Wav Viewer

The Wav Viewer app can be used to view and play back 8-bit unsigned or 16-bit signed mono WAV files. Sample WAV files may be found in the WAV/ folder of the SD card, and WAV files captured using the Audio app will be placed in the AUDIO/ folder.

This is an External-apps-informations (.ppma file on the SD card).

Creating Compatible WAV Files

Using a PC, WAV files can be converted from existing audio using Audacity or ffmpeg:

# 8-bit unsigned mono, 48000 Hz
ffmpeg -i lovely_music.mp3 -ar 48000 -ac 1 -acodec pcm_u8 lovely_music.wav

# 16-bit signed mono, 48000 Hz
ffmpeg -i lovely_music.mp3 -ar 48000 -ac 1 -acodec pcm_s16le lovely_music.wav

[!NOTE] Only mono WAV files with 8-bit unsigned or 16-bit signed PCM encoding are supported. Stereo or other formats will show an error on load.

File Information Displayed

Once a file is opened, the app shows:

Field	Description
File	Filename
xx-bit mono	Bit depth (8 or 16) and channel count
Sample rate	e.g. 48000Hz
Title	Embedded title tag from the WAV file header (if present)
Duration	Total length in seconds

Waveform Display

• The main waveform panel shows the audio samples for the current view window.
• Below the waveform, a compressed amplitude overview bar shows the overall signal level across the entire file using a color spectrum (darker = quieter, brighter = louder).
• A small window indicator shows which portion of the full file is currently visible in the waveform.

Controls

Control	Description
Open	Open a .WAV file from the SD card
▶ / ■	Start or stop audio playback
Vol	Audio output volume
Position (s / ms)	Navigate to a specific time position in the file
Sample	Navigate by sample number
Scale	Zoom the waveform view (1 = 1 sample per pixel, higher = zoomed out)
Cursor A	Position of cursor A (cyan) on the waveform (0–239 pixels)
Cursor B	Position of cursor B (magenta) on the waveform (0–239 pixels)
Delta	Time difference between Cursor A and Cursor B, shown as duration and equivalent frequency

Playback

Pressing ▶ starts audio playback from the current position. A progress bar tracks playback through the file. The position fields update live during playback. Waveform view changes made during playback are applied once playback finishes.