JP4739898B2 - Reproduction time display method of encoded data and reproduction apparatus using the same - Google Patents

Description

  In the present invention, after data seek (fast forward / rewind) in encoded data recording compressed music or video in MP3 (MPEG-1 Audio Layer 3) format, WMA (Windows (registered trademark) Media Audio) format, etc. The present invention relates to a reproduction time display method of encoded data for calculating a reproduction resumption time and displaying the reproduction resumption time, and a reproduction apparatus for audio, video, etc. using the same.

  Conventionally, as a technique related to an audio apparatus for reproducing music encoded data in a reproducing apparatus having a function of displaying the reproduction time of encoded data recording compressed music or video such as MP3 format, for example, the following document There was something described in.

JP 2004-45590 A

  In a conventional audio apparatus of this type, as described in Patent Document 1, encoded data obtained by encoding audio data according to a predetermined audio compression method such as MP3 is filed for each song and stored in a storage medium (for example, , DVD (Digital Versatile Disc), hard disk, etc.) and have the function to play continuously or specify a desired song, the function to display the playing time and playback time for each song, etc. ing.

The reproduction function is realized by, for example, an individual circuit (hardware) or a software codec using a central processing unit (hereinafter referred to as “CPU”). In the case of downsizing the device, the size of the device increases when realized by hardware, and therefore a method realized by a software codec or the like is employed.

For example, when the playback function is realized by a software codec , it is necessary to calculate the playback restart time in order to display the playback restart time after data seek (fast forward / rewind) in the encoded data. As a conventional method for calculating the playback resumption time after data seek in encoded data, for example, methods shown in FIGS. 6 and 7 are known.

  FIG. 6 is a diagram showing a reproduction time calculation method in conventional encoded data, and FIG. 7 is a diagram showing a reproduction time calculation method in other conventional encoded data.

  In the encoded data reproduction time calculation method shown in FIG. 6, in the encoded data 1 for one song, the encoded data 1a from the beginning 2-1 to the reproduction resume position 2-2 after data seek is decoded by the decoder 3 ( The size of the decoded data 4 after decoding is obtained, and the reproduction time at the reproduction restart position 2-2 is calculated from this size.

  In another encoding data reproduction time calculation method shown in FIG. 7, for example, encoded data in a streaming format for real-time reproduction is used. In the case of streaming format encoded data, as described in Patent Document 1, etc., one piece of encoded data 5 is composed of a plurality of frames (decoding units) FR0, FR1, FR2, FR3, FR4, FR5,.・ It is composed of. Each frame FR0,... Has header data FH, and the header data FH includes data capable of calculating the time at which the frames FR0, FR1,. When the playback restart time at the playback restart position 6 after data seek is obtained, the playback restart time is calculated using the header data FH of the frame (for example, FR3) at the playback restart position 6.

  The conventional encoding data reproduction time calculation method as shown in FIGS. 6 and 7 has the following problems (a) to (c).

(A) Reproduction time calculation method of FIG. 6 For example, in an audio apparatus that reproduces encoded data using a software codec, when reproduction is resumed from the middle of encoded data 1 by an operation such as data seek as shown in FIG. In order to calculate the reproduction resume time at (reproduction resume position 2-2), the first encoded data 1 (the beginning 2-1) to the reproduction resume position 2-2 are decoded, and the size of the decoded data 4 is obtained. The playback restart time is calculated, but with such a method, the computation process takes time and the playback start response (response) becomes worse.

(B) Playback Time Calculation Method in FIG. 7 In the case of streaming format encoded data, the playback time calculation method as shown in FIG. 7 takes time until the frame (for example, FR3) at the playback start position 6 is acquired. The playback start response is poor.

(C) Response improvement method As a response improvement method in (a) and (b), for example, time information of decoded data 1 or frames FR0 , FR1,... Is secured in advance as a table (storage medium). In addition, a method of shortening the calculation process of the reproduction restart time is conceivable, but it is difficult to implement in an audio apparatus that cannot prepare a sufficient memory area for creating a table due to downsizing of the apparatus.

