WebM Cutter

How to Cut WebM Video Online

1. Upload Your WebM File: Drag and drop or click "Add Files" to select WebM files from OBS recordings, browser screen captures, downloaded YouTube clips, or Twitch VODs. Batch is supported — drop in several files and apply the same cut range to each.
2. Set Start Time and Duration (VIDEO_TRIM): Enter a start time and a duration to keep. Both fields accept seconds (12.5) or HH:MM:SS.sss format (00:01:30.500). Add multiple trim segments to extract several clips from one source — each pair produces its own output file.
3. Choose Codec and Quality (Optional): Default is stream-copy — no re-encoding, bit-identical to source, output stays VP8/VP9 with Opus or Vorbis audio. To re-encode for a smaller file or frame-accurate cut, pick VP9 (CRF 0-63, default 31), AV1 (CRF 0-63, slower but ~30% smaller than VP9), or VP8 (legacy compatibility). Resize to 1080p / 720p / 480p / 360p / 240p or scale by percentage.
4. Cut and Download: Click Cut. Files process in your browser session — download individually or as a ZIP. No sign-up, no watermark, no upload to a server.

Why Cut WebM Files?

WebM is the open, royalty-free container Google built for HTML5 video — VP8 / VP9 / AV1 video paired with Opus or Vorbis audio. It's the default output for most browser-based screen recorders, OBS Studio's lightweight option, yt-dlp's preferred download format for YouTube, and the format Discord uses for animated stickers. Cutting WebM is useful for:

• Trimming OBS recordings — OBS often ships hour-long sessions when you only wanted the 30-second highlight. Stream-copy cutting extracts the segment in seconds with zero quality loss, no waiting for re-encode.
• Browser screen capture excerpts — Chrome's MediaRecorder API, Loom downloads, and most WebRTC capture extensions output WebM. Cut down a 20-minute walkthrough to the 90-second portion that actually demonstrates the bug.
• Downloaded YouTube and Twitch clips — yt-dlp pulls YouTube as .webm (VP9 + Opus) by default. Trim to the exact moment of a goal, joke, or game-winning play without converting first.
• Social platform length caps — Instagram Reels: 90s. TikTok: 60s for max engagement. YouTube Shorts: 60s. X video: 2:20. Cut the WebM down to fit before uploading so the platform doesn't auto-chop the wrong moment. (Most platforms re-encode on upload anyway, so a quick stream-copy cut here loses nothing.)
• Discord and chat sharing — Discord's free 8 MB / Nitro 25 MB caps mean a 5-minute WebM at decent bitrate won't fit. Cut to the 20-second clip you actually want to share.
• Removing bloated intros and dead air — Strip the 10 seconds of black screen at the start of an OBS capture, the long pause before a Zoom recording started, or the show's title card from a downloaded VOD.

For a different output container after cutting, see WebM to MP4 or WebM to GIF.

Stream-copy vs Re-encode — When to Use Which

Property	Stream copy (default)	Re-encode (VP9 / AV1 / VP8)
Speed	Seconds for any file size	Proportional to clip length and codec
Quality	Bit-identical to source	Slight loss unless CRF 18-23
Cut precision	Snaps to nearest keyframe (1-10s)	Frame-accurate
Output codec	Same as input (VP8 / VP9 / AV1)	Any: VP9, AV1, VP8
Audio	Original Opus / Vorbis preserved	Re-encoded to Opus by default
File size	Proportional to duration kept	Variable by CRF / bitrate
Best for	Quick extraction, lossless	Frame-accurate cuts, smaller file, codec change

If you only need to keep "minutes 2-5 of this 20-minute screen recording" and don't care about a specific frame, stream-copy is faster and lossless. If you need the cut to land on the exact frame a button was clicked or a goal was scored, enable re-encode.

WebM Codec Quick Guide

Codec	CRF Range	Default	Use Case
VP8	4-63	10	Legacy WebM, broadest browser support pre-2017
VP9	0-63	31	Modern WebM, YouTube's default, ~50% smaller than VP8
AV1	0-63	30	Newest, ~30% smaller than VP9, slower to encode
Opus (audio)	—	128 kbps	Default WebM audio, best quality-per-bit below 128 kbps
Vorbis (audio)	—	128 kbps	Legacy WebM audio, kept for compatibility

Lower CRF = higher quality and larger file. CRF 23 is a typical "visually lossless" target for VP9; CRF 30 for AV1 produces similar visual quality at smaller size.

Frequently Asked Questions

Will the cut WebM still play in Chrome, Firefox, and Discord?

Yes. Stream-copy preserves the original VP8 / VP9 codec and Opus / Vorbis audio exactly — if it played in Chrome before the cut, it plays after. WebM has been natively supported in Chrome, Firefox, Edge, and Opera since 2010, and Safari added VP9 / WebM playback in macOS Big Sur (2020). Discord renders WebM inline on every platform.

My WebM is from OBS — does cutting preserve the audio sync?

Yes. Stream-copy mode copies the video and audio streams in lockstep, so any sync that was correct in the source stays correct in the output. Re-encode mode re-times audio to the new keyframe boundaries, which also stays in sync. The only situation where sync drifts is if the source itself had drift (some long OBS captures with VFR), in which case re-encoding to a constant frame rate often fixes it.

Why does the cut start a few seconds earlier than I asked for?

Stream-copy mode can only cut at keyframes (I-frames), and most WebM encoders place keyframes every 5-10 seconds by default. Asking to start at 00:01:23 may snap back to 00:01:18 if that's the nearest preceding keyframe. If you need the cut to land exactly on 00:01:23, enable re-encode in step 3 — that produces a frame-accurate cut at the cost of some encoding time.

Can I extract just the audio (Opus / Vorbis) from the cut?

Yes — use WebM to Opus or WebM to OGG instead, which extracts the audio stream during the conversion. For an MP3 or WAV instead, see WebM to MP3 or WebM to WAV.

What's the maximum WebM file size or length?

There's no fixed cap. Cutting runs in your browser, so the practical limit is your device's RAM and how patient you are with the file load. Multi-GB OBS captures and 4-hour Twitch VOD downloads work fine. Stream-copy is fast enough that even 4-hour 4K WebM files cut in well under a minute since no transcoding happens.

Can I make multiple cuts from one WebM in a single pass?

Yes. Add multiple trim segments — each pair of start time + duration produces a separate output clip. Useful for pulling several highlights from a long stream, splitting a lecture recording into chapters, or extracting every appearance of a specific player from a sports VOD.

Should I cut first or convert WebM to MP4 first?

Cut first, always. Cutting in stream-copy mode is essentially free (seconds) and lossless, and reduces the file size before the slower transcode step. A 5-minute clip pulled from a 60-minute WebM transcodes to MP4 about 12x faster than transcoding the full hour and trimming the MP4 afterward. See WebM to MP4 for the conversion step.

Does cutting remove the audio track?

No, by default both video and audio streams are copied to the output. If you specifically want a silent clip (for over-dubbing, looping background, or a muted social post), set the audio codec option to "no audio" before cutting. The output will be a video-only WebM.

What's the difference between cutting and trimming a WebM?

Same operation in practice. Some editors reserve "trimming" for shaving the start and end of a clip while keeping the middle, and "cutting" for extracting a middle portion or splitting at a point. XConvert's cutter handles all three patterns — set start time to your in-point and duration to how much to keep. See also WebM Trimmer for the same workflow framed slightly differently.