KR20040085714A - Method for recording and play-back data - Google Patents

Abstract

PURPOSE: A data recording and reproducing method is provided to confirm a number indicated by count parts when decoding encoded data, and to calculate a frame sequence or a current play time, then to display the calculated play time, thereby displaying an exact decoding time during a scan play process. CONSTITUTION: A system receives digital data. The system encodes the inputted data into frame units, and inserts count parts by frames to count the encoded frames. The system stores the encoded data. The system decodes the encoded data by inserting count parts by frames. The system confirms a number indicated by the count parts while decoding, and calculates a frame sequence or a current play time. The system displays the calculated play time.

Description

Method for recording and play-back data

According to the present invention, in frame data such as MP3, the frame information data specifying each frame is added, and when the compressed audio file is decoded, the frame information data is detected and the frame position is calculated in units of frames. A data recording and reproducing method of displaying a decoding progress time on a display.

Recently, in the compression of information, MPEG (Moving Picture Experts Group) generally refers to a group of video experts who set standards for digital video and digital audio compression. It may also refer to the information compression technology being handled.

In other words, the MPEG standard is a defined set of algorithms and a technique for the compression and decompression of video and audio, and the formation of a melted data stream comprising auxiliary service data added to the compressed video and audio data.

In particular, MPEG audio decoding apparatus, for example. The MP3 player reads the MPEG data stream recorded and stored in the memory or the CD, decodes the audio data of the MPEG stream, and restores the original audio signal.

However, although the MPGE standard is quite flexible, it has a fundamental flaw related to the packet type nature of the MPEG format. That is, there is no information about the position of each frame encoded in the data stream.

Therefore, in general, in order to know the position of the frame, when decoding the data stream and playing through the decoder, the decoding time per frame can be inferred from the bit rate or fs (frame rate).

Progress time = decoding time per frame (bit rate or fs) * number of frames

In order to know the number of frames, a start position is designated on the data stream using a timer, and the number of frames is calculated by searching the start position by a bit rate or a frame rate.

However, there is a problem in that the number of frames for detecting the advancing time cannot be accurately determined due to the absence of information on the position of each frame, and there is a problem in that a separate start position must be searched.

In addition, in order to solve the above problem, in the case of CD MP3, the number of frames is calculated by calculating the number of frames per sector unit in sector units. That is, the sector is in 2048 byte units and each frame has about five numbers of 417 bytes.

However, although the number of frames can be determined more accurately than the inference of bit rate or fs in units of sectors, an error occurs in calculating the number of frames due to the absence of position information for MP3 frames in sectors.

Therefore, since the exact position of the frame is not known at the time of reading the data stream and played back through the decoder, the playback time cannot be calculated accurately, and also during the scan playback (very fast playback, very fast reverse playback), Even if the track is located in the middle of the song, the exact running time is not calculated and track jump cannot be controlled accurately.

Accordingly, the present invention was created to solve the above problems, and in count data such as MP3, the count part is indicated when decoding the encoded data by encoding the frame unit and inserting a count part for each frame. It is an object of the present invention to provide a data recording and reproducing method for displaying the calculated reproduction time after calculating the sequence or the current reproduction time of the frame by checking the number of frames.

1 illustrates a block structure and a byte of a frame on a data stream to which a data recording method according to the present invention is applied.

2 is a block diagram of an MPEG audio decoding apparatus to which a data reproducing method according to the present invention is applied.

※ Explanation of code for main part of drawing

10: optical disc 11: optical pickup

12: RF unit 13: signal processing unit

14 Decoder 15 D / A Converter

16: micom 17: memory

18: Indicator

Data recording method according to the present invention for achieving the above object, the first step of receiving input digital data; Encoding the input data in units of frames but inserting a count part for each frame to count frames; And three steps of storing the encoded data.

On the other hand, the data reproduction method according to the present invention, the step of decoding the encoded data encoded by the frame unit by inserting a count part for each frame; Calculating the order of frames or the current playback time by checking the number indicated by the count part during the decoding; And three steps of displaying the calculated playback time.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of the progress time display method in the MPEG audio decoding apparatus according to the present invention will be described in detail.

1 shows a block structure and a byte of a frame on a data stream to which the data recording method according to the present invention is applied, and each frame to be compressed is sequentially connected to the data stream.

The frame is composed of header information and MPEG data, and when the frame is compressed, frame information data is added to the header information as 3 bytes as shown below.

frame # 1: 00, 00, 01

frame # 2: 00, 00, 02

frame # 3: 00, 00, 03

::

That is, each frame is composed of MPEG header (H) + Count (C) + MPEG data (D) by adding frame information data to header information.

