Bitrate
Bitrate is the amount of data used per second of audio, measured in kbps — higher bitrate means better quality and larger files.
Bitrate is the amount of data used to encode each second of audio, measured in kilobits per second (kbps). Higher bitrate produces better audio quality and larger file sizes; lower bitrate produces smaller files with audible compression artifacts. For MP3: 64 kbps is AM radio-ish quality (sufficient for pure voice), 128 kbps is FM radio-ish (casual music), 192 kbps is near-CD-quality, 256-320 kbps approaches CD-quality. For AAC: roughly 75% of the MP3 equivalent bitrate produces similar quality — 96 kbps AAC ≈ 128 kbps MP3. For WAV: bitrate is fixed by sample rate × bit depth × channels — 44.1 kHz × 16-bit × 2 channels = 1411 kbps (10× higher than compressed formats). Voice content tolerates much lower bitrates than music because human voice frequency range is narrower — podcast and audiobook bitrates can go as low as 48-64 kbps mono without audible degradation. Variable bitrate (VBR) adjusts bitrate dynamically per audio segment, producing better overall quality at a given average bitrate than constant bitrate (CBR).
How it works
Bitrate tradeoffs: lower bitrate = smaller file + potentially audible artifacts; higher bitrate = larger file + better quality (up to a point). Beyond ~256 kbps for music and ~128 kbps for voice, bitrate increases don't produce audible improvement for most listeners — diminishing returns set in. For podcast distribution, 64-96 kbps MP3 or AAC is standard — small enough for fast download, high enough for clear voice. For music streaming, 256-320 kbps is typical. For archival or professional work, lossless (WAV or FLAC) eliminates bitrate tradeoffs by storing the full audio. Bitrate should match content type: mono voice at 64 kbps is fine; stereo music at 64 kbps sounds bad. Bitrate is independent of sample rate — you can have high-sample-rate low-bitrate (poor quality) or low-sample-rate high-bitrate (wastes bitrate) files. Most tools calculate bitrate automatically when you set a quality target; manual bitrate control is typically only needed for specific platform requirements.
Examples
Podcast at 64 kbps mono MP3
A 60-minute podcast episode = ~28 MB file. Small enough for fast download on mobile data, voice quality clear.
Music at 256 kbps AAC
Apple Music default. A 4-minute song = ~7.5 MB. Near-indistinguishable from CD quality for most listeners.
WAV fixed bitrate
CD-quality WAV (44.1 kHz, 16-bit, stereo) = 1411 kbps fixed. A 4-minute song = ~40 MB. Used for masters and archival.
Why this matters for Indian-language TTS
For Indian distribution, bitrate matters because mobile data costs are consumption-bound — smaller files reduce listener data consumption. Hindi/Tamil/Malayalam podcasts at 48-64 kbps mono are common; audiobooks often use 64 kbps for the file-size savings. VoisLabs exports MP3 at a default bitrate optimised for voice quality and file size; WAV export on Studio/Pro tier bypasses bitrate considerations entirely.
Related terms
MP3
MP3 is a lossy audio compression format that produces small files with good audio quality — the de f…
AAC (Advanced Audio Coding)
AAC is a lossy audio codec that produces better audio quality than MP3 at the same bitrate — the def…
WAV
WAV (Waveform Audio File Format) is an uncompressed audio container developed by Microsoft and IBM, …
Sample Rate
Sample rate is how many times per second audio is measured — 44.1 kHz is CD standard, 48 kHz is vide…
Mono vs Stereo
Mono is single-channel audio; stereo is two-channel (left + right) audio with directional informatio…
Learn more
Frequently Asked Questions
What bitrate should I use for a podcast?
Is higher bitrate always better?
What's variable vs constant bitrate?
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