{"$schema":"https://toolsly.tools/schemas/tool-manifest-v1.json","generated":"2026-06-03T08:49:42.511Z","discovery":{"catalog":"https://toptool.io/tools.json","llmsTxt":"https://toptool.io/llms.txt","sitemap":"https://toptool.io/sitemap.xml"},"relatedTools":[{"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-wav","name":"MP4 to WAV","url":"https://toptool.io/mp4-to-wav"},{"slug":"mp4-to-aac","name":"MP4 to AAC","url":"https://toptool.io/mp4-to-aac"},{"slug":"mp4-to-flac","name":"MP4 to FLAC","url":"https://toptool.io/mp4-to-flac"},{"slug":"webm-to-mp3","name":"WEBM to MP3","url":"https://toptool.io/webm-to-mp3"},{"slug":"mov-to-mp3","name":"MOV to MP3","url":"https://toptool.io/mov-to-mp3"},{"slug":"avi-to-mp3","name":"AVI to MP3","url":"https://toptool.io/avi-to-mp3"}],"kind":"converter","slug":"mp4-to-mp3","name":"MP4 to MP3","description":"Extract the audio track from an MP4 video as an MP3 file — free online.","longDescription":"Pull the audio track out of an MP4 and save it as a high-quality VBR MP3 (around 190 kbps, ffmpeg quality 2). The video stream is discarded — this is the right tool when you want a podcast, lecture, music clip, or voice memo extracted from a video file. The conversion runs locally via ffmpeg.wasm, so your file never leaves your device. Performance depends on your CPU: extracting audio is typically faster than re-encoding video, but very long or 4K sources may still be slow. For best results keep inputs under about 500 MB.","category":"video","categoryName":"Video","keywords":["mp4 to mp3","convert mp4 to mp3","mp4 to mp3 converter","mp4 to mp3 online","mp4 to mp3 free","online mp4 to mp3","change mp4 to mp3","mp4 mp3 converter","free mp4 to mp3","online mp4 to mp3 converter","extract audio from video","mp4 audio extractor","video to mp3"],"url":"https://toptool.io/mp4-to-mp3","runsOn":"client","multiple":false,"batch":false,"input":{"type":"file","extensions":[".mp4"],"mimeTypes":["video/mp4"]},"output":{"type":"file","extension":".mp3","mimeType":"audio/mpeg"},"options":[],"invocation":{"webUi":"https://toptool.io/mp4-to-mp3","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."}}