Following the header information is a LIST 'movi' chunk that contains chunks of the actual data in the streams; that is, the pictures and sounds themselves. The data chunks are grouped into 'rec' chunks.
Like any RIFF chunk, the data chunks contain a four-character code to identify the chunk type. The four-character code that identifies each chunk consists of the stream number and a two-character code that defines the type of information encapsulated in the chunk. For example, a waveform chunk is identified by a of 'wb' two-character code. If a waveform chunk corresponded to the second LIST 'hdrl' stream description, it would have a '01wb' four-character code.
Since all the format information is in the header, the audio data contained in these data chunks does not contain any information about its format. An audio data chunk has the following format (the ## in the format represents the stream identifier):
WAVE Bytes '##wb'
BYTE abBytes[];
Video data can be compressed or uncompressed DIBs. An uncompressed DIB has BI_RGB specified for the biCompression field in its associated BITMAPINFO structure. A compressed DIB has a value other than BI_RGB specified in the biCompression field.
A data chunk for an uncompressed DIB contains RGB video data. These chunks are identified with a two-character code of "db" (db is an abbreviation for DIB bits). Data chunks for a compressed DIB are identified with a two-character code of 'dc' (dc is an abbreviation for DIB compressed). Neither data chunk will contain any header information about the DIBs. The data chunk for an uncompressed DIB has the following form:
DIB Bits '##db'
BYTE abBits[];
The data chunk for a compressed DIB has the following form:
Compressed DIB '##dc'
BYTE abBits[];