{"$schema":"https://toolsly.tools/schemas/tool-manifest-v1.json","generated":"2026-06-02T15:45:19.750Z","discovery":{"catalog":"https://toptool.io/tools.json","llmsTxt":"https://toptool.io/llms.txt","sitemap":"https://toptool.io/sitemap.xml"},"relatedTools":[{"slug":"webm-to-mp4","name":"WebM to MP4","url":"https://toptool.io/webm-to-mp4"},{"slug":"video-trimmer","name":"Video Trimmer","url":"https://toptool.io/video-trimmer"},{"slug":"video-compress","name":"Compress Video","url":"https://toptool.io/video-compress"},{"slug":"mp4-to-aac","name":"MP4 to AAC","url":"https://toptool.io/mp4-to-aac"},{"slug":"mkv-to-mp4","name":"MKV to MP4","url":"https://toptool.io/mkv-to-mp4"},{"slug":"avi-to-mp4","name":"AVI to MP4","url":"https://toptool.io/avi-to-mp4"},{"slug":"mp4-to-mov","name":"MP4 to MOV","url":"https://toptool.io/mp4-to-mov"},{"slug":"mp4-to-gif","name":"MP4 to GIF","url":"https://toptool.io/mp4-to-gif"}],"kind":"converter","slug":"mp4-to-webm","name":"MP4 to WebM","description":"Convert MP4 video to WebM (VP9 + Opus) — free, runs entirely in your browser.","longDescription":"Re-encode an MP4 file as a WebM container with VP9 video and Opus audio. WebM is the open, royalty-free format used by YouTube and most browsers — great for embedding video on the web with small file sizes. The conversion runs locally via ffmpeg.wasm, so your video never leaves your device. Sources taller than 1080p are automatically downscaled to 1080p so the browser doesn't run out of memory mid-encode. Performance depends on your CPU: expect roughly real-time encoding (a 5-minute 720p video may take 1–2 minutes). For best results keep inputs under ~500 MB.","category":"video","categoryName":"Video","keywords":["mp4 to webm","convert mp4 to webm","mp4 to webm converter","mp4 to webm online","mp4 to webm free","online mp4 to webm","change mp4 to webm","mp4 webm converter","free mp4 to webm","online mp4 to webm converter","mp4 to vp9","encode mp4 as webm"],"url":"https://toptool.io/mp4-to-webm","runsOn":"client","multiple":false,"batch":false,"input":{"type":"file","extensions":[".mp4"],"mimeTypes":["video/mp4"]},"output":{"type":"file","extension":".webm","mimeType":"video/webm"},"options":[{"type":"select","key":"bitrate","label":"Video bitrate","defaultValue":"1M","choices":[{"value":"2M","label":"High (2 Mbps)"},{"value":"1M","label":"Medium (1 Mbps)"},{"value":"500k","label":"Low (500 kbps)"}],"help":"Higher bitrate = better quality and larger file. 1 Mbps is a good default for 720p web video."}],"invocation":{"webUi":"https://toptool.io/mp4-to-webm","api":null,"notes":"Currently runs client-side in the user's browser. Drop a file on the UI at `webUi` and download the converted result. A remote MCP/REST API is planned."}}