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Forums     Plugins     r8brain PRO Converting 88.2 kHz sample to 44.1


My thanks to neilwilkes and drick for comments.

After converting 88.2 to 44.1 using r8brainpro I used Minnetonka's CD-dts software to create dts bitstreams.  Then used a simple (Nero 7) burning software to put it on CD.

This was extremely satisfactory with the exception that since the initial material was tape at 15 ips copied to Alesis HD24XR there were no track marks.

So I had to take the dts (a copy of the 4 ch material) and import it to my Alesis Masterlink and put in the marks.

I should also mention that we are taking 4 ch material recorded during the 70s-80s-90s and were initially archiving to hard drive on the Alesis HD4XR but now found a way to preserve it also on CDs, and conveniently listen to it.


Just playing around with dts...question:

I can (for my own amusement and not commercial) decode a dts disc and get the analog outputs and mix to stereo.  No big deal.

I tried an experiment, which failed.  I took the dts track from a commercial DVD and fed it onto an Alesis Masterlink ML9600 unit.  It plays back fine, though it's at 48k.  I made a CD and tried to do a sample-rate conversion to 44.1 Did not work.

Question: Is there copy protection or some reason why it would not work.  I would have liked to make a dts disc for my amusement and experimentation from the source material.


Sorry, I can't comment - I'm not familiar with DTS that much.

4-ch-guy: I tried an experiment, which failed.  I took the dts track from a commercial DVD and fed it onto an Alesis Masterlink ML9600 unit.  It plays back fine, though it's at 48k.  I made a CD and tried to do a sample-rate conversion to 44.1 Did not work.

4-ch-guy: Question: Is there copy protection or some reason why it would not work.  I would have liked to make a dts disc for my amusement and experimentation from the source material.

Yes.  It's a player dependant thing really.  Most will fail, but there are a select few where it will work.  In those where it does not work there will be one of 2 problems faced:

1 - Static noise (most common)

2 - Incorrect playback speed (rarer, but still quite common)

The reason for the failure is that you are mixing up 2 different bitstreams.

DTS-DVD uses a standard header, and this tells a DVD player the stream is a discrete DTS Core Audio file at a sample rate of 48KHz, maybe 96KHz, maybe 5.1, maybe 6.1 - all this is in the header & extensions (extensions are used when anything apart from the core stream is included - more on this later).

DTS-CD takes the multiplexed bitstream from a starting point of 44.1KHz (remember this is a CD we are talking about here) and fudges the header to make is look like a 16/44.1 stereo WAV file.  It isn't though, it is a DTS-CD file at either (surround) 44.1 or (stereo) 88.2KHz.  Attempting to SRC this will in 99% of cases result in failure unless you decode to 5 mono WAV files, SRC those & then re-encode to DTS-CD again - with the potential reduction in quality implied by the perceptual process.  If the DVD bitstream does use extensions, then attempting to SRC is guaranteed to end in failure.

DTS Process works by starting off with a core stream.  This can be from 16 to 24-bit, and for DTS-DVD streams will always be 48KHz.  Therefore the highest quality DTS-DVD Core Audio stream is at 24/48 resolution.

For DTS-CD, it is 24/44.1 at the highest resolution.

To get more channels and/or higher resolution, DTS uses extensions to the core stream.

If your source is a 24/96 stream, the resulting encoded file will have the 24/48 core stream & the remainder in an extension to the core that is both invisible to the disc author but also to the end user.  It's there though.  Same for the 6.1 channel counts.

The thinking behind this is to ensure that a DTS stream will always play back on any DTS decoder chip as long as the encoding was carried out correctly in the first place - all complexity is in the encode stage.  Your player - if it supports DTS at all - will always be capable of outputting the core stream, meaning that if you are trying to play a new 24/96 encoded stream (as on the Depeche Mode or Genesis DTS-DVD sets) on a player that has decoders only capable of 24/48 resolution, you will still get sound.  It will be limited to 48KHz resolution though.

