# Hardware Constraints

Yoto device specifications relevant to card making: cover image dimensions, LED display format, audio pipeline, device types, and label printing templates.

## Cover images

| Specification | Value |
|---|---|
| Format | JPEG or PNG |
| Dimensions | 1500×1500 px (square, 1:1) |
| File size | Under 2 MB recommended |
| Colour space | sRGB |

YotoShelf generates cover images at 1500×1500 and converts to JPEG before upload.

## LED display (Mini)

The Yoto Mini has a 16×8 pixel LED matrix display that shows per-track chapter icons.

| Specification | Value |
|---|---|
| Format | PNG |
| Canvas dimensions | 16×16 px (scaled to 16×8 on device) |
| Colour | Monochrome (single colour; any colour displays as lit/unlit) |

## Audio pipeline

Yoto expects AAC audio with these constraints:

| Specification | Value |
|---|---|
| Format | AAC (MPEG-4 audio) |
| Bitrate | 64 kbps |
| Sample rate | 44.1 kHz |
| Channels | Stereo (or mono for speech) |
| Container | M4A |

YotoShelf transcodes any uploaded format to this spec via ffmpeg.

## Device types

| Device | Screen | LED matrix |
|---|---|---|
| Yoto Player (3rd gen) | Cover art display | No |
| Yoto Mini | None | 16×8 LED |
| Yoto Player Mini (2024) | Cover art display | No |

## Label printing

YotoShelf generates printable card labels in PDF format:

| Template | Sheet size | Labels per sheet | Label dimensions |
|---|---|---|---|
| Avery L7160 | A4 | 21 | 63.5×38.1 mm |
| Avery 5160 | Letter | 30 | 2⅝×1 inch |

Labels include the card cover image, title, and a QR code linking to the collection share page.