SYSTEM AND METHOD OF SMART AUDIO LOGGING FOR MOBILE DEVICES

• US 20120078397A1
• Filed: 03/30/2011
• Published: 03/29/2012
• Est. Priority Date: 04/08/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: LEE, Te-Won, EL-MALEH, Khaled Helmi, YOO, Heejong, SHIN, Jongwon
• Granted Patent: US 9,112,989 B2
• Time in Patent Office: Days
• US Class Current: 700/94
• CPC Class Codes: G10L 17/00 Speaker identification or verification techniques
• CPC Class Codes: G10L 2015/088 Word spotting
• CPC Class Codes: G10L 25/78 Detection of presence or absence of voice signals switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 2020/10546 specifically adapted for audio data
• CPC Class Codes: H04M 1/6008 in the transmitter circuit
• CPC Class Codes: H04M 1/656 for recording conversations
• CPC Class Codes: H04M 1/72433 for voice messaging, e.g. dictaphones for answering incoming calls H04M1/64

Abstract

A mobile device that is capable of automatically starting and ending the recording of an audio signal captured by at least one microphone is presented. The mobile device is capable of adjusting a number of parameters related with audio logging based on the context information of the audio input signal.

Claims

1. A method of processing a digital audio signal for a mobile device, the method comprising:

receiving acoustic signal by at least one microphone;

converting the received acoustic signal into the digital audio signal;

extracting at least one auditory context information from the digital audio signal;

in response to automatically detecting a start event indicator, performing an audio logging for the digital audio signal; and

in response to automatically detecting an end event indicator, ending the audio logging.

2. The method of processing a digital audio signal according to claim 1, wherein the converting comprises:

transforming the received acoustic signal into an electrical signal;

sampling the electrical signal to obtain the digital audio signal; and

storing the digital audio signal into a buffer,

wherein the sampling is based on a sampling frequency and a data width.

3. The method of processing a digital audio signal according to claim 1, wherein the at least one auditory context information relates to at least one of followings—

audio classification, keyword identification, or speaker identification.

4. The method of processing a digital audio signal according to claim 3, wherein the at least one auditory context information is based at least in part on one of followings—

signal energy, signal-to-noise ratio, spectral tilt, or zero-crossing rate.

5. The method of processing a digital audio signal according to claim 3, wherein the at least one auditory context information is based at least in part on non-auditory information.

6. The method of processing a digital audio signal according to claim 5, wherein the non-auditory information comprises scheduling or calendaring information.

7. The method of processing a digital audio signal according to claim 1, wherein the detecting the start event indicator comprises:

selecting at least one context information from the at least one auditory context information; and

in response to comparing the selected context information with at least one pre-determined thresholds, determining if the start event indicator has been detected.

8. The method of processing a digital audio signal according to claim 1, wherein the detecting the start event indicator is based at least in part on non-auditory information, and wherein the non-auditory information comprises scheduling or calendaring information.

9. The method of processing a digital audio signal according to claim 1, wherein the performing the audio logging comprises:

updating at least one parameter related with the converting based at least in part on the at least one auditory context information;

in response to determining if an additional processing is required based at least in part on the at least one auditory context information, applying the additional processing to the digital audio signal to obtain processed audio signal; and

storing the processed audio signal into a memory storage.

10. The method of processing a digital audio signal according to claim 9, wherein the additional processing includes signal enhancement processing.

11. The method of processing a digital audio signal according to claim 10, wherein the signal enhancement processing includes at least one of followings—

acoustic echo cancellation (AEC), receiving voice enhancement (RVE), active noise cancellation (ANC), noise suppression (NS), acoustic gain control (AGC), acoustic volume control (AVC), or acoustic dynamic range control (ADRC).

12. The method of processing a digital audio signal according to claim 11, wherein the noise suppression is based on plurality of microphones.

13. The method of processing a digital audio signal according to claim 9, wherein the additional processing includes signal compression processing.

