The VideoLAN Forums

I've got a 4K HDR MKV video file. When I use the snapshot feature, the resulting image is a grey, washed-out shot missing most of its colour. What can I do to fix this?

While I'm at it, is there a way to exclude the black bars on the tops/sides from the snapshot? I also know these bars aren't part of the video itself.

Regards

Please open Tools -> Messages (set Verbosity to 2) before you start the playback, and then paste the full resulting log here or on Pastebin.com if it's too long.

And upload a short sample of your original problematic file to Zippyshare.com or to WeTransfer.com and then post the link to the file here.
https://www.zippyshare.com
https://wetransfer.com

If needed cut it with DGsplit and read here about how to do it:
https://forum.videolan.org/viewtopic.ph ... 35#p193335
100 MB max should be enough.

Please open Tools -> Messages (set Verbosity to 2) before you start the playback, and then paste the full resulting log here or on Pastebin.com if it's too long.

And upload a short sample of your original problematic file to Zippyshare.com or to WeTransfer.com and then post the link to the file here.
https://www.zippyshare.com
https://wetransfer.com

If needed cut it with DGsplit and read here about how to do it:
https://forum.videolan.org/viewtopic.ph ... 35#p193335
100 MB max should be enough.

But I can't open the video without it playing. How can I open the tools before it starts?

You run VLC, you open Tools -> Messages, you set Verbosity to 2 and then you open the video and save the log at the end.

You run VLC, you open Tools -> Messages, you set Verbosity to 2 and then you open the video and save the log at the end.

Do I have to watch the whole thing? It's three hours.

No, you can stop it after 30 seconds.

No, you can stop it after 30 seconds.

Done. You mentioned "the log at the end." Is it this thing? It's from the Messages window.

main error: Timestamp conversion failed for 184643001: no reference clock
main error: Could not convert timestamp 0 for FFmpeg
direct3d11 error: SetThumbNailClip failed: 0x800706f4

Read my first post again, carefully.
I asked for the FULL log, from the very beginning to the very end AND for a sample file.

Read my first post again, carefully.
I asked for the FULL log, from the very beginning to the very end AND for a sample file.

Yes, I know about that stuff.

But WHERE is the log?

Where you saved it using the Save As button.

Where you saved it using the Save As button.

VLC doesn't have a "Save As" button that I can see.

There's nothing where the video file is saved either (aside from the video file itself).

I made sure to set verbosity to 2, watched over a minute (and much more) of footage, but still nothing.

Here's the log. I'll work on getting the sample too.
https://www.dropbox.com/s/axd14jd852ed18e/log.log?dl=0

This log is quite empty
As I said, you MUST open the messages window BEFORE playing the video. I don't see the opening sequence in your log so you haven't done it.

And you have paused the video. I've never asked you to do that, never. I said you can STOP it after 30 seconds.

I strongely suggest you to read carefully my posts again and to apply instructions step by step.

This log is quite empty
As I said, you MUST open the messages window BEFORE playing the video. I don't see the opening sequence in your log so you haven't done it.

And you have paused the video. I've never asked you to do that, never. I said you can STOP it after 30 seconds.

I strongely suggest you to read carefully my posts again and to apply instructions step by step.

https://www.dropbox.com/s/axd14jd852ed18e/log.log?dl=0

OK, fine, but you have forgotten to make a screenshot during the playback, which is your issue.
And we do need a sample file because I've tried with many HEVC 10-bit videos and I can't reproduce the problem. Check post #2.

OK, fine, but you have forgotten to make a screenshot during the playback, which is your issue.
And we do need a sample file because I've tried with many HEVC 10-bit videos and I can't reproduce the problem. Check post #2.

I didn't forget anything. No mention was made that I needed to take a snapshot for the log.

https://www.dropbox.com/s/axd14jd852ed18e/log.log?dl=0

As for the video, a friend said the problem must be because I don't have an HDR display so "tone-mapping" hasn't been properly applied to the snapshots, and that I need to find a way around this.

