README

flac-pascal

FLAC decoder in Pascal.

Usage

The FLAC unit in flac.pas contains a FLAC decoder which can be invoked using the following function:

function FLAC2PCM(flac: TStream; 
                  pcm: TStream; 
                  var streamInfoBlock: TStreamInfoBlock): LongWord;

• flac: TStream containing a FLAC file.
• pcm: TStream where the decoded FLAC file will be written to.
• streamInfoBlock: TStreamInfoBlock contains metadata about the FLAC file such as number of channels, sample rate, and bits per sample. Useful fields are listed below:

  TStreamInfoBlock = record
    sampleRate:           DWord; 
    numberOfChannels:     Word;  
    bitsPerSample:        Word;  
    totalSamplesInStream: Int64; 
    bytesPerSample:       Integer;
  end;

• returns: FLAC_STATUS_SUCCESS if successful.

The PCM format produced is big endian, interleaved channels, where the bytes per sample is rounded up to the nearest byte, e.g. if the FLAC file contains 20 bits per sample, it will be rounded up to 24 bits (3 bytes). TStreamInfoBlock.bytesPerSample also contains the bytes per sample of the PCM.

Sample Program

Included is a sample program FLACTester.pas which converts a test.flac file to test.pcm. It also prints out the TStreamInfoBlock for the FLAC file.

Supported

• [x] All sample rates
• [x] All channel configurations, up to 8 channels
• [x] Up to 32 bits per sample
• [x] All encoding modes (constant, verbatim, fixed, and LPC)
• [ ] Well tested
• [ ] Error handling