Convert Apple Lossless Audio Codec (.alac) to WebM Video (.webm) online for free. Fast, secure audio conversion with no watermarks or registration.
Upload your .m4a file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .webm file when it's ready.
ALAC is Apple's lossless audio codec. WebM is Google's open-source multimedia container designed for web content, supporting Opus and Vorbis audio. WebM is natively supported by Chrome, Firefox, Edge, and Android.
Converting ALAC to WebM encodes the lossless audio using Opus (the preferred WebM codec) for web distribution. Starting from ALAC's perfect PCM ensures the Opus encoder produces optimal output — a single lossy step from lossless source material.
WebM with Opus provides the best quality-per-bitrate of any web audio format. Opus outperforms AAC and Vorbis at every bitrate, making it ideal for web applications. Converting ALAC to WebM/Opus creates the most efficient web audio from your lossless Apple sources.
For web developers, WebM is royalty-free and widely supported in browsers. The lossless ALAC source ensures optimal Opus encoding quality.
FFmpeg decodes ALAC to perfect PCM and encodes using libopus into a WebM container. Opus supports 6-510 kbps with automatic speech/music detection. The lossless source means only one lossy step occurs. The WebM container uses the Matroska EBML structure. M4A metadata can be mapped to WebM tags.
Opus at 128 kbps from ALAC sounds transparent to most listeners — significantly better than AAC at the same bitrate. The lossless source ensures the best possible Opus output. At 64 kbps, Opus handles both speech and music well.
| Device | ALAC | WebM |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Native | Partial |
| iPhone/iPad | Native | Partial |
| Android | Partial | Native |
| Linux | Partial | Native |
| Web Browser | No |
Resolution: N/A
Bitrate: 320 kbps
OGG Vorbis preferred
Resolution: N/A
Bitrate: 256 kbps
AAC format required
Resolution: N/A
Bitrate: 128 kbps
Lossless FLAC/WAV for best quality
Resolution: N/A
Bitrate: 128 kbps
MP3 mono for spoken word
ALAC to WebM/Opus produces the highest-quality web audio from lossless Apple sources. Single-generation Opus encoding from perfect PCM ensures optimal results.
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| Native |
| Funktion | ALAC | WebM |
|---|---|---|
| Fullstandigt namn | Apple Lossless Audio Codec | WebM Video |
| Filandelse | .m4a | .webm |
| Bast for | Lossless | Web optimized |