KR100592688B1 - Method of buffering for playing a mass storage audio file - Google Patents

Abstract

The present invention relates to a method of buffering an audio file. In an embedded system that does not include an exclusive RAM memory or a large RAM memory, an audio file is played by efficiently buffering a large audio file (eg MP3) into a small RAM memory. It provides a method for doing so. According to the present invention, it is not necessary to increase the size of the RAM memory additionally to play a large audio file, and the embedded system can efficiently and efficiently perform the audio playback additional function without additionally installing an exclusive RAM memory. It is possible to develop competitive embedded system without burdening product cost.

Buffering, Memory Blocks, Buffer Space, Large Audio Files, ID3 Tags, Garbage Data

Description

Method of buffering for playing a mass storage audio file}             

1 illustrates one embodiment of memory allocation in accordance with the present invention;

2A and 2B are an embodiment flowchart of a buffering method for playing a large audio file according to the present invention;

The present invention relates to a method of buffering an audio file, and more particularly, to efficiently buffer a large audio file (for example, MP3, etc.) in a small RAM memory in an embedded system without an exclusive RAM memory or a large RAM memory. A method for playing an audio file.

Recently, with the development of digital multimedia technology, users can enjoy audio files, for example, MP3 files, etc. through digital devices.

In general, an embedded system capable of playing MP3 files includes an MP3 player, a digital broadcast receiver, a digital broadcast recorder, and a mobile communication terminal.

MP3 files are stored in the hard disk or flash memory of the embedded system, and MP3 files stored in the hard disk or flash memory are buffered into the RAM memory according to a user's audio file selection, and the playback starts.

On the other hand, in recent years, the size of the audio file is increasing in order to meet the various needs of the user (eg, high-quality music and lyrics providing function, etc.). For example, the size of a high quality MP3 file with a playback time of about 5 minutes exceeds 10 megabytes ("MB").

Therefore, in order to seamlessly play an audio file having a large size, a RAM memory having a size larger than that audio file size should be provided in the embedded system.

However, in the case of an embedded system in which an audio reproduction function is additionally installed except for an audio-only player, that is, a unique function of a corresponding device (for example, a broadcast reception function and a mobile device in a digital broadcast receiver) in a digital broadcast receiver or a mobile communication terminal, etc. The communication terminal is equipped with an audio playback function as an additional function in addition to the call function. In such a case, data allocation for a unique function is made to most of the RAM memory, and the RAM memory size is increased for large audio file playback. This is a burden on the manufacturer because it must increase the cost of the product.

The present invention has been proposed to solve the above problems and to meet the above demands. The present invention provides a small capacity for a large audio file (e.g., MP3, etc.) in an embedded system that is not equipped with a dedicated RAM memory or a large RAM memory. An object of the present invention is to provide a method for efficiently buffering a RAM memory of an audio file to be played.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

1 is a diagram illustrating an embodiment of memory allocation according to the present invention. Hereinafter, the present invention will be described with an example of buffering and playing MP3 files stored in a hard disk of a digital broadcasting receiver into a RAM memory (hereinafter referred to as "memory"). It will be apparent to those skilled in the art that the number and the size of the buffer free space may be allocated differently according to the specification of the memory and the memory use in the digital broadcasting receiver.

As shown in Fig. 1, a plurality of memory blocks are allocated to a memory, that is, memory blocks M1 having a size of m1 + r1, memory blocks M2 having a size of m2 + r2 and memory blocks M3 having a size of m3 + r3. Allocate buffer free space Buf_remain in RAM memory.

Here, the memory block M1, the memory block M2 and the memory block M3 have the same size (m1 = m2 = m3 = 1 MB, r1 = r2 = r3 = 64 kilobytes (hereinafter referred to as "KB")). In particular, the memory block M1 and the memory block M2 are memory areas used to play audio files (i.e., areas where the audio player reads and plays data buffered in the memory blocks M1 and memory block M2), and the audio file reproduction order is the memory. From the front of the block M1 to the rear of the memory block M2. In addition, the memory block M3 is a memory area used to read audio files stored in the hard disk into memory (that is, an area in which the memory manager reads the audio files into memory to buffer the audio files stored in the hard disk). )to be.

The buffer free space Buf_remain has a size of 64 KB and is an area in which data that is not directly required for audio file reproduction, that is, ID3 tag and garbage data is temporarily buffered.

In the present invention, when performing buffering for playing an audio file, data of the audio file stored in the hard disk is sequentially read into the memory block M3, and the corresponding data is analyzed (confirming data not directly required for playing the audio file). After copying some of the audio files read from memory block M3, except the data that are not directly needed for playback, to the memory block M1 and temporarily copying some of the data not directly needed for audio file playback to the buffer free space Buf_remain. The data copied to the memory block M1 is reproduced.

