Apparatus and method for reproducing audio data

1 . An apparatus for reproducing audio data comprising:

a non-silent sound/silent sound determining section adapted to determine whether said audio data is a non-silent sound or a silent sound in accordance with a level of said audio data, to thereby generate a first determination result;

a speech sound/non-speech sound determining section adapted to determine whether said audio data is a speech sound or a non-speech sound in accordance with an absolute value of a difference between left-side and right-side stereochannel component levels of said audio data, to thereby generate a second determination result; and

an audio data selecting/removing unit adapted to select or remove said audio data in accordance with said first and second determination results.

2 . The apparatus as set forth in claim 1 , wherein said non-silent sound/silent sound determination unit comprises:

a first comparator adapted to compare the left-side stereochannel component level of said audio data with a first threshold value;

a second comparator adapted to compare the right-side stereochannel component level of said audio data with said first threshold value; and

a logic circuit connected to outputs of said first and second comparators, said logic circuit being adapted to generate said first determination result.

3 . The apparatus as set forth in claim 1 , wherein said speech sound/non-speech sound determining section comprises:

an absolute value calculating unit adapted to calculate the absolute value of the difference between the left-side and right-side stereochannel component levels of said audio data; and

a third comparator connected to said absolute value calculating circuit, said third comparator being adapted to compare the absolute value with a second threshold value, to thereby generate said second determination result.

4 . The apparatus as set forth in claim 1 , wherein the level of said audio data is one of a peak value and an average square value of at least part of said audio data.

5 . An apparatus for reproducing a plurality of M frames (M= 2 , 3 , . . . ) audio data comprising:

a non-silent sound/silent sound determining section adapted to determine whether each of said M frames is a non-silent sound or a silent sound in accordance with left-side and right-side stereochannel component levels of said each of said M frames, to thereby generate a first determination result;

a speech sound/non-speech sound determining section adapted to determine whether each of said frames is a speech sound or a non-speech sound in accordance with an absolute value of a difference between the left-side and right-side stereochannel component levels of said each of said M frames, to thereby generate a second determination result; and

a frame selecting/removing unit adapted to select N frames (N=1, 2, . . . and N<M) from said M frames and remove (M-N) frames from said M frames in accordance with pairs of said first and second determination results of said M frames, thus reproducing only said N frames.

6 . The apparatus as set forth in claim 5 , wherein the pairs of said first and second determination results have priorities so that a pair of said first and second determination results showing said non-silent sound and said speech sound, respectively, have a highest priority; a pair of said first and second determination results showing said non-silent sound and said non-speech sound, respectively, have a second highest priority; and a pair of said first and second determination results where said first determination result show said silent sound have a lowest priority.

7 . The apparatus as set forth in claim 5 , wherein said non-silent sound/silent sound determination unit comprises:

a first comparator adapted to compare the left-side stereochannel component level of said audio data with a first threshold value;

a second comparator adapted to compare the right-side stereochannel component level of said audio data with said first threshold value; and

a logic circuit connected to outputs of said first and second comparators, said logic circuit being adapted to generate said first determination result.

8 . The apparatus as set forth in claim 5 , wherein said speech sound/non-speech sound determining section comprises:

an absolute value calculating unit adapted to calculate the absolute value of the difference between the left-side and right-side stereochannel component levels of said audio data; and

a third comparator connected to said absolute value calculating circuit, said third comparator being adapted to compare the absolute value with a second threshold value, to thereby generate said second determination result.

9 . The apparatus as set forth in claim 5 , wherein the level of said audio data is one of a peak value and an average square value of at least part of said audio data.

10 . A method for reproducing audio data comprising:

determining whether said audio data is a non-silent sound or a silent sound in accordance with a level of said audio data, to thereby generate a first determination result;

determining whether said audio data is a speech sound or a non-speech sound in accordance with an absolute value of a difference between left-side and right-side stereochannel component levels of said audio data, to thereby generate a second determination result; and

selecting or removing said audio data in accordance with said first and second determination results.

11 . The method as set forth in claim 10 , wherein said non-silent sound/silent sound determination comprises:

comparing the left-side stereochannel component level of said audio data with a first threshold value to generate a first comparison result;

comparing the right-side stereochannel component level of said audio data with said first threshold value to generate a second comparison result; and performing a logic operation upon said first and second comparison results to generate said first determination result.

12 . The method as set forth in claim 10 , wherein said speech sound/non-speech sound determining comprises:

calculating the absolute value of the difference between the left-side and right-side stereochannel component levels of said audio data; and

comparing the absolute value with a second threshold value, to thereby generate said second determination result.

13 . The method as set forth in claim 10 , wherein the level of said audio data is one of a peak value and an average square value of at least part of said audio data.

14 . A method for reproducing a plurality of M frames (M=2, 3, . . . ) audio data comprising:

determining whether each of said M frames is a non-silent sound or a silent sound in accordance with left-side and right-side stereochannel component levels of said each of said M frames, to thereby generate a first determination result;

determining whether each of said frames is a speech sound or a non-speech sound in accordance with an absolute value of a difference between the left-side and right-side stereochannel component levels of said each of said M frames, to thereby generate a second determination result; and

selecting N frames (N=1, 2, . . . and N<M) from said M frames and removing (M-N) frames from said M frames in accordance with pairs of said first and second determination results of said M frames, thus reproducing only said N frames.

15 . The method as set forth in claim 14 , wherein the pairs of said first and second determination results have priorities so that a pair of said first and second determination results showing said non-silent sound and said speech sound, respectively, have a highest priority; a pair of said first and second determination results showing said non-silent sound and said non-speech sound, respectively, have a second highest priority; and a pair of said first and second determination results where said first determination result show said silent sound have a lowest priority.

16 . The method as set forth in claim 14 , wherein said non-silent sound/silent sound determination comprises:

comparing the left-side stereochannel component level of said audio data with a first threshold value to generated a first comparison result;

comparing the right-side stereochannel component level of said audio data with said first threshold value to generate a second comparison result; and

performing a logic operation upon said first and second comparison results to generate said first determination result.

17 . The apparatus as set forth in claim 14 , wherein said speech sound/non-speech sound determining comprises:

calculating the absolute value of the difference between the left-side and right-side stereochannel component levels of said audio data; and

comparing the absolute value with a second threshold value, to thereby generate said second determination result.

18 . The method as set forth in claim 14 , wherein the level of said audio data is one of a peak value and an average square value of at least part of said audio data.