Film-Tech Forum ARCHIVE: dcp and blu ray sources

This is topic dcp and blu ray sources in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by George Murray (Member # 6991) on 10-28-2013, 11:49 PM:

are dcps and blu rays sourced from the same masters? and if they are wouldnt that make the quality of the two media formats identical or darn close? Has anyone done a direct dcp vs blu ray comparison and can comment on the difference in image quality?

Posted by Brad Miller (Member # 2) on 10-29-2013, 03:15 AM:

Most of the time they are pretty close. Take something like the two recent Star Trek movies. The blurays are extremely well authored.

I was however quite disappointed with the bluray of This is the End that I watched part of. It has a video-ish smeared look to it with screwed up gamma. The DCP did NOT look like that.

Its really hit and miss.

Posted by Scott Norwood (Member # 30) on 10-29-2013, 07:13 AM:

Even if the scan is the same, they use different compression schemes.

Posted by Mike Blakesley (Member # 26) on 10-29-2013, 03:33 PM:

I have found that if I convert a blu-ray to a DCP using software like DVD-o-matic, the sound seems to come out a bit different than if I play the same disk on our blu-ray player. (Oppo) This is converting from a MKV file using the source sound. It's not a huge difference but there is a difference....unless it's the old ears playing tricks?

Posted by Brad Miller (Member # 2) on 10-29-2013, 05:24 PM:

How is it different? Does your Oppo have 6 channel analog outputs? I ask because the older model Panasonic BDP-30 players had really crappy quality 6 channel discrete outputs and you might be in the same scenario.

What processor do you have and how is the Oppo tied into it?

Posted by Aaron Garman (Member # 1653) on 10-29-2013, 05:50 PM:

When creating the MKV from Blu-ray, is it pulling the lossless or lossy core track?

I'm not too familiar with DVD-O-Matic, but does it convert lossless to LPCM or is it converting the lossy core for audio? That could explain differences...

AJG

Posted by Steve Guttag (Member # 268) on 10-29-2013, 06:03 PM:

The Oppo has discrete 6-channel (or 8-channel) outputs and the DACs are pretty good. The upper-end Oppos have even better DACs but the standard Oppo is no slouch on the D/A department.

Posted by Lincoln Spector (Member # 6835) on 10-29-2013, 06:08 PM:

quote: Scott Norwood
Even if the scan is the same, they use different compression schemes.

And different color spaces. BDs only have 8-bit color. 2D DCPs have 12-bit.

A well-made Blu-ray can look acceptable on a big screen, but not as good as a DCP.

Posted by Carsten Kurz (Member # 5396) on 10-30-2013, 06:35 AM:

When ripping a DVD or BluRay, usually you can choose which of the tracks is extracted. Typically, it is left unaltered in the MKV.

DVD-o-matic converts it to LPCM. Which, in the case of lossless Dolby and DTS formats, should be a 1:1 copy. It also conforms to 48KHz/24Bit if needed, though.

That said, there is, of course, not a single way to do it, depending on which tracks you choose and how you play DCP and BluRay against each other, they may sound slightly different. BluRay Players may have additional audio processing enabled as well.

- Carsten

Posted by Steve Guttag (Member # 268) on 10-30-2013, 06:39 AM:

So what ripping program are you all using on the BluRays and DVDs?

Posted by Carsten Kurz (Member # 5396) on 10-30-2013, 06:39 AM:

MakeMKV

- Carsten

Posted by Aaron Garman (Member # 1653) on 10-30-2013, 03:35 PM:

I use MakeMKV and DVDFab. Depends on the job, but also, if one fails. If it's TrueHD, I use DVDFab because it will give me a TrueHD+core track that works with tsmuxer that somehow, MakeMKV won't.

TrueHD is a bag of hurt. DTS-MA is so much easier to work with.

AJG