CONVERT AAC → W64 (AAC to W64)
Fast, secure AAC to W64 conversion. No registration required.
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HOW TO CONVERT AAC → W64
Upload the AAC
Drop or select your AAC file. The upload is encrypted and the file is queued for conversion.
Transcode via FFmpeg
FFmpeg decodes the AAC stream to PCM internally, then re-encodes as W64 at the bitrate you select.
Download the W64
The W64 is delivered as a direct download; metadata and cover art transfer automatically where possible.
Why this pair exists — AAC is the Advanced Audio Codec, more efficient than MP3 and ubiquitous in modern streaming. Ergo, the W64 route. Converting AAC to W64 changes the audio container without re-recording anything. Whether you are moving from a studio master to a distribution format or just making a file playable on an old car stereo, KaijuConverter re-encodes the audio with FFmpeg at your chosen bitrate and preserves sample rate, channels and ID3 tags. The source AAC file stays untouched. A quick refresher — AAC is the Advanced Audio Codec, more efficient than MP3 and ubiquitous in modern streaming. By contrast, W64 is an audio format with specific trade-offs between file size, bitrate flexibility, and device support.
Why convert AAC to W64
AAC Audio is great in its own niche, but Sony Wave64 is either more universally playable or better suited to the device you are targeting. Converting lets you ship the audio without asking listeners to install a codec. The loss in quality between the two is negligible at sensible bitrates.
AAC vs W64 — Technical specifications
Side-by-side comparison of the technical details.
AAC
- MIME type
- audio/aac
- Extensions
- .aac, .m4a, .mp4 (container-dependent)
- Standard
- ISO/IEC 14496-3
- Variants
- AAC-LC, HE-AAC, HE-AACv2, AAC-LD, xHE-AAC
- Sample rates
- 8-96 kHz
- MIME Type
- audio/aac
- Extension
- .aac
- Category
- Audio Files
- Full Name
- AAC Audio
- Conversion Engine
- FFMPEG
W64
- MIME type
- audio/x-w64
- MIME Type
- audio/x-w64
- Extension
- .w64
- Category
- Audio Files
- Full Name
- Sony Wave64
- Conversion Engine
- FFMPEG
- Max size
- 2^64 bytes
- Relative
- RF64 (EBU 64-bit WAV)
| Specification | AAC | W64 |
|---|---|---|
| MIME type | audio/aac | audio/x-w64 |
| Extensions | .aac, .m4a, .mp4 (container-dependent) | — |
| Standard | ISO/IEC 14496-3 | — |
| Variants | AAC-LC, HE-AAC, HE-AACv2, AAC-LD, xHE-AAC | — |
| Sample rates | 8-96 kHz | — |
| MIME Type | audio/aac | audio/x-w64 |
| Extension | .aac | .w64 |
| Category | Audio Files | Audio Files |
| Full Name | AAC Audio | Sony Wave64 |
| Conversion Engine | FFMPEG | FFMPEG |
| Max size | — | 2^64 bytes |
| Relative | — | RF64 (EBU 64-bit WAV) |
AAC vs W64 — Strengths and limitations
What each format does best, and where it falls short.
AAC Strengths
- Better quality than MP3 at equal bitrate — the industry standard since 2000s.
- Universally supported on every smartphone, OS, and browser.
- Efficient on battery thanks to widespread hardware decoding.
- Scales from 8 kbps speech (HE-AACv2) to lossy-transparent 320 kbps.
- Five-channel + LFE surround support out of the box.
Limitations
- Patent-encumbered — encoders have licensing fees, which is why open alternatives (Opus, Vorbis) exist.
- Slightly more complex to encode than MP3.
- Raw .aac streams carry no seek index — tooling often prefers M4A/MP4 containers.
W64 Strengths
- Unlimited file size (64-bit chunks).
- Professional DAW compatibility.
- Bit-exact lossless.
Limitations
- Less universal than WAV.
- Niche — only matters for very large sessions.