14. The method of processing a digital audio signal according to claim 13, wherein the signal compression processing includes speech compression or audio compression.

15. The method of processing a digital audio signal according to claim 13, wherein at least one compression parameter is determined based on the auditory context information.

16. The method of processing a digital audio signal according to claim 15, wherein said at least one compression parameter includes compression mode, bitrate, or channel number.

17. The method of processing a digital audio signal according to claim 9, wherein the memory storage comprises a local memory inside the mobile device or a remote memory connected to the mobile device through a wireless channel.

18. The method of processing a digital audio signal according to claim 17, wherein the memory storage is selected based at least in part on the auditory context information.

19. The method of processing a digital audio signal according to claim 1, wherein the detecting the end event indicator comprises:

selecting at least one context information from the at least one auditory context information; and

in response to comparing the selected context information with at least one pre-determined thresholds, determining if the end event indicator has been detected.

20. The method of processing a digital audio signal according to claim 1, wherein the detecting the end event indicator is based at least in part on non-occurrence of auditory event during pre-determined period of time.

21. The method of processing a digital audio signal according to claim 1, wherein the detecting the end event indicator is based at least in part on non-auditory information, and wherein the non-auditory information comprises scheduling or calendaring information.

22. An apparatus for processing a digital audio signal for a mobile device, the apparatus comprising:

at least one microphone configured to receive acoustic signal;

a converter configured to convert the received acoustic signal into the digital audio signal;

a context identifier configured to extract at least one auditory context information from the digital audio signal;

a start event manager configured to automatically detect a start event indicator;

an end event manager configured to automatically detect an end event indicator; and

an audio logging processor configured to;

perform an audio logging for the digital audio signal in response to the detecting of the start event indicator; and

end the audio logging in response to the detecting of the end event indicator.

23. The apparatus for processing a digital audio signal according to claim 22, wherein the converter configured to:

transform the received acoustic signal into an electrical signal;

sample the electrical signal to obtain the digital audio signal; and

store the digital audio signal into a buffer,

wherein the sampling is based on a sampling frequency and a data width.

24. The apparatus for processing a digital audio signal according to claim 22, wherein the at least one auditory context information relates to at least one of followings—

audio classification, keyword identification, or speaker identification.

25. The apparatus for processing a digital audio signal according to claim 24, wherein the at least one auditory context information is based at least in part on one of followings—

signal energy, signal-to-noise ratio, spectral tilt, or zero-crossing rate.

26. The apparatus for processing a digital audio signal according to claim 24, wherein the at least one auditory context information is based at least in part on non-auditory information.

27. The apparatus for processing a digital audio signal according to claim 26, wherein the non-auditory information comprises scheduling or calendaring information.

28. The apparatus for processing a digital audio signal according to claim 22, wherein the start event manager configured to:

select at least one context information from the at least one auditory context information;

compare the selected context information with at least one pre-determined thresholds; and

determine if the start event indicator has been detected in response to the comparing.

29. The apparatus for processing a digital audio signal according to claim 22, wherein the detecting the start event indicator is based at least in part on non-auditory information, and wherein the non-auditory information comprises scheduling or calendaring information.

30. The apparatus for processing a digital audio signal according to claim 22, wherein the audio logging processor configured to:

update at least one parameter related with the converter based at least in part on the at least one auditory context information;

determine if an additional processing is required based at least in part on the at least one auditory context information;

apply the additional processing to the digital audio signal to obtain processed audio signal, in response to the determining; and

store the processed audio signal into a memory storage.

31. The apparatus for processing a digital audio signal according to claim 30, wherein the additional processing includes signal enhancement processing.

32. The apparatus for processing a digital audio signal according to claim 31, wherein the signal enhancement processing includes at least one of followings—

acoustic echo cancellation (AEC), receiving voice enhancement (RVE), active noise cancellation (ANC), noise suppression (NS), acoustic gain control (AGC), acoustic volume control (AVC), or acoustic dynamic range control (ADRC).

