Coded data generation or conversion – Digital code to digital code converters
Reexamination Certificate
2002-04-19
2004-09-21
Wamsley, Patrick (Department: 2819)
Coded data generation or conversion
Digital code to digital code converters
C348S423100
Reexamination Certificate
active
06794995
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to an information reproducing apparatus for reproducing digital information composed of coded signals of audio and video.
2. Description of Related Art
Various coding (data compressing) technologies have been proposed to compress data size of audio or video at high efficiency. For example, in the field of portable music players, the music player conforming to the MPEG Audio Layer 3 (MP3) system (“MPEG” is short for “Moving Picture Experts Group”), the coding system for recording a larger quantity of music signals at a higher sound quality in a semiconductor memory of a limited capacity is becoming pervasive. Besides the MP3 system, new coding systems are provided one after another such as the Advanced Audio Coding (AAC) system and the Windows Media Audio (WMA) system.
Generally, in the field of severe competition of new product development, the life cycle of products is very short. For example, when a new system is widely spread, the reproducing apparatus conforming only to the former coding system may not be applicable to the new system, and the user has to purchase a new product conforming to the new system.
In such reproducing apparatus, however, the hardware configuration is not so much different if the coding system is changed, and only the algorithm differs slightly in the portion for decoding the information.
Accordingly, a reproducing apparatus applicable to different coding systems by realizing the decoding process by decoding software and installing plural types of decoding software on a semiconductor memory mounted on the reproducing apparatus has been developed. In addition, a reproducing apparatus applicable to the new decoding technology by rewriting a coding program installed in a semiconductor memory mounted on the reproducing apparatus is also developed.
A portable music player applicable to plural types of coding systems is disclosed, for example, in Japanese Patent Laid-Open Publication (Kokai) No. H11-167400.
FIG. 1
is a functional block diagram showing a schematic configuration of a compact music player
100
disclosed in this publication.
As shown in
FIG. 1
, the compact music player
100
has an input I/F unit
102
, a first semiconductor memory
103
, a second semiconductor memory
104
, a digital signal processing circuit
105
, and a Digital to Analog (D/A) converter
106
. In the input interface (I/F) unit
102
, audio digital data coded by using a predetermined audio coding technology is inputted. In the first semiconductor memory
103
, audio digital data inputted from the input I/F unit
102
is stored. In the second semiconductor memory
104
, a decoding program inputted from the input I/F unit
102
to decode in reverse process of coding is stored. The digital signal processing circuit
105
decodes the audio digital data stored in the first semiconductor memory
103
by the decoding program stored in the second semiconductor memory
104
. The D/A converter
106
converts the output signal from the digital signal processing circuit
105
into an analog signal.
According to the compact music player
100
, using the decoding program, stored in the second semiconductor memory
104
, corresponding to the audio digital data stored in the first semiconductor memory
103
, the audio digital data stored in the first semiconductor memory
103
is decoded. Therefore, music can be reproduced from the audio digital data regardless of the compression coding system of audio digital data stored in the first semiconductor memory
103
.
In the compact music player
100
, whole or part of the second semiconductor memory
104
is composed of a programmable flash memory. Accordingly, if the corresponding decoding program is not written preliminarily in the second semiconductor memory
104
, a new decoding program can be stored by updating the content of the second semiconductor memory
104
, so that music signals corresponding to various compression decoding systems can be reproduced.
In addition, in the compact music player
100
, plural types of decoding processing programs are installed on the second semiconductor memory
104
. Based on the information about the coding process added to each music digital signal, a decoding process program corresponding to the compression coding system can be selected from the plural types of decoding process programs, and decoding is processed, so that music signals corresponding to various compression coding systems can be reproduced.
In such reproducing apparatus, however, to be applicable to plural types of coding systems, a sufficient capacity must be kept in the semiconductor memory to install plural types of decoding program. However, the programmable and nonvolatile semiconductor memories such as flash memories are expensive, and if a flash memory of a large capacity is incorporated, it adds to the cost of the reproducing apparatus.
Although the semiconductor memory storing the decoding programs stores plural types of decoding programs by increasing its capacity, only one of decoding programs corresponding to the coding system of the music digital data is used while actually reproducing the music digital data. Therefore, it is not an efficient manner in the use of the expensive semiconductor memory.
Moreover, in order to suppress the capacity of semiconductor memory, it may be considered to store a corresponding decoding program every time to update the content of the semiconductor memory to be applicable to the plural types of decoding systems. In this method, however, in order to install a corresponding decoding program, an external device such as a personal computer is required to connect to the reproducing apparatus each time. In other words, in a place where the personal computer or other external device is not available, the corresponding decoding program cannot be installed on the reproducing apparatus. The portable music player is often used outdoors, its convenience is restricted significantly.
SUMMARY OF THE INVENTION
An apparatus for reproducing digital information coded in a coding system in an embodiment of the present invention, the coded digital information and a decoding program describing a decoding algorithm to decode the digital information recorded in an information recording medium, includes: a reading unit configured to read out the coded digital information and the decoding program recorded in the information recording medium; a program memory configured to store the decoding program read out from the reading unit; a signal processing unit configured to decode the digital information read out from the reading unit by the decoding algorithm of the decoding program stored in the program memory; and a conversion unit configured to convert the digital information decoded in the digital signal processing unit into a predetermined format, and to output the converted digital information.
An information recording medium in an embodiment of the present invention, recording digital information to be reproduced by an information reproducing apparatus configured to decode the digital information and to convert the decoded digital information into a predetermined output format, includes: a digital information file storing the digital information coded the digital information in a predetermined coding system; and a program file storing a decoding program describing a decoding algorithm to decode the coded digital information.
A method for reproducing digital information in an embodiment of the present invention includes: reading out coding information of the digital information to be reproduced from an information recording medium in which the digital information coded in a predetermined coding system and a decoding program describing a decoding algorithm to decode the coded digital signal are recorded together; reading out the decoding program corresponding to the coding information read out from the information recording medium; storing the read out decoding program to a program memory; reading out the digital information t
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Wamsley Patrick
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