  Such problems (a) to (c) are also applicable to playback devices such as video devices other than audio devices.

In order to solve the conventional problems, the reproduction time display method of encode data in the present invention, in advance to calculate the average size of the decoded data for the encoded data, after the seek of the encoded data, from the head of the encoded data A first size from the beginning of the decoded data to the reproduction resuming position is predicted from the size to the reproduction resuming position after the seek and the average size, and the first size per time of the decoded data is predicted. The first predicted time at the reproduction resume position is calculated and displayed by dividing by the size, and after reproduction of the encoded data after the seek of the encoded data, the reproduction resume position of the decoded data from the second size to the playback position it is currently played, the decoded data Is added to the first prediction time after divided by the size of somewhere between, it calculates a second estimated time of the playback position, displaying the second prediction time as the playback time.

In other encode data playback time display method in the present invention, previously calculated average playback time of the frame in the encoding data composed of a plurality of frames, after the seek of the encoded data, the head of the encoded data The first predicted time at the playback restart position is calculated and displayed from the number of frames to the playback restart position after seek and the average playback time, and the encoded data after the seek of the encoded data is displayed. After resuming reproduction, the number of frames from the reproduction resumption position to the reproduction position currently being reproduced is divided by the average reproduction time, and then added to the first prediction time to obtain a second prediction of the reproduction position . The time is calculated and the second predicted time is displayed as the reproduction time.

  In the playback apparatus according to the present invention, playback means for playing back and fast forward / rewind encoded data, display means for displaying the time of the playback restart position and fast forward / rewind position in the encoded data, Control means for executing the reproduction time display method by a program.

  According to the playback time display method of encoder data and the playback apparatus using the same according to the present invention, the playback restart time is predicted and calculated after fast forward / rewind. The processing time can be shortened compared to the method of calculating the time after acquiring the decoded data or streaming data up to this time, and the response at the time of resuming playback can be obtained without creating a table that requires a large memory area as in the past. It becomes possible to improve. Furthermore, even when there is an error between the display time and the actual playback position time, the display time is adjusted, so that an accurate time can be displayed.

As the best mode for carrying out the invention, examples of the present invention will be described below.

(Configuration of Example 1)
FIG. 2 is a schematic configuration diagram showing the encoded data reproducing apparatus according to the first embodiment of the present invention.

  This reproduction apparatus for encoded data is an apparatus for reproducing the conventional encoded data 1 as shown in FIG. 6 or the conventional encoded data 5 in the streaming format as shown in FIG. 7 using a software codec. As the streaming format encoded data 5, for example, various data in which audio data is encoded by a compression encoding method such as MP3 format or WMA format can be applied.

The reproduction apparatus shown in FIG. 2 has an internal bus 10 for signal transmission. The internal bus 10 includes control means (for example, a control unit configured by a CPU) 11 for controlling the entire apparatus, work data, and the like. A data memory 12 composed of a memory (RAM) that can be read and written at any time, a program memory 13 composed of a read-only memory (ROM) for storing a program such as a software codec , and encoded encoded data (see FIG. The data storage unit 14 is connected to a storage medium such as a flash memory in which the encoded data 1 of FIG. 6 or the encoded data 5) of FIG. The control unit 11 also has a function as a reproducing unit.

  The internal bus 10 further displays an operation unit 15 having buttons for operating playback start, playback end, fast forward / rewind, etc., an audio output unit 16 such as a headphone terminal for outputting audio, and data. Display means (for example, a display unit composed of a liquid crystal display (LCD)) 17 and an I / O port 18 for inputting / outputting signals (hereinafter referred to as “I / O”) are connected. Has been.

(How to play encoded data)
Assume that one piece of encoded data 1 or 5 as shown in FIG. 6 or FIG. 7 is filed for each piece of music and stored in the data storage unit 14 of FIG.

