FLAC Audio Codec: what it is, how it works and what it does

Definition and Principles

FLAC (Free Lossless Audio Codec) is an audio format that allows data compression without loss of quality. Its architecture is based on the exact reconstruction of the original signal after decoding, distinguishing it from lossy codecs by not discarding audible information.

Technical Specifications

According to technical specifications, both the encoder and decoder must meet the following minimum requirements:

• Channel modes: Mandatory support for at least Mono and Stereo.
• Sample rate: Must support rates up to 192 kHz.
• Bit resolution: Mandatory support for 16-bit and 24-bit resolutions.
• Floating-point configuration: Handling of 24-bit FLAC audio data must be available with floating-point audio configuration.

File Containers

The FLAC format can be stored within different file containers, each with specific functional restrictions:

1. Native FLAC: Extension .flac, which supports both encoding and decoding.
2. MPEG-4: Extensions .mp4 and .m4a, limited exclusively to decoding (decode only).
3. Matroska: Extension .mkv, limited exclusively to decoding (decode only).

Scope and Limitations

The scope of FLAC focuses on the intact preservation of the audio signal. An evident operational limitation is that, when packaged in MPEG-4 or Matroska containers, functionality is restricted to playback (decoding), preventing direct encoding in those specific formats according to the provided evidence.

Interpretation in Products

The presence of FLAC in a product indicates support for high-fidelity audio. Verification of compatibility must consider not only the file extension but also the device's ability to handle high sample rates (up to 192 kHz) and 24-bit resolutions, especially when using floating-point configuration.

Note: The specifications cited come from technical standards that define the minimum requirements for implementing FLAC encoders and decoders.