Audio signal transient detection

A method of detecting whether a transient exists within an audio signal, comprising:

• dividing a segment of a digital audio signal into blocks;
• calculating a norm value for each of a plurality of the blocks, resulting in a set of norm values for the plurality of blocks, each said norm value representing a measure of signal strength within a corresponding block;
• identifying a maximum norm value across said plurality of the blocks;
• identifying a different second maximum norm value, subject to a specified constraint, across said plurality of the blocks;
• applying a preliminary criterion to the norm values;
• if the preliminary criterion is not satisfied, outputting a signal indicating that the segment does not include any transient;
• if the preliminary criterion is satisfied, applying a test criterion to the norm values;
• if the test criterion is applied but not satisfied, outputting a first signal indicating that the segment does not include any transient;
• and
• if the test criterion is applied and satisfied, outputting a second signal indicating that the segment includes a transient,
• wherein at least one of the preliminary criterion and the test criterion includes whether the maximum norm value is at least a specified degree larger than the second maximum norm value.

A non-transitory computer-readable medium storing computer-executable process steps for detecting whether a transient exists within an audio signal, said process steps comprising:

• dividing a segment of a digital audio signal into blocks;
• calculating a norm value for each of a plurality of the blocks, resulting in a set of norm values for the plurality of blocks, each said norm value representing a measure of signal strength within a corresponding block;
• identifying a maximum norm value across said plurality of the blocks;
• identifying a different second maximum norm value, subject to a specified constraint, across said plurality of the blocks;
• applying a test criterion to the norm values;
• if the test criterion is not satisfied, outputting a first signal indicating that the segment does not include any transient;
• and
• if the test criterion is satisfied, outputting a second signal indicating that the segment includes a transient,
• wherein the test criterion includes whether the maximum norm value is at least a specified degree larger than the second maximum norm value.