WO2002076079A1

WO2002076079A1 - Melody encoding method and a mobile terminal used to carry out said method

Info

Publication number: WO2002076079A1
Application number: PCT/FR2002/000651
Authority: WO
Inventors: Christophe Castres; Frédéric Hochedez
Original assignee: Alcatel
Priority date: 2001-03-21
Filing date: 2002-02-21
Publication date: 2002-09-26
Also published as: FR2822621A1

Abstract

The invention relates to a method for encoding a melody comprising a set of data in order to obtain a coded melody. Some of said data are notes and the method comprises a note encoding step so that each note is represented by a note identification code (N1, N2, etc.). The encoding method is characterised in that the note identification code (N1, N2, etc.) is a binary code that occupies at most two bytes.

Description

METHOD OF CODING MELODY AS WELL AS A MOBILE TERMINAL FOR CARRYING OUT THIS METHOD

The invention relates to a melody coding method as well as a mobile terminal enabling this method to be implemented. Specifically, the invention relates to a method of coding a melody consisting of a set of data to obtain a coded melody, some of said data being notes, said method comprising a step of coding a note so that each of said notes is represented by a note identification code. As is known, one of the services offered by access providers to radiocommunication networks such as GSM (Global System for Mobile Communications) networks lies in the transmission of short messages. Thus, the SMS (Short Message Service) protocol allows the exchange of messages, generally of text type, between mobile terminals or a fixed entity such as a computer or a specialized server in particular, to a mobile terminal. A recent evolution of the SMS protocol called EMS protocol (Enhanced Messaging Service) allows the transmission of messages in which sounds are defined in particular. From the transmission via the EMS protocol, the user can have a wide variety of melodies that can replace the ringtones already available on mobile terminals.

To be transmitted according to the EMS protocol, a melody is coded in a format designated by the name of iMelody. This format is specified for IrMC (Infrared Mobile Communications) in document 3GPP TS (Generation Partnership Project Technical Specifications) 23.040 V4.1.0 relating to the EMS protocol.

The iMelody format belongs to the category UTF-8 (Unicode Transformation Format), and is based on an ASCII (American National Standard Code for Information Interchange) coding, in which each character - number or letter - is coded on eight bits corresponding to a byte. Generally, a melody consists of a set of data. After the coding of this melody, each of the data is represented by an Identification code.

Some of the melody data are notes defined by their frequencies and their respective durations.

According to the iMelody format, the identification code for each frequency is a function of the octave code and the note tone code. The octave of the note, represented by a number preceded by a character, is coded on two bytes. By default, a certain octave value is used. The tone of the note in said octave, represented by one or even two letters depending on whether the tone contains a sharp or a flat, is coded on one or two bytes. Thus, in the case of the iMelody format, the identification code of each frequency occupies one to four bytes.

The identification code for each duration supposes the coding of a basic duration (by default) as well as the coding of a specific duration which allows a possible extension of the basic duration ¹ . In the case of the iMelody format, the identification code for the duration of a note occupies one or even two bytes. ^• >. ^• .

Thus, the coding of a note, including the coding of duration and that of frequency, occupies between two and six bytes.

Other so-called specific data are contained in the melody and correspond in particular to the volume, style and rests of the melody. In iMelody format, the volume of a note, represented by a two-digit whole number preceded by a letter, is coded in three bytes. Similarly, the melody style, represented by a number preceded by a letter, is coded on two bytes. In addition, each of the rests is coded on two or even three bytes.

The tempo of a melody, corresponding to the cadence of the notes, is coded on three bytes. Thus, the complete coding of a melody according to the iMelody format represents a large number of bytes. Consequently, the storage of such a melody requires a large capacity memory which limits the number of melodies stored in the mobile terminal. In addition, the iMelody format is organized in the form of text lines containing the identification codes of the data constituting a melody and separated from each other by special characters also in the form of codes.

The structure of the iMelody format presented above does not currently make it possible to correctly play a melody on a mobile terminal because the operation making it possible to identify a datum, for example a note, cannot be performed quickly enough, that is to say -to say in the time interval separating one note from another. Indeed, the length of the coding of the data being variable and the characters separating each line being also coded, a very long step of research then of analysis of each code over its entire length is necessary to identify the associated data. .

