add capturing 24 bit sample

Fireworks transmit its input samples as 24 bit data.
But the format of AMDTP seems not to be comformable to IEC 61883-6.

This is an example of AudioFirePre8's one common isochronous packet.
Each datum are shown as 32 bit little endian (MSB to LSB).
0x3F110018
0x9000897B
0x000004C6
0x00FFFFF8
0x00000060
0x00000040
0x00000024
0x00000028
0x00000021
0x00000034
0x00000000
0x00000000
0x00000000
0x00000000
0x00000000
0x00000000
0x00000000
0x00000000
0x80000000

The first two data are common isochronous packet headers.
It means its format is "Audio and Music" and event type is
"Basic format for AM824".

And the last datum is for MIDI (LABEL = 0x80).

But each Audio data has no labels. The label is always 0x00.
It should be 0x4X (X differs depending on sample width) because
its format is already shown as AM824 data in CIP header.

I have no idea whether fireworks has two modes, IEC 61883-6 comformant or not...