Then, if the size of the remaining data of the audio file is larger than that of the memory block M1 while the reproduction of the data copied to the memory block M1 is in progress, the data copied to the buffer free space Buf_remain is copied to the front of the memory block M2 and the memory Copy some data of the audio file read in the block M3 to the rest after the front part of the memory block M2, and temporarily copy some of the data that is not directly needed to play the audio file in the buffer free space Buf_remain to the memory block M2. Play back the copied data.

By repeating the above process, the data constituting the audio file stored in the hard disk is sequentially read into the memory block M3, and the data copied in the buffer free space Buf_remain and some data of the audio file read in the memory block M3 are read. The audio file is reproduced by sequentially buffering the memory blocks M1 and M2.

Hereinafter, a state in which data of an audio file is buffered in a memory block and a buffer free space will be described in detail with reference to FIGS. 2A and 2B.

2A and 2B are flowcharts of an embodiment of a buffering method for playing a large audio file according to the present invention.

First, a memory block M1, a memory block M2, and a memory block M3 having the same size are allocated to the memory, and a buffer free space Buf_remain is allocated to the memory (200). Here, the memory block M1 has the size of m1 + r1, the memory block M2 has the size of m2 + r2, the memory block M3 has the size of m3 + r3, m1 = m2 = m3 = 1 MB, r1 = r2 = r3 = 64 KB, and the buffer free space Buf_remain has a size of 64 KB.

Thereafter, when a specific audio file reproduction request signal is input (201), the total size (total_size) of the corresponding audio file stored in the hard disk is checked (202).

Then, data from the first portion of the audio file to the portion corresponding to m3 is read into the memory block M3 (203).

Then, the data read into the memory block M3 is analyzed to determine the size of data (area) that is not directly necessary for audio reproduction (204). Here, data that is not directly needed for audio playback, i.e., ID3 tag and garbage data (e.g. lyrics data), is present at the beginning of the audio file, from the beginning of the audio file read into the memory block M3 to m3. The data up to that part is analyzed to determine the size of the data that is not directly needed for audio reproduction.

Then, skip size (skip_size) and skip size 2 (skip_size2) are obtained, and ID3_tag_dect is set if ID3 tag exists (205). Here, ID3_tag_dect is for protecting ID3 tag.

In order to prevent data that is not directly needed for such audio playback from being read by the audio player (aka skip), the size of data not directly needed for audio playback is set to skip size (skip_size), and the skip size is set to the ID3 tag. The sum of the size and the size of garbage data is obtained (skip_size = ID3 tag size + garbage data size).

Then, skip size 2 (skip_size2) in consideration of the data size (storage access data size, hereinafter referred to as "read_size") that can read audio files stored in the hard disk into the memory at one time. Is set, and skip size 2 is obtained by adding "1" to the value obtained by dividing the skip size by the read size and multiplying the read size again (skip_size2 = [(skip_size / read_size) +1) * read_size]). Here, the basic unit for reading audio files stored in the hard disk or flash memory at one time is determined, and the read size has a size of 512 bytes (hereinafter referred to as "B").

When the process of "205" is described using the data address as an example, the ID3 tag starts with the first data address 0x49, the second data address 0x44, and the third data address 0x33, which are the first part of the audio file, and thus the ID3 tag is checked. Check for the presence of

Then, the sixth data address, the seventh data address, the eighth data address, and the ninth data address are checked to obtain the total size of the ID3 tag. [ID3 data size = (6th data & 0x7f) << 21 + (7th data & 0x7f) << 14 + (8th data & 0x7f) << 7 + (6th data & 0x7f) + 10 (ID3 head data size)].

Since garbage data exists at the beginning of the audio file or after the ID3 tag and before the start value, which is the beginning of the actual audio playback data, the data a and the data addresses 0xf0 to 0xfe If the data b with the data comes out continuously, the data a and the data b are recognized as the start value of the audio file, and the garbage is checked from the front part of the audio file or the part after the ID3 tag to the part before the data a and data b comes out. Find the size.

In the same manner as above, the skip size 2 is obtained by adding the size of the ID3 tag and the size of the garbage data. For example, if the skip size is 312 B and the lead size is 512 B, the skip size 2 is obtained as 512 B. If the skip size is 678 B and the lead size is 512 B, the skip size 2 is determined to be 1024 B, and the skip size is Is 1234 B and the lead size is 512 B, skip size 2 is determined to be 1536 B.

Thereafter, data from the first portion of the audio file to the portion corresponding to m3 + skip size 2 is read back into the memory block M3 (206).

For example, if the skip size is 312B and the skip size 2 is 512B, data 1 MB as much as m3 and data 512B as the skip size 2 are read into the memory block M3 as shown in Table 1 below. Here, 1 MB of data equal to m3 includes data 312 B corresponding to the skip size.