Besides the iMelody format, other melody formats are known dedicated to the transmission of melodies, in particular by the SMS protocol. However, such formats are of the “owner” type in the sense that the transfer of messages is limited to that between terminals of the same manufacturer. Furthermore, said formats are not compatible with the EMS protocol.

The aim of the present invention is to develop a coding method making it possible to significantly reduce the memory space necessary for storing melodies, in particular those available in the iMelody format, on any mobile terminal.

The present invention also aims to develop a coding method for playing a melody on a mobile terminal. To this end, the invention provides a method of coding a melody consisting of a set of data to obtain a coded melody, some of said data being notes, said method comprising a step of coding a note so that each of said notes is represented by a note identification code, characterized in that said note identification code is a binary code occupying at maximum two bytes.

According to the invention, a melody format is thus created from binary coding instead of coding from ASCII characters.

The coding of a note according to the invention is therefore carried out whatever the note on two bytes against two to six bytes following the note for the iMelody format. In this way, the method according to the invention makes it possible to store melodies in a more compact format than the iMelody format. This frees up the memory space necessary to store a melody * and can make it possible to store a greater number of melodies in the mobile terminal or a longer melody. In addition, the coding method according to the invention is of binary type si. although the identification codes of the data constituting a melody are arranged one after the other. In addition _> all, the codes have a determined length. Such a structure makes it possible to read the melody on a mobile terminal. Indeed, the identification of a piece of data constituting a melody is direct and therefore rapid because it is carried out without prior analysis and targeting research.

The notes of a melody are notably defined by their frequencies and their respective durations.

According to the invention, said frequencies are represented by a binary frequency identification code occupying at most one byte.

The frequency identification code occupies a maximum of one byte, whether or not the note is composed of a sharp or a flat, instead of one to four bytes for the iMelody format.

According to the invention, each of said durations is represented by a binary duration identification code occupying a maximum of one byte and of preferably five bits, instead of one or even two bytes for the iMelody format, a significant saving of space.

The melody can also contain rests. Advantageously, the method according to the invention can thus comprise a step of coding the silence of a melody, so that each of the silences is represented by a binary silence identification code occupying at most one byte, instead of two or even three bytes for iMelody format.

Silences are either long or short, or defined by the composer.

The short silence is inserted between two notes of the same frequency and 0 makes it possible to reduce the coding length of the second note. Thus, in this case, the use of short silence makes it possible to identify a note from the sole identification code of the corresponding duration. The short silence identification code occupies a single byte, including the second note duration identification code. Similarly, in the case of a succession of notes of the same frequency, only the first note is coded in two bytes by its frequency and its duration, the following notes being

^. coded as indicated above as short rests.

The long silence meanwhile: ^• indicates the end of a melody; , it can also be used to indicate the minimum time interval before a possible replay of the melody.

The method according to the invention can also include a step of coding so-called specific data, chosen in particular from the volume, the style of a melody, so that each of said specific data is represented by a binary specific data identification code. 5 occupying a maximum of one byte.

Thanks to the coding according to the method of the invention, it is possible to establish a bijective relationship between the melody coded according to the invention and a message coded in ASCII characters.

In this way, a melody encoded according to the invention can be converted 0 to iMelody and vice versa. So a melody transmitted by message in the iMelody format can be converted according to the invention, stored and played in a mobile terminal. And conversely, a melody present in the mobile terminal, downloaded or composed by the user of said mobile terminal, is convertible into iMelody format. According to a preferred embodiment, the coding method according to the invention is implemented for the composition of a melody.

Thus, the user of the mobile terminal can personalize his terminal and use in the latter as ringtones melodies longer than those proposed by the iMelody format. Advantageously, the melody according to the invention can be transmitted in the form of a message by the Enhanced Messaging Service protocol. ^_•,. ^• • ^' *. . . . -

Indeed, a melody encoded according to the invention and converted according to the iMelody format is compatible with the EMS protocol. according to

the melody according to the invention is capable of being transmitted from a transmitting terminal to a receiving terminal.

