Sign in
← AI PulseAug 20, 2026

Wire · news · Multi-source brief

Grok Video Model Extends Existing Videos with Text Prompts

The Grok video model from xAI can extend existing videos by generating new content based on a text prompt, seamlessly continuing from the input video's last frame.

By Illumora Editorial

Source · Aug 20, 2026, 3:13 PM · On Illumora · Aug 20, 2026, 4:03 PM

Media from the primary source — shown here so you can stay on Illumora.

Synthesized from multiple allowlisted primaries on the same event. Lanes →

Brief drafted by Illumora’s editorial model from the linked primary source. Ops desk reviews flagged pieces. How we write →

Read the source →xAI Docs — Video Extension | SpaceXAI Docs
Save

xAI has introduced a video extension capability for its Grok video model, allowing users to lengthen existing video content. This feature generates new video segments that pick up from the final frame of an input video, guided by a text prompt describing the desired continuation.

Users can provide the source video via a public URL, a base64-encoded data URI, or a file_id from the Files API. The input video must be in .mp4 format, encoded with supported codecs such as H.265, H.264, or AV1.

Key Points

  • The Grok video model extends existing videos using a text prompt.
  • Input videos must be .mp4 files with codecs like H.265, H.264, or AV1.
  • Input video duration must be between 2 and 15 seconds.
  • The extended portion can range from 2 to 10 seconds, with a default of 6 seconds.
  • Output video resolution is capped at 720p, matching the input's aspect ratio and resolution.
  • The duration parameter controls only the length of the extended segment.

Context

According to xAI, the video extension functionality is part of the broader Grok model capabilities, which also include video generation, image-to-video, and reference-to-video features. The Grok model supports various input methods for source videos, including direct URLs and file_ids from its Files API, as detailed in the xAI documentation.

Why It Matters

This capability offers builders a method to programmatically extend video content, potentially streamlining workflows for dynamic content creation or automated video editing tasks. The ability to specify continuation with a text prompt could enable more flexible and scalable video production.

What To Do

  • Review the xAI documentation for the Grok video model's extension feature.
  • Test the video extension in the Playground with various input videos and text prompts.
  • Note the constraints on input video duration (2 to 15 seconds) and extension duration (2 to 10 seconds).
  • Compare the output resolution and aspect ratio to ensure it meets project requirements.