SLN to AC3 Converter

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.

AC3 is the file format associated with Dolby Digital, a perceptual audio coding technology from Dolby Laboratories. This lossy format encodes up to 5.1 channels of surround sound (left, center, right, left surround, right surround, and LFE) into a bitstream typically ranging from 192 to 640 kbps. The algorithm applies a modified discrete cosine transform with psychoacoustic analysis to discard audio information below the threshold of human perception, producing compact files without obvious quality loss. AC3 became the mandatory audio standard for DVD-Video and is widely used in Blu-ray discs, digital television broadcasts (ATSC), and streaming delivery. A primary advantage is multichannel surround capability, bringing cinematic spatial audio into home theater systems. The format also maintains excellent dialogue clarity through its dedicated center channel, ideal for film and television content. Widespread hardware decoder support in receivers, TVs, and set-top boxes means AC3 audio plays back reliably across an enormous installed base of consumer electronics.