Outputs · NDI · SRT · RTMP · External

Send a page out of Glider itself — NDI with alpha, SRT, RTMP streaming, DeckLink SDI fill and key, or full screen on a display — like vMix's Outputs, Stream and External Output.

Frame-locked outputs, genlock, and what goes on the wire.

Every output is frame-locked. Its clock runs at the page's rate exactly — 59.94 is 60000/1001, not 60 — and the renderer is steered onto that clock, so each output frame carries exactly one new picture: no frame repeated, none skipped. Without the lock, a renderer at 60 fps feeding a 59.94 output skips a frame every 16.7 seconds, and two clocks at the same rate repeat and skip whenever their phases cross.

With a DeckLink card in the output, the output's clock follows the card's: the depth of the card's playout buffer steers it, a few hundred parts per million at most. A card locked to a house reference (genlock) therefore genlocks the graphics too; the External row says whether the card is genlocked or free running.

Outputs render the page's own pixels at any screen scale: a 1920×1080 page is a 1920×1080 frame on a Retina or 150% display too, never painted larger and shrunk.

Status saysMeaning
50 fps, frame-lockedEvery frame of the last second went out, on time.
Locking to 59.94 fps…The renderer is being brought onto the output clock — the first second or so after an output starts.
N repeated, N skippedFrames the renderer delivered late in the last second (the machine was too busy).
SRT · N frames dropped (the encoder cannot keep up)ffmpeg could not encode in real time: lower the bitrate or the page size, or use a faster machine. 4K H.264 in software needs a strong CPU.
N underruns (the card repeated a frame)A DeckLink card ran out of frames; it repeated the last one rather than show nothing.
OutputOn the wire
NDI8-bit BGRA with straight alpha, at the page's size and rate.
SRT, RTMPH.264, 4:2:0, BT.709 matrix, legal range — and tagged so, so every decoder shows the colours that were authored.
External, fill only10-bit 4:2:2 Y'CbCr, BT.709, legal range, converted by Glider: the levels do not depend on the card. Choose 8-bit RGB to let the card convert instead.
External, fill + key or internal keyer8-bit RGB with alpha: the card makes the key from it.
FullscreenThe page's sRGB values, untouched by the display's colour profile.