{"$schema":"https://toolsly.tools/schemas/tool-manifest-v1.json","generated":"2026-05-20T20:47:38.146Z","discovery":{"catalog":"https://toolsly.tools/tools.json","llmsTxt":"https://toolsly.tools/llms.txt","sitemap":"https://toolsly.tools/sitemap.xml"},"relatedTools":[{"slug":"video-trimmer","name":"Video Trimmer","url":"https://toolsly.tools/video-trimmer"},{"slug":"video-compress","name":"Compress Video","url":"https://toolsly.tools/video-compress"},{"slug":"mp4-to-webm","name":"MP4 to WebM","url":"https://toolsly.tools/mp4-to-webm"},{"slug":"mp4-to-mkv","name":"MP4 to MKV","url":"https://toolsly.tools/mp4-to-mkv"},{"slug":"mp4-to-mov","name":"MP4 to MOV","url":"https://toolsly.tools/mp4-to-mov"},{"slug":"mp4-to-gif","name":"MP4 to GIF","url":"https://toolsly.tools/mp4-to-gif"},{"slug":"mp4-to-mp3","name":"MP4 to MP3","url":"https://toolsly.tools/mp4-to-mp3"},{"slug":"mp4-to-wav","name":"MP4 to WAV","url":"https://toolsly.tools/mp4-to-wav"}],"kind":"converter","slug":"mp4-to-aac","name":"MP4 to AAC","description":"Extract the AAC audio track from an MP4 video — free online, no re-encode.","longDescription":"Pull the audio track out of an MP4 and save it as a raw .aac file. The video stream is discarded and, on the happy path, the audio isn't re-encoded at all — ffmpeg's `-c copy` simply repackages the existing AAC stream from the MP4 container into a bare AAC file. That makes this nearly instant, even for long clips, and means there's zero generation loss: the bytes that go in are the bytes that come out. Almost every MP4 uses AAC audio, so this works for the vast majority of files. If a particular MP4 has an unusual audio codec (or a stream that can't be copied directly), the conversion will surface a clear error and you can use mp4-to-mp3 instead. The conversion runs entirely in your browser via ffmpeg.wasm — nothing is uploaded.","category":"video","categoryName":"Video","keywords":["mp4 to aac","convert mp4 to aac","mp4 to aac converter","mp4 to aac online","mp4 to aac free","online mp4 to aac","change mp4 to aac","mp4 aac converter","free mp4 to aac","online mp4 to aac converter","extract audio from mp4","mp4 audio extractor","mp4 to aac no re-encode","extract aac from mp4"],"url":"https://toolsly.tools/mp4-to-aac","runsOn":"client","multiple":false,"batch":false,"input":{"type":"file","extensions":[".mp4"],"mimeTypes":["video/mp4"]},"output":{"type":"file","extension":".aac","mimeType":"audio/aac"},"options":[],"invocation":{"webUi":"https://toolsly.tools/mp4-to-aac","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."}}