Blu-ray movies screen capture

[amstrad]

Hi,

I want do some screen shot of Blu-ray movies,
and public on this forum

But have some problems - how ?
I turn Off hardware acceleration and use print screen,
but quality of pictures is low.

On blu-ray.com I see beautifu quality of screens.

[ricwhite]

From what I read, I don't think posting the exact method is allowed on this forum for some reason. I don't take computer image captures, but I understand that you need some specific software in order to do it. Do a search on google for computer image captures and blu-ray and you'll probably get some information on how it's done.

[InfectedStranger]

Originally Posted by amstrad

Hi,

I want do some screen shot of Blu-ray movies,
and public on this forum

But have some problems - how ?
I turn Off hardware acceleration and use print screen,
but quality of pictures is low.

On blu-ray.com I see beautifu quality of screens.

I don't have any idea what you're talking about, describe further, please.

[Bobby Henderson]

A lot of people ask about frame grabs since the leading software DVD player programs (Power DVD, WinDVD) as well as Apple's Quicktime player allow users to capture still frames to the clip board and then paste them into applications like Photoshop or Paint Shop Pro.

[Cinema Squid]

Originally Posted by ricwhite

Maybe somebody can explain the "issues" with this because I really don't understand all the secrecy.

There's a number of ways to make them using free software like mplayer, ffmpeg, avisynth, etc. which is probably how most are doing it.

I'd be more than happy to post my own methodology using mplayer which is pretty simple, but there does seem to be some kind of "first rule of fight club" in effect. I'm not sure if this is the official stance of the forum or just conventional wisdom, however, so I've erred on the side of caution - it would be nice to get a moderator opinion on the matter.

[ricwhite]

Originally Posted by Cinema Squid

There's a number of ways to make them using free software like mplayer, ffmpeg, avisynth, etc. which is probably how most are doing it.

I'd be more than happy to post my own methodology using mplayer which is pretty simple, but there does seem to be some kind of "first rule of fight club" in effect. I'm not sure if this is the official stance of the forum or just conventional wisdom, however, so I've erred on the side of caution - it would be nice to get a moderator opinion on the matter.

Thanks for your comment, Cinema Squid. So, is there something "wrong" about taking a screenshot? I do it all the time with video games and I post them on forums. Almost EVERY forum dedicated to DVD or HD DVD or Blu-ray HAS screenshots of movies. EVERY reviewer who reviews movies posts screenshots of the movies including Blu-ray movies. (Just look at all the computer image captures of movie frames posted here on this site). So, I guess I don't understand what is wrong with telling people how to do it.

If somebody -- like a moderator -- would explain to me why they are nervous about the "knowledge" being released, I would really appreciate it. Since I'm the administrator of the Screenshot Thread here, I get emails quite often asking me how to take computer image captures and I'm unable to tell them how to do it or why there's secrecy involved. (I only take photographs). So, I would certainly appreciate an explanation so I can answer those questions when people ask me. It almost sounds like there are the few "chosen" ones who have some "approval" of some kind to take BD screenshots while the rest of us are not allowed. I assume there must be some "rules" or regulations or guidelines or conditions. Very weird.

[Moefiz]

Already have one going for quiet sometime now...

https://forum.blu-ray.com/showthread...screen+capture

[StretchMaK]

If you are asking about screen shots from your computer why not just print screen and paste into paint and then save as what ever file you want it to be?

[rubberghost]

if it is so "hush-hush" it probably has something to do with the BDA. have you tried asking them? they're not that difficult to deal with.

[Ataneruo]

I know for a fact that Arcsoft Total Media Theatre lets you easily capture blu-ray screenshots and save them to your hard drive. I have no compunction about saying so because if there was something "illegal" about doing so, Arcsoft wouldn't have it in their program.

[rubberghost]

Cinematized, Mac, BD drive. = maybe.

[ricwhite]

Originally Posted by StretchMaK

If you are asking about screen shots from your computer why not just print screen and paste into paint and then save as what ever file you want it to be?

That doesn't work for Blu-ray movies.

