How do I extract the audio from a MP4 file as AAC?
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Upload the MP4 file and we demux the audio track, then transcode it to AAC. There is no second video pass and no quality loss beyond what the AAC codec itself introduces.
What audio bitrate does the AAC file use?
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Default AAC bitrate is 192 kbps (transparent for music). You can override to 320 kbps (audiophile) or 96-128 kbps (voice / podcast / smaller file). The choice is exposed in the advanced options before extraction.
Will I lose audio quality going from MP4 to AAC?
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If AAC is lossless (WAV, FLAC), every sample is preserved exactly. If AAC is lossy (MP3, AAC, OGG, Opus), the AAC codec recompresses — at 192 kbps this is transparent for almost all content. Recovering quality that was already gone in the MP4 source is impossible.
Does the extracted AAC keep the original sample rate?
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By default yes — a 48 kHz audio track in MP4 becomes 48 kHz in AAC. If you need 44.1 kHz (CD-quality) for compatibility with older players, the advanced options expose a sample-rate dropdown that resamples with a high-quality filter.
Can I extract audio from multiple MP4 files to AAC in one batch?
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Yes — drop a folder of MP4 files in and we extract audio in parallel. Pro users get more parallel workers; on a 50-file batch this is the difference between 90 seconds and 8 minutes.
Will the AAC file be tagged with title / artist / album?
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If the MP4 container has chapter or stream metadata, we copy artist / title / album fields into the AAC container where the AAC format supports tags. Otherwise the AAC file is untagged — use a tag editor (Mp3tag, Picard) post-export for richer tags.
How long does extracting AAC from a MP4 file take?
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Audio extraction is much faster than video re-encoding — typically 5-15% of source duration. A 1-hour MP4 -> AAC finishes in 3-9 minutes on the standard pipeline.
Can I extract just a section of the MP4 audio as AAC?
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Not in this single tool — extract the full audio as AAC here, then use /audio-trim/ or /audio-cutter/ to clip the section. The two-step path is faster than a combined operation because we avoid re-decoding the whole file twice.
Is my MP4 file private during audio extraction?
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Yes — same privacy model as every conversion: isolated workers, automatic deletion within minutes, no human review of content. See /privacy/.
Why does my AAC file have silent gaps?
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Silent gaps usually mean the MP4 file had a multi-track audio layout and we picked the wrong stream. Use the "audio stream" option to explicitly pick stream 0, 1, etc., or re-mux all streams to a multi-track AAC container where AAC supports it.
Can the AAC extraction be stereo / mono / 5.1?
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Channel layout is preserved from MP4 by default — a 5.1 MP4 produces a 5.1 AAC where the codec supports it (AAC, FLAC, OGG, Opus). You can force stereo or mono via the channel-downmix option, which is useful for podcast workflow.
Does the extracted AAC play on iPhone / Android / car stereo?
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MP3 plays everywhere. AAC / M4A plays on Apple and most Android. OGG / Opus needs a recent player on iOS. Advanced options expose a "device" preset that picks the AAC codec most likely to play on your target.