Confirm animation from the container itself and inspect how it is assembled. The checker reads ANIM and ANMF structures to report loop behavior, total duration, individual delays, frame rectangles, blending, disposal, and per-frame payload encoding.
How to use WebP Animation Checker
- Choose still or animated WebP files; both are accepted so the report can answer the animation question directly.
- Run the checker to parse animation flags, control data, and every readable frame header without changing the image.
- Use frame-level timing and rectangle data to diagnose unexpected playback, then download the JSON for engineering review.
What this tool is good at
When to use WebP Animation Checker
Make a precise animation decision
Confirm motion, loops, frame count, duration, rectangles, blending, and disposal before publishing or transcoding. The result is based on the selected file's actual bytes or decoded frames, so it can support a concrete publishing or engineering decision instead of a filename-based assumption.
Troubleshoot a private production asset
Use the browser-local workflow for client images, unreleased campaigns, product media, or internal fixtures when sending the source to a generic third-party utility would create unnecessary exposure.
Document repeatable asset checks
Keep the generated output or JSON report with a ticket, content review, or migration record. Compare stored delays with playback in the destination because browsers can clamp rapid frames and pause background activity. This makes the finding reproducible for another editor or developer.
How to choose the right settings
Start from the intended destination
Compare stored delays with playback in the destination because browsers can clamp rapid frames and pause background activity. Choose settings or interpret results in the context of the actual CMS, browser, editor, size budget, animation player, or privacy policy that will consume the WebP.
Separate container facts from visual judgment
RIFF chunks, dimensions, alpha values, and encoded bytes answer technical questions, while perceived sharpness, acceptable motion, and brand appearance still require a human preview at the real display size.
Retain the authoritative original
The report describes stored controls rather than rendering performance, and it does not export complete frame images. Keep the source until the derivative or report has been reviewed, downloaded, and tested in the destination workflow.
Practical workflow and output details
ANIM and ANMF structures are parsed locally, including loop count, per-frame timing, geometry, flags, and nested encoding types. File bytes remain in the current browser tab; only static application code or codec assets are fetched, and no image-processing request is sent to PicConverters.
The report describes stored controls rather than rendering performance, and it does not export complete frame images. The tool reports or changes only the scope named on the page and avoids implying broader repair, anonymity, visual quality, or cross-application compatibility than the operation can establish.
Format behavior and limitations
A loop count of zero means infinite looping in WebP animation; it does not mean play zero times.
Reported duration comes from stored frame delays. Actual playback can vary because browsers may clamp extremely short delays or pause background tabs.
Frequently asked questions
Can a .webp extension tell me whether it moves?
No. Still and animated WebP share the same extension. The ANIM and ANMF structures provide the reliable answer.
Why are frame rectangles smaller than the canvas?
Animations can update only part of the canvas to save bytes. Blending and disposal rules combine those rectangles during playback.
Does this extract frames?
No. It reports animation structure. Use the Animated WebP Frame Extractor for complete PNG frame files.
Related WebP tools
WebP Frame Extractor
Decode every complete frame from an animated WebP and download lossless numbered PNG files with frame delays.
Animated WebP Compressor
Reduce animated WebP dimensions and optionally sample frames while preserving a genuine timed animation output.
WebP File Analyzer
Create a detailed local report covering WebP encoding, dimensions, chunks, payload bytes, overhead, animation, alpha, and metadata.