[Cinema Squid]

Originally Posted by Ataneruo

I know for a fact that Arcsoft Total Media Theatre lets you easily capture blu-ray screenshots and save them to your hard drive. I have no compunction about saying so because if there was something "illegal" about doing so, Arcsoft wouldn't have it in their program.

Cyberlink specifically removed the screenshot feature from PowerDVD Ultra version 8 for Blu-ray, so I can only assume there has been some pressure from the BDA or other vested parties to discourage screenshot taking. I would not be surprised if Arcsoft were under similar pressure. All of the open solutions require a "Step 0" which is probably the source of most of the hesitancy around posting specific methods. I will say that none of the open solutions work with copy-protected material and leave the details and extrapolation of that as an exercise for the sly reader.

With that being said, I personally prefer to dump many pre-generated bitmaps and sort through the results with a nice image browser, rather than trying to locate and frame step to specific shots while watching the movie (which can be troublesome with BD-Java navigation restrictions). My current method uses mplayer to dump all the I-frames of a movie file. These occur between 1-2 per second, so doing this typically results in 7000-10000 image files to sort through at a total cost of approximately 10-15GB of disc space.

Assuming the BD-ROM drive is attached at X:, I use the following mplayer command-line:

mplayer -nosound -vo png:z=5 -vf framestep=I X:\BDMV\STREAM\00000.m2ts

This exports each I-frame of the specified M2TS file to a losslessly compressed PNG file. Then it is simply a matter of picking out those bitmaps that you want to keep and deleting the rest. Picking out the correct M2TS or set of M2TS is another discussion altogether, although for most non-seamlessly branched movies this is usually just the largest one.

Depending on the horse-power of your computer and amount of available disc space, you can tweak the png z-value for better or worse compression. Since I only keep a dozen or so shots, I use a midrange Z compression and then recompress the keepers with a more aggressive value (as well as convert downscaled JPG versions) using ImageMagick.

That's it... although there are many other interesting things you can do with mplayer such as autodetect the crop / aspect ratio:

mplayer -vf cropdetect X:\BDMV\STREAM\00000.m2ts

[ricwhite]

Thanks for the explanation. I think most people think that getting a screenshot of a BD movie just requires pressing a single button and then pasting the clipboard contents into a paint or photo program and saving it as a jpeg. It is more complex than that and time consuming if you don't have a powerful computer. At this point, I'll stick with photographing my display. Others that have good computers and BD drives, however, may find your information valuable.

Just a question, though. When you dump all those I-frames of a movie file (maybe 10,000 of them) doesn't all of that processing just bind up your computer? Doesn't it take a lot of processing time? Also, I would imagine going through 10,000 images to select 15 or so can take a while.

[Gremlin]

Just use a decent digicam and take a pic of the screens you wish to post.
There are a lot of pics here that show even better quality then screencaps.

[ricwhite]

Originally Posted by Gremlin

Just use a decent digicam and take a pic of the screens you wish to post.
There are a lot of pics here that show even better quality then screencaps.

"Better" than "computer image captures" is possible, I guess. However, it would be somewhat artificial. A computer screen capture is a "pure" image that minimizes any factors that affect the image. It is exactly how the image was rendered with the only variable being how well your computer monitor is calibrated to view it. Photographs, on the other hand, introduce TONS of variables -- all of which affect the image to one degree or another. Some might say that some of those variables actually make the image look a little better.

So, I would say that a computer image capture is the most ACCURATE depiction of a movie frame, but a photograph can sometimes look a little better because it artificially changes the accuracy to make the image look brighter, punchier, more or less saturated, etc.

For example: The following two images are from a scene in Iron Man. Which do you think looks better?

Image One




Image Two





The first image was a computer image capture. The second image was a photograph of a 106" screen with an LCD projector. The first image is more "accurate". The second image is a little brighter. There's no way a "photograph" can be as "accurate" as a computer image capture. It can be "different" and, while not as accurate, some people like that difference a little more.

