init Files

libraries/lvgl/demos/music/README.md

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+# Music player demo
+
+## Overview
+The music player demo shows what kind of modern, smartphone-like user interfaces can be created on LVGL. It works the best with display with 480x272 or 272x480 resolution.
+
+
+![Music player demo with LVGL embedded GUI library](screenshot1.gif)
+
+## Run the demo
+- In `lv_conf.h` or equivalent places set `LV_USE_DEMO_MUSIC 1`
+- With `LV_DEMO_MUSIC_AUTO_PLAY` enabled a ~60 sec demo will be played.
+- After `lv_init()` and initializing the drivers call `lv_demo_music()`
+
+## How the spectrum animation works
+- `assets/spectrum.py` creates an array of spectrum values from a music. 4 band are created with 33 samples/sec: bass, bass-mid, mid, mid-treble.
+- The spectrum meter UI does the following:
+	- Zoom the album cover proportionality to the current bass value
+	- Display the 4 bands on the left side of a circle by default at 0°, 45°, 90°, 135°
+	- Add extra bars next to the "main bars" with a cosine shape. Add more bars for the lower bands.
+	- If there is a large enough bass, add a random offset to the position of the bars. E.g. start from 63° instead of 0°. (bars greater than 180° start again from 0°)
+	- If there is no bass, add 1 to the offset of the bars (it creates a "walking" effect)
+	- Mirror the bars to the right side of the circle
+	
+## Using spectrum.py
+- install `librosa` with `pip3 install librosa`	
+- run `python spectrum.py my_file.mp3`
+- see the result in `spectrum.h`