SLN to CDDA Converter

Prepare Asterisk SLN recordings for CD audio CDDA format

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CD-Ready Audio

Convert Asterisk SLN recordings to CDDA — Red Book standard audio ready for burning onto physical compact discs.

Works Everywhere

Run the SLN to CDDA conversion from any browser — desktop, laptop, or mobile. No burning software needed for the conversion itself.

Secure Conversion

Your telephony recordings are handled privately. SLN files and CDDA outputs are deleted automatically after use.

How to convert SLN to CDDA

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose cdda or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your cdda file right afterwards

About formats

SLN (Signed Linear) is a headerless raw audio format storing 16-bit signed linear PCM samples at 8000 Hz mono, most closely associated with Asterisk) — the open-source PBX framework developed by Digium (now Sangoma Technologies). Within Asterisk, SLN serves as the native internal audio representation: every codec transcoding operation passes through signed linear as an intermediate step. This makes SLN the backbone of Asterisk's codec translation architecture. The format contains nothing but raw samples — no headers, no metadata, no framing — so parameters must be known in advance. While this lack of self-description might seem limiting, it is actually an advantage in telephony where sample format is fixed by convention and every overhead byte matters across thousands of simultaneous channels. The 8000 Hz rate aligns with the G.711 standard for traditional telephony, capturing the full 300-3400 Hz voice band. Asterisk also supports extended variants (sln16, sln32, sln48) for wideband audio. SLN files require no decoding — just direct memory mapping — making them ideal for real-time mixing, conferencing, and prompt playback in high-density VoIP environments.
Initial release: 1999
CDDA (Compact Disc Digital Audio), known as the Red Book standard, defines audio stored on music CDs. Jointly developed by Sony and Philips and published in 1980, it established parameters that shaped digital audio for decades: 16-bit linear PCM at 44.1 kHz stereo, yielding 1,411.2 kbps uncompressed. Each disc holds up to 80 minutes organized into tracks with index points, sub-channel data for text display, and error correction codes (CIRC) ensuring reliable playback despite minor scratches. When audio is ripped from a CD, the resulting stream is often saved with the .cdda extension as raw PCM before conversion. The most obvious advantage is uncompressed, lossless nature — what reaches your ears is mathematically identical to the studio master at the specified resolution. Robust error correction provides excellent resilience, maintaining audio integrity even when disc surfaces suffer moderate wear. Having sold billions of units since the first commercial release in 1982, CDDA established baseline quality expectations for digital music and remains the reference against which compressed codecs are measured.
Developer: Sony / Philips
Initial release: October 1980

Frequently Asked Questions

Why convert SLN to CDDA?

CDDA is the Red Book audio standard for CDs. Converting SLN to CDDA prepares telephony recordings for burning onto audio discs.

Will the quality match real CD audio?

The format will be CD-compliant (44.1 kHz, 16-bit stereo), but the source is 8 kHz telephony audio — quality reflects the original recording.

What software works with CDDA?

CD burning software like ImgBurn, Nero, and iTunes, plus audio editors like Audacity, handle CDDA format audio.

Can I convert a batch at once?

Upload multiple SLN recordings and convert them all to CDDA simultaneously — efficient for disc project preparation.

Is the process secure?

Uploaded SLN files are deleted right after conversion. CDDA outputs are automatically removed within 24 hours.