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Re: No Misunderstanding Here - The Documentation is Clear

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>The 1.5 kbs is not always used on a 'regular' DTS encoded disc.<

Half-rate DTS is known as just that, half-rate, so "regular" DTS is 1.5Mb/s. That is what my reference intended. Sorry for any confusion caused.

>Also 'normal' DTS doesn't have a frequency range up to 24kHz. One of te losses in the lossy coding scheme is that hf above 20kHz is filtered to save bitspace.<

No. From DTS' own literature (this particular example from http://www.dtsonline.com/dtsposition.pdf): "For 48 kHz sampling, DTS has response to 24 kHz at 1.5 Mbit/s and response to 19 kHz at 754 kbit/s."

>You forget that there are twice as many samples available in the 20-24kHz range with DTS9624.<

Wrong again. There aren't. The frequency range up to 24kHz is delivered by the core data, to remain backward compatible it has to be sampled at 48kHz. In a DTS 96/24 decoder, the 48kHz data is upsampled, so the actual content has no more samples. From the document previously referenced:

"The input digital audio signal with a sampling frequency up to 96 kHz and a word length up to 24 bits is processed in the core branch and extension branch. In the core branch input audio is low-pass filtered to reduce its bandwidth to below 24 kHz, and then decimated by a factor of two, resulting in a 48 kHz sampled audio signal. The purpose of this LPF decimation is to remove signal components that cannot be represented by the core algorithm."

>I doubt that the DTS9624 encoding extends the frequency range to a 'useless' 48kHz frequency range.<

Nope (I thought you were the tech guy around here?). The same AES document contains two graphs, the first shows uncompressed 96kHz PCM with a frequency response extending to 48kHz. The second shows the behaviour of the two DTS encoder halves, the core data, which rolls of steeply just before 24kHz and the residual component which mirrors the response of the uncompressed PCM right out to 48kHz.

As I said, try to get hold of some DTS technical documents, the 96/24 example in particular, prior to jumping the gun about the system's operation.


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