AVI to SLN Converter

Extract AVI audio as Asterisk PBX signed linear format

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Video to VoIP Audio

Pull audio from AVI and encode it as SLN — ready for use as hold music, prompts, or greetings on your Asterisk PBX platform.

Files Stay Private

Your AVI uploads are deleted right after conversion, and SLN files are removed within 24 hours. Telephony audio remains confidential.

Quick Turnaround

Server-side processing means your AVI to SLN conversion completes in seconds. Download and deploy the audio on your phone system right away.

How to convert AVI to SLN

1

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

2

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

3

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

About formats

AVI (Audio Video Interleave) is one of the oldest and most recognized multimedia container formats, introduced by Microsoft in November 1992 as part of its Video for Windows technology. Built on the Resource Interchange File Format (RIFF) structure, AVI interleaves audio and video data in alternating chunks, allowing synchronized playback without requiring sophisticated stream management. The format is codec-agnostic, meaning it can hold video compressed with virtually any codec, from early Cinepak and Indeo to modern DivX, Xvid, and H.264 streams. This flexibility contributed to widespread adoption across personal computers throughout the 1990s and 2000s. One notable characteristic is a straightforward internal structure that makes AVI files relatively easy to edit and process at the binary level compared to more complex modern containers. AVI also supports multiple audio streams, enabling multilingual content within a single file. However, the original specification has limitations, including a 2 GB file size ceiling in older implementations and no native support for variable frame rates or advanced subtitle formats. The OpenDML extensions (AVI 2.0) addressed the size limitation by allowing files to exceed the original boundary. Despite being decades old, AVI remains one of the most universally recognized multimedia formats and is still widely supported by media players and editing tools across all major operating systems.
Developer: Microsoft
Initial release: November 10, 1992
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

Frequently Asked Questions

Why convert AVI to SLN?

SLN is the native raw audio format for Asterisk PBX systems. Converting AVI audio to SLN creates prompts and audio files for VoIP platforms.

What is the SLN format exactly?

SLN stands for signed linear — an 8kHz, 16-bit signed integer, little-endian raw audio format used by the Asterisk open-source PBX platform.

Can I use SLN outside of Asterisk?

SLN is closely tied to Asterisk PBX. While SOX and some audio tools can read it, the format exists primarily for telephony applications.

Will voice prompts sound clear?

SLN captures 16-bit PCM at 8kHz, which is standard telephony quality. Speech extracted from AVI sounds clear through PBX phone systems.

Is the conversion process fast?

Audio extraction and SLN encoding are handled on our servers. Most AVI files process in under a minute — ready for your Asterisk system.