Audio codecs for Delphi

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A collection of freeware open-source audio codecs is a part of VC Freeware components.

The following audio codecs are implmentated in native Delphi source code and are ready to use. Most of them are based on original C/C++ soucre codec from different sources.

Codec Version Description Unit Reference RTP Profile
G.711 11/88 Logarithmic, 8 kHz, 64 kbit/s, CBR codec used mostly in telephony since 1972. Has two slightly different versions: μ-law (North America and Japan) and A-law (most other countries). unaG711.pas ITU G.711 RFC 3551
G.722.1 05/05 Transform-based codec, 16 kHz, 24/48 kbit/s, CBR codec providing high quality with moderate bitrate optimized for both speech and music. unaG7221.pas ITU G.722.1 RFC 5577
GSM-FR 6.10 RPE-LTP speech codec, 8 kHz, 13 kbit/s, moderate quality, low bitrate and complexity. WAV49 modification by Microsoft ACM implementation has a different bit order and is also supported. unaGSM.pas ETSI EN 300 961,
ref C-code
RFC 3551
IMA ADPCM/DVI4/VDVI 6.10 ADPCM codec, 8 kHz, 32 kbit/s, low quality, very low complexity. unaADPCM.pas IMA ADPCM specification RFC 3551

Download all codec sources as a part of VC Freeware components.