When the song title data to be played back is input from the operation unit 15 in FIG. 2, the control unit 11 follows the playback program stored in the program memory 13 and encodes data for one song corresponding to the input song title data. 1 or 5 is read from the data storage unit 14 and stored in the data memory 12. The control unit 11 decodes the encoded data 1 or 5 stored in the data memory 12 in accordance with the software codec program stored in the program memory 13, displays the playback time for one song on the display unit 17, and plays back the playback time. Is displayed on the display unit 17 and the reproduced audio is output from the audio output unit 16. When the reproduction is completed, the operations of the audio output unit 16 and the display unit 17 are stopped under the control of the control unit 11.

(Outline of reproduction time display method of encoded data in FIG. 1)
FIG. 1 is a flowchart showing a reproduction time display method for encoded data according to the first embodiment of the present invention.

  When there is a fast forward / rewind operation input through the operation unit 15 in FIG. 2 (step S10), data seek in the encoded data 1 or 5 is performed under the control of the control unit 11, for example, the reproduction resume position in FIG. It stops at 2-2 or the playback restart position 6 in FIG.

  Next, the control unit 11 calculates (calculates) the current position (the reproduction resume position 2-2 in FIG. 6 or the reproduction resume position 6 in FIG. 7) according to the program (step S20). The predicted position time is calculated (step S30), and the predicted time is displayed on the display unit 17 (step S40).

  Here, when the encoded data 1 of FIG. 6 is used, the control unit 11 calculates the average size of the decoded data for the encoded data 1 based on the format, bit rate, and sampling frequency of the encoded data 1 in advance. And stored in the data memory 12 or the like. The control unit 11 calculates the average size and the size of the encoded data 1a up to the current position (reproduction resume position 2-2), predicts the size of the decoded data 4 for the encoded data 1a, and calculates the predicted time of the current position. And displayed on the display unit 17. After the reproduction is resumed, the control unit 11 adds the reproduction time obtained from the decoded data 4 to the predicted reproduction time, and causes the display unit 17 to display the reproduction time.

  Similarly, when the encoded data 5 in the streaming format shown in FIG. 7 is used, the average reproduction time of the frames FR0, FR1,... Is calculated in advance by the control unit 11 and stored in the data memory 12 or the like. Based on the average playback time, the control unit 11 calculates the predicted time of the current position (playback resume position 6) and displays it on the display unit 17. After the reproduction is resumed, the control unit 11 calculates the time at the current position from the time information of the frame header FH and causes the display unit 17 to display it.

  However, since the predicted time calculated by the above method is a time obtained from the average value, an error occurs between the predicted time when the reproduction is resumed and the time of the position where the reproduction is actually performed. In order to correct this error, display adjustment is performed by the control unit 11 (step S50), and the process ends (step S60).

  When the fast forward / rewind is continuously executed, the processes of steps S20 to S50 in FIG. 1 are repeatedly executed.

(How to find the average size of decoded data in Fig. 1)
The average size of the decoded data in FIG. 1 (for example, the size of PCM (Pulse Code Modulation) data) can be calculated from equation (1).
PCM data size = sampling frequency x sampling size
× Number of channels (1)
However, sampling frequency: Conversion from analog signal to digital signal for 1 second
Number of times (eg, 32KHz, 44.1KHz)
Sampling size: When converting from an analog signal to a digital signal,
Number of bits representing the height of the sampled waveform
(Example: 8 bits, 16 bits)
Number of channels: monaural (1), stereo (2)

For example, calculating equation (1) when the sampling frequency is 44.1 KHz, the sampling size is 16 bits, and the number of channels is stereo (2) is as follows.
PCM data size = 44100 (44.1 KHz) x 16 x 2
= 1411200 bits = 176400 bytes (per second)

(How to find the average playback time of frames in Fig. 1)
(A) In the case of WMA format The average frame playback time can be calculated from equation (2).
Average playback time per frame = playback time of one song ÷ number of frames per song (2)
However, the playback time of one song = Duration (playback time)-Preroll (until the song plays)
(Silence time)
Number of frames in one song = Packets
(Duration, Preroll, and Packets are encoded data according to the WMA format specification.
It is data that exists inside. )

  For example, when the playback time of one song = 1 minute and the number of frames = 60, the average playback time of frames is 1 second.