- Competes with RF64.
Quality & Compatibility
Lossy-to-lossy transcoding (most cross-format audio jobs) loses a tiny amount of quality on each pass — usually inaudible at our default VBR ~190 kbps for music or 96 kbps for speech. Lossy-to-lossless conversions freeze the existing quality but cannot improve it; lossless-to-lossy is only as good as the target bitrate you choose.
Tips for Best Results
- Pick 128 kbps for podcasts and voice, 192–256 kbps for music, 320 kbps only if the audio will be edited further downstream.
- Keep the AAC master alongside the W64 — re-encoding a lossy format twice accumulates audible artefacts.
- For mono voice content, convert to mono W64 explicitly to halve file size without any quality loss.
Frequently Asked Questions
Lossy-to-lossy conversions (most combinations) re-compress the audio, which technically introduces some loss. At a 192 kbps or higher target it is inaudible on normal equipment. Lossy-to-lossless conversions freeze the existing quality but cannot improve it; lossless-to-lossy transcodes are only as good as the target bitrate you choose.
For voice content (podcasts, audiobooks, lectures) 128 kbps is indistinguishable from higher bitrates. For music, 192-256 kbps covers most listening; 320 kbps is the ceiling for W64 and the right choice for audio you plan to edit further. Above that, prefer a lossless target instead.
Yes. Title, artist, album, year and cover art travel from the AAC container to the W64 container automatically where both formats support them. If a tag field has no W64 equivalent, it is dropped silently. Use any tag editor (Mp3tag, MusicBrainz Picard) to fine-tune afterwards.
AAC Audio
Source formatAAC is a lossy audio codec that delivers better sound quality than MP3 at similar bitrates. It is the default audio format for Apple Music, YouTube, and most streaming services.
Sony Wave64
Target formatWave64 (W64) is an extension of the WAV format developed by Sony that breaks the 4 GB file size limit of standard WAV by using 64-bit chunk sizes. It is used in professional audio production for very long or multi-channel recordings.
Going the other way? Convert W64 back to AAC with the same engine.
Common Use Cases
Share across platforms
Send W64 files to anyone without worrying about whether they have the right software for AAC.
Embed in documents
Drop W64 output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
W64 often produces smaller files than AAC for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
AAC vs W64 — Typical file sizes
Approximate file sizes for common scenarios.
- Speech podcast (64 kbps) 1 MB/min
- 3-min music track (128 kbps) 3 MB
- 3-min music track (256 kbps) 6 MB
- 1-hour 24-bit 48 kHz mono ~620 MB
- 48-hour field recording ~30 GB
Lossless 24-bit Hi-Res Audio or Full Discographies?
Converting pristine FLAC/ALAC collections while preserving 192kHz master dynamics without exhausting mobile bandwidth? Dedicated multi-threaded workstation converters handle entire folders instantly.
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High-throughput enterprise pipeline for files up to 2,048 MB, 50-file batches, ISO PDF/A, and priority processing.
Lossless batch chain processing preserving full ID3v2 metadata tags and embedded artwork.
Multi-CPU discography conversion with AccurateRip CRC verification and DSP mastering.
Related comparisons
See these formats side by side to understand which fits your use case best.
Related Guides
AAC Audio Format: The Complete Technical Guide
Complete technical guide to AAC: AAC-LC, HE-AAC v1/v2, AAC-ELD profiles, MDCT filter bank, TNS, PNS, joint stereo, bitrate reference, M4A vs ADTS containers...
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Complete guide to AAC audio format: AAC-LC vs HE-AAC profiles, M4A containers, Apple AAC vs FDK AAC encoders, quality comparison with MP3, and streaming...
Read guide →M4A Format: MPEG-4 Audio — Apple Lossless, AAC & iTunes Explained
Learn what M4A files are, the difference between AAC and ALAC inside M4A, why Apple uses M4A instead of MP3, and how to convert M4A to MP3, FLAC, or WAV.
Read guide →
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