**BETA** Flex Video Speed ⚡🅡🅞🅣🅘

Speed ramping a video isn't just "play some frames faster" - speed it up and you're dropping frames, slow it down and you need frames that don't exist yet. Flex Video Speed handles both directions, with speed_factor swinging from −100 to 100 (negative values reverse playback while also slowing or speeding it, tying it conceptually to the pack's FlexVideoDirection and FlexVideoSeek siblings) and an interpolation_mode that pulls in real frame-interpolation methods for the slow-motion case. Like Flex Video Frame Blend, it ships marked BETA.

How it works

At speed_factor near ±1, you're close to normal playback; push it further from zero and frames get skipped (speeding up) or synthetic in-between frames get generated (slowing down). interpolation_mode is the control for how those in-between frames are made: none just duplicates or drops frames - the cheapest, choppiest option; linear does a plain crossfade blend; Farneback uses classic optical-flow estimation; rife47 and rife49 use two versions of RIFE, a well-established neural frame-interpolation model that estimates real motion between frames rather than blending or duplicating. fast_mode and ensemble are standard RIFE knobs - fast_mode trades some quality for speed, ensemble runs a heavier, higher-quality pass at the cost of more compute - and scale_factor (0.25 to 4) resizes the internal processing resolution RIFE works at, a common way to trade speed/VRAM against motion-estimation accuracy on this kind of model. feature_param is fixed to speed_factor, so a FEATURE can push the speed itself up and down reactively - a clip that lurches into slow-motion on a loud hit, say.

Inputs and outputs that matter

• images (required, IMAGE) - your source sequence.
• speed_factor (default 1, −100 to 100) - negative reverses, magnitude sets speed.
• interpolation_mode - none, linear, Farneback, rife47, or rife49.
• fast_mode / ensemble (booleans, default on) - RIFE quality/speed trade-offs.
• scale_factor - 0.25, 0.5, 1, 2, or 4; internal processing resolution for RIFE.
• opt_feature (optional, FEATURE) - drives speed_factor reactively.
• Output - a single IMAGE batch.

Installing it

Via ComfyUI Manager: search "RyanOnTheInside," install, restart. Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/ryanontheinside/ComfyUI_RyanOnTheInside.git
cd ComfyUI_RyanOnTheInside
pip install -r requirements.txt

then restart. RIFE-based interpolation modes typically pull their own model weights on first use, the same convention most RIFE-backed nodes across ComfyUI follow - expect a one-time download the first time you actually select rife47 or rife49.

Common issues & troubleshooting

Slow-motion looks choppy despite a slow speed_factor. Check interpolation_mode isn't set to none - that mode just holds/duplicates frames rather than generating real in-between motion, which reads as stuttery at low speeds. Switch to rife47/rife49 for genuinely smooth slow-motion.

RIFE mode is slow or runs out of VRAM. Drop scale_factor below 1, or disable ensemble, before assuming the node itself is broken - both are direct, expected quality-for-speed trade-offs on RIFE-family models.

Being beta, don't be surprised by rough edges - treat it as an experimental node, and if results look wrong at extreme speed_factor values, try dialing closer to ±1 first to confirm the base pipeline behaves before pushing to the extremes.