 1 MB (including the front of the audio file with skip size 312 B)  512 B (skip size 2)

Then, in step 206, the remaining data except for the skip size data 312 B is copied from the data read in the memory block M3 (the front part of the audio file + skip size 2) to the memory block M1 by m1. The state of M1 is set to full (207).

In the buffering state of the memory block M1, as shown in the following [Table 2], in front of the memory block M1, data remaining after subtracting the skip size data 312 B from the data corresponding to the front of the audio file is buffered and the memory block M1 At the rear of the data, some data 312B of the data corresponding to the skip size 2 is buffered.

 1 MB-312 B (Audio file front section-skip size)  312 B (Skip size 2)

If ID3_tag_dect is set (ID3_tag_dect is set when ID3 tag is present in step "205"), the data read in memory block M3 (front part of audio file + skip size 2) in step "206". Of the remaining data except for data equal to m1 + skip size, data 200 B corresponding to the skip size 2-skip size is copied to the buffer free space Buf_remain (208).

That is, as shown in [Table 3], a portion of the data 200B of the skip size 2 that was not copied to the memory block M1 in the process “207” among the data size 512 B read in the process “206” is buffered as shown in the following [Table 3]. Copy it to the free space Buf_remain.

 200 B (Skip Size 2-Skip Size)  64 KB-200 B (empty space)

Then, the remaining data size (remain_size) of the audio file after buffering is set, and data reproduction buffered in the memory block M1 is started (209). Here, the remaining data size of the audio file is set to the value obtained by subtracting the data size buffered in the memory block M1 from the total size of the audio file [remain_size = total_size-(m1 + skip_size2)].

Thereafter, while checking the audio file playing state, that is, the data playing state buffered in the memory block M1 (210), if the remaining data size (remain_size) of the audio file is larger than m1, the first of the remaining data of the audio file is stored in the memory block M3. Data from the portion to the portion corresponding to m3 (1 MB) is read (211).

Then, leave the portion corresponding to the skip size 2-the skip size empty from the front part of the memory block M2,

In the process of "211", m2-(skip size 2-skip size) data is copied from the data read in the memory block M3 after the empty portion of the memory block M2, and the state of the memory block M2 is full. (212).

That is, as shown in the following [Table 4], the space of skip size 2-skip size 200B is emptied in the front part of the memory block M2, and the m2 size of the data read in the memory block M3 from the next part of the vacant space. Data corresponding to (Skip size 2-Skip size) is copied.

 200 B (empty space) 1 MB-200 B [m2 size-(skip size 2-skip size)]

If ID3_tag_dect is set (ID3_tag_dect is set when ID3 tag is present in step "205"), the memory block is configured to skip data 200 B corresponding to the skip size 2-skip size copied to the buffer free space Buf_remain. Copies to the empty portion of M2 and copies the remaining data in memory block M3 by m2-(Skip size 2-Skip size) from the beginning of memory block M3 [m3-(Skip size 2-Skip) Data after the position corresponding to the size)] is copied to the buffer free space Buf_remain at the skip size 2-skip size (213).

That is, as shown in the following [Table 5], the data 200B copied in the buffer free space Buf_remain is copied to the front part of the memory block M2, and the existing data is kept intact in the front part of the memory block M2.

 200 B (data from Buf_remain)  1 MB-200 B (keep it as it is)

Then, as shown in the following [Table 6], the data 200B of the skip size 2-the skip size of the remaining data of the memory block M3 is copied to the front part of the buffer free space Buf_remain.

 200 B (Skip Size 2-Skip Size)  64 KB-200 B (empty space)

Thereafter, the remaining data size (remain_size) of the audio file after buffering is reset, and data playback buffered in memory block M2 is started, and all data buffered in memory block M1 is deleted to free memory block M1 (214). Here, the remaining data size of the audio file is set to a value obtained by subtracting m2, the data size buffered in the memory block M2, from the remaining data size of the audio file set in step 209 [remain_size- = m2]. That is, after the data playback buffered in the memory block M1 is finished in the audio file playback order, the data buffered in the memory block M2 is played back. At this time, when the reproduction of the data buffered in the memory block M1 is completed, all the data buffered in the memory block M1 is deleted to proceed with the reproduction of the buffered data in the memory block M2 while the memory block M1 is empty.

Then, while checking the audio file reproduction state, that is, the data reproduction state buffered in the memory block M2 (215), if the remaining data size (remain_size) of the audio file is larger than m2, the first of the remaining data of the audio file to the memory block M3 The data from the portion to the portion corresponding to m3 (1 MB) is read (216).

Then, from the front part of the memory block M1 where all the data is deleted, the skip size 2-the skip size is left blank, and m1-(skip size 2-skip size) in the data read in the memory block M3. ) Is copied after the empty portion of the memory block M1, and the state of the memory block M1 is set to full (217).