The invention also relates to a mobile terminal characterized in that it comprises means for carrying out the process ei above. f

The characteristics and objects of the present invention will emerge from the detailed description below with reference to the appended figures, presented by way of illustration and in no way limitative. In these figures:

• Figure 1 is a schematic view of a mobile terminal according to the invention. • Figure 2 is an example of the structure of a coded melody according to the invention. FIG. 1 shows a mobile terminal comprising means (not shown) for implementing the method of coding a melody according to the invention. The terminal 1 includes in particular means 2 for entering data constituting melodies and means 3 for listening to melodies. The melodies are capable of being transmitted in the form of a message by a radiocommunication network from a transmitting terminal to a receiving terminal each consisting, for example, of a terminal 1 such as that shown in FIG. 1.

Generally, a melody consists of a set of data. These data include first of all notes defined by their frequencies and their respective durations. The data constituting a melody can also include so-called specific data such as the style, the volume, the rests, as well as other data such as the volume change command, the tempo, the sequence (s) and the effects. melody specials.

According to the invention each note, defined by its frequency and duration, is represented by a binary identification code occupying a maximum of two bytes. ^..,

The frequency of each note can be broken down into two elements:

• ^ octave of the note, - ^{• •} - - - - '.

• the tone of the note in the octave (twelve tones possible, taking into account the sharps and flats).

The octave can be represented by an integer from 0 to 8 and therefore can be coded on four bits. An example of possible identification codes for four-bit tones is given in Table 1 below.

The combination of the octave and pitch identification codes forms the identification code for the frequency of the notes. In the case presented, said code for identifying the frequency of the notes occupies one byte.

Table 1

In order to be played by the terminal, the value of the actual frequency of the note is reconstituted for example using a reference table (see Table 2 below) embedded in terminal 1 (stored for example in a memory of the latter) and containing the values of the twelve tones of the highest octave, each of these values being stored in two bytes.

There is indeed a mathematical formula allowing to calculate the real frequency of a note in a certain octave (from 0 to 8 according to the invention) and of a certain tone by knowing the so-called reference frequency of a note of the same tone placed in another octave called reference. According to the invention, the reference octave is octave 8. The formula is presented below:

. ,, „Reference frequency actual frequency = ^^

Table 2

Still according to the invention, the code for identifying the duration of a note is broken down into a part associated with a basic duration of the note (depending on a reference duration or by default), and a part corresponding to a specific duration (dotted note, double dotted note, etc.) which allows a possible extension of the base duration of the note.

By way of example, the possible values of the codes for identifying the basic durations according to the invention are presented in Table 3 below. The basic durations identification code occupies three bits. The identification code for specific durations occupies two bits, for example. In the case presented, the duration identification code therefore occupies five bits.

Table 3

To play the melody, the value of the basic duration is reconstituted for example using the following formula, from the identification code of the selected basic duration:

actual base duration = ^ _urèedebase tempo 2 ^duredebase

This formula refers to the tempo of the melody, corresponding to the cadence of the notes. The tempo is expressed in beats per minute or bpm, and is between 0 and 900. The tempo can be represented by a three-digit integer coded on ten bits.

For example, the volume of a melody is represented by an integer from 0 to 15, coded on four bits.

Furthermore, the volume change command which in particular makes it possible to increase or decrease the volume of a melody by one level can be coded on two bits. This identification code of the volume change command can be included in the byte containing the note duration identification code. In this way, this identification code of the volume change command indicates that a volume change must take place from this note. Another specific datum of a melody according to the invention is the style, which can be either natural, continuous or staccato and can be coded on two bits.

In addition, the melody may contain long, short or defined rests by the composer, which can be coded according to the invention on a byte. The short silence is inserted between two notes of the same frequency and makes it possible to reduce the coding length of the second note. Thus, in this case, the use of short silence makes it possible to identify a note by the sole identification code of the duration. The short silence identification code occupies a single byte, including the second note duration identification code. Similarly, in the case of a succession of notes of the same frequency, only the first note is coded in two bytes by its frequency and its duration, the following notes being coded as indicated above as short rests.

The long silence indicates the end of a melody; it can also be used to indicate the minimum time interval before a possible replay of the melody.

When the melody contains one or more sequences, i.e. data which define the beginning or the end of repetition (s) of notes as well as the number of repetitions, this or these latter (s) is (are) encoded at most on two bytes, one byte identifying the beginning of the sequence and being placed at the beginning of the latter, and another byte identifying the end of the sequence and being placed at the end of the latter.

