SLN to FAP Converter

Transform Asterisk SLN recordings into FAP audio format

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Specialized Output

Convert Asterisk SLN telephony audio into FAP format — meeting the specific requirements of niche audio applications.

Web-Based Conversion

No specialized software needed locally. Run the SLN to FAP conversion from any modern browser.

Secure Processing

Your telephony recordings remain private. SLN files and FAP outputs are deleted automatically after processing.

How to convert SLN to FAP

1

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

2

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

3

Let the file convert and you can download your fap 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
FAP is a byte-swapped variant of the PAF (Paris Audio File) format associated with the Ensoniq PARIS digital audio workstation, a recording environment popular among project-studio engineers in the late 1990s. Where standard PAF stores sample data in big-endian order, FAP reverses the byte layout for little-endian architectures, enabling direct memory mapping on Intel-based processors without a runtime byte-swap penalty. The underlying payload is uncompressed linear PCM at up to 24-bit depth and 96 kHz sampling, preserving full studio-grade fidelity. Because there is no lossy coding stage, recordings survive unlimited edit cycles with zero generational loss — a critical property during tracking and mixing. The SoX command-line utility maintains read/write support for FAP, making it the most accessible tool for converting legacy PARIS sessions to modern formats. Despite its niche origins, FAP demonstrates solid engineering: the header is minimal and deterministic, eliminating ambiguity that sometimes plagues chunk-based containers. Advantages include bit-perfect audio preservation, fast I/O on x86 hardware due to native byte order, and straightforward interoperability with raw PCM tools.
Developer: Ensoniq
Initial release: 1998

Frequently Asked Questions

Why convert SLN to FAP?

FAP is a specialized audio format required by certain applications. Converting SLN to FAP enables use in those specific workflows.

What software reads FAP files?

SoX and certain specialized audio tools can process FAP format audio data.

Is FAP widely supported?

FAP is a niche format with limited support. It is used in specific technical or legacy applications rather than general media playback.

Can I convert multiple files?

Upload a batch of SLN recordings and convert them all to FAP in one pass — efficient for processing multiple telephony files.

How is my data protected?

Uploaded SLN files are removed after conversion, and FAP output files are deleted within 24 hours.