# Outputs · NDI · SRT · RTMP · External: External (SDI) & fullscreen

> DeckLink fill + key, and display outputs.

Glider documentation · Playout & On Air · Web page: https://cgglider.com/docs/outputs/external/

Sections of this page: [How outputs work](https://cgglider.com/docs/outputs.md) · [Frame timing & colour](https://cgglider.com/docs/outputs/timing.md) · [Sources, channels & signals](https://cgglider.com/docs/outputs/sources.md) · [NDI](https://cgglider.com/docs/outputs/ndi.md) · [External (SDI) & fullscreen](https://cgglider.com/docs/outputs/external.md) · [SRT](https://cgglider.com/docs/outputs/srt.md) · [RTMP streaming](https://cgglider.com/docs/outputs/rtmp.md) · [API](https://cgglider.com/docs/outputs/api.md)

External outputs need Blackmagic Desktop Video. Pick the device, a format (Page format picks the device's progressive mode matching the page's size and rate), which output it plays, and the key mode. Fill + key needs a card with two connectors per channel (a Duo 2, Quad 2, 4K Extreme, 8K Pro); the card's attributes decide what the Key list offers.

- Playback is scheduled on the card a few frames ahead (three, four for 10-bit), so the SDI signal never stutters when the machine is busy — the last frame repeats instead, and the status counts it.
- Pixel format: 10-bit YUV (Rec. 709) for fill only; fill + key and the internal keyer always send 8-bit RGB.
- The fill is premultiplied (shaped), as SDI keyers expect.
- Fullscreen outputs open a borderless window on the chosen display (or the first one that is not the main display) showing the output's fill or key.
- The EXTERNAL button in the editor's menu bar, like vMix's External button, turns every External and fullscreen output on or off at once; it lights red while they are on air.