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Track short-term RMS amplitude

trk_rms.Rd

Computes the short-term root-mean-square (RMS) amplitude of audio signals using the libassp C library (Scheffers 2012) . By default, output is expressed in dB (short-term power). A fast, low-memory energy measure suitable as a voicing or loudness feature.

Usage

trk_rms(listOfFiles, beginTime = 0, centerTime = FALSE, endTime = 0, windowShift = 5, windowSize = 20, effectiveLength = TRUE, linear = FALSE, window = "HAMMING", toFile = TRUE, explicitExt = "rms", outputDirectory = NULL, assertLossless = NULL, logToFile = FALSE, convertOverwrites = FALSE, keepConverted = FALSE, verbose = TRUE)

Arguments

listOfFiles

Character vector of audio file paths. Any format supported by av is accepted; non-native inputs are transcoded automatically.

linear

Logical. If TRUE, return linear RMS amplitude instead of dB. Default FALSE (dB scale).

beginTime

Start time for the extracted portion in seconds. Default: NULL (beginning of signal). Note: uses beginTime/endTime (seconds) matching DSP function conventions, unlike read_audio() which uses begin/end.

centerTime

Numeric or logical. Single-frame analysis time point in seconds; overrides beginTime, endTime, and windowShift. Default FALSE.

endTime

The end time of the section of the sound files that should be analysed (in seconds). Use 0 for end of file.

windowShift

Numeric. Frame shift in milliseconds; sets output frame rate (1000 / windowShift Hz). Default 5.0 ms (200 Hz). Must be strictly less than 32 ms (the 512-sample analysis window at 16 kHz). Values other than the training default (5 ms) may slightly reduce accuracy.

windowSize

Numeric. Smoothing filter window size in milliseconds, applied to both median (periodicity) and mean (F0) post-processing filters. Default 15 ms.

effectiveLength

Logical. Make window size effective rather than exact. Default FALSE.

window

Character. Analysis window function type. Default "BLACKMAN". See AsspWindowTypes for supported types.

toFile

Logical. If TRUE, write SSFF output files and return the count written. If FALSE, return an AsspDataObj (single file only). Default TRUE.

explicitExt

By default, a character "d" will be prepended to the file name suffix when writing the output to file. The user can also specify an explicit extension which will be used instead.

outputDirectory

The directory where the slice file should be stored. If not defiled (NULL), the sparse slice file will placed in the same folder as the media file.

assertLossless

Character vector of additional file extensions to treat as losslessly encoded.

logToFile

Logical. Write processing log to a file in outputDirectory rather than the console. Default FALSE.

convertOverwrites

Logical. Allow transcoding to overwrite existing files. Default FALSE.

keepConverted

Logical. Retain intermediate transcoded files. Default FALSE.

verbose

Logical. Show a progress bar (sequential path) or a progress-aware parallel apply (pbapply/pbmcapply, if installed).

Value

If toFile = FALSE: an AsspDataObj with track:

RMS[dB]

REAL32, dB (or linear amplitude if linear = TRUE), n_frames x 1 column. Short-term RMS amplitude per frame.

Frame rate: 1000 / windowShift Hz (default 200 Hz). If toFile = TRUE: integer count of files written, returned invisibly.

Details

Window function defaults to HAMMING (not BLACKMAN as in other libassp functions). Set linear = TRUE for raw amplitude values without log conversion.

See also

wrassp::rmsana