playback device.

  In this embodiment, in order to improve the reliability of the calculated corrected total playback time, when the error width between the total playback time and the corrected total playback time at the time after the process of step S5 is wide (S501), the total The average of the reproduction time and the corrected total reproduction time is set as the total reproduction time (S502).

  In this embodiment, when the error width between the total reproduction time and the corrected total reproduction time is wide, by taking the average of these times, it is possible to suppress the user's uncomfortable feeling with respect to the time display.

(Fourth embodiment)
FIG. 6 is an explanatory diagram for describing a fourth embodiment relating to a digital playback device.

  In this embodiment, in order to increase the reliability of the calculated corrected total playback time, if the playback elapsed time exceeds the corrected total playback time after the process of step S5 (S601), the playback elapsed time is corrected to the corrected total playback time. Time is used (S602).

  In this embodiment, when the elapsed playback time exceeds the corrected total playback time, the elapsed playback time is set as the corrected total playback time, thereby preventing an event that exceeds the total playback time of the display.

  In addition, although the above-mentioned 2nd-4th embodiment may be individual, it may be what combined all or some embodiment. Furthermore, as a display example of the playback time display unit 23, it is possible to use the progress of playback on the bar display or to display the remaining time.

  Although several embodiments have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, combinations, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 100 Digital reproducing apparatus 10 Operation part 11 Optical disk 12 Spindle motor 13 Optical pick-up 14 RF amplifier 15 File analysis part 16 Digital signal processing part 17 Control part 18 D / A converter 19 Audio | voice output part 20 Servo control part 21 Biaxial driver 22 Spindle driver 23 Playback time display

Claims (4)

A playback unit for playing back a digital audio signal in a variable bit rate format from a stored storage medium;
A file analysis unit for extracting the total data size of the digital audio signal and the reproduced data size;
A digital signal processing unit that performs decoding processing of the digital audio signal and extracts a reproduction elapsed time of the digital audio signal in the course of decoding processing;
Based on the elapsed playback time, the total data size, and the played back data size, a control unit that calculates the corrected total playback time by (playback elapsed time) / (reproduced data size) × (total audio data size);
And a display unit for displaying the corrected total reproduction time.   2. The digital reproduction according to claim 1, wherein the calculation of the corrected total reproduction time starts after the set time has elapsed from the total reproduction time of the recording medium calculated based on an average bit rate of the digital audio signal sampled before the reproduction is started. apparatus.   When the difference between the total playback time of the recording medium calculated based on the average bit rate of the sampled digital audio signal and the corrected total playback time is wide, the average of the total playback time and the corrected total playback time is corrected to the total playback The digital playback device according to claim 1, wherein time is used.   The digital playback according to claim 1, wherein when the total playback time of the recording medium calculated based on the average bit rate of the sampled digital audio signal exceeds the corrected total playback time, the playback elapsed time is set as the corrected total playback time. apparatus.

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