33. The apparatus for processing a digital audio signal according to claim 32, wherein the noise suppression is based on plurality of microphones.

34. The apparatus for processing a digital audio signal according to claim 30, wherein the additional processing includes signal compression processing.

35. The apparatus for processing a digital audio signal according to claim 34, wherein the signal compression processing includes speech compression or audio compression.

36. The apparatus for processing a digital audio signal according to claim 34, wherein at least one compression parameter is determined based on the auditory context information.

37. The apparatus for processing a digital audio signal according to claim 36, wherein said at least one compression parameter includes compression mode, bitrate, or channel number.

38. The apparatus for processing a digital audio signal according to claim 30, wherein the memory storage comprises a local memory inside the mobile device or a remote memory connected to the mobile device through a wireless channel.

39. The apparatus for processing a digital audio signal according to claim 38, wherein the memory storage is selected based at least in part on the auditory context information.

40. The apparatus for processing a digital audio signal according to claim 22, wherein the end event manager configured to:

select at least one context information from the at least one auditory context information;

compare the selected context information with at least one pre-determined thresholds; and

determine if the end event indicator has been detected in response to the comparing.

41. The apparatus for processing a digital audio signal according to claim 22, wherein the detecting the end event indicator is based at least in part on non-occurrence of auditory event during pre-determined period of time.

42. The apparatus for processing a digital audio signal according to claim 22, wherein the detecting the end event indicator is based at least in part on non-auditory information, and wherein the non-auditory information comprises scheduling or calendaring information.

43. An apparatus for processing a digital audio signal for a mobile device, the apparatus comprising:

means for receiving acoustic signal by at least one microphone;

means for converting the received acoustic signal into the digital audio signal;

means for extracting at least one auditory context information from the digital audio signal;

means for automatically detecting a start event indicator;

means for performing an audio logging for the digital audio signal in response to the detecting the start event indicator;

means for automatically detecting an end event indicator; and

means for ending an audio logging for the digital audio signal in response to the detecting the end event indicator.

44. The apparatus for processing a digital audio signal according to claim 43, wherein the means for converting comprises:

means for transforming the received acoustic signal into an electrical signal;

means for sampling the electrical signal to obtain the digital audio signal; and

means for storing the digital audio signal into a buffer,

wherein the sampling is based on a sampling frequency and a data width.

45. The apparatus for processing a digital audio signal according to claim 43, wherein the at least one auditory context information relates to at least one of followings—

audio classification, keyword identification, or speaker identification.

46. The apparatus for processing a digital audio signal according to claim 45, wherein the at least one auditory context information is based at least in part on one of followings—

signal energy, signal-to-noise ratio, spectral tilt, or zero-crossing rate.

47. The apparatus for processing a digital audio signal according to claim 45, wherein the at least one auditory context information is based at least in part on non-auditory information.

48. The apparatus for processing a digital audio signal according to claim 47, wherein the non-auditory information comprises scheduling or calendaring information.

49. The apparatus for processing a digital audio signal according to claim 43, wherein the means for detecting the start event indicator comprises:

means for selecting at least one context information from the at least one auditory context information;

means for comparing the selected context information with at least one pre-determined thresholds; and

means for determining if the start event indicator has been detected in response to the comparing.

50. The apparatus for processing a digital audio signal according to claim 43, wherein the detecting the start event indicator is based at least in part on non-auditory information, and wherein the non-auditory information comprises scheduling or calendaring information.

51. The apparatus for processing a digital audio signal according to claim 43, wherein the means for performing the audio logging comprises:

means for updating at least one parameter related with the means for converting based at least in part on the at least one auditory context information;

means for determining if an additional processing is required based at least in part on the at least one auditory context information;

means for applying the additional processing to the digital audio signal to obtain processed audio signal, in response to the determining; and

means for storing the processed audio signal into a memory storage.

52. The apparatus for processing a digital audio signal according to claim 51, wherein the additional processing includes signal enhancement processing.

