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.