Film-Tech Forum ARCHIVE: Sensitivity to dirt and scratching on BDs

This is topic Sensitivity to dirt and scratching on BDs in forum Film-Yak at Film-Tech Forum ARCHIVE.

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Posted by Leo Enticknap (Member # 534) on 12-10-2011, 06:12 AM:

I have now had several occasions when both the BD drive in my computer and the player in the projection booth at work have frozen and stopped with a read error. The reason has always been fingerprint marks, dirt or scratches on the disc. On all but one occasion, cleaning the playing surface with some isopropanol and a lens cloth has solved the problem, and the one disc for which it didn't had a deep lateral scratch on it, which was beyond help.

It does strike me that BDs are more sensitive than DVDs to contamination on the playback surface. I've played DVDs in a similar condition, without bothering to clean them and with no problem. Given that the size of each data pit and thus the laser beam is so much smaller, that makes logical sense I guess: it takes a physically smaller and less dense bit of crap to prevent the laser beam from reaching and bouncing off the pit of a BD than a DVD.

It does make me wonder, though, whether, once arthouses start screening BDs on a regular basis as a cheap alternative to film prints (in the way that some already do with DVDs), if we aren't going to have quite a few disrupted shows.

Posted by Gordon McLeod (Member # 33) on 12-10-2011, 11:11 AM:

We have already started to see that in one art location At that location all DVD and Blue Rays are transfered to a Hard Drive and played from there for the run

Posted by Victor Liorentas (Member # 5272) on 12-10-2011, 11:42 AM:

I had a new one yesterday,I was trying to cue a blu-ray up and it played fine but would not respond to any commands such as stop!
It kept on playing,I had to unplug the Pioneer player to bring order to the Galaxy!

Posted by Paul Mayer (Member # 355) on 12-10-2011, 11:42 AM:

More than likely Leo, or at least it will become a much more widespread practice to do check screenings/disc cleanings before shows. But with consumer discs, even a successful pre-screening doesn't guarantee that the next playback will be glitch-free. I imagine those screens that had reputations for showing dirty scratched prints in the film days will continue their crap media handling practices and have reputations for skipping and freezing and cancelled shows.

Yeah, the BD format is more sensitive to physical contamination. When the format was being developed, it was predicted that there would be such issues. One of the proposed solutions was to enclose the discs in caddies to minimize the exposure of the discs to contamination. But that method was ultimately deemed to be too cumbersome to use in a consumer format. In the end the BD format ended up with an extra scratch-resistant layer applied to the surface of the disc. Still, BDs are rather delicate things.

I like Gordon's observation. It's probably best for a professional operation to rip the BD to a hard drive and then do playback from the drive. I'm building my first HTPC and will be playing with doing such things for my future private screenings. Having the file on hard disc also gives one the chance to remove all the extra stuff that won't be needed/wanted during playback (extra soundtrack languages, subtitles, home video labels, etc.).

Posted by Mike Blakesley (Member # 26) on 12-10-2011, 08:38 PM:

How do you get around the "copy protection" when ripping a BD to a hard drive?

Posted by Brad Miller (Member # 2) on 12-10-2011, 08:41 PM:

I believe this is what most people are using.

Posted by Claude S. Ayakawa (Member # 1401) on 12-10-2011, 09:44 PM:

When playing movies on DVDs and BDs in a theatre, how do you get around from not showing copyright infringement warnings, menus and other things that are not part of the movie you are showing?

-Claude

Posted by Joe Redifer (Member # 3) on 12-10-2011, 11:30 PM:

Does ANY DVD HD copy the lossless audio tracks and/or convert them to full bitstream uncompressed audio?

Posted by Mike Blakesley (Member # 26) on 12-10-2011, 11:59 PM:

Claude - what we do is, start the movie, pause the player, and close the douser (the thing that keeps the light off the screen) before we let the audience in. The only "telltale" that it's a BR is the "play" symbol up in the left corner when we start the show.

