AAC to FLAC - Convert audio online

Conversion Results:
# Output File Source File Action

How to convert AAC to FLAC:

1. Click the "Choose Files" button to select multiple files on your computer or click the "URL" button to choose an online file from URL, Google Drive or Dropbox. The source file can also be video format. Video and audio file size can be up to 200M. You can use file analyzer to get source audio's detailed information such as track name, genre, bitrate and sampling rate.

2. Set target audio format, bitrate and sample rate. The target audio format can be WAV, WMA, MP3, OGG, AAC, AU, FLAC, M4A, MKA, AIFF, OPUS or RA.

3. Click the "Convert Now!" button to start batch conversion. It will automatically retry conversion on another server if one fails, please be patient while converting. The output files will be listed in the "Conversion Results" section. Click icon to show file QR code or save file to cloud storage services such as Google Drive or Dropbox.

AAC vs FLAC:
Name AAC FLAC
Full name Advanced Audio Coding Free Lossless Audio Codec
File extension .aac .flac
MIME audio/aac audio/x-flac
Developed by Bell Labs, Fraunhofer Institute etc. Xiph.Org Foundation
Type of format Audio compression format Audio file format
Introduction Advanced Audio Coding (AAC) is an audio coding standard for lossy digital audio compression. Designed to be the successor of the MP3 format, AAC generally achieves better sound quality than MP3 at similar bit rates. AAC has been standardized by ISO and IEC, as part of the MPEG-2 and MPEG-4 specifications. FLAC (Free Lossless Audio Codec) is an audio coding format for lossless compression of digital audio, and is also the name of the reference codec implementation. Digital audio compressed by FLAC's algorithm can typically be reduced to 50-60% of its original size and decompress to an identical copy of the original audio data.
Technical details AAC supports inclusion of 48 full-bandwidth audio channels in one stream plus 16 low frequency effects channels, up to 16 "coupling" or dialog channels, and up to 16 data streams. The quality for stereo is satisfactory to modest requirements at 96 kbit/s in joint stereo mode; however, hi-fi transparency demands data rates of at least 128 kbit/s. The technical strengths of FLAC compared to other lossless formats lie in its ability to be streamed and decoded quickly, independent of compression level. In a comparison of compressed audio formats, FFmpeg's FLAC implementation was noted to have the fastest and most efficient embedded decoder of any modern lossless audio format.
Associated programs foobar2000, AIMP, DirectShow, QuickTime, VLC media player. Windows 10, Android, Blackberry 10 and Jolla devices.
Sample file sample.aac sample.flac
Wikipedia AAC on Wikipedia FLAC on Wikipedia