Film-Tech Forum ARCHIVE: Blu - Ray, Scaler & Sound...

This is topic Blu - Ray, Scaler & Sound... in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Michael Harlow (Member # 1353) on 02-02-2013, 06:05 AM:

Hello, lovely Film-Tech members, I am after a quick piece of advice please?
We have a Barco DCP2K-19B projector, Doremi Server and so on, CP750 for the sound.
We have a Sony Blu-Ray player and a Gefen Scaler (AV Pro II), but we seem to have a sound issue...
The Blu Ray goes through the scaler and then to the projector, the sound for the blu ray goes straight from the "digital" output on the blu ray player to "input 3" on the CP750, the scaler is not looking after the sound...?
The issue we have that the Blu Ray only seems to use L and R screen channels and nothing else.. i have checked the settings of the player and it all looks ok.
Is this normal behavior..? can i get the CP750 to output all 6 channels as it does on normal film sound from the Doeremi?
Sorry for the long post, any advice, as always is welcome
Michael.

Posted by Carsten Kurz (Member # 5396) on 02-02-2013, 06:42 AM:

You need to configure the BluRay Player for RAW/Bitstream Output, and the CP750 for AC3 decoding on the digital input.

Then you also need to select a multichannel track when playing the disc - usually they have a selection of stereo and multichannel tracks.

Sooner or later you could run into trouble with discs that have no AC3 tracks, as BluRays may contain different surround sound formats, but the CP750 will only decode Dolby's consumer variant.

In theory, some BluRay Players may transcode other formats to AC3/SP-DIF RAW, but it depends on the specific player and some transcodings may even be forbidden by licensing.

Which BD player are you using?

- Carsten

Posted by Michael Harlow (Member # 1353) on 02-02-2013, 07:40 AM:

Carsten, thank you very much for taking the time to reply. I will try this when i get to the cinema, the blu-ray player we are using is a Sony BDP-S185.
Thank you for your help, will let you know how i get on later today.
Michael

Posted by Marco Giustini (Member # 4544) on 02-02-2013, 09:43 AM:

As Carsten said, you can bypass the Gefen, no problem. The upside of using the Gefen is that you then use it as a gateway for all your alternative content. Using the 750 you need to make sure you have the proper cable. Also, you have sync controls on the Gefen, while on the 750 you need to access the setup software.
Are you sure they did not connect the analog output of the Gefen to the analog input of the 750?

Besides that, it's as Carsten says, it's a BD issue. The usually decodes AC3 streams with no configuration needed.

Posted by Dennis Benjamin (Member # 1137) on 02-02-2013, 11:01 AM:

Ironic that this subject gets brought up again.

I did more testing this morning to try and figure out a way to run those Blu-Rays that have only the "DTS MASTER AUDIO" soundtracks in surround. Currently, I have to downmix them to 2.0 audio in order to play through a Dolby CP-750.

I have officially given up on this endeavor. If we happen to play a Blu-Ray that only has the "DTS MASTER AUDIO" soundtrack, then it will have to play in Stereo.

Oh well.

Posted by Antti Nayha (Member # 4980) on 02-02-2013, 11:13 AM:

Dennis: I’m not sure if this was already brought up, but there are Blu-Ray players which can be set to re-encode other multichannel formats to Dolby Digital.

One such player is Samsung BD-D8200N/D8500N (those may be euro-specific models, but others exist as well).

Posted by Chris Slycord (Member # 4239) on 02-02-2013, 04:28 PM:

Also, if you rip a blu-ray you could use a piece of software out there called eac3to that lets you convert the audio to your choice of ac3/dts/flac. Then you could reburn the bluray from the files left and so you'd have an ac3 bluray of the movie.

http://www.videohelp.com/tools/eac3to

Posted by Antti Nayha (Member # 4980) on 02-02-2013, 04:58 PM:

If you decide to go through the trouble of ripping the disc, I would suggest that you play the file instead then – either on a hardware player or a dedicated PC.

Optical media for screenings = evil.

Posted by Marco Giustini (Member # 4544) on 02-02-2013, 05:05 PM:

definitely a hardware player if you don't want the issue of vertical sync!

Posted by Carsten Kurz (Member # 5396) on 02-02-2013, 06:27 PM:

I never came across discs with only DTS in europe, but I heard they do exist in the US.

Some players decode DTS to 8ch LPCM and play this through HDMI. You may then try to capture the multichannel sound from the HDMI audio. There are external converter boxes that loop through the HDMI video and output audio to either multichannel analog or S/P-DIF.
Once you use one of these converters, the setup will be a lot more complicated than the plain AC3 input to the CP750. Datasats AP20 will decode dts formats as well, but it's a bit more expensive than the CP750, sure no retrofit solution for existing CP750 users.