53. The apparatus for processing a digital audio signal according to claim 52, wherein the signal enhancement processing includes at least one of followings—

acoustic echo cancellation (AEC), receiving voice enhancement (RVE), active noise cancellation (ANC), noise suppression (NS), acoustic gain control (AGC), acoustic volume control (AVC), or acoustic dynamic range control (ADRC).

54. The apparatus for processing a digital audio signal according to claim 53, wherein the noise suppression is based on plurality of microphones.

55. The apparatus for processing a digital audio signal according to claim 51, wherein the additional processing includes signal compression processing.

56. The apparatus for processing a digital audio signal according to claim 55, wherein the signal compression processing includes speech compression or audio compression.

57. The apparatus for processing a digital audio signal according to claim 55, wherein at least one compression parameter is determined based on the auditory context information.

58. The apparatus for processing a digital audio signal according to claim 57, wherein said at least one compression parameter includes compression mode, bitrate, or channel number.

59. The apparatus for processing a digital audio signal according to claim 51, wherein the memory storage comprises a local memory inside the mobile device or a remote memory connected to the mobile device through a wireless channel.

60. The apparatus for processing a digital audio signal according to claim 59, wherein the memory storage is selected based at least in part on the auditory context information.

61. The apparatus for processing a digital audio signal according to claim 43, wherein the means for detecting the end event indicator comprises:

means for selecting at least one context information from the at least one auditory context information;

means for comparing the selected context information with at least one pre-determined thresholds; and

means for determining if the end event indicator has been detected in response to the comparing.

62. The apparatus for processing a digital audio signal according to claim 43, wherein the means for detecting the end event indicator is based at least in part on non-occurrence of auditory event during pre-determined period of time.

63. The apparatus for processing a digital audio signal according to claim 43, wherein the means for detecting the end event indicator is based at least in part on non-auditory information, and wherein the non-auditory information comprises scheduling or calendaring information.

64. A non-transitory computer-readable medium comprising instructions for processing a digital audio signal for a mobile device, which when executed by a processor cause the processor to:

receive acoustic signal by at least one microphone;

convert the received acoustic signal into the digital audio signal;

extract at least one auditory context information from the digital audio signal;

automatically detect a start event indicator;

perform an audio logging for the digital audio signal in response to the detecting the start event indicator;

automatically detect an end event indicator; and

end the audio logging in response to the detecting the end event indicator.

65. The computer-readable medium according to claim 64, wherein the instructions which when executed by a processor cause the processor to convert the received acoustic signal are configured to cause the processor to:

transform the received acoustic signal into an electrical signal;

sample the electrical signal to obtain the digital audio signal; and

store the digital audio signal into a buffer, wherein the sampling is based on a sampling frequency and a data width.

66. The computer-readable medium according to claim 64, wherein the at least one auditory context information relates to at least one of followings—

audio classification, keyword identification, or speaker identification.

67. The computer-readable medium according to claim 66, wherein the at least one auditory context information is based at least in part on one of followings—

signal energy, signal-to-noise ratio, spectral tilt, or zero-crossing rate.

68. The computer-readable medium according to claim 66, wherein the at least one auditory context information is based at least in part on non-auditory information.

69. The computer-readable medium according to claim 68, wherein the non-auditory information comprises scheduling or calendaring information.

70. The computer-readable medium according to claim 64, wherein the instructions which when executed by a processor cause the processor to detect the start event indicator are configured to cause the processor to:

select at least one context information from the at least one auditory context information;

compare the selected context information with at least one pre-determined thresholds; and

determine if the start event indicator has been detected in response to the comparing.

71. The computer-readable medium according to claim 64, wherein the instructions which when executed by a processor cause the processor to detect the start event indicator are configured to detect the start event indicator based at least in part on non-auditory information, and wherein the non-auditory information comprises scheduling or calendaring information.