Hope this helps a little.

www.opusproductions.com

Multichannel Audio Specialists

DVD-A, DVD-V Authoring

Mixing & Mastering to most formats


To Neilwilkes:

Thanks for your insightful explanation.  What you wrote makes sense.  My experience with r8brainpro for SRC has been to take 4 .wav files from 88.2 to 44.1 and then create a dts bitstream of the 4 channels.  Then output thru burning software to a CD.  The CD is played on any number of non-dts players and fed to a MILLENIUM dts decoder

http://www.5point1.com/content-248-1422.html

...and then to preamps or whatever.  The original material was on 4 ch tape.  We xfer it to Alesis HD24XR, then do the above.  I wondered whether the DVD dts stream would SRC and did the experiment.  Thanks again.


Well worth a try - you may have had one of those rare setups where it all worked properly.

Trouble there - as I found when I made DTS-CD from 24/48 WAV files & encoded to DTS-WAV at 24/44.1 - was that even though the speed was correct off my Denon players, it was not reliably correct on other peoples setups & I got a lot of emails about playback being just too fast.  The new DTS-HD MAS encoder won't even let you try this - SurCode will and the Nuendo one will also - but not the DTS created ones.  Maybe this is why?

Those HD24 are nice machines for what you pay, arent they?

I'm going to buy myself a couple of them this year methinks for live tracking. (One 24-track master, another for backup on the night as I lost 75 minutes on a recording once in a live show whilst I was mixing FOH, the recording "engineer" was not paying attention.  Aargh.  Never again.

But I ramble, and I am sorry about that.

www.opusproductions.com

Multichannel Audio Specialists

DVD-A, DVD-V Authoring

Mixing & Mastering to most formats


So I found out that it was not meant to be.  That's ok.  It was a worthwhile experiment.

Yes I use SurCode to encode.  The 4ch analog tape material is transcribed to 4 ch of a HD24XR.  When @ 88.2 I SRC it and get 4 .wav files at 44.1.  The I assign them to whatever positions in the SurCode 5.1 format I want.  I now have two formats onto which the analog (deteriorating) old tape has been transcribed to: dts 4 ch and hard drive on the Hd24XR.

One more thing: I found subsequently, and after doing many tranfers to dts that I now take whatever original channel the bass player was on (usually channel 4).  In additiona to assigning that to SURROUND LEFT on SurCode, I also assign it to the Sub.

Thanks for your (forgive the pun) INPUT :-)


Neil:

One more thing:

from your website: "Tapes that are suffering from Hydrolysis can also be recovered, allowing you to rescue those old masters you thought were beyond recovery. "

I forgot to mention that we take the old tapes and "bake:" them, using a food dehydrator.

I can bake six at a time.  Usually 145 degrees for about 2-3 hours.  The dehydrator trays have a central hole which allows me (without modification of the trays) to bake tapes on my plastic NAB reels.


4-ch-guy: Neil:

One more thing:

from your website: ''Tapes that are suffering from Hydrolysis can also be recovered, allowing you to rescue those old masters you thought were beyond recovery. ''

I forgot to mention that we take the old tapes and ''bake:'' them, using a food dehydrator.

I can bake six at a time.  Usually 145 degrees for about 2-3 hours.  The dehydrator trays have a central hole which allows me (without modification of the trays) to bake tapes on my plastic NAB reels.

They work really well from what I have heard.

Any decent electrical slow cooker will - main thing is the constant temperature & not too hot.  You can use expensive, dedicated ovens, but it's not usually necessary unless the tape is very badly damaged in which case I always outsource to a place just up the road from here.

www.opusproductions.com

Multichannel Audio Specialists

DVD-A, DVD-V Authoring

Mixing & Mastering to most formats


Never saw that earlier comment.

For creating an artificial LFE where you feel you really, really must there is IMHO a better way to proceed than that.

DTS LFE should be band limited with a 48dB/Octave slope LPF at 80Hz.  Dobly used to say 120, but they would.

Try taking all 4 quad tracks, and pointing them all at the main output.

Turn off any normalize.

Insert your LPF (I use UAD Cambridge, but Sonic Foundry do a good one too) and run an export to a single mono wav file.  This should be just the content from all 4 tracks below 80Hz to your LFE.

Bring it back into the project, and adjust according to taste & flavour.

www.opusproductions.com

Multichannel Audio Specialists

DVD-A, DVD-V Authoring

Mixing & Mastering to most formats

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