Does the M4A to FLAC converter keep ID3 / metadata tags?
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Yes — title, artist, album, year, track number, and album art are read from the M4A container and written into the FLAC container where the format supports tags. All common targets (MP3, AAC, FLAC, OGG) handle tags fine; raw WAV does not.
我可以批量转换成 M4A 成百上千个文件 FLAC 吗?
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Yes — drop a folder of M4A 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.
Yes — uploaded M4A files are processed in isolated workers and deleted within minutes. We never play back, store long-term, or share the audio content. The full retention window is in /privacy/.
转换一个 1小时 M4A 到 FLAC 需要多久?
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Same-codec re-mux: 10 to 30 seconds. Re-encode to a different codec: typically 10 to 20% of source duration, so a 1-hour M4A → FLAC finishes in 6 to 12 minutes. Batch jobs parallelize across workers for further speedups.
Why is the FLAC louder or quieter than the M4A source?
If the M4A download is unprotected (no DRM), yes. DRM-encrypted streams (Spotify, Apple Music tracks) are encrypted at the bit level and we cannot process them. Bandcamp, SoundCloud downloads, personal recordings, and podcast files convert cleanly.