Hi Zarak,

At the introduction of the DVD format, Dolby Digital was the mandatory soundtrack format. dts was always optional at the discretion of the disc producer. Since a royalty is paid to Dolby and dts for the use of the compression algorithm for each, maybe it's a matter of economics.

I'm not up on the agreements for Blu-ray.

Dolby Digital is also the required transmission format for HDTV broadcasting.

Regards,

Alan

Alan Lofft,
Axiom Resident Expert (Retired)