If ID3_tag_dect is set (ID3_tag_dect is set when ID3 tag is present in step "205"), the memory block M1 stores the skip size 2-the skip size data 200 B copied to the buffer free space Buf_remain. Copy to the empty portion of the memory block and copy the remaining data in the memory block M3 by m1-(skip size 2-skip size) from the beginning of the memory block M3 [m3-(skip size 2-skip size) Data from the position corresponding to the position corresponding to the &quot;) is copied to the skip size 2-the skip size to the buffer free space Buf_remain (218).

Thereafter, the remaining data size (remain_size) of the audio file after buffering is reset, and the data block buffered in the memory block M1 is started, and all the data buffered in the memory block M2 is deleted to empty the memory block M2 (219). Here, the remaining data size of the audio file is set to a value obtained by subtracting m1, the data size buffered in the memory block M1, from the remaining data size of the audio file set in step 214 [remain_size- = m1].

Thereafter, the processes "211" to "219" are repeatedly performed until the reproduction of the audio file is completed, that is, until the remaining data size (remain_size) of the audio file is smaller than m1 (or m2). Alternately to block M1 and memory block M2, all remaining data of the audio file is buffered (220).

Then, when the reproduction of the audio file is completed, that is, when all the data buffered in the memory block M1 and the memory block M2 are reproduced, the memory block M1, the memory block M2, the memory block M3, and the buffer free space Buf_remain are released (221).

While the content of the present invention has been described by way of examples, the embodiments of the present invention are merely illustrative of the present invention and should not be construed as limiting the scope of the present invention. Those skilled in the art to which the present invention pertains may modify or alter the present invention in various forms within the principles and scope described in the claims herein.

As described above, the present invention does not need to additionally increase the size of the RAM memory for playing a large audio file, and can efficiently perform the audio reproducing additional function without additionally installing an audio dedicated RAM memory in an embedded system. As a result, it is possible to develop a competitive embedded system without burdening product cost.

Claims (3)

In a state in which memory block M1 (size m1 + r1), memory block M2 (size m2 + r2), memory block M3 (size m3 + r3), and buffer free space Buf_remain (size r) are allocated to memory, a specific audio file A first step of checking a total size (total_size) of a corresponding audio file when a reproduction request signal for the input is input; Skip size 2 (skip_size2) in consideration of skip size (skip_size) and storage medium access data size (read_size) for skipping playback by determining data unnecessary for audio reproduction by reading data of the audio file by m3 into the memory block M3. Setting a second step; The data of the audio file is read back into the memory block M3 by m3 + skip_size2, and the remaining data except for skip_size data is copied from the data read into the memory block M3 to the memory block M1, and the data read into the memory block M3. Copies the remaining data (data not copied to the memory block M1) except m1 + skip_size to the buffer free space Buf_remain by skip_size2-skip_size, and total_size- (m1) of the remaining data size (remain_size) of the audio file. reproducing data copied to the memory block M1 after setting to + skip_size2); If the set remain_size is larger than m1, a space of skip_size2-skip_size is left in front of the memory block M2, and the remaining data of the audio file is read by m3 into the memory block M3, and the next space is left in the memory block M2. Copy data corresponding to m2- (skip_size2-skip_size) from the data read into the memory block M3, copy the data copied into the buffer free space Buf_remain into the empty space of the memory block M2 by skip_size2-skip_size, Copying skip_size2-skip_size data (data not copied to the memory block M2) from the data read at the m3- (skip_size2-skip_size) position of the memory block M3 to the Buf_remain and resetting remain_size to remain_size-m2. A fourth step of reproducing the data copied to the memory block M2 later; And If the reset remain_size is larger than m2, the space of skip_size2-skip_size is left in front of the memory block M1, and the remaining data of the audio file is read by m3 into the memory block M3, and the space after the memory block M1 is empty. Copy the data of m1- (skip_size2-skip_size) from the data read in the memory block M3, and copy the data copied in the buffer free space Buf_remain into the empty space of the memory block M1 by skip_size2-skip_size, Copy skip_size2-skip_size data (data not copied to the memory block M1) from the data read in the m3- (skip_size2-skip_size) position of the memory block M3 to the buffer free space Buf_remain, and remain_size remains_size-m1. A fifth step of reproducing data copied to the memory block M1 after resetting to The lure is, the fourth step until a remain_size the reset is smaller than m1 or m2 and buffering method for a large-capacity audio file is played to perform the fifth step repeatedly. According to claim 1, The skip size (skip_size) is obtained by adding the size of the ID3 tag (ID3 Tag) and the size of the garbage data (garbage data), the buffering method for playing a large audio file. The method of claim 2, The skip size 2 (skip_size2) is set to a value obtained by adding "1" to the value obtained by dividing the skip size (skip_size) by the storage medium access data size (read_size) and multiplying the storage medium access data size (read_size). Buffering method for playing large audio files.

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