INFORMATION PROCESSING METHOD AND INFORMATION PROCESSING DEVICE

1 . A decoding apparatus comprising:

a buffer operative to temporarily store digital data for a plurality of channels in units of predetermined sizes;

a channel selection acknowledging unit operative to acknowledge an input signal for selection of a channel; and

a decoding unit operative to read from the buffer the digital data for the channel selected by the input signal acknowledged by the channel selection acknowledging unit.

2 . The decoding apparatus according to claim 1 , further comprising:

a receiver operative to receive radio waves containing signals of a plurality of channels; and

a converter operative to sequentially convert the broadcast waves received by the receiver so as to generate the digital data for a plurality of channels.

3 . The decoding apparatus according to claim 2 , wherein the converter comprises a plurality of band pass filters each operative to extract a frequency component corresponding to a given channel from the broadcast waves received by the receiver, and a plurality of analog-to-digital converters each operative to subject the frequency component extracted by the band pass filter to analog-to-digital conversion so as to output the digital data, the number of band pass filters and analog-to-digital converters being determined by the number of channels received by the receiver.

4 . The decoding apparatus according to claim 2 , wherein

the converter comprises a band pass filter operative to extract frequency components corresponding to the plurality of channels from the broadcast waves received by the receiver, and an analog-to-digital converter operative to subject the frequency components extracted by the band pass filter to analog-to-digital conversion so as to output the digital data, and

the decoding unit comprises a digital filter operative to separate the digital data output by the analog-to-digital converter into data for respective channels.

5 . The decoding apparatus according to claim 1 , further comprising a decoding process controller operative to switch at least a part of the decoding process performed by the decoding unit to a simplified process until a predetermined time condition is met since the channel selection acknowledging unit acknowledges the input signal for selection of a channel.

6 . A broadcast reproduction system comprising a decoding apparatus operative to decode broadcast data and a reproduction apparatus operative to decode the broadcast data and output the decoded data, wherein

the decoding apparatus comprises:

an auxiliary receiver operative to receive broadcast waves containing signals of a plurality of channels;

an auxiliary converter operative to convert the broadcast waves received by the auxiliary receiver and sequentially generate digital data for the plurality of channels;

a buffer operative to temporarily store digital data for a plurality of channels generated by auxiliary converter, in units of predetermined sizes;

a channel selection acknowledging unit operative to acknowledge an input signal for selection of a channel; and

an auxiliary decoding unit operative to read from the buffer the digital data for the channel selected by the input signal acknowledged by the channel selection acknowledging unit and to decode the read data so as to output auxiliary output data, wherein

the reproduction apparatus comprises:

a main receiver operative to receive the broadcast waves;

a switching unit operative to acknowledge the input signal for selection of a channel;

a main converter operative to extract, from the broadcast waves, the signal of the channel selected by the input signal acknowledged by the switching unit and to subject the extracted signal to conversion, thereby generating the digital data for the selected channel;

a main decoding unit operative to decode the digital data generated by the main converter and to generate main output data; and

an output unit operative to output the auxiliary output data generated by the auxiliary decoding unit or the main output data generated by the main decoding unit, wherein

the switching unit further controls the switching of outputs such that the auxiliary output data is obtained from the decoding apparatus and is output to the output unit until a predetermined timing condition is met since the input signal for selection of a channel is obtained.

7 . The broadcast reproduction system according to claim 6 , wherein

the auxiliary decoding unit halts the decoding process when a predetermined period of time has elapsed since the decoding process is started.

8 . The broadcast reproduction system according to claim 6 , wherein

the auxiliary decoding unit and the main decoding unit decode the digital data coded by inter-frame prediction, and

the switching unit controls the switching of outputs such that the main output data generated by the main decoding unit is output to the output unit after the arrival of the first I picture for the channel selected by the input signal for selection of a channel at the main decoding unit is detected.

9 . The broadcast reproduction system according to claim 6 , wherein

the switching unit controls the switching of outputs such that, in response to the acknowledgement of the input signal for selection of a channel, the auxiliary output data is output to the output unit when an image of the auxiliary output data output by the decoding apparatus represents an image currently occurring in the channel selected by the input signal.

10 . A broadcast data reproduction apparatus comprising:

first and second processor units each operative to extract and decode a signal for a given channel from broadcast waves containing signals of a plurality of channels, in accordance with an input signal for selection of a channel; and

an output unit operative to output data decoded by the first processor unit or the second processor unit, wherein the speed of decoding process performed by the second processor unit is higher than that of the first processor unit, and

the output unit outputs the data decoded by the second processor unit for a predetermined period of time since the input signal is input and outputs the data decoded by the first processor unit at other periods.

11 . The broadcast data reproduction apparatus according to claim 10 , wherein

the second processor unit halts the decoding process when a predetermined period of time has elapsed since the input signal is input.

12 . The broadcast data reproduction apparatus according to claim 10 , wherein

the second processor unit sequentially store in a memory a part of data derived from simultaneously subjecting signals for a plurality of channels contained in the broadcast waves to a part of the decoding process, and the second processor unit completes the decoding process by reading data for the given channel from the digital data thus stored and by subjecting the data thus read to the remainder of the process.

13 . A broadcast data reproduction apparatus comprising:

a first input unit operative to receive radio waves containing a plurality of channels;

a decoding unit operative to extract, from the radio waves received by the first input unit, and decode a signal for a channel selected by an input signal for selection of a channel and to generate main output data;

a second input unit operative to obtain, from an external apparatus, auxiliary output data derived from decoding the signal for the channel selected by the input signal; and

an output unit operative to output the auxiliary output data obtained by the second input unit for a predetermined period of time since the input signal is input and to output the main output data generated by the decoding unit at other periods.

14 . An information processing method for performing first and second processes on a data stream being received and sequentially outputting the processed stream, comprising:

receiving a plurality of data streams;

performing the first process on the plurality of data streams so as to generate a plurality of items of intermediate data sequentially;

temporarily storing the plurality of items of intermediate data in a buffer in units of predetermined sizes; and

in response to an input signal selecting a data stream, reading an item of intermediate data corresponding to the selected data stream from the buffer, and performing the second process on the data thus read so as to generate output data.

15 . A computer program product comprising:

a module that receives radio waves containing signals for a plurality of channels;

a module that converts the broadcast waves so as to generate digital data for the plurality of channels sequentially;

a module that temporarily stores the digital data for the plurality of channels in a buffer in units of predetermined sizes;

a module that acknowledges an input signal for selection of a channel; and

a module that reads the digital data for the channel selected by the input signal from the buffer and decodes the data thus read.

16 . A recording medium having embodied thereon a computer program product comprising:

a module that receives radio waves containing signals for a plurality of channels;

a module that converts the broadcast waves so as to generate digital data for the plurality of channels sequentially;

a module that temporarily stores the digital data for the plurality of channels in a buffer in units of predetermined sizes;

a module that acknowledges an input signal for selection of a channel; and

a module that reads the digital data for the channel selected by the input signal from the buffer and decodes the data thus read.