Grok Imagine extend vs Flux 3 extend
Grok Imagine extend is 8 credits, 2–10s, silent. Flux 3 extend is 21 credits, 5–20s, with native audio.
Grok Imagine Extend is 8 credits, 2–10 seconds, audio false. Flux 3 Extend Video is 21 credits, 5–20 seconds, native audio true. One is a silent cheap continue. The other is an audio continue. Stay in the family of the keeper. Do not hop a talking Flux take onto a silent Grok row and expect the sentence to keep going.
Both slugs are extend-video. Both want a clip that already exists. Neither is a longer generate. The split is sound, sticker, and duration, not a quality ranking of xAI against Black Forest Labs.
Silent cheap continue
Catalog, Grok Imagine Extend: slug grok-imagine-extend, category extend-video, audio false, durations 2s through 10s every second, 8 credits, resolution unset. Description: continue an existing Grok Imagine video at a chosen timestamp.
Audio false means the hop is picture. It does not grow a soundtrack the Grok Imagine Video row already baked in. That generate is 7 credits, 6 / 10 / 15 / 20 / 30 seconds, 720p, native audio. Plan the bed, the line, and the room on the generate. The extend will not sing.
Use Grok extend when:
- The keeper is a Grok Imagine clip.
- You need 2–10 more seconds of that picture.
- You can live without new native audio on the hop — score already laid, or the feed is muted, or you will replace sound in an editor.
- Eight credits is the right price for a continue you might throw away.
Do not use Grok extend when the next beat is a spoken line. The row will not sell you that line. Do not use it on a Flux, Veo, or Seedance keeper and expect the look to hold. In-family is the point of a hop. A translator this is not.
Timestamp matters. The description is continue at a chosen timestamp, not only from the last frame you happened to export. If the useful action starts at 0:04, hop from 0:04. Hopping from a dead last frame is how you buy 8 credits of empty room.
Two through ten seconds is a menu. Pick 3s if the action is 3s. Padding to 10s on a silent hop is how hands smear with no dialogue to hide it.
Caption still applies. A silent hop on a mute feed needs burned-in captions more, not less. Add captions to video. Captions for silent autoplay is the job the soundtrack will not do.
The AI video generator is not a substitute for knowing which extend slug you are on. Eight credits is cheap. Eight credits of the wrong family is still a seam.
Audio continue at 21 credits
Catalog, Flux 3 Extend: slug flux-3-extend-video, category extend-video, audio true, durations 5s through 20s every second, 21 credits, resolution unset. Provider: Black Forest Labs. Description: FLUX.3 continues an existing clip beyond its final frame, generating footage consistent with the original motion and scene; source clip must be MP4, under 50 MB and under 15 seconds.
Black Forest Labs called FLUX.3 Video generally available on 4 August 2026. BFL’s own early evals (23 July 2026, cited from BFL, not as Versely benchmarks) reported preference against Grok Imagine Video 69%, among other vendors. That is a generate-eval, with a date, from the vendor. It is not a reason to hop a Grok file onto Flux extend. It is not a Versely leaderboard.
Native audio true means the hop continues sound with picture. Room, line, foley — write them if you need them. A mute prompt still returns audio you did not choose. If you will replace the bed, say no music.
Use Flux 3 extend when:
- The keeper is a Flux 3 clip (T2V or first-last, 9 credits, 5–20s, native audio on those generate cards).
- You need 5–20 more seconds with sound.
- The source is MP4, under 50 MB, and under 15 seconds.
- You would rather pay 21 than lose the identity in a new T2V.
Do not use Flux 3 extend when there is no source clip. That is Flux 3 Text to Video at 9 credits. Do not use it when the source is 16 seconds. The catalog cap on the input is under 15 seconds. A 20-second Flux generate cannot be the input to this hop until you trim it under 15s. Read that twice if your habit is “always click 20.”
Twenty-one versus eight is not a quality multiplier. It is the audio-continue sticker versus the silent-continue sticker, in two families. Paying 21 for a silent hop you will mute is the expensive way to ignore Grok’s 8-credit row — and only if the keeper was Imagine anyway. If the keeper is Flux, Grok’s row is the wrong family even at 8.
Resolution is unset on both extend cards. Do not invent 4K. Grok Imagine Video generate lists 720p. Flux 3 T2V’s description ceiling is 1080p. The hops inherit a look; they do not publish a new 4K ticket.
Stay in the family of the source
A hop is a continuation of identity. Cross-family hops fail as look changes, not as error messages.
- Imagine keeper → Grok Imagine Extend. Silent, 2–10s, 8 credits.
- Flux 3 keeper → Flux 3 Extend. Native audio, 5–20s, 21 credits, source under 15s.
- Veo keeper → VEO 3.1 Extend Video. Native audio, 7s, 720p, 40 credits. Not this page, and not a 20-second menu.
If you need the other family’s sound behaviour, you needed the other family’s generate. Do not generate talking Flux at 9 credits and hop silent Grok at 8 to “save.” You will pay 17 for a seam. Do not generate silent-looking Imagine and hop Flux to “add a voice.” Flux extend continues a Flux scene. It is not a dialogue plugin for an Imagine file.
Same-family order:
- Generate until the last frame (or the timestamp) would ship.
- Inspect sound on the generate, because only some hops will continue it.
- Hop inside the family, at the duration you can actually use.
- Caption the finished file. Caption styles after the hop.
Grok generate at 7 credits plus one 8-credit silent hop is 15 credits for up to 40 seconds of picture if you started at 30s and added 10s — with the hop mute. Flux generate at 9 plus one 21-credit audio hop is 30 credits, and the source to the hop must be under 15s, so the generate you feed it is not the 20s tick unless you trim.
Those two arithmetic lines are why the pick is not “which extend is better.” It is which generate you already committed to, and whether the next seconds must talk.
When to generate instead of extend
Extend is leftover time on a keeper. It is the wrong tool when:
- The blocking is wrong. Restage is a generate.
- You wanted 30 seconds in one pass. Grok Imagine Video already lists 30s at 7 credits, 720p, native audio. Seedance 2.5 lists 4–30s at 47 credits, 720p, native audio. Flux 3 T2V stops at 20s. Hopping around those ceilings is an edit with seams.
- You wanted 4K dialogue. Veo 3.1 is 40 credits, 4 / 6 / 8s, 4K, native audio. Neither extend card is that ticket.
- The Flux source is already 15s+. Trim or start a new T2V. Do not feed a 20s file into a hop that asks for under 15s.
- You need a spoken hop on an Imagine keeper. You cannot buy that on
grok-imagine-extend. Re-generate the talking take at 7 credits, or move the job to a native-audio family before you need the hop.
BFL USD rates on BFL’s site are BFL’s. Do not quote them as Versely prices. Versely bills 8 credits and 21 credits on these two cards.
Silent cheap continue versus audio continue is the whole page. Eight credits, 2–10s, audio false, Imagine family. Twenty-one credits, 5–20s, audio true, Flux 3 family, source under 15s. Pick the one that matches the file you are holding.
Run that continue from Versely.
FAQ
Will Grok Imagine Extend continue the native audio from Imagine Video?
No. audio is false on the extend row. Picture continues. Lay the bed on the 6 / 10 / 15 / 20 / 30s generate, or accept a silent hop.
Can I feed a Grok clip into Flux 3 extend to add a voice?
Not as a production plan. Flux 3 extend continues a Flux scene, with a source that must be MP4, under 50 MB, and under 15 seconds. A cross-family hop is a look change. If you need Flux sound, generate Flux first.