Re: VLC & GOM Screenshots

[email protected] wrote:
> I really like the VLC player but my screenshots keep coming as solid green.
> I unistall the player then reinstall. Screenshots work a few days then go green again. I'm getting ready to delete VCL forever. Seems related to Windows update (Ver 10). I also often get error messages when I use my GOM player screenshot. The error # is 0 x 80070057.
> Thanks
> Gary

Are you using Windows 10 "snippingtool.exe" ?

To show the basic principle, there is FFMPEG and its "gdigrab".
It has the ability to capture from the regular graphics plane.
To place graphics in the regular graphics plane, "disable hardware acceleration".

There are two other graphics planes. There is VMR7/VMR9 for
video playback, and they would have been popular for video playback
in a previous generation. This would be the DirectShow and KCodec Pack
path. Attempting to capture them would likely give a green rectangle.

The third plane, is 3D capture in games. There is some apparent
difference between "windowed" games and "full screen" games. This
too makes a difference to the "surface or plane" of capture. NVidia
provides in-game Shadowplay??? to capture some of that. I've never
tried this plane, limiting my capture to the front plane only
(unaccelerated).

There are a lot of rules to remember.

Windows 7 is the last full-service OS. You could buy a copy of the
"FRAPS" third party product, and capture everything. FRAPS cheated
by injecting a DLL in every program folder, and the filter driver
(at a guess that's what it amounts to), it intercepts graphics
calls, and it records graphics calls rather than pixels as such.
That's how it was able to do such a thorough job. But the author of
that, lost the battle with Microsoft - FRAPS could never be made to
work with Win8/8.1/10 so the author stopped selling it.

Windows 7 allows recording at 60FPS.
Win8/8.1/10 has a capped recording rate of 30FPS.

For lowest latency and jitter, you disable Aero effects.

The graphics business has been working on a "secure enclave" hardware
capability for some time, and this too is intended to prevent memory
copying from a graphics card. All that has to happen, is some Hollywood
DRM cuts in, requests security, and then a gdigrab method won't work
(because for the front plane, it's just taking copies of the double buffer).

Another thing you might have noticed, is the VGA connector disappeared
from new video cards. This completes the route of "analog bypass". Without
unencrypted analog output, many attempts to do external capture of
monitor content are thwarted. Hollywood has won. Sneaky, eh?
First the YPbPr analog coax cable output disappears, then they
set to work setting the VGA connector on fire. Villains.

With the analog hole closed, HDMI or DisplayPort can use HDCP (encrypted
digital stream), to thwart these types of cards. In their heyday, this
class of card was around $100 each. You want the units with passthru,
two HDMI connectors, one HDMI-in, one HDMI-out, and then the
capture device can be put "in-line" with the monitor output you
want to capture. This capture concept is also available in USB3
capture box format - however, you need the "best-in-class" USB3
for that, it must be chipset USB3, not add-on chip USB3. One of
the USB3 products actually has a "benchmark" of sorts which will
declare your USB3 port "a loser" for you :-) This is why I
selected some PCI Express cards to demonstrate the concept, as
the developers can select a decent number of PCI Express lanes
as needed. If a x4 interface is needed, they'll just put an
x4 connector on it.

https://www.amazon.com/Elgato-Game-Capture-HD60-Pro/dp/B014MQIVPS

https://www.amazon.com/Elgato-Game-Capture-4K60-MK-2/dp/B07VWXCXM7

If your OS uses HDCP, the earlier version of HDCP was cracked,
as the keys leaked for it. (Thus there have been HDCP strippers
shipping from China in disguise as "buffers". You put a stripper
plus the capture card, for example.) But that stopped
when HDCP 2.1 or so came out, as that one might not be cracked yet.
Capturing an HDCP monitor cable signal gives "colored snow" as the
only object captured. No recognizable image at all.

*******

Summary: Try to use another OS. Win7 is a nice choice.
          Try to disable hardware acceleration in the things you do. (Prefs:Tick Box)
          Don't really expect screen capture to work worth a damn in future.
          Go hardware capture for some fun.

I wouldn't be too quick to condemn the application developers,
because they have to know all the above inside-out, to stand
a chance of making anything work. And as Windows 10 is a rolling
release, the feature they just made work, could be "broken on Tuesday".

    Paul