siDecompressionParam atom ('wave')

Mentioned in

• Sound sample data

Overview

The siDecompressionParam atom provides the ability to store data specific to a given audio decompressor in the SoundDescription record. As example, some audio decompression algorithms, such as Microsoft’s ADPCM, require a set of out-of-band values to configure the decompressor. These are stored in an atom of this type.

This atom contains other atoms with audio decompressor settings and is a required extension to the sound sample description for MPEG-4 audio. A 'wave' chunk for 'mp4a' typically contains (in order) at least a 'frma' atom, an 'mp4a' atom, an 'esds' atom, and a Terminator atom ('0x00000000').

The contents of other siDecompressionParam atoms are dependent on the audio decompressor.

Topics

Data fields

• Size
• Type
• Extension atoms

See Also

Extending sound sample descriptions

• siSlopeAndIntercept atom
• Format atom ('frma')
• Terminator atom ('0x00000000')
• MPEG-4 elementary stream descriptor atom ('esds')
• Audio channel layout atom ('chan')
• Subtitle follows track reference atom ('folw')