1) Field of the Invention
The present invention relates to technology for reading tag data included in a compressed data file.
2) Description of the Related Art
Advancement in data compression technology in recent years has made it possible to compress audio data such as songs, music, etc. and video data such as movies and be used as digital data. The compressed digital data is recorded on an optical recording medium such as a compact disk (CD), a digital versatile disk or digital video disk (DVD), or a magneto optical recording medium such as a mini disk (MD), or a magnetic recording medium such as a hard disk. The digital data is decoded and played in a predetermined format by a suitable player.
For instance, MP3 (MPEG1 Audio Layer 3) is a widespread audio data compression technology that allows compression of audio data such as songs, music, etc. without degrading the sound quality. The music data compressed by means of the MP3 method is stored on a CD in the form of an MP3 file and is played by an MP3 file player. However, when the number of MP3 files on a CD becomes considerable, it is difficult to recognize the contents of the MP3 files merely by their titles. Therefore, an area called ID3Tag is secured in the MP3 file for storing text data pertaining to the MP3 file such as the title of the music data, artist name, etc. The format of the ID3Tag that is compatible with most of the MP3 file players is called ID3Tag Ver1. A fixed length data area of 128 bytes, containing data such as the title, artist name, etc. of the MP3 file, is appended to the end of the MP3 file.
A process of how an MP3 file player reads the ID3Tag is explained next.
Thus, the conventional MP3 file player automatically reads the ID3Tag before playing the MP3 file specified by the user. Even if the ID3Tag is blank, the conventional MP3 player without fail performs reading of the ID3Tag and only then plays the music data, resulting in unnecessary delay. The audio player disclosed in Japanese Patent Laid-Open Publication No. 2002-245720 is provided with a read specifying unit which allows the user to specify beforehand whether to read the ID3Tag prior to playing the MP3 file. If the user specifies that the ID3Tag is not be read, the audio player directly plays the MP3 file without reading the ID3Tag, and if the user specifies that the ID3Tag is to be read, the audio player plays the MP3 file after reading the ID3Tag. Thus, when the user specifies that the ID3Tag is not be read, the loading of the MP3 file can be started early; however, the ID3Tag data will not be displayed on the audio player. If the user specifies that the ID3Tag is to be read, the process until the time the MP3 file is played gets very complex, as shown in
According to the technology disclosed in Japanese Patent Laid-Open Publication No. 2002-245720, specification can be made in the audio player not to read the ID3Tag to shorten the duration until the next file is played. However, even though the duration is reduced, the disadvantage is that the user will not be able to see the data of the ID3Tag.
It is an object of the present invention to at least solve the problems in the conventional technology.
According to an aspect of the present invention, a method for reading tag data of a compressed data file that includes compressed data and a data tag appended to the compressed data at a predetermined position, and performing a predetermined process based on a type of compressed data, includes searching a starting position of the tag data in the compressed data file, retrieving the tag data, and then searching a starting position of the compressed data.
According to another aspect of the present invention, a device that reads tag data of a compressed data file that includes compressed data and a data tag appended to the compressed data at a predetermined position and performs a predetermined process based on a type of compressed data, includes a searching/retrieving unit that first searches a starting position of the tag data in the compressed data file, retrieves the tag data, and then searches a starting position of the compressed data.
According to still another aspect of the present invention, a computer-readable recording medium stores therein a computer program that causes a computer to implement the above method.
The other objects, features, and advantages of the present invention are specifically set forth in or will become apparent from the following detailed description of the invention when read in conjunction with the accompanying drawings.
Exemplary embodiments of the present invention-are explained next with reference to the accompanying drawings. The present invention is not limited by these embodiments and modes of operation.
The method for reading tag data of a compressed data file according to the present invention can be applied to any compressed data file to which tag data of a fixed length containing information pertaining to the compressed data is appended at a predetermined position of the compressed data such as music data and video data containing compressed audio data and video data. For instance, the method can be applied to reading of tag data carried out by the compressed data player that reads compressed data file to which tag data of a fixed length is appended to the beginning of the compressed data or, as shown in
The compressed data player reads the tag data from the found address (step S22), retrieves the text data recorded in the data area, and displays the text data of the compressed data player on the display unit (step S23). Following this, the compressed data player searches for the starting position address of the compressed data in the compressed data file to be accessed (step S24), and starts the reading process of the compressed data (step S25), thereby ending the reading process of the tag data of the compressed data file.
It is also possible to provide a computer program that causes a computer to read the tag data of a compressed data file appended to a predetermined position of the compressed data. The computer program can be provided either in installable form or executable form on a computer-readable recording medium such as a compact disk read only memory (CD-ROM), a floppy (Registered Trademark) disk, a DVD. Alternatively, the computer program can be stored on another computer connected to a network such as the Internet, and downloaded from the network. This enables the computer to load and execute the computer program.
According to the present embodiment, when switching from a currently playing compressed data file to another compressed data file, the compressed file player searches for the starting position address of the tag data of the other compressed data file, reads the tag data, and then searches for the starting position address of the compressed data, and performs the predetermined process. Consequently, when switching from one compressed data file to another, the duration up to the time when the processing of the other compressed data file begins is shortened.
A practical example will be explained below. In this practical example, an MP3 file shown in
The reading unit 11 then carries out the reading process of the ID3Tag 3b (step S22), and the system controller 16 displays the read data on the display unit 14 (step S23). Once the reading process of the ID3Tag 3b is completed, the reading unit 11, searches for the starting position address of the MP3 file 1b (step S24) and starts the reading process of the music data 2b (step S25). When reading, the reading unit 11 first retrieves from the head data of the MP3 file, information such as bit rate, sampling rate, etc., required for playing the music data, followed by the music data 2b. The decoding unit 12 carries out a decoding process on the read music data. The output unit 13 carries out the playing process of the music data by outputting sound signals, thereby ending the ID3Tag reading process.
A case of the user inputting, by means of the input unit 15, the instruction to play the MP3 file 1b while the MP3 file 1a is playing has been presented as an example. However, the process of the MP3 file player 10 remains the same for playing the next MP3 file 1b after the current MP3 file 1a has finished playing.
If the user instructs, by means of play instruction, to play another MP3 file, in the conventional method, the reading unit 11 first searches for the starting point address of the requested MP3 file 1, searches for and reads the starting point address of the ID3Tag 3, and once again searches for the starting point address of the MP3 file 1 to play the music data 2. On the contrary, in the present practical example, the reading unit 11 searches for the starting point of the ID3Tag 3 and follows it up with a search for the starting point of the MP3 file 1, then starts reading the data, thus playing the MP3 file 1. In other words, in the present practical example, as shown in
According to the present practical example, when there is an instruction for the currently playing MP3 file 1 to be changed, the starting point of the ID3Tag 3 of the MP3 file 1 to be played next is searched and read following which the starting point of the music data 2 of the MP3 file 1 is searched and played. Consequently, the duration between the stopping of the previous MP3 file 1 and starting of the next MP3 file 1 is reduced. Further, the display of the data stored in the ID3Tag 3 as well as the reduction of the duration up to the time the data is displayed is achieved without the user having to specify.
Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.
Number | Date | Country | Kind |
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2004-160620 | May 2004 | JP | national |