2026-10-02

Spotify Canvas needs an exact 3–8 second loop (and Spotify’s own words: ‘even slightly off’ fails the upload)

Spotify Canvas is the short looping visual that replaces a track's album art in the Now Playing view — Spotify's own support page describes it plainly: "Canvas is an 8-second visual loop that shows in a vertical format to fill the screen." You add one from the Music tab at artists.spotify.com or the Spotify for Artists mobile app, on a per-track basis. The spec behind that loop is short enough to fit in four lines, which makes it easy to assume "close enough" will clear it. Spotify's own upload-error page says otherwise, in its own words: "If the length or size is even slightly off, the upload can fail."

What Spotify's own guidelines actually require

The Canvas guidelines page lists the spec as four requirements: "3-8 seconds long," "Vertical 9:16 ratio," "Between 720px - 1080px tall," and "An MP4 or JPG file." The fix-an-upload-error page restates the same four numbers and adds the one sentence that explains why so many uploads bounce: "If the length or size is even slightly off, the upload can fail." Neither page states a maximum file size in megabytes — despite several unrelated blog posts claiming a specific number — so that's left out here rather than repeated as fact.

Picking the loop before you trim it

The guidelines page names three loop styles worth choosing between before you pick an in/out point: "Continuous Loop has a satisfying seamless loop," "Hard Cut has clear edit points (they can be artfully disguised)," and "Rebound plays your clip forwards, then reverses it (an easy way to get a smooth loop)." NearVid doesn't build any of these for you — there's no reverse-playback or boomerang operation in its toolset — so Rebound in particular means finding (or re-filming) a clip that already plays convincingly in both directions, then trimming to that exact stretch. What NearVid does help with is the same guidance the page gives for footage itself: "Choose footage without talking, singing, or rapping. The clips are only 3-8 seconds long, so won't sync with the lyrics," and "Avoid rapid video cuts or intense flashing graphics." A longer source clip — a live-show pan, a studio B-roll shot, a slow zoom — gives you more candidate 3-to-8-second windows to choose from than a clip you filmed at exactly 8 seconds on purpose.

Cutting the exact window with NearVid's Trim

NearVid's Trim operation is a lossless stream copy — it cuts at the start and end points you type in, in seconds, down to a decimal (12.4, not just 12), without re-encoding a single frame. That matters more for an 8-second loop than for a longer clip: it's short enough that every frame is visible on every repeat, so a re-encode's compression artifacts would actually show, and a loop that lands at 8.3 seconds instead of under 8.0 is exactly the kind of "slightly off" the upload-error page warns about. Load the longer source file, pick an operation, type the in and out points for the window you chose, and NearVid cuts it — nothing uploads anywhere to do that; the trim runs in the browser tab itself.

The one part that's still on you: going vertical

NearVid's Trim and Convert operations change timing and, for Convert, the codec/container — not the frame itself. Neither has a crop or resize step anywhere in NearVid's actual toolset (confirmed directly against src/workspace.js and the two engine modules it calls). If your source footage is landscape — a horizontal phone recording, a widescreen camera take, most desktop screen captures — NearVid can trim it to 8 seconds precisely, but it will still be the wrong shape for Canvas's "vertical 9:16 ratio" requirement. The fix has to happen before the file reaches NearVid: shoot vertically in the first place, or export a vertical crop from whatever editor framed the shot. This is the one line in Spotify's spec NearVid genuinely can't help with — worth knowing up front rather than discovering it after an upload bounces.

If the upload still fails on an already-short, already-vertical clip

A clip that's already the right length and shape can still fail Canvas's "MP4 or JPG" requirement if it came out of a screen recorder or an editor that exports WebM or MKV by default. For that case, NearVid's "Convert to MP4" operation re-encodes to H.264 video and AAC audio and saves the result as an actual .mp4 file, entirely on-device, using your browser's own built-in encoder (WebCodecs, via Mediabunny) rather than one NearVid bundles. That's also why it's gated on browser support: NearVid checks for it quietly before showing the option, so the card only appears once your specific browser and file both qualify — on a browser where it doesn't, Trim and Convert-to-WebM still work, just not this one path. If an 8-second loop is already an MP4, Convert isn't a step you need at all; Trim alone gets you there.

What this doesn't do

NearVid doesn't upload to Spotify for Artists, doesn't validate a finished file against Spotify's own checker before you try, and can't crop, resize, or add a reverse-playback effect — the vertical framing and the loop style (Continuous Loop, Hard Cut, Rebound) are creative and framing choices that have to be true of the footage going in. What it does do is the two lines of Spotify's own spec that are purely mechanical: getting the duration exactly right without re-encoding, and fixing the container if the file isn't an MP4 yet — both without the clip, which is unreleased and unmastered audio-adjacent material for most artists using Canvas, ever leaving the device it's on.

The honest summary

Spotify's own Canvas guidelines boil down to four lines — 3-8 seconds, vertical 9:16, 720-1080px tall, MP4 or JPG — and its own upload-error page is explicit that "even slightly off" is enough to fail. Two of those four lines are exactly what NearVid's lossless Trim (frame-accurate, decimal-second duration) and Convert to MP4 (on-device H.264+AAC, browser-support gated) already do. The third — turning the footage vertical in the first place — is still the part only the person filming or editing it can fix.