1. Field of the Invention
This invention relates to an information recording apparatus and an information recording method, and more particularly to recording ending control and recording restarting control at the time of ending and restarting information recording onto an information storage medium.
2. Description of Related Art
Audio information such as voices and/or music are sometimes recorded on an information storage medium such as an optical disc after they are compressed. If the recording is temporarily interrupted or stopped in response to a temporary recording stop or interruption instruction, the input of audio information to be recorded is stopped after the reception of the instruction. When the recording restart instruction is received, the input of the audio information to be recorded is restarted to restart the information recording.
According to a conventional control method of the recording interruption and restart which controls input state of the audio information to be recorded, if data to be recorded at the time of interruption and restart have large level difference therebetween and the audio information including the interrupted portion is continuously reproduced, a sudden noise may possibly occur at the interruption timing.
This problem may occur at the time of simply stopping the audio information recording and at the time of reproducing recorded information which includes recording interrupted portion recorded with high recording level. This problem may also occur at the time of simply starting new audio information recording and at the time of reproducing recorded information which include recording start portion record with high recording level.
In order to overcome this problem, fade-out and fade-in processing are introduced. Namely, at the time of interruption or ending of recording (hereinafter referred to as xe2x80x9crecording interruption timexe2x80x9d), the audio information to be recorded is faded out after the recording interruption instruction is received. At the time of restart or start of recording (hereinafter referred to as xe2x80x9crecording restart timexe2x80x9d), the audio information to be recorded is faded in after the recording restart instruction is received. Thus, the audio information recording level at the recording interruption time and the recording restart time are made substantially zero level. Here, xe2x80x9cfade-outxe2x80x9d is processing which gradually decreases the recording level of audio information finally down to zero level, and xe2x80x9cfade-inxe2x80x9d is processing which sets the recording level of audio information to zero at first and then gradually increases the recording level up to a normal level.
However, in the fade-out and fade-in processing, it is necessary to gradually decrease the recording level within a predetermined time period after the instruction of recording interruption, and again gradually increase the level. Therefore, if audio information is recorded after compression, the recording processing becomes complicated.
It is an object of the present invention to provide information recording apparatus and method which achieve fade-in and fade-out with simple processing and which enable information recording such that undesired sudden noise is avoided at the time of reproducing recorded information at the portion including the recording interruption and restart points.
According to one aspect of the present invention, there is provided an information recording apparatus for recording digital information inputted from outside onto an information storage medium, including: a multiplexing unit for multiplexing the digital information by a plurality of window functions to generate a plurality of multiplied digital information, each of the plurality of window functions having a fade-out time-axis characteristic and having overlaps with neighboring window functions on time axis; a recording unit for recording the plurality of multiplied digital information corresponding to the respective window functions; an ending unit for changing ending multiplexed digital information which are the multiplied digital information corresponding to the window function including a recording end timing of the digital information to zero information, and for ending recording the digital information after recording the zero information onto the information storage medium in place of the ending multiplexed digital information.
According to the same aspect of the present invention, there is provided an information recording method for recording digital information inputted from outside onto an information storage medium, including the steps of: multiplexing the digital information by a plurality of window functions to generate a plurality of multiplied digital information, each of the plurality of window functions having a fade-out time-axis characteristic and having overlaps with neighboring window functions on time axis; recording the plurality of multiplied digital information corresponding to the respective window functions; changing ending multiplexed digital information which are the multiplied digital information corresponding to the window function including a recording end timing of the digital information to zero information, and ending recording the digital information after recording the zero information onto the information storage medium in place of the ending multiplexed digital information.
In accordance with the above information recording apparatus and method, the window functions which are multiplied by the digital information has the time-axis characteristics. When the recording of the digital information is ended, the ending multiplexed digital information is changed to zero information and the recording of the digital information is ended after the zero information is recorded on the information storage medium in place of the ending multiplexed digital information. By this, the recording level variation of the digital information just before the ending of the recording becomes similar to the fade-out characteristic of the window function. Therefore, the fade-out is achieved by a simple processing at the recording ending time of the digital information, and it is possible to avoid noise generation at the time of reproduction, due to the sudden decrease of the digital information recording level.