There are boxes like this, but the specs tell you nothing about what they actually do with the different HDMI surround formats - you have to test it.

http://www.amazon.com/Vanco-280573-HDMI-Audio-Extractor/dp/B00AB40EWY/ref=sr_1_3?ie=UTF8&qid=1359851145&sr=8- 3&keywords=hdmi+deembedder

The Gefen AV Pro II has nice audiofeatures as well - but won't help you with DTS encoded audio, it will only decode Dolby surround formats, just like the CP750.

- Carsten

Posted by Steve Guttag (Member # 268) on 02-02-2013, 07:04 PM:

Note...it is entirely possible that on a disc-by-disc (depending on BluRay player), you will need to select LPCM or Dolby Digital if you are using a CP750. The CP750 handles, PCM (and will perform a prologic/II matrix decode), and AC3 over the coax or Toslink inputs. if the disc does not have Dolby Digital and you select "bitstream" then you likely will not have sound. But if the disc DOES have Dolby digital, then bitstream will get you AC3 audio. Then there are those discs that have damn near every format and the player may allow you to select most/all permutations so it may take a combination of selecting what type of output you want your player to provide AND then selecting the proper track!

There is a nifty device coming out from Crestron...the HD-XSP

It is a full bore HDMI audio extractor that can handle all of the whiz-bang audio in one box and send the picture on to the projector.

If the lower bandwidth audio is sufficient, Extron has the SSP 7.1

Naturally, one can also use an A/V receiver (consumer) but the model life-times are very short and it is becoming increasingly popular to only have preamp outputs on the higher-end system.

Personally, I'm looking to go a bit more professional and reliable.

Posted by Antti Nayha (Member # 4980) on 02-02-2013, 07:06 PM:

quote: Carsten Kurz
I never came across discs with only DTS in europe, but I heard they do exist in the US.

Funny that it’s you who should mention that… The last two that I encountered were actually German Blu-Ray releases:
Gremlins 2
The Quiet Earth

Posted by Carsten Kurz (Member # 5396) on 02-02-2013, 08:08 PM:

I may have just been lucky - I just found a graph showing BD audio codec distribution on titles between 2007 and 2011 - 53% DTS-HD, 19% Dolby TrueHD...

Basically, every BD player with a DTS decoder per spec should be able to send discrete multichannel audio over HDMI in LPCM. That would at least help with external HDMI audio extractors. Of course, for a CP750 with S/P-DIF in, you would still need an AC-3 transcoding (or an option to use the discrete analog inputs if not needed for other purposes).

The CP750 is simply not a good choice...

- Carsten

Posted by Marco Giustini (Member # 4544) on 02-03-2013, 03:49 AM:

Carsten,
What would you suggest instead?

Posted by Carsten Kurz (Member # 5396) on 02-03-2013, 06:52 AM:

Datasat AP20. Not only solves the DTS decoding issue, but also takes care of HDMI video switching and passthrough. It is a bit more expensive than the CP750, but for a still more flexible equivalent, the slightly cheaper 8ch version would do.

Plus, if you take a CP750 and need an auditorium level control, it will cost you something like 600US$ for a CAT 868. While the AP20 can use any of the shelf pot and cabling, like existing ones from e.g. a CP65 installation.

So, the effective price difference between a CP750 and an AP20-8ch is small. And I do not even mention that the AP20' features are way beyond the CP750.

If you're stuck with a CP750, I guess I would look into a BD-Player with internal DTS decoding and then use an external HDMI 8ch LPCM converter.
The problem is that, for general domestic use players, these features are rarely documented exactly. You simply have to do some testing. Or, through a lot more money at it, like with the EXTRON devices Steve mentioned.
But hey, this is for the occasional BluRay presentation with DTS-only soundtracks. I don't want to spend 1000-2000US$ just for that capability.

The Gefen AV Pro II can decode 8ch LPCM from HDMI. If Michael can find a BluRay Player with internal DTS decoding, it could solve the issue for less than 100US$.

BTW - Oppo has new and lower priced BluRay Players now, the 103 and 105. Unfortunately, though even the low cost model has RS232 control, they still ignore the idea of deactivating the OSD completely.

If Dennis' CP750 has the analog multichannel aux inputs unused, he could simply buy a Player (again, like the Oppo 103) with discrete multichannel analog outs and feed these to the CP750. hat would enable ALL DVD and BluRay multichannel formats for him.

- Carsten

Posted by Marco Giustini (Member # 4544) on 02-03-2013, 07:29 AM:

I have never used the AP20, only read the specs.
Automation-wise I don't really think that you'll ever need a remote fader: if you have a Dolby you can control the fader from any remote screen in real time. On a doremi you can run a macro. Why would you need a remote?
You could actually send RAW commands from your mobile. Or you could use an android app a friend of mine has developed!

That said, it really depends on the price list of the AP20. The 750 is quite limited in features - still featuring the old fashion 31-bands EQ! - but it's quite cheap.

