Dolby Digital - 16bit Only? How to tell?

[dvdboy]

Although some Dolby Encoders support 24bit Audio Source Files, as far as I can tell, unlike DTS, Dolby Digital AC3 for DVD is only ever 16bit.

Does anyone know a tool that reads this information out of an ac3 file to prove / disprove this statement?

Cheers!

[tebasuna51]

Although some Dolby Encoders support 24bit Audio Source Files, as far as I can tell, unlike DTS, Dolby Digital AC3 for DVD is only ever 16bit.
Ac3 encoders (Aften for instance) support 16, 24, 32 bit int and also 32 float.
The internal ac3 data (frequency domain) support a precision equivalent to 24 bit always, it doesn't matter what is the original audio source.
Ac3 decoders, normally, convert the ac3 data to 32 float and after to the desired format.

Does anyone know a tool that reads this information out of an ac3 file to prove / disprove this statement?
Don't exist. With lossy compresion we can't know the source precision. The DTS header have a field 'Source PCM Resolution' to store this data but isn't reliable, I see dts made with 16 bit wavs with this field set to 24.