72. The computer-readable medium according to claim 64, wherein the instructions which when executed by a processor cause the processor to perform the audio logging are configured to cause the processor to:

update at least one parameter related with the converting based at least in part on the at least one auditory context information;

determine if an additional processing is required based at least in part on the at least one auditory context information;

apply the additional processing to the digital audio signal to obtain processed audio signal, in response to the determining; and

store the processed audio signal into a memory storage.

73. The computer-readable medium according to claim 72, wherein the additional processing includes signal enhancement processing.

74. The computer-readable medium according to claim 73, wherein the signal enhancement processing includes at least one of followings—

acoustic echo cancellation (AEC), receiving voice enhancement (RVE), active noise cancellation (ANC), noise suppression (NS), acoustic gain control (AGC), acoustic volume control (AVC), or acoustic dynamic range control (ADRC).

75. The computer-readable medium according to claim 74, wherein the noise suppression is based on plurality of microphones.

76. The computer-readable medium according to claim 72, wherein the additional processing includes signal compression processing.

77. The computer-readable medium according to claim 76, wherein the signal compression processing includes speech compression or audio compression.

78. The computer-readable medium according to claim 76, wherein at least one compression parameter is determined based on the auditory context information.

79. The computer-readable medium according to claim 78, wherein said at least one compression parameter includes compression mode, bitrate, or channel number.

80. The computer-readable medium according to claim 72, wherein the memory storage comprises a local memory inside the mobile device or a remote memory connected to the mobile device through a wireless channel.

81. The computer-readable medium according to claim 80, wherein the memory storage is selected based at least in part on the auditory context information.

82. The computer-readable medium according to claim 64, wherein the instructions which when executed by a processor cause the processor to detect the end event indicator are configured to cause the processor to:

select at least one context information from the at least one auditory context information;

compare the selected context information with at least one pre-determined thresholds; and

determine if the end event indicator has been detected in response to the comparing.

83. The computer-readable medium according to claim 64, wherein the instructions which when executed by a processor cause the processor to detect the end event indicator are configured to detect the end event indicator based at least in part on non-occurrence of auditory event during pre-determined period of time.

84. The computer-readable medium according to claim 64, wherein the instructions which when executed by a processor cause the processor to detect the end event indicator are configured to detect the end event indicator based at least in part on non-auditory information, and wherein the non-auditory information comprises scheduling or calendaring information.

85. A method for a mobile device, the method comprising:

in response to automatically detecting a start event indicator, processing first portion of audio input signal to obtain first information;

determining at least one recording parameter based on the first information; and

reconfiguring an audio capturing unit of the mobile device based on the determined at least one recording parameter.

86. The method according to claim 85, wherein the reconfiguring the audio capturing unit occurs during an inactive portion of the audio input signal.

87. The method according to claim 85, wherein the at least one recording parameter includes information indicative of a sampling frequency or a data width for an A/D converter of the mobile device.

88. The method according to claim 85, wherein the at least one recording parameter includes information indicative of the number of active microphone of the mobile device.

89. The method according to claim 85, wherein the at least one recording parameter includes timing information indicative of at least one microphone'"'"'s wake up interval or active duration.

90. The method according to claim 85, wherein the first information is context information describing an environment in which the mobile device is recording.

91. The method according to claim 85, wherein the first information is context information describing a characteristic of the audio input signal.

92. The method according to claim 85, wherein the start event indicator is based on a signal transmitted over a wireless channel.

93. The method according to claim 85, further comprising:

processing second portion of the audio input signal to obtain second information;

enhancing the audio input signal by suppressing a background noise to obtain an enhanced signal;

encoding the enhanced signal to obtain an encoded signal; and

storing the encoded signal at a local storage within the mobile device.

94. The method according to claim 93, further comprising determining a degree of the enhancing the audio input signal based on the second information.

95. The method according to claim 93, wherein the encoding the enhanced signal comprises:

determining an encoding type based on the second information;

determining at least one encoding parameter for the determined encoding; and

processing the enhanced signal based on the determined encoding type and the determined at least one encoding parameter to obtain the encoded signal;

wherein the at least one encoding parameter comprises bitrate or encoding mode.