According to still another aspect of the present invention, there is provided an information recording apparatus for recording digital information inputted from outside onto an information storage medium, including: a multiplexing unit for multiplexing the digital information by a plurality of window functions to generate a plurality of multiplied digital information, each of the plurality of window functions having a fade-in time-axis characteristic and having overlaps with neighboring window functions on time axis; a recording unit for recording the plurality of multiplied digital information corresponding to the respective window functions; a starting unit for changing the multiplied digital information corresponding to the window function including a recording start timing of the digital information to zero information, and for starting recording the digital information to be recorded after the recording start timing, after recording the zero information onto the information storage medium.
According to similar aspect of the invention, there is provided an information recording method for recording digital information inputted from outside onto an information storage medium, including the steps of: multiplexing the digital information by a plurality of window functions to generate a plurality of multiplied digital information, each of the plurality of window functions having a fade-in time-axis characteristic and having overlaps with neighboring window functions on time axis; recording the plurality of multiplied digital information corresponding to the respective window functions; changing the multiplied digital information corresponding to the window function including a recording start timing of the digital information to zero information, and starting recording the digital information to be recorded after the recording start timing, after recording the zero information onto the information storage medium.
In accordance with the above information recording apparatus and method, the window functions which are multiplied by the digital information has the time-axis characteristics. When the recording of the digital information is started, the multiplexed digital information corresponding to the window function including the recording start timing is changed to zero information, and the recording of the digital information is started after the zero information is recorded. By this, the recording level variation of the digital information just after the start of the recording becomes similar to the fade-in characteristic of the window function. Therefore, the fade-in is achieved by a simple processing at the start time of the digital information, and it is possible to avoid noise generation at the time of reproduction, due to the sudden decrease of the digital information recording level.
According to still another aspect of the present invention, there is provided an information recording apparatus for recording digital information inputted from outside onto an information storage medium, including: a multiplexing unit for multiplying the digital information by a plurality of window functions to generate a plurality of multiplied digital information, each of the plurality of window functions having a time-axis characteristic including a fade-in portion and a fade-out portion and having overlaps with neighboring window functions on time axis; a recording unit for recording the plurality of multiplied digital information corresponding to the respective window functions; an interruption unit for changing interruption multiplexed digital information which are the multiplied digital information corresponding to the window function including a recording interruption timing of the digital information to zero information, and for interrupting recording the digital information after recording the zero information onto the information storage medium in place of the interruption multiplexed digital information; and a restarting unit for changing the multiplied digital information corresponding to the window function including a recording restart timing of the digital information to zero information, and for restarting recording the digital information to be recorded after the recording restart timing, after recording the zero information onto the information storage medium.
According to the similar aspect of the present invention, there is provided an information recording method for recording digital information inputted from outside onto an information storage medium, including the steps of: multiplying the digital information by a plurality of window functions to generate a plurality of multiplied digital information, each of the plurality of window functions having a time-axis characteristic including a fade-in portion and a fade-out portion and having overlaps with neighboring window functions on time axis; recording the plurality of multiplied digital information corresponding to the respective window functions; changing interruption multiplexed digital information which are the multiplied digital information corresponding to the window function including a recording interruption timing of the digital information to zero information, and interrupting recording the digital information after recording the zero information onto the information storage medium in place of the interruption multiplexed digital information; and changing the multiplied digital information corresponding to the window function including a recording restart timing of the digital information to zero information, and restarting recording the digital information to be recorded after the recording restart timing, after recording the zero information onto the information storage medium.
