Step 1: Drop your FLAC files using the button above or by deposit and leave.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Receive your converted AC3 files.
FLAC to AC3 Conversion FAQ
How do I convert FLAC audio to AC3 without quality loss?
+
Upload the FLAC file and our converter chooses the AC3 codec / bitrate combination that matches the source. Lossless target (AC3 = WAV / FLAC / ALAC) preserves every sample; lossy target (AC3 = MP3 / AAC / OGG) defaults to 192 kbps which is transparent for spoken-word audiobooks and most music.
How much quality do I lose converting FLAC to AC3?
+
Some, and it is permanent — this is the one direction where information is genuinely thrown away. FLAC holds every sample exactly; AC3 discards what a psychoacoustic model predicts you will not hear. At 192 kbps and above that prediction is good enough to be transparent on most material and most equipment. Keep the FLAC as your master, because you cannot get back to it from the AC3. FLAC uses linear prediction plus Rice coding to reach roughly 50-60% of the original size while decoding back to bit-identical PCM. AC-3 is lossy multichannel audio, normally 5.1 at 384 or 448 kbps, with metadata for dialogue normalisation and downmixing.
Will my track titles and album art survive the FLAC to AC3 conversion?
+
Not intact. FLAC carries a proper metadata block, but AC3 has no standard place for artist, album, track number or cover art, so tags are dropped rather than mangled. Keep the FLAC as the tagged copy, or re-tag afterwards with a tool like Mp3tag or MusicBrainz Picard. AC-3 is inefficient by modern standards and is not accepted by browsers, phones or most web players without a downmix to stereo.
What bitrate does the AC3 file use?
+
Default is 192 kbps for lossy AC3; pass-through for lossless AC3. Override to 320 kbps for audiophile or 64-96 kbps for spoken-word audiobooks (transparent for voice, halves the file size).
Will going from FLAC to AC3 reduce my audio quality?
+
If FLAC is lossy and AC3 is lossless (e.g. MP3 → WAV), the AC3 file is no better than the FLAC — you can't recover information that's already been thrown away. If FLAC is lossless and AC3 is lossy, expect the AC3 codec to recompress; at 192 kbps this is transparent for most content.
Does the FLAC to AC3 converter keep ID3 / metadata tags?
+
Yes — title, artist, album, year, track number, album art, and chapter markers (important for audiobooks) are read from FLAC and written into the AC3 container where the AC3 format supports tags. M4B audiobook structure round-trips into M4B and AAX → M4B output.
Can I batch convert hundreds of FLAC files to AC3?
+
Yes — drop a folder of FLAC files in and we process them in parallel. Premium has more parallel workers and no per-file size cap, so a 500-file batch finishes in minutes rather than tens of minutes.
Will the AC3 keep the same sample rate as FLAC?
+
By default yes (48 kHz FLAC → 48 kHz AC3). If you need to downsample for compatibility (e.g. 96 kHz → 44.1 kHz for CD burning) the advanced sample-rate option does this with high-quality resampling.
Can I normalize loudness in the FLAC to AC3 step?
+
Yes — the loudness-normalize option applies ITU-R BS.1770 / EBU R128 normalization to the AC3 output, targeting -14 LUFS (streaming standard), -16 LUFS (podcast standard), or -23 LUFS (audiobook standard). Useful when batch-converting tracks with varying mastering levels.
Will the AC3 play on my car stereo / iPod / audiobook app?
+
MP3 plays universally. AAC plays on Apple, most Android, Sonos. FLAC plays on Sonos and Android, less well on older iPods. M4B audiobooks play with chapter navigation on iOS Books, Audiobookshelf, and Smart Audiobook Player. The advanced options include device presets.
Is my FLAC file private during conversion?
+
Yes — uploaded FLAC files are processed in isolated workers and deleted within minutes. We never play, store, or share the audio content. Especially important when working with personal audiobook libraries.
How long does converting a 10-hour audiobook FLAC to AC3 take?
+
Same-codec re-mux: 10-30 seconds. Re-encode to a different codec: typically 10-20% of source duration, so a 10-hour audiobook finishes in 60-120 minutes. Chapter markers survive the round-trip and split cleanly.