96. The method according to claim 93, further comprising:

automatically detecting an end event indicator; and

in response to the detecting an end event indicator, determining a long-term storage location for the encoded signal between the local storage within the mobile device and a network storage connected to the mobile device through a wireless channel.

97. The method according to claim 96, wherein the determining the long-term storage location is based on a priority of the encoded signal.

98. An apparatus for a mobile device, the apparatus comprising:

an audio logging processor configured to;

automatically detect a start event indicator;

process first portion of audio input signal to obtain first information, in response to the detecting of the start event indicator; and

determine at least one recording parameter based on the first information; and

an audio capturing unit configured to reconfigure itself based on the determined at least one recording parameter.

99. The apparatus according to claim 98, wherein the audio capturing unit configured to reconfigure itself during an inactive portion of the audio input signal.

100. The apparatus according to claim 98, wherein the at least one recording parameter includes information indicative of a sampling frequency or a data width for an A/D converter of the audio capturing unit.

101. The apparatus according to claim 98, wherein the at least one recording parameter includes information indicative of the number of active microphone of the mobile device.

102. The apparatus according to claim 98, wherein the at least one recording parameter includes timing information indicative of at least one microphone'"'"'s wake up interval or active duration.

103. The apparatus according to claim 98, wherein the first information is context information indicative of environment in which the mobile device is recording.

104. The apparatus according to claim 98, wherein the first information is context information indicative of a characteristic of the audio input signal.

105. The apparatus according to claim 98, wherein the start event indicator is based on a signal transmitted over a wireless channel.

106. The apparatus according to claim 98, the audio logging processor further configured to:

process second portion of the audio input signal to obtain second information;

enhance the audio input signal by suppressing a background noise to obtain an enhanced signal;

encode the enhanced signal to obtain an encoded signal; and

store the encoded signal at a local storage within the mobile device.

107. The apparatus according to claim 106, the audio logging processor further configured to determine a degree of the enhancing the audio input signal based on the second information.

108. The apparatus according to claim 106, wherein the audio logging processor configured to:

determine an encoding type based on the second information;

determine at least one encoding parameter for the determined encoding; and

process the enhanced signal based on the determined encoding type and the determined at least one encoding parameter to obtain the encoded signal;

wherein the at least one encoding parameter comprises bitrate or encoding mode.

109. The apparatus according to claim 106, the audio logging processor further configured to:

automatically detect an end event indicator; and

in response to the detecting an end event indicator, determine a long-term storage location for the encoded signal between the local storage within the mobile device and a network storage connected to the mobile device through a wireless channel.

110. The apparatus according to claim 109, wherein the determining the long-term storage location is based on a priority of the encoded signal.

111. An apparatus for a mobile device, the apparatus comprising:

means for automatically detecting a start event indicator;

means for processing first portion of audio input signal to obtain first information in response to detecting the start event indicator;

means for determining at least one recording parameter based on the first information; and

means for reconfiguring an audio capturing unit of the mobile device based on the determined at least one recording parameter.

112. The apparatus according to claim 111, wherein the means for reconfiguring the audio capturing unit occurs during an inactive portion of the audio input signal.

113. The apparatus according to claim 111, wherein the at least one recording parameter includes information indicative of a sampling frequency or a data width for an A/D converter of the audio capturing unit.

114. The apparatus according to claim 111, wherein the at least one recording parameter includes information indicative of the number of active microphone of the mobile device.

115. The apparatus according to claim 111, wherein the at least one recording parameter includes timing information indicative of at least one microphone'"'"'s wake up interval or active duration.

116. The apparatus according to claim 111, wherein the first information is context information indicative of environment in which the mobile device is recording.

117. The apparatus according to claim 111, wherein the first information is context information indicative of a characteristic of the audio input signal.

118. The apparatus according to claim 111, wherein the start event indicator is based on a signal transmitted over a wireless channel.