Posted by Dustin Mitchell (Member # 372) on 12-11-2011, 12:15 AM:

We do the same as Mike. I think it was 2 years back we ran a marathon of all the Potter films followed by a midnight premier of the latest one. What I did to keep the audience from seeing the menus FBI warning/etc each time I loaded a new disc was to time them all the weekend before so I could close the douser and switch the sound until the disc had reached the main menu. Since by default 'play feature' is usually selected when the disc menu pops up once enough time had elapsed plus a few seconds worth of buffer all I had to do was hit play, open the douser, and switch the sound.

Unfortunately all we had was a DVD player so the picture really looked terrible. If it had been Blu Ray I don't think the audience would have even realized we were playing a DVD.

Posted by Brad Miller (Member # 2) on 12-11-2011, 12:19 PM:

At least you guys are trying for showmanship from consumer video formats. Way too many theaters I have seen just run through the menu and FBI warnings in front of the audience.

We had to do a bit of custom programming to get around these issues on the DCS, but the end result is that there is no "play" nonsense on the screen and the entire show is automated starting with previews/snipes on the DCP player and changes over to the bluray player.

Posted by Chris Slycord (Member # 4239) on 12-11-2011, 12:25 PM:

quote: Mike Blakesley
How do you get around the "copy protection" when ripping a BD to a hard drive?

In addition to what Brad posted, there's also this

Posted by Paul Mayer (Member # 355) on 12-11-2011, 02:42 PM:

quote: Joe Redifer
Does ANY DVD HD copy the lossless audio tracks and/or convert them to full bitstream uncompressed audio?

I'm pretty sure it does, but will find out for sure in the next couple of weeks. AnyDVD HD is what I'll be using for region code removal. I already use AnyDVD on my existing desktop (and on my former work laptop) and it has performed well. Slyfox has been really good about updating with the latest encryption schemes too.

Posted by Brad Miller (Member # 2) on 12-11-2011, 04:31 PM:

Does either of those programs actually permit you to strip the stupid previews, home video logos and the FBI threats like DVD Shrink does? How about subtitles and audio tracks you don't want? Can they "squeeze" it into a 25GB disc?

Posted by Paul Mayer (Member # 355) on 12-11-2011, 06:21 PM:

That's my understanding, but it will be another couple of weeks before I get everything assembled enough to play with this on the new hardware and see what it really can do. As for getting the ripped version (minus all the extra crap) back onto another 25 or 50GB disc, that is what it is supposed to be able to do. We'll see.

For me, those edited/cleaned up files will end up on the 2TB storage drive within the HTPC. At some point down the road I guess I will be burning some of those files to writable BDs as backups.

Posted by Joe Redifer (Member # 3) on 12-11-2011, 07:05 PM:

In the grand scheme of things, I don't think that stripping all of that other stuff out will allow you to fit most movies onto a 25GB disc. Some of them, you bet. Maybe even a lot. But I am betting that most will still need over 25 GB. I bet most come to 26 GB.

I can only imagine the satisfying feeling of stripping out all of those idiotic commercials, trailers, FBI paranoia screens (of which there are sometimes multiple) and menus. God damn I hate menus on pretty much any Hollywood disc. They almost always animate and make noise. Often you must wait for the animation to complete before you are allowed to use the disc. And they show scenes from the movie. I hate that. I'm about to watch the movie, don't spoil it for me! Who likes menus like that? Please let me know so that I can dislike you!

Posted by Brad Miller (Member # 2) on 12-11-2011, 09:09 PM:

It would appear I actually hate home video disc menus more than Joe does. I wouldn't have been as nice.

Personally I feel if a theater is booking a movie and it isn't available in 35mm or DCP, the STUDIO should have the responsibility of SHIPPING a blu-ray/DVD with nothing on it but the damn movie.

Posted by John Wilson (Member # 269) on 12-11-2011, 09:52 PM:

quote: Brad Miller
Does either of those programs actually permit you to strip the stupid previews, home video logos and the FBI threats like DVD Shrink does? How about subtitles and audio tracks you don't want? Can they "squeeze" it into a 25GB disc?

