SolarOS 4.13.4 manual · app

recorder

Interactive GUI/TUI counterpart to arecord. Recorder writes PCM WAV files so the channel count, sample rate, and resolution travel with the recording and the result can be played immediately. It accepts any registered signed-16-bit PCM capture stream. On the Waveshare board it initially selects audio0.capture. Mono/stereo output, 8/16-bit file resolution, and sample rates from 8 kHz through 48 kHz are converted from the selected stream as necessary.

Usage:

recorder [--tui] [file.wav]

The optional path supplies the initial recording folder and filename. The Setup view can edit the filename or select another destination directory with the shared file browser. When the filename is empty, each recording gets a unique local-time name such as rec-260810-113045.wav; a numeric suffix avoids overwriting a file created in the same second. Recorder remembers its selected input, folder, format, hardware input gain, output volume, and visualizer in .recorder/settings.bin on the current storage root. An explicit path argument overrides the remembered folder. The filename is not remembered, so reopening Recorder cannot accidentally reuse a one-off name.

Recorder selects its graphical interface on a graphical shell and its text interface on a port shell. --tui forces the text interface even when the launching shell has graphics.

Tab switches between Record and Setup. The Record view uses the shared cassette widget by default; V cycles through Cassette, Oscilloscope, and Spectrum. R starts recording, Space pauses or resumes, S stops and finalizes the WAV header, and P plays the most recent or selected recording. M starts or stops monitoring: it continuously streams the selected input to the default output and visualizer. Monitoring can remain enabled when recording starts and can be toggled while the WAV writer continues. Up/Down changes monitor and playback volume. The cassette reels move during recording and playback, but remain still during monitoring. Oscilloscope and Spectrum remain live during monitoring. Active visualizers are presented on the 40 ms app tick (nominally 25 frames per second), independently of the audio block rate.

Setup selects the capture stream, recording folder, mono/stereo conversion, sample rate, 8/16-bit WAV resolution, input gain, and output volume. Enter on Folder opens the WAV-filtered browser. D selects its current directory as the recording folder; Enter on a WAV file plays it and returns to Record. Input gain is not a generic stream multiplier: Recorder enables it only when the selected capture stream belongs to an audio device that advertises hardware input-gain control. Thus audio0.capture on the Waveshare controls the ES7210 microphone gain, while an unrelated generic stream shows Input gain: n/a. The hardware gain is system-wide; Recorder does not add hidden digital amplification to the saved PCM.

The text interface exposes the same setup values, browser, transport keys, monitoring, pause behavior, and playback path. Recorder is resumable: capture, monitoring, or playback continues while its UI session is in the background, and closing the app stops the worker and finalizes an active recording.