Drop your CD audio tracks into the box below. The CDWAVMP3 engine encodes 320 kbps CBR MP3 in your browser tab — files never leave your device. No signup, no plugin, no upload to the cloud.
$ cdwavmp3 encode --in track03.cda --out mp3 --bitrate 320
[ok] reading CDA frame 0x0001 — 44100 Hz / 16-bit / stereo
[ok] LAME encoder warmed up in 312 ms
encoding .. 100%
[ok] CRC verified — track03.mp3 written · 4.21 MB · 7.4 s
queue depth: 1 · local thread: complete · GPU: idle
The online tool runs the same LAME-based encoder pipeline as the desktop build, wrapped in a WebAssembly runtime that ships inside the page. Your file is read, decoded, encoded, and packaged entirely inside your browser sandbox. Once the download starts, the source bytes are released from memory.
Drop one or several .cda files into the box. The reader picks up the raw audio frames directly from your CD-ROM or from files you exported earlier. Nothing is sent to a server.
.cda, .wav, .flac, .aiff.mp3 320 kbps CBR by default.flac, .aac, .ogg, .wavMP3 is the default. Switch to FLAC for archival, AAC for Apple devices, or OGG for open-source players. The bitrate slider only affects lossy targets — FLAC is always lossless.
A typical four-minute track at 320 kbps finishes in well under eight seconds on a 2018 or newer machine. When the green check lights up, click Save .mp3 and the browser hands you the file.
The free online tier covers roughly 90% of the home use cases we see. Hit the wall? Pro removes the cap and unlocks the desktop engine for batch jobs.
Online conversions feel instant because the queue isn't a queue in the usual sense. Files are processed by a swarm of stateless WebAssembly workers running in each visitor's browser. Your place in line is the place your browser holds the file open — usually under ten seconds.
The drag-and-drop target uses the File API and streams the audio bytes into a WebAssembly ring buffer. The ring buffer holds up to 200 MB per slot and self-purges once the source is sealed. A SHA-256 digest of the input is written to the session's manifest for integrity verification.
The LAME MP3 encoder runs inside the WebAssembly sandbox on the user's own CPU and, on supporting hardware, dispatches the quantization loops to the GPU via WebGPU. Output frames are tagged with their original CDA position so metadata survives the trip. CRC32 is computed on each frame.
Every encoded frame is re-decoded and compared against the source. The verifier runs the patented error-correction layer (the same logic that recovers 96.3% of scratched discs in the desktop build) to catch silent corruption before the file is packaged. Any failure triggers an automatic re-encode with a longer psychoacoustic window.
The packaged .mp3 (and any optional sidecar) is offered to the browser as a Blob URL. The source file's ring buffer is zeroed, the manifest entry is closed, and a download countdown appears. No byte of the file ever crosses the network — the entire path is local.
Online is fastest for a single track. Desktop is right for a full CD. Pro is right for the engineer who lives in batch queues. Here is the line where each one starts to make sense.
| Capability | Free Online | Free Desktop | Pro Desktop |
|---|---|---|---|
| Per-file size limit | 200 MB | Unlimited | Unlimited |
| Session queue ceiling | 5 files | 99 tracks | Unlimited |
| Output formats | MP3 / AAC / FLAC / OGG / WAV | MP3 / AAC / FLAC / OGG / WAV | + ALAC, OPUS, WMA, sidecar in one pass |
| Default bitrate | 320 kbps CBR MP3 | 320 kbps CBR MP3 | 320 kbps CBR MP3, or user preset |
| Runs offline? | No | Yes | Yes |
| GPU acceleration | Browser-dependent | NVIDIA + Apple Silicon | NVIDIA + Apple Silicon + AMD ROCm |
| DRM-aware ripping | Not supported | Disc-level only | Disc-level + advanced recovery |
| Cost | Free | Free | $19.99 one-time |
The line. If you are converting a handful of tracks you already have on disk, the online tool is enough. If you are ripping a full CD, want offline use, or process more than five files at a time, the free desktop build is the right step. Pro is for engineers who automate.
No. The encoder runs inside your browser as WebAssembly. Read the developer console — you will see the encode loop ticking locally on your CPU. The page makes zero POST requests with audio bytes. The only network traffic is the initial page load and the static encoder bundle.
The free online tier caps each file at 200 MB, which covers roughly 90 minutes of uncompressed CD audio or about two hours of high-bitrate FLAC. Beyond that, switch to the free desktop build — there is no per-file cap and you can queue an entire disc at once.
Inputs: CDA, WAV, FLAC, AIFF, and the raw PCM you get from a CD-ROM dump. Outputs: MP3 (128–320 kbps CBR), AAC (128–256 kbps), FLAC (level 5 lossless), OGG Vorbis (q5–q10), and WAV (passthrough). Sidecars are produced in a single pass — one in, up to five out.
Three common reasons. First, the tab is not focused — browsers throttle background tabs to ~1% CPU. Second, the source is a slow CD-ROM and reads faster than the disc can deliver. Third, the machine lacks WebGPU and falls back to a single-thread encode. In every case the file is finished correctly; it just takes longer to hit 100%.
Yes, with one caveat. If the source is lossless (CDA, WAV, FLAC) and the target is MP3 at 320 kbps CBR, the encode is transparent on double-blind ABX testing — verified against the iTunes and LAME reference builds. If the source is already lossy (a 128 kbps MP3, for example), re-encoding it as 320 kbps MP3 cannot recover the data lost in the first encode. Pick FLAC as the sidecar in that case.
Drop a file into the online tool above — or grab the free desktop build and process a full disc without the browser in the way. Either way, the encoder is the same one trusted by 2.4 million users worldwide.