As far as DVD Fab goes...yes, yes and yes.

Posted by Chris Slycord (Member # 4239) on 12-12-2011, 01:50 AM:

quote: Brad Miller
Does either of those programs actually permit you to strip the stupid previews, home video logos and the FBI threats like DVD Shrink does? How about subtitles and audio tracks you don't want? Can they "squeeze" it into a 25GB disc?

As mentioned above, DVDFab does it. It's dirt-easy. Select Blu-ray Copy and then main feature. Then choose the video track you want and deselect the audio tracks you don't followed by the subtitles you don't like. You can either rip to a HD directory (which copies blu-ray directory structures) or tell it to use an iso target. And you can tell it what type of media you'll be using which it'll then show you what percentage of that medium's capacity you'll be using up.

Posted by Michael Putlack (Member # 6523) on 12-12-2011, 02:15 AM:

Whenever we get Blu-ray from a distributor the disks are without menus, previews, or fbi warning and just goes straight into the feature. We usually make our own dvd of trailers to play before the feature presentation.

Posted by Frank Angel (Member # 248) on 12-12-2011, 11:14 AM:

The beauty of playing off a hard drive copy is that you can get only the movie and I would guess 9 times out of 10 computer playback is more reliable than optical disc. If nothing else, there are no contamination issues to worry about. Then there is the beauty of no menu crap.

I once got screwed where a player which I had in pause waiting for some academic to give his bs introduction to a movie (a movie that SPEAKS FOR ITSELF, but instead we had to listen to him babble away), the player finally went out of pause and back to start so I had to quickly recue it missed -- up came the Fox HOME ENTERTAINMENT logo before the actual movie FOX logo, telling everyone it was a DVD. There was obvious displeasure heard from the audience -- the venue hadn't let people know they were going to watch a DVD (a BIG mistake in my mind).

In situations where I can't do a rip to HDrive, I now insist on dual playback -- two players running as close to sync as I can manually get them into a switcher so that if one freezes, and won't go passed some damn pit somewhere, bingo, I am back on the screen lickty split.

I got burned once with a disc that wouldn't play passed a point more than an hour into the film at a kids show -- 200 screaming kids -- it wasn't a fun matinee. I vowed that would never happen to me again. When we were showing some Chaplin stuff to an audience of 4000, I said it was either two players running simultaniously or yourself another lad. From then on we use dual.

This BTW, harks back to the thread about which players 1) have a way of completely disabling the on-screen menu, especially the damn function indications (PLAY, PAUSE, etc.), or at least 2) will allow the player to stay in pause indefinately or a REALLY LONG TIME, like a half an hour or more. No way I want the audience to see ANYTHING that reminds them of the inferior medium they are watching, even if they are told beforehand that it's a DVD or BRD. There is just something about actually seeing stuff they see at HOME playing on a theatre screen that ruins the presentation, at least for me, it's just embarrassing. A shame we are forced to resort to such crap.

And what's even more maddening, as Brad says, the studio or Swank of whoever is renting to art houses is still charging a "non-home" licence fee...like $300 to $1000, so they should be also supplying theatrical, non-home DVD or BRD versions -- i.e., just the MOVIE. I say they should even add a standard 10 or 15 second lead-in in black in front of the first frame of the movie so if we are stuck with a player that insists on showing the PLAY indication, we can keep the douser closed until that passes and we will still be clean in black. What studio will respect their own product enough to do this for art houses forced to run home movies? My face is laughing at the thought.

Posted by Leo Enticknap (Member # 534) on 12-12-2011, 11:45 AM:

DVDFab includes a facility to re-author the front end in the ripping process, so that it'll jump straight to the main menu when the disc is inserted without displaying the copyright death threats for 20 seconds first.

However, it won't strip out any copyright messages, distributor logos etc. that appear between pressing the "play main feature" button and the film actually starting. The way I deal with this is to rehearse the disc, making a note of the sequence of titles and logos that appears between pressing the play button and the actual movie starting. The cue sheet might look something like this:

Insert Disc > Select English > main menu (with sound).

