VideoGenReview

What each AI video model's release notes say changed

Extension in AI video release notes

Extension continues a finished clip with a further generation that picks up where the clip ended, so it grows in steps. As of 2026-09-25.

Runway's notes show extension first: Gen-3 Alpha clips could be extended to 40 seconds in total in September 2024 and Gen-3 Alpha Turbo clips to 34. Adobe's Generative Extend in the Premiere Pro beta, in October 2024, used the Firefly Video Model to lengthen footage already on a timeline, to cover a gap or hold a shot longer.

Later notes carry it into APIs. Midjourney's V1 extended in steps of about four seconds in June 2025, Veo 3.1's extension reached Vertex AI in preview in December 2025, and LTX's extend endpoint in February 2026 adds frames at the start or at the end.

Extension is the older route to long clips. Each piece is still a short generation, which is why the question page on 30-second clips counts single generations instead.

Where the term appearsOne dot per dated entry.Where the term appears2024-09-04Runway, Gen-3 Alpha2024-09-23Runway, Gen-3 Alpha Turbo2024-10-14Adobe Firefly Video, Firefly Video Model2025-06-18Midjourney video, Midjourney V1 video2025-12-08Google Veo, Veo 3.12026-02-18LTX, Not named in the note
Fig. 1 One dot per dated entry.
Entries that show the term, oldest first, read 2026-09-25.
DateLineVersionWhat changed
4 September 2024RunwayGen-3 AlphaGen-3 Alpha clips can be extended to 40 seconds in total
23 September 2024RunwayGen-3 Alpha TurboGen-3 Alpha Turbo clips extend to 34 seconds
14 October 2024Adobe Firefly VideoFirefly Video ModelGenerative Extend in the Premiere Pro beta lengthens clips to cover gaps and hold shots longer
18 June 2025Midjourney videoMidjourney V1 videoThe V1 video model animates images, with low or high motion and extensions of about 4 seconds
8 December 2025Google VeoVeo 3.1Veo 3.1 video extension reaches Vertex AI in preview
18 February 2026LTXNot named in the noteAn extend endpoint adds frames at the start or the end

Inclusion rule. Entries whose note uses or shows the term. Order. By date, oldest first; undated rows last.

1In the notes

Gen-3 Alpha videos can be extended an additional 5 or 10 seconds to create up to 40s of generated video.

Runway, changelog

Extend generations up to 34s in Gen-3 Alpha Turbo.

Runway, changelog

Generative Extend allows you to extend clips to cover gaps in footage, smooth out transitions, or hold on shots longer for perfectly timed edits.

Adobe, news release: Firefly Video Model launch

Once you have a video you like you can “extend” them - roughly 4 seconds at a time - four times total.

Midjourney, V1 video model announcement

Veo 3.1 supports video extension in Preview.

Google Cloud, Vertex AI release notes

for extending video duration by generating additional frames at the beginning or end.

LTX, API changelog
  • Extensions in Gen-3 Alpha
    Gen-3 Alpha clips can be extended to 40 seconds in totalRunway, changelog / since 2024-09-04 / checked 2026-09-25
  • Gen-3 Alpha Turbo Extensions
    Gen-3 Alpha Turbo clips extend to 34 secondsRunway, changelog / since 2024-09-23 / checked 2026-09-25
  • October 14
    Generative Extend in the Premiere Pro beta lengthens clips to cover gaps and hold shots longer2024Adobe, news release: Firefly Video Model launch / since 2024-10-14 / checked 2026-09-25
  • Introducing Our V1 Video Model
    The V1 video model animates images, with low or high motion and extensions of about 4 secondsMidjourney, V1 video model announcement / since 2025-06-18 / checked 2026-09-25
  • December 8
    Veo 3.1 video extension reaches Vertex AI in preview2025Google Cloud, Vertex AI release notes / since 2025-12-08 / checked 2026-09-25
  • Extend Video Endpoint
    An extend endpoint adds frames at the start or the endLTX, API changelog / since 2026-02-18 / checked 2026-09-25

2Other terms

3Notes read