The screenshot is done internally, it has nothing to do with your display but it might have something to do with the driver of your graphics card.


I suspect your file to be HEVC 10-bit 4:2:2 but I still can't reproduce the issue with such files I have. Even an HEVC 12-bit 4:4:4 makes correct screenshots on my system.
This is the reason why we DO need a sample of your file. Please upload one, check post #2.

The screenshot is done internally, it has nothing to do with your display but it might have something to do with the driver of your graphics card.

I suspect your file to be HEVC 10-bit 4:2:2 but I still can't reproduce the issue with such files I have. Even an HEVC 12-bit 4:4:4 makes correct screenshots on my system.
This is the reason why we DO need a sample of your file. Please upload one, check post #2.

Is this right?

https://www.dropbox.com/s/0pzlg0tb8tlsr ... 0.mkv?dl=0

Is this right?
https://www.dropbox.com/s/0pzlg0tb8tlsr ... 0.mkv?dl=0

It is. And that's really an interesting sample.


Please, could you provide a longer sample file ? Say 200 or 300 MB.
And I can reproduce the issue with this sample, the colors of the screenshots are wrong while other players are doing it right.

You should create a new ticket on the VLC Trac with your above report, the link to your sample file, and the link to this thread:
https://code.videolan.org/videolan/vlc/-/issues

Is this right?
https://www.dropbox.com/s/0pzlg0tb8tlsr ... 0.mkv?dl=0

It is. And that's really an interesting sample.


Please, could you provide a longer sample file ? Say 200 or 300 MB.
And I can reproduce the issue with this sample, the colors of the screenshots are wrong while other players are doing it right.

You should create a new ticket on the VLC Trac with your above report, the link to your sample file, and the link to this thread:
https://code.videolan.org/videolan/vlc/-/issues

Thanks. I have two questions.

When I followed the instructions using DGSplit, it spent ages creating 100 100MB samples instead of just 1 100MB sample. What did I do wrong? If I can fix this, I'll submit the ticket (and provide you the larger sample) regardless of the response to the following question.

You mentioned other players. Do you have any suggestions for good (free) players that can take proper HD snapshots? Preferably one that can display frame numbers and exclude black bars from the snapshots.

In DGsplit, you need to tick the option "Stop after x chunk(s) written". Set it to 1 chunk.




You can try MPC-HC and MPV. I don't know if they can show the frame number.
But the black bars are part of your video, it has been encoded like that. And the image has an usual aspect ratio (~1.42). There is not much you can do but to use the VLC crop video filter when playing back: menu Tools -> Effects and Filters -> Video Effects -> Crop

In DGsplit, you need to tick the option "Stop after x chunk(s) written". Set it to 1 chunk.




You can try MPC-HC and MPV. I don't know if they can show the frame number.
But the black bars are part of your video, it has been encoded like that. And the image has an usual aspect ratio (~1.42). There is not much you can do but to use the VLC crop video filter when playing back: menu Tools -> Effects and Filters -> Video Effects -> Crop

Thanks. Here's the 300MB sample. Please let me know if it helped or not. https://www.dropbox.com/s/k7m05ydeixuo3 ... 0.mkv?dl=0

I'll check out those players.

I'll work on the ticket. I didn't think signing up was such a process.

In DGsplit, you need to tick the option "Stop after x chunk(s) written". Set it to 1 chunk.

You can try MPC-HC and MPV. I don't know if they can show the frame number.
But the black bars are part of your video, it has been encoded like that. And the image has an usual aspect ratio (~1.42). There is not much you can do but to use the VLC crop video filter when playing back: menu Tools -> Effects and Filters -> Video Effects -> Crop

New development. I tried MPC-HC, and the colours are washed out for the video itself, not just the screenshots.

With MPC-HC you should use madVR renderer:
http://www.madvr.com