(B) In the case of MP3 format Since 1152 pieces of audio data are included in one frame due to the specification, in the case of data with a sampling frequency of 44.1 KHz, the average playback time of the frame is as follows.
1152 ÷ 44100 = 0.0261 seconds (1 second: x = 44100: 1152)

(Current position calculation, predicted time calculation example in Fig. 1)
FIG. 3 is a flowchart showing an example of the current position calculation (S20) and the predicted time calculation (S30) in FIG.

In step S10, when fast-forwarding is input five times by the operation unit 15, the current position is calculated in step S20. For example, if the frame number before input is 100, +5 is added to the frame number to obtain 105. Next, in step S30, the predicted time of the frame position after seeking the encoded data 5 is calculated by the equation (3) as the time to be displayed during fast forward / rewind.
Predicted time = average playback time per frame x frame position (= frame number)
... (3)
For example, if the average frame playback time is 1 second and the frame position is 60th,
1 × 60 = 60 seconds.

In addition, when calculating the predicted time from the average size of the decoded data, for example, when the position is 1 Mbyte from the beginning of the file,
1048576 (1 Mbyte) ÷ 176400 = 5.9 seconds (1048576: 176400 = x: 1)
It becomes.

  The predicted time obtained in this way is displayed in step S40 in FIG. When resuming playback, the position time of the frame (= Presentation Time, which is data existing in the encoded data according to the WMA format specification) is acquired from the frame where playback is resumed, and the playback time is restarted. Calculate (= Presentation Time-Preroll). At this time, if there is an error between the recalculated time and the displayed time, display adjustment is performed in step S50 of FIG.

(Example of display adjustment in Fig. 1)
FIG. 4 is a flowchart showing an example of display adjustment in FIG.
When there is a reproduction time notification request in the control unit 11 of FIG. 2 (step S51), the control unit 11 determines whether or not the recalculated time is greater than the display time (step S52). When the determination result is “recalculated time <display time”, the display time immediately before the resumption of reproduction is displayed on the display unit 17 (step S53), and the display adjustment process is ended (step S60). When the determination result is “recalculated time ≧ display time + 1s (seconds)”, (display time immediately before resuming reproduction + 1s) is displayed on the display unit 17 (step S54), and the display adjustment process is terminated (step S60). . When the determination result is “recalculated time ≧ display time and recalculated time <display time + 1s”, the recalculated time is displayed on the display unit 17 (step S55), and the display adjustment process is terminated. (Step S60).

5A and 5B are diagrams showing an example of display adjustment in FIG.
FIG. 5A is a diagram showing a display adjustment example when the time (for example, “00:59”) calculated from the frame header FH at the time of resuming reproduction is smaller than the displayed time (for example, “10:00”). It is.

  In this case, in order to prevent rewinding of the display time, the display time is continuously displayed until the reproduction time exceeds the display time. When the time at the playback position exceeds the time being displayed, the display time is updated in accordance with the time at the playback position.

  FIG. 5B shows a display adjustment example when the time (for example, “1:01”) calculated from the frame header FH at the time of resuming reproduction is larger than the currently displayed time (for example, “10:00”) by at least a second digit. FIG.

  In this case, the display time is updated within one second (in the figure: after 300 ms) in order to prevent time skip of the display time (which seems to have been reproduced from “1:01”). Thereafter, the display time is updated in accordance with the time of the reproduction position.

(Effect of Example 1)
According to the first embodiment, after fast-forwarding / rewinding, the time at which playback is resumed is predicted and calculated. Therefore, the time after obtaining decode data or streaming data up to the playback resume position as in the past is obtained. The processing time can be shortened as compared with the method of calculating, and the response at the time of resuming reproduction can be improved without creating a table that requires a large memory area as in the prior art. Furthermore, even when there is an error between the display time and the actual playback position time, the display time is adjusted, so that an accurate time can be displayed.