In accordance with the above information recording apparatus and method, the window function which are multiplied by the digital information have a time-axis characteristic including fade-in portion and fade-out portion. When the digital information recording is interrupted, the interruption digital information is changed to zero information and the recording of the digital information is interrupted after the zero information is recorded on the information storage medium. When the digital information recording is restarted, the multiplexed digital information corresponding to the window function including the recording restart timing is changed to zero information and the digital information recording is restarted after the zero information is recorded on the information storage medium. Thus, the digital information recording level just before the interruption or just after the restart become similar to the fade-out or fade-in characteristic of the window function. Therefore, the fade-out and fade-in can be achieved by a simple processing at the interruption/restart time of the digital information, and it is possible to avoid noise generation at the time of interruption/restart, due to the sudden great variation of the digital information recording level.
According to still another aspect of the present invention, there is provided an information recording apparatus for recording digital information inputted from outside onto an information storage medium, including: a multiplexing unit for multiplexing the digital information by a plurality of window functions to generate a plurality of multiplied digital information, each of the plurality of window functions having a time-axis characteristic including a fade-in portion and a fade-out portion and having overlaps with neighboring window functions on time axis; a recording unit for recording the plurality of multiplied digital information corresponding to the respective window functions; an interruption unit for changing the digital information including a recording interruption timing of the digital information to zero information, and for interrupting recording the digital information after recording the zero information onto the information storage medium in place of the multiplexed digital information including the recording interruption timing; and a restarting unit for changing, after a recording interruption, the digital information including a recording restart timing of the digital information to zero information, and for restarting recording the digital information to be recorded after the recording restart timing, after recording the zero information onto the information storage medium in place of the multiplexed digital information including the recording restart timing.
According to the similar aspect of the present invention, there is provided an information recording method for recording digital information inputted from outside onto an information storage medium, including the steps of: multiplexing the digital information by a plurality of window functions to generate a plurality of multiplied digital information, each of the plurality of window functions having a time-axis characteristic including a fade-in portion and a fade-out portion and having overlaps with neighboring window functions on time axis; recording the plurality of multiplied digital information corresponding to the respective window functions; changing the digital information including a recording interruption timing of the digital information to zero information, and interrupting recording the digital information after recording the zero information onto the information storage medium in place of the multiplexed digital information including the recording interruption timing; and changing, after a recording interruption, the digital information including a recording restart timing of the digital information to zero information, and restarting recording the digital information to be recorded after the recording restart timing, after recording the zero information onto the information storage medium in place of the multiplexed digital information including the recording restart timing.
In accordance with the above information recording apparatus and method, the window functions which are multiplied by the digital information have a time-axis characteristic including fade-in portion and fade-out portion. When the digital information recording is interrupted, the digital information including the recording interruption timing is changed to zero information and the recording of the digital information is interrupted after the zero information is recorded on the information storage medium in place of the multiplexed digital information including the recording interruption timing. When the digital information recording is restarted, the digital information including the recording restart timing is changed to zero information and the digital information recording is restarted after the zero information is recorded on the information storage medium in place of the multiplexed digital information including the recording restart timing. Thus, the digital information recording level just before the interruption or just after the restart become similar to the fade-out or fade-in characteristic of the window function. Therefore, the fade-out and fade-in can be achieved by a simple processing at the interruption/restart time of the digital information, and it is possible to avoid noise generation at the time of interruption/restart, due to the sudden great variation of the digital information recording level.
Preferably, each of the window functions has the overlap for a half of a time period of the window function on a time-axis. By this, the multiplexed digital information which accurately corresponds to the original information can be generated and recorded.
In a preferred embodiment, the digital information may be audio information. By this, the noise generation can be avoided at the recording end, start and interruption/restart time of recorded audio information.
Further, in a preferred embodiment, the window function may be adapted to remove distortion in Modified Discrete Cosine transform coding system. Thus, the fade-out and fade-in can be achieved by a simple processing at ending, start and interruption/restart time of the digital information recording using MDCT coding system, and it is possible to avoid noise generation.
The nature, utility, and further features of this invention will be more clearly apparent from the following detailed description with respect to preferred embodiment of the invention when read in conjunction with the accompanying drawings briefly described below.