DTSwise, I used to be a fan of the brand, but I think they made big mistakes in the past and personally I feel I shouldn't trust them anymore.
I would rather invest money in a Home Theatre receiver to be connected to the 6ch input of the 750.
Again, I appreciate that FIR filters are ineteresting, I am not saying that 31-band EQ is better!

Posted by Carsten Kurz (Member # 5396) on 02-03-2013, 11:42 AM:

A lot of cinemas simply want wall controls. Remote control apps would be no option there.

If people spend the money for a CP650, they could as well afford the AP20, which has WAY more options right out of the box.

The JSD80 is a very nice CP as well, but even that is limited compared to the AP20.

CP750=DCP only, no bells and whistles at all. What do I gain from AC3 only, when as it seems most BluRays come with DTS now?

We now have more and more special events where we could actually use a mix of film-sound and external sources. The AP20 is the only CP capable of integrating classic music acts with filmsound due to his flexible routing.

Plus, to my knowledge it's the only CP currently available with access and routing options for ALL 16 DCI audio channels simultaneously.

- Carsten

Posted by Marco Giustini (Member # 4544) on 02-03-2013, 12:01 PM:

Sure, I am not saying that the features available on an AP20 are not interesting. Just that I tend to be sceptical with DTS now.

Does anybody know the list price of an AP20? Again, the 750 is limited but also quite cheap.

Posted by Steve Guttag (Member # 268) on 02-03-2013, 12:04 PM:

The AP20 is certainly a flexible piece...it was designed to be. The HDMI inputs was a nice touch too.

The CP750 does provide a very cost effective solution for DCinema with Alternate content accommodation, if you limit yourself to "low bandwidth" multichannel audio or pre-decoded multi-channel. If I have an Oppo connected to the CP750's analog inputs...it provides, from a BluRay stand point, the same level of audio but at a fraction of the cost of the AP20 with a BluRay player. Likewise, if the customer just wants AC3 or prologic from 2.0 LPCM...then the CP750 is fine.

In a more sophisticated room, the CP750 is insufficient, for sure and devices like the AP20, DCP200/300, Crestron, RANE, BiAmp....and on down the line until the system fits the need of the room. There are some that will be just fine with taking the analog stereo output and getting a prologic decode too!

As I said earlier, a device like the one Crestron is coming out with will be very appealing to my upper-end/more sophisticated rooms where there will be considerable switching upstream (that will far exceed the capabilities of a device like an AP20). It is all a matter of fitting the boxes to the needs of the room/customer and now we have a very considerable range! There is no reason to have to even limit ourselves to "Cinema" industry boxes...DCinema outputs LPCM...there are many boxes that can take that and do with it what is needed. I would put the CP750 towards the bottom end of the scale in terms of functionality but I would also say it satisfies about 90% of the systems I've installed and, without exception, people have liked the way it sounds too (though I think it is getting credit for using LPCM discrete tracks versus some poorly set up knockoff-SR film boxes).

Posted by Steven J Hart (Member # 2340) on 02-03-2013, 12:40 PM:

Please pardon my ignorance, but why use a scaler at all? We run our blu-ray hdmi output directly into the projector's DVI input, then create custom screen and lens files for each common blu-ray aspect ratio. This seems to work like a charm. We use the second DVI input for our screen advertising (from a hardware player) and have screen and lens files programmed in for that as well.

As for audio, we take the coax out from the blu-ray and run it through a Denon Pro preamp (with balanced XLR analog outputs) which decodes whatever audio format coming from the blu-ray into 7.1 analog which is fed into our USL JSD-100 analog inputs.

Posted by Marco Giustini (Member # 4544) on 02-03-2013, 03:52 PM:

I guess it's for VGA, composite, component and all sort of strange analog video you may want to feed to the projector.

If you only plan to use BDs or DVDs, you can set your BD player to scale everything to 1080 and be happy.

Speaking of scalers, I am surprised that the Barco scaler does not support 24p...

Posted by Steve Guttag (Member # 268) on 02-03-2013, 04:06 PM:

If you are running just a BluRay and you have a fixed output rate...then a scaler may not be needed.

If you are handling a multitude of video formats/resolutions...then scalars are indispensable. If you want to have a smooth crossfade between a DVD or BluRay to a laptop outputting "XGA or like analog"...or have HDCAM mixed in there...they are handy. If your lens can zoom out to 2048 but can't zoom all of the way from 1920 for scope a scaler can take care of that. Scalars support more input rates, typically, than a DCinema projector. And while it is possible to do some scaling within a series 2 projector (less so in a series 1), you would fill up your preset slots with all of the permutations. But again, if you JUST have a 1080p output and a handful of aspect ratios...then a scaler may not be needed and even ad a layer of complexity that isn't desired.