Press start film, then:
Studio Canal Logo (with sound)
"Interviews do not represent views of studio" title
Canal Classics logo (with sound)
Actual film starts with Paramount logo, 37 secs after hitting play

Credit roll starts at 1'56'23"
Ends 2'01'26" - "© Bloody Awful Productions, 2009", holds in centre of screen; fade to black; music continues over black to 2'01'59"; two second pause then back to menu with sound.

So when the time comes to start, I hit play with a cardboard dowser in position over the lens and the audio muted. About 20 seconds in I start to take the lights down, and then after the last logo with sound (that I don't want to show) has faded out, hit unmute and remove the cardboard.

Posted by Frank Angel (Member # 248) on 12-13-2011, 11:18 AM:

Leo, I and I am sure your audiences applaude you for being so meticulous and dedicated to your presentation, but NO ONE should be forced to jump through those kinds of hoops to make the studios look good.

That's like renting a room in a 5 star hotel and handed a vacuum cleaner and cleaning supplies when you check in and told to spruce up the room yourself.

Posted by Paul Mayer (Member # 355) on 12-13-2011, 12:17 PM:

Perhaps that's true, but nonetheless those of us who are forced by circumstance to present home video sources in a professional theater venue will go to these lengths. I've been doing the same sorts of things for years at my Japanese movie screenings.

Posted by Bruce Hansen (Member # 281) on 12-13-2011, 08:28 PM:

BTW, the reason that BRs are rather sensitive to surface defects, is that the recorded layer is very close to the front surface of the disc. This was done to get 25G per layer. The less plastic defects the laser passes through, the smaller the spot it can make.

CDs have the recorded layer on the back side of the disc (never scratch the back side of a CD, that will destroy the recording). DVDs have the recorded layer in the middle.

Posted by Frank Angel (Member # 248) on 12-14-2011, 10:32 AM:

Paul...yup, been doing it for decades for older titles, and not only with digital but even before that with film -- needing to spend hours repairing prints that should have been junked to wring the best performance possible. Point is, we shouldn't have HAD to do it. It's the studios disrespecting BOTH the filmmaker's work -- all those hundreds of people you see in the credit crawl from the director on down -- to the paid patrons sitting in our theatre. I lay it right at the studio's ugly corporate feet.

And Bruce, thanks; never knew that about the physical structure of the different media.

Posted by Leo Enticknap (Member # 534) on 12-15-2011, 12:41 PM:

quote: Bruce Hansen
CDs have the recorded layer on the back side of the disc (never scratch the back side of a CD, that will destroy the recording). DVDs have the recorded layer in the middle.

Sorry to be an irredemably anal geek, but that's not totally right. You're absolutely right in pointing out that CD-Rs are different from any other type of optical disc, in that in a factory pressed CD and a DVD (both factory pressed and consumer-burnt) the dye layer is sandwiched between two substrates (clear transparent discs), with the label on top of one of them. In a recordable DVD, the laser shines through the bottom substrate (i.e. the one without the label stuck on it) to burn and read it.

A CD-R or RW has just one substrate. On one side of the substrate a "pre-groove" track is carved into it to guide the burning laser. On top of that pre-groove track is the dye layer that is burnt by the laser. On top of the dye layer is a reflective layer, to ensure that the light does actulaly bounce. On top of that reflective layer is printed the label.

The bottom line is that unlike with DVD-Rs and BD-Rs, on which the only side you've got to be really careful about is the side through which the laser reads and writes, with a CD-R you've got to be very careful not to scratch either side, because if you scrape away a bit of label you may well take some of the actual recording layer with it.

This guide explains the chemistry in lots of detail.

Posted by Bruce Hansen (Member # 281) on 12-18-2011, 06:12 PM:

Leo,

You may have miss-read something:

quote:
The polycarbonate substrate makes up most of the disc, including the area that is read by the laser (opposite the label side on CDs). It is present on both sides of a DVD

There is no polycarbonate layer on the back side of a CD.