Convert AVI to AMR — Free Online Converter

AVI is Microsoft's general-purpose video container capable of holding video and audio in a wide variety of codecs. AMR (Adaptive Multi-Rate) is a specialized narrowband speech codec standardized by ETSI/3GPP, operating at bitrates between 4.75 and 12.2 kbps. AMR was designed for GSM cellular voice transmission and is optimized exclusively for human speech — it performs remarkably well on voice content but produces poor results with music or complex audio. Converting AVI to AMR extracts the audio track and encodes it for mobile voice applications.

AMR is the standard audio format for voice memos on many Nokia, Samsung, and legacy Android phones. If you have AVI recordings of meetings, interviews, or lectures and need to create the smallest possible voice files for MMS, voice memo apps, or VoIP systems, AMR is the format that achieves the most extreme compression while keeping speech intelligible. At 12.2 kbps, a one-hour recording takes under 6 MB.

FFmpeg decodes the AVI audio stream to raw PCM, resamples it to 8 kHz mono (the AMR-NB requirement), and encodes using the libopencore_amrnb encoder at the selected bitrate (4.75–12.2 kbps). AMR-NB operates on 20ms frames with algebraic CELP coding, analyzing speech patterns to achieve extreme compression. The codec applies voice activity detection (VAD) and comfort noise generation (CNG) to further reduce bandwidth during silence periods.