CODEC procedures are similar to I/O procedures (IOProcs). They are dynamic-link library (DLL) routines that operate on data within a file or buffer. Based on the data content, a particular CODEC procedure is loaded typically by a file format IOProc to either compress or decompress the data
OS/2 multimedia currently supports image and digital video CODECs. The following table describes the video CODEC procedures provided with OS/2 multimedia.
┌──────────┬──────────────┬──────────────────────┬──────────────────────────┐ │CODEC │Format │FOURCC │Description │ ├──────────┼──────────────┼──────────────────────┼──────────────────────────┤ │ULDC │Ultimotion │ULTI │Decompressor │ ├──────────┼──────────────┼──────────────────────┼──────────────────────────┤ │INDEO │Indeo 2.1 │rt21/RT21 │Compressor/Decompressor │ ├──────────┼──────────────┼──────────────────────┼──────────────────────────┤ │INDDEC32 │Indeo 3.1/3.2 │iv31/IV31/iv32/IV32 │Decompressor │ ├──────────┼──────────────┼──────────────────────┼──────────────────────────┤ │ULCORT │Ultimotion │ULTI │Real-time compressor │ ├──────────┼──────────────┼──────────────────────┼──────────────────────────┤ │ULCOASYM │Ultimotion │ULTI │Frame-step compressor │ ├──────────┼──────────────┼──────────────────────┼──────────────────────────┤ │INDRTR31 │Indeo 3.1 │IV31 │Real-time compressor │ ├──────────┼──────────────┼──────────────────────┼──────────────────────────┤ │INDFSR31 │Indeo 3.1 │IV31 │Frame-step compressor │ ├──────────┼──────────────┼──────────────────────┼──────────────────────────┤ │MONDO │Uncompressed │DIB │Supports SW │ │ │ │ │monitor/RGB16-YUV411 │ │ │ │ │playback │ ├──────────┼──────────────┼──────────────────────┼──────────────────────────┤ │AUTOPROC │FLI/FLC │flic │Supports AutoDesk Animator│ │ │ │ │playback │ ├──────────┼──────────────┼──────────────────────┼──────────────────────────┤ │MPGDC │MPEG │MPEG │MPEG hardware interface │ │ │ │ │CODEC │ └──────────┴──────────────┴──────────────────────┴──────────────────────────┘
OS/2 multimedia also provides a set of audio CODECs; however, there is no public interface to install new audio CODECs or to interface to audio CODECs directly.
The following table describes the audio CODEC procedures used internally within OS/2 multimedia for playing files that contain compressed audio.
┌──────────┬──────────────┬──────────┬───────┬───────┬──────────────────────────┐ │CODEC │Format │Format Tag│Comp. │Decomp.│Description │ ├──────────┼──────────────┼──────────┼───────┼───────┼──────────────────────────┤ │IMAADPCM │MS ADPCM │2 │X │X │Compression is not │ │ │ │ │ │ │real-time │ ├──────────┼──────────────┼──────────┼───────┼───────┼──────────────────────────┤ │IMAADPCM │IMA ADPCM │17 │X │X │Real-time compression │ └──────────┴──────────────┴──────────┴───────┴───────┴──────────────────────────┘