Any file up to 500 MB. Drop several files and they come back as one ZIP. Many image, audio and video conversions run in your browser; anything else is uploaded and removed within the hour.
Convert your M4A audio files into the versatile OPUS format for modern web streaming and low-latency applications. This tool allows developers and content creators to transition audio from the Apple-standard container to an open-source format optimized for the internet.
M4A is a container format typically utilizing the AAC codec, widely used in the Apple ecosystem. In contrast, OPUS is an open, royalty-free audio codec designed for interactive real-time communication and streaming. When you convert M4A to OPUS, you are essentially repackaging the audio stream into a more efficient container that performs exceptionally well across low-bandwidth connections and modern web browsers.
Since both formats are lossy, the conversion involves transcoding. However, because OPUS is highly efficient, you can maintain high perceptual audio quality while keeping file size changes insignificant.
We built this project so anyone can convert files without paywalls, accounts, or hidden limits. Here is what that promise means in practice.
Every converter on ConvertX is free to use: no trials, no premium tiers, and no credit packs. We will never put core conversion features behind a subscription. Whether you convert one photo or a hundred files a week, the price stays zero.
Many image, audio, and video conversions run entirely in your browser. Your files never leave your device for those jobs. When server processing is required for documents or specialized formats, uploads are handled securely and removed automatically — typically within one hour.
A quick guide to strengths and trade-offs of popular formats — so you pick the right one before converting.
Music, podcasts, voice recordings, and sound effects.
Common extensions: MP3, WAV, FLAC, OGG, AAC, M4A, OPUS
Raster and vector graphics for web, print, and photography.
Common extensions: PNG, JPG, WebP, AVIF, GIF, SVG, HEIC, TIFF
Office files, PDFs, ebooks, and plain text.
Common extensions: PDF, DOCX, XLSX, PPTX, ODT, EPUB, TXT
Clips, streams, screen recordings, and movies.
Common extensions: MP4, WebM, MOV, MKV, AVI, MPEG