Finally, according to the invention, special effects such as the vibrator function or the backlight of the terminal according to the melody can be coded on one or even two bytes. A melody coded according to the invention is formed of three parts, represented in FIG. 2: the header E, the musical part M and the final part F, containing the identification codes of the data constituting the melody one after the other from others sequentially. Thus, the header E is coded on ten bytes, and in particular makes it possible to assign an extension to the melody for storage, to define the length of the musical part and to indicate the version and the format of the coding defined according to the invention. The E header also contains the style, the tempo of the melody and possibly its volume. Optional data concerning the name of the composer of the melody and the title of the melody can also be included in the header.

The musical part M is composed of the identification codes of the notes followed by those of the rests coded on a byte and finally that of the sequence of the melody. When the melody includes special effects - (not shown), these are part of the musical part M. In this way, we find one after the other:

• the identification code NI of the first two-byte note, including the frequency identification code FI and the duration identification code Dl, • the identification code SI of the first silence, defined by the composer, on one byte,

• the identification code N2 of the second note, in two bytes, including the frequency identification code F2 and the duration identification code D2, • the identification code S2 of the second silence, defined by the composer , on one byte,

• the identification code SQ1 at the start of the SQ sequence of the melody,

• the identification code N3 of the note (s) to be repeated The identification code SQ2 from the end of the sequence SQ of the melody, and so on until the end of the musical part M. The final part F, based in particular on the use of a long silence, is coded on a maximum of one byte and indicates the end of the melody ^

The coding according to the invention makes it possible to establish a bijective relationship between the coded melody and a message coded in ASCII characters and transmitted by the EMS protocol. After conversion, the melody coded according to the invention can be transmitted by a radiocommunication network from a transmitting terminal to a receiving terminal in the form of a message.

As mentioned above, the method according to the invention can be used to compose a melody directly on a terminal or to transform a melody coded in another format (iMelody for example) into a coded melody according to the invention. To play a coded melody according to the invention and composed or downloaded to a terminal, means for reading the terminal will search directly and. quickly the information contained in the coded melody using the frequency tables. ^• *. ^{•• ••} • ^• - • ^• *

The coding according to the invention can be compatible with other transmission protocols than the EMS or SMS protocols.

A melody coded according to the invention occupies two to three times less space than a same melody coded according to the iMelody format necessary for the transmission of message in ASCII by the EMS protocol.

Of course, the above description has been given purely by way of illustration. Without going beyond the ambit of the invention, any means can be replaced by equivalent means. In particular, to reconstruct the real value of a frequency, one can use a formula instead of a table.

Claims

1. A method of coding a melody consisting of a set of data to obtain a coded melody, some of said data being notes, said method comprising a step of coding a note so that each of said notes is represented by a code d 'note identification (NI, N2, ...), characterized in that said note identification code (NI, N2, ...) is a binary code occupying a maximum of two bytes.

2. Method according to claim 1, characterized in that, said notes being defined by their frequencies and their respective durations, said frequencies are represented by a binary frequency identification code (FI, F2, ...) occupying at most one byte.

3. Method according to one of claims 1 or 2, characterized in that, said notes being defined by their frequencies and their respective durations, said durations are represented by a duration identification code (Dl, D2 ,. „) binary Occupying a maximum of one byte, and preferably five bits.

4. Method according to one of claims 1 to 3, characterized in that some of said data being rests, said method comprises a step of coding silence so that each of the rests is represented by a code for identifying silence ( SI, S2, ...) binary occupying a maximum of one byte.

5. Method according to one of claims 1 to 4, characterized in that some of said data being so-called specific data, chosen in particular from the volume, the style and the rests of said melody, said method comprises a step of coding said data specific so that each of said specific data is represented by a specific data identification code (SI, S2, ...) occupying a maximum of one byte.

6. Method according to one of claims 1 to 5, characterized in that said coding is carried out so as to establish a bijective relationship between said coded melody and a message coded in ASCII characters.

7. Method according to one of claims 1 to 6, characterized in that it is implemented for the composition of a melody.

8. Method according to one of claims 1 to 7, characterized in that said melody is capable of being transmitted in the form of a message by the Enhanced Messaging Service protocol.

9. Method according to one of claims 1 to 8, characterized in that said melody is capable of being transmitted from a transmitting terminal to a receiving terminal.

10. Mobile terminal (1) characterized in that it comprises means for carrying out said method according to one of the preceding claims.