[Bobby Henderson]

If the BDA is putting legal pressure on companies like Cyberlink to prohibit frame capture features then the BDA is showing some blatant ignorance of the video compression technology used in Blu-ray.

Both MPEG-4 AVC and Microsoft VC1 compression formats rely a great deal on inter-frame compression techniques. Because of this fact, any still frame capture from a BD will be flawed. Lots of data just isn't there in frame grabs.

If someone went to the insane trouble of capturing every frame from a BD movie and tried to encode it into a pirated version he would end up with a copy grossly inferior to the original.

Perhaps 10 or 20 years from now the situation may be different. We may see video formats using something similar to what D-cinema delivers -a discrete, separate still image with mild levels of compression for every film frame. That's what JPEG2000 does in D-cinema. The virtual print files those theaters play is just a container for a couple hundred thousand still images. In that situation, a software player on a computer with frame grab capture for every movie frame could be a very bad thing.

I have an old version of PowerDVD that could do frame grabs from DVD discs. One thing it would not do is grab every frame. It would skip past a few for every step. That may be one compromise.

[Gremlin]

Ricwhite, I agree. however you have a good projector which can produce a better picture then what you see on a pc monitor. they also both use different technologies so the same frame dont look the same. let me ask you this: how close are your camera's screenshots to what you really see on your projector?

[ricwhite]

Originally Posted by Gremlin

Ricwhite, I agree. however you have a good projector which can produce a better picture then what you see on a pc monitor. they also both use different technologies so the same frame dont look the same. let me ask you this: how close are your camera's screenshots to what you really see on your projector?

You are viewing BOTH computer image captures and photo screenshots on a monitor, so the viewing monitor affects both equally. Also, I think you're misunderstanding how computer image captures work. You are NOT taking a snapshop of the MONITOR. You're talking a snapshot of the frame on the movie itself. Even if you had NO MONITOR, you will still be able to capture the frames of pure images and record them on your hard drive. The only thing the monitor is used for is VIEWING the recorded image captures.

Photographs, however, are affected by DOZENS of variables during the "taking" process (unlike computer images captures). The only variable on computer image captures is the viewing monitor. Computer image captures will ALWAYS be more "accurate" than photo screenshots. AlWAYS. It's IMPOSSIBLE for a photograph of a display to be more accurate than a computer image capture. More "accurate", however, doesn't necessarily mean better looking -- which is very subjective.

My photo screenshots are about 90% accurate with what I'm seeing on the screen (whereas computer image captures are close to 100% accurate). I've done a lot of tweaking of my set-up and my camera in order to achieve that. Cameras tend to push certain colors (usually red -- although mine pushes greens), so I had to offset that with projector and camera adjustments.

Cameras also tend to over or under saturate the colors (usually over-saturate). I adjusted down saturation in both the projector and camera in order to come close to the saturation I'm seeing on the screen (and sometimes I've had to go into Photoshop and reduce saturation even more because it was inaccurate still).

Cameras also tend to mess with exposure -- often over-exposing the image -- which blows out the whites and washes out the image. Exposure is VERY difficult to adjust post-picture, so it has to be done while the photo is being taken. I use an aperture priority setting which then uses an auto-exposure. However, I usually have to step down the exposure by 1/3 or 2/3 depending on the scene in order to get close to the correct exposure.

But I agree with you that some photos of displays look better to me than the "pure" image captures -- usually because the colors were more "punchy" or the image was brighter. However, those changes would make the image less "accurate", but maybe more pleasing to the eye. More accurate is not always the best looking.

For example: With the two images I posted earlier, IMAGE ONE is more accurate than IMAGE TWO; however, many people like the brighter quality of IMAGE TWO -- even if it IS less accurate.

[Gremlin]

Ricwhite, I know how screencaps work , what I meant for the topic poster, is that he can use a camera since its not bad at all comparing to screencaps.

but help we out on something - I agree a capture is 100% accurate, and you say the digicam photo is 90% true to what you see.. I looked at both pics and the top one looks like a dvd compared to the bottom, so even at 90% what you see is in fact closer to the bottom one... or am I wrong?