119. The apparatus according to claim 111, further comprising:

means for processing second portion of the audio input signal to obtain second information;

means for enhancing the audio input signal by suppressing a background noise to obtain an enhanced signal;

means for encoding the enhanced signal to obtain an encoded signal; and

means for storing the encoded signal at a local storage within the mobile device.

120. The apparatus according to claim 119, further comprising means for determining a degree of the enhancing the audio input signal based on the second information.

121. The apparatus according to claim 119, wherein the means for encoding the enhanced signal comprises:

means for determining an encoding type based on the second information;

means for determining at least one encoding parameter for the determined encoding; and

means for processing the enhanced signal based on the determined encoding type and the determined at least one encoding parameter to obtain the encoded signal;

wherein the at least one encoding parameter comprises bitrate or encoding mode.

122. The apparatus according to claim 119, further comprising:

means for automatically detecting an end event indicator; and

in response to the detecting an end event indicator, means for determining a long-term storage location for the encoded signal between the local storage within the mobile device and a network storage connected to the mobile device through a wireless channel.

123. The apparatus according to claim 122, wherein the means for determining the long-term storage location is based on a priority of the encoded signal.

124. A non-transitory computer-readable medium comprising instructions which when executed by a processor cause the processor to:

automatically detect a start event indicator;

process first portion of audio input signal to obtain first information in response to detecting the start event indicator;

determine at least one recording parameter based on the first information; and

reconfigure an audio capturing unit of the mobile device based on the determined at least one recording parameter.

125. The computer-readable medium according to claim 124, wherein the instructions which when executed by a processor cause the processor to reconfigure the audio capturing unit are configured to reconfigure the audio capturing unit during an inactive portion of the audio input signal.

126. The computer-readable medium according to claim 124, wherein the at least one recording parameter includes information indicative of a sampling frequency or a data width for an A/D converter of the audio capturing unit.

127. The computer-readable medium according to claim 124, wherein the at least one recording parameter includes information indicative of the number of active microphone of the mobile device.

128. The computer-readable medium according to claim 124, wherein the at least one recording parameter includes timing information indicative of at least one microphone'"'"'s wake up interval or active duration.

129. The computer-readable medium according to claim 124, wherein the first information is context information indicative of environment in which the mobile device is recording.

130. The computer-readable medium according to claim 124, wherein the first information is context information indicative of a characteristic of the audio input signal.

131. The computer-readable medium according to claim 124, wherein the start event indicator is based on a signal transmitted over a wireless channel.

132. The computer-readable medium according to claim 124, wherein the instructions which when executed by a processor to cause the processor to:

process second portion of the audio input signal to obtain second information;

enhance the audio input signal by suppressing a background noise to obtain an enhanced signal;

encode the enhanced signal to obtain an encoded signal; and

store the encoded signal at a local storage within the mobile device.

133. The computer-readable medium according to claim 132, wherein the instructions which when executed by a processor to cause the processor to determine a degree of the enhancing the audio input signal based on the second information.

134. The computer-readable medium according to claim 132, wherein the instructions which when executed by a processor cause the processor to encode the enhanced signal are configured to cause the processor to:

determine an encoding type based on the second information;

determine at least one encoding parameter for the determined encoding; and

process the enhanced signal based on the determined encoding type and the determined at least one encoding parameter to obtain the encoded signal;

wherein the at least one encoding parameter comprises bitrate or encoding mode.

135. The computer-readable medium according to claim 132, wherein the instructions which when executed by a processor to cause the processor to:

automatically detect an end event indicator; and

in response to the detecting an end event indicator, determine a long-term storage location for the encoded signal between the local storage within the mobile device and a network storage connected to the mobile device through a wireless channel.

136. The computer-readable medium according to claim 135, wherein the instructions which when executed by a processor cause the processor to determine the long-term storage location are configured to cause the processor to determine the long-term storage location based on a priority of the encoded signal.