Audio Format Guide for Twitch Streamers
Streaming audio involves multiple format decisions: what OBS encodes during the live stream, what Twitch saves as VODs, and how to archive or share stream recordings after the fact. Each has different requirements.
OBS Audio Settings for Streaming
OBS default audio encoding: AAC at 160 kbps. This is good for most streamers — AAC is efficient, widely compatible, and the standard for RTMP streaming to Twitch, YouTube, and Kick. For higher quality, use 320 kbps AAC if your upload bandwidth allows. Set sample rate to 48 kHz (the broadcast standard). Stereo is standard for streams with music; mono is acceptable for pure talk or gaming streams and saves bandwidth.
Twitch VODs: AAC in MP4
Twitch saves VODs as MP4 files with AAC audio. When you download your VOD from the Twitch Dashboard, you get an MP4. To extract audio from a Twitch VOD for a podcast clip, use the MP4 to MP3 converter. To save the full VOD audio in high quality, use the MP4 to WAV converter and then re-encode to FLAC for archiving.
Opus for Low Latency Communication
Opus is the codec used by Discord, WhatsApp, and WebRTC for voice chat — it is designed for ultra-low latency and excellent voice quality at low bitrates. For Twitch streaming itself, Opus is not the right choice — Twitch's RTMP ingest uses AAC. But for Discord calls, voice in browser-based tools, and any WebRTC streaming, Opus is the automatic choice. You cannot select Opus in OBS for Twitch RTMP streams.
Archive Formats for Stream Recordings
For long-term archiving of stream recordings: FLAC gives you lossless compression at roughly half the size of WAV, with full metadata support. WAV is simpler and universally supported but takes more storage. At 48 kHz stereo AAC 320 kbps, a 4-hour stream is about 576 MB as MP4. As FLAC (lossless), the same content is roughly 2-3 GB. For a true archive, FLAC is the right choice — you can always convert to smaller formats later.
Converting Stream Recordings for Sharing
Common conversion needs: MP4 VOD to MP3 (podcast clip or highlight reel audio), MP4 VOD to WAV (for audio editing in Audacity or similar), WAV recording to OGG (sharing on open platforms). Use the MP4 to MP3 or MP4 to WAV converter at audioutils.com. For full-resolution archives, convert MP4 to FLAC using the lossless export path via WAV intermediary.