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In Reply to: Is MLP flawed? posted by uzun on April 03, 2003 at 09:41:11:
but this is what people were talking about.A compression algorithm like mp3 is designed to put out data at a constant rate. A lossless compression will not be like this. Depending on the predictability of the incoming data, it will put out more bits or less bits per unit time. It has to put out enough bits to completely represent the incoming data, or it will not be lossless.
So there are times, according to what was written here earlier, when MLP puts out too much data for the available bandwidth. To stop this from happening, you can remove some information from the original signal, so you put in some filtering perhaps.
Not a big deal, probably not of audible consequence. But it would be a factor limiting the bandwidth below theoretical maximum of the samplling rate.
Follow Ups:
It isn't all Nyquist. You can have a smoother rolloff if you limit before encode.But, don't listen to me. I've been known to sleep with the enemy and shoot them in the morning.
After the bistream has been unpacked & decoded there is a constant bitrate to the DAC. Buffer control is done on the DSP side which takes care of overruns and underruns. A properly designed system will operate in real-time and avoid all these problems.
What we can say with 100% certainty is that you will never get the "master tape" sound, with watermarking and HF roll off applied.No matter how good your DA's get, you can never get back what has been ruined.
(a) Master tapes:
SnaggS, it may seem incredible to you, but I try to AVOID titles from analog master tapes (unless it’s for legacy music). But in the end, it’s LPCM digital masters at 24bit @192kHz (or 32bit @ 384kHz) which are the ideal.(b) Your alleged MLP "roll-off":
As countered elsewhere by people with FIRST HAND experience, the "HF roll-off" optional technique you mention with MLP, is virtually NEVER NEEDED with real music on DVD-A. (SnaggS, can’t you get it???) Sure, if you blast white noise continuously into all six channels at the highest frequencies and intensities, then you’ll be pushing the limits of the DVD playback system, although MLP will still make a pretty decent job of it (but anyway, is that real music?).Moreover, this situation is indeed mentioned in the technical paper (and no SnaggS, they’re not trying to "hide" it from the public domain), because as a technical paper, it rightly mentions all signal compression optimisation tools available to the user. That built-in flexibility is a "good thing". In fact, what it is doing is getting the very most out of the DVD playback media.
Furthermore, the actual studio masters have no such practical limitations, so any such concern becomes completely irrelevant for recording engineers. Indeed, with LPCM / MLP, the studios have the means to create a high-definition lossless master which is totally portable to ANY consumer playback media (past, present, or future) — whatever the limitations or otherwise which that particular media possesses.
(c) Optional watermarking:
As for watermarking, this is certainly open to debate (for SACD and CD as well!), but I have numerous classical DVD-As (among other styles) which do not have any watermarking. Anyway, classical music is not really the target of mass-pirates.(d) The "best" DVD-A can be (and frequently IS) =
1. For classical/acoustic:
good artist => good location => good microphones => 24bit/192kHz A-to-D converters => 96kHz (5ch + LFE) or 192kHz (stereo) / 24 bit LPCM master => MLP encoder => robust multibit encryption => dual-layered DVD-9 media => long play lengths well in excess of 70min (St Teldec’s St. Matthaus Passion approaches 3hours at 96kHz/24bit in 5.1 surround).2. For rock/pop:
popular artist => good studio => good microphones & direct feeds from instruments => 24bit/192kHz A-to-D converters => up to and exceeding 48 tracks realtime mixing & floating point DSP => 96kHz (5ch + LFE) or 192kHz (stereo) / 24 bit LPCM master => MLP encoder => robust multibit encryption => dual- layered DVD-9 media => long play lengths well in excess of 70min.Also to be mentioned should be these added-value items:- videos; artist bios; interviews; realtime song lyrics; other album trailers; fan-club / concert info; web links etc. etc. not to mention Dolby & DTS mixes, and now the possibility of including a redbook CD on the other side.
Meanwhile, the proportion of DVD players with DVD-A (MLP) decoders is increasing all the time. Soon they’ll practically ALL have MLP decoders in them.
Your patience is admirableI hope you're aware that SnaggS has not yet listened to a single DVD-A on a DVD-A player... I think he just doesn't like the way the name "DVD-A" sounds, and decided to go on a crusade of his own.
Best
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