Therefore, frame information data composed of three bytes for sequentially counting each frame is added to the header information while sequentially configuring and compressing the header information and the MPEG data D on the data stream.

Since the frame information data is a 3-byte counter and the counter C can be up to FFFFFF, the number of frame information data that can be added to the header information is 167777215. Can be displayed.

frame # 167777215: FF, FF, FF

On the other hand, when the sampling frequency is 44.1Khz, the generation period per frame is 1152 sample * (1 / 44.1Khz), which is 0.0261sec, and the number of frames can be countered up to 167777216, so that the compressed frame is decoded. If you calculate the total play time,

Total playing time = 167777216 * 0.00261sec = 438216 seconds (about 121 hours)

In addition, the sequentially configured frames compressed on the stream can be recorded and stored for a long time as an audio file in a memory or an auxiliary memory device for decoding the audio decoding device.

When the audio file stored in the memory or the auxiliary storage device such as an optical disc is decompressed through a decoder, the frame information data which sequentially counts each frame in the stream is detected and the position of the frame is determined by the following calculation. It's hard.

Decoding Duration = (1152sample * (1 / 44.1Khz)) * Count

TABLE 1

Frame position Counter (C) Decoding Time One One O.O261 2 2 O.O521 : : : 167777216 FFFFFF 438.216

In Table 1 above, the sampling frequency is 1 / 44.1Khz and 128 Kbps. The decoding progress time for each frame position is shown.

2 illustrates a configuration of an MPEG audio decoding apparatus to which a decoding progress time display method to which a data reproduction method according to the present invention is applied is applied. In a specific embodiment of the present invention, the MPEG audio decoding apparatus is, for example, as an example. The CD MP3 player includes an optical pickup 11, an RF unit 12, a digital signal processing unit 13, an audio decoder 14, a D / A converter 15, a microcomputer 16, a memory 17, and the like. It can be configured to include.

The memory 17 is a device for downloading and storing audio data compressed to MP3 through an interface means, and the audio decoder 14 decodes audio data stored in a CD and a memory to a D / A converter. Output

In addition, the microcomputer 16 is a device for inputting a user's operation signal, according to the user's function selection. For example, signals such as play, fast play, very fast forward and very fast fast rewind are configured to be input and control the storage and playback of MP3 audio files.

In addition, the display unit 18 displays a progress time calculated by using the frame information data generated when the audio file stored in the optical disc or the memory is read out and decoded by the decoder 14. Same as

For example, when the user's operation signal is "play", the microcomputer 16 reads out the audio file stored in the memory or the optical disk, decodes the data through a decoder, and plays the data through a D / A converter.

At this time, the frame information data is detected and the decoding progress time calculated by the above-described calculation method is displayed on the display as 'play time'.

Also, even when the user's operation signal is very fast forward or very fast rewind, the frame information data on the frame is decoded by decoding the audio file regardless of the playback operation of the D / A converter. Is detected and the decoding progress time calculated by the above-described calculation method is displayed on the display.

Accordingly, while decoding and reproducing (play / FF / FR) the audio file stored in the optical disk or the memory, the frame information data is selectively detected and the frame position is identified by a frame counter to output the displayed decoding progress time together. .

As mentioned above, preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and those skilled in the art can improve other various embodiments within the spirit and technical scope of the present invention disclosed in the appended claims below. Changes, substitutions or additions will be possible.

In the data recording and reproducing method according to the present invention, which is constructed and configured as described above, the count part is instructed when decoding the encoded data by encoding the frame unit and inserting a count part for each frame in MPEG data such as MP3. By calculating the order of frames or the current playback time, and then displaying the calculated playback time to display the correct decoding progress time not only at the time of audio file playback but also at the time of scan playback. It is a very useful invention in which scan control is possible because it is possible to check whether a jump is executed.

Claims (5)

A first step of receiving digital data; Encoding the input data in units of frames but inserting a count part for each frame to count frames; And And three steps of storing the encoded data. The method of claim 2, And said frame comprises a predetermined amount of samples. Decoding the encoded data by inserting a count part for each frame and encoding each frame; Calculating the order of frames or the current playback time by checking the number indicated by the count part during the decoding; And And a three step of displaying the calculated reproduction time. The method of claim 3, wherein And the frame is composed of a predetermined amount of samples. The method of claim 3, wherein And the reproduction time is calculated as (samples per frame / sampling frequency) * number of counters.