In addition, this invention is not limited to the said Example 1, A various deformation | transformation and utilization form are possible. Examples of such modifications and usage forms include the following (A) and (B).
(A) The formats of the encoded data 1 and 5 in FIGS. 6 and 7, the configuration of the playback apparatus in FIG. 2, and the processing contents in FIGS. 3 and 4 can be changed to those other than those shown in the figure.
(B) In the first embodiment, the audio apparatus that reproduces music encoded data has been described. However, the reproduction and fast-forwarding of data that records encoded music, video, and the like, such as a video apparatus that reproduces music and video encoded data. The present invention can be applied to various playback devices having a function of performing / rewinding and a function of displaying the time of the playback position and the fast forward / rewind position.

It is a flowchart which shows the reproduction time display method in Example 1 of this invention. It is a block diagram which shows the reproducing | regenerating apparatus in Example 1 of this invention. It is a flowchart which shows the example of the present position calculation in FIG. 1, and prediction time calculation. It is a flowchart which shows the example of a display adjustment in FIG. It is a figure which shows the example of a display adjustment of FIG. It is a figure which shows the reproduction time calculation method of the conventional encoding data. It is a figure which shows the reproduction time calculation method of the other conventional encoding data.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Control part 12 Data memory 13 Program memory 14 Data storage part 15 Operation part 16 Audio | voice output part 17 Display part

Claims (5)

Calculate the average size of the decoded data with respect to the encoded data in advance,
After seeking the encoded data,
Predicting a first size from the beginning of the decoded data to the reproduction restart position from the size from the beginning of the encoded data to the reproduction resume position after the seek and the average size;
Dividing the first size by the size per time of the decoded data to calculate and display a first predicted time at the playback resume position;
After resuming reproduction of the encoded data after the seek of the encoded data,
The second size of the decoded data from the reproduction restart position to the currently reproduced reproduction position is divided by the size of the decoded data per time, and then added to the first predicted time to obtain the reproduction position of the reproduction data. Calculate a second predicted time;
A method for displaying a reproduction time of encoded data, wherein the second predicted time is displayed as a reproduction time. Previously calculated average playback time of the frame in the encoding data composed of a plurality of frames,
After seeking the encoded data,
From the number of frames from the beginning of the encoded data to the playback restart position after the seek and the average playback time, a first predicted time at the playback restart position is calculated and displayed,
After resuming reproduction of the encoded data after the seek of the encoded data,
After dividing the number of frames from the playback resume position to the currently playing playback position by the average playback time, add the first predicted time to calculate a second predicted time of the playback position ;
A method for displaying a reproduction time of encoded data, wherein the second predicted time is displayed as a reproduction time. The encoded data is constituted by the plurality of frames having a header data having the data can be calculated reproduction time according to said frame,
After resuming playback of the encoded data after the seek of the encoded data,
Wherein the playback time the frame is calculated from the header data comprises currently playing, until said more than second predicted time to display the second prediction time, the reproduction time calculated from the header data 3. The reproduction time display method for encoded data according to claim 2, wherein the reproduction time calculated from the header data is displayed after the second predicted time is exceeded . After resuming playback of the encoded data after the seek of the encoded data,
Wherein the playback time the frame is calculated from the header data includes the currently reproduced, wherein, when more than one second greater than the second prediction time is within one second, the displayed second 4. The reproduction time display method for encoded data according to claim 3, wherein the predicted time is updated to the reproduction time calculated from the header data . Reproduction means for performing reproduction and fast forward / rewind of encoded data;
Display means for displaying the playback resume position and fast forward / rewind position time in the encoded data;
Control means for executing the reproduction time display method for encoded data according to any one of claims 1 to 4 by a program,
A playback apparatus comprising:

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