DCP playback with VLC?

[Frank Cox]

So now that I have these new zippy computers I decided to see if I could play some DCP policy trailers. I tried this with my old computers a while back and everything ran so slowly it was a slideshow.

Now I can play the sound and it's fine, and I can play the video and it's also fine. But I can't play both at the same time. Am I missing something or trying to load the DCP the wrong way? Or does this just not work this way?

[John Thomas]

VLC will unpack mxf files which are just containers, and play the contents of them (i.e. just the picture mxf or just the audio mxf). In order for VLC to play a DCP "properly" it would need to read the CPL (Content Play List), which instructs a DCP player on which mxf files to play and when. As far as I know VLC does not do that.

The DCP-O-Matic player is far, far better suited for testing unencrypted DCPs locally. A great feature would be a Windows context menu item that would allow you to right click on a directory in explorer and choose "Play with DCP-O-Matic Player"

[Randy Stankey]

What kind of video card do you have in the computer? Some video cards might not have the horsepower to handle full resolution video. The stock video cards in some computers don't.

Check your video card to be sure it's up to speed. Also check the configuration to be sure it's being used correctly. Third, check VLC to be sure that it is configured to use said video card.

When I bought my current computer, I opted out of the stock video card in favor of one more suited to my video playback and editing needs. The computer is over 15 years old and still chugging along, nicely.

[Carsten Kurz]

VLC uses no optimizations for the J2K decoding, that's why it's slow. DCP-o-matic player is a lot better, also as it actually plays back CPLs, not just MXF files. That means, it will play VF/OV combos, subtitles, etc., audio channels are configurable, etc.

There are some hints on VLC forums that VLC is able to play DCPs by CPL, but only when starting it up through CLI and point it to the DCP path. As DCP-o-matic player works much better, I never bothered. Sometimes I use VLC to open a DCP MXF video file through the GUI just to extract a full-res image snap shot for some reference purpose (latest versions of DCP-o-matic player will do that as well).

I don't know if you ever installed DCP-o-matic on your previous computers, but for a cinema operator, I'd say it's a must to have that suite of applications at hand.


https://dcpomatic.com/download

If you have trouble building it for your Rocky 9, Carl will most certainly help you out, I suggest the DCP-o-matic forum for getting support.

[Hamzah Batha]

Another shoutout to DCP-O-Matic Player. Great bit of software!

[Leo Enticknap]

Some video cards might not have the horsepower to handle full resolution video. The stock video cards in some computers don't.

Most will handle that resolution (though for a typical monitor the DCI containers would have to be scaled and letterboxed, e.g. from 2048x858 to 1920x858 in the case of 2K scope, which adds to the GPU's workload), but will struggle to convert the DCI color space to the required video output, and especially with the bandwidth. For consumer video that ranges from, say, 1-3 MBPS for a typical YouTube video, up to 20-30 for a BD. A typical studio DCP is between 150 and 250. That is really why you need a badass graphics card of the sort used by game geeks to play DCPs on a PC without glitches and stutters.

[Frank Cox]

There's just a standard on-board Intel video whatever-it-is here.

But I don't think that's the issue or at least not the primary issue.

I tried playing a couple of my "Turn off your cell phone and shut up" trailers since they're right here on my computer. The video plays fine when I select that mxf. (Looks good too.) The audio plays fine when I select that xmf.

I just don't know how to select and play both at the same time with VLC or if it can do that.

I looked at dcp-o-matic once back when Carl first started it but I kind of got lost in the weeds and never really did anything with it. Maybe it's time to take another look at.

[Leo Enticknap]

Maybe try file > open media > show more options > play another media synchronously?

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[Carl Hetherington]

I would hope that your computer can play 2K DCPs back pretty well with DCP-o-matic - the tricky part is decoding the JPEG2000 quickly enough, and at the moment that's all done on the CPU, so your graphics card shouldn't really matter.

Maybe the Centos 9 packages will work on Rocky? If not, let me know - I should be able to add Rocky Linux RPMs to the download page without too much difficulty.

[Ryan Gallagher]

Only way to know is to try. (DCPomatic player that is). Though I've never tried to use it into ALT inputs to play back on screen... I've only ever used it for file manipulation and DCP inspection.

If you are not concerned about quality sacrifices and these DCPs in question are non-encrypted. DCP-o-matic can also EXPORT a project audio/video to an MP4 file. You can add existing DCPs to a project, then just export them to remux everything back into a more PC/ALT friendly MP4.

I've even used it as a crude editor in a pinch to manipulate existing video files and trim them, or add fade-ins/outs.

Definitely a tool worth getting familiar with. They are very helpful and responsive to bugs/issues over on the DCP-o-matic forums too.

[Frank Cox]

Maybe try file > open media > show more options > play another media synchronously?

Well, howzabout dat! Someone give that man a cigar!

Great picture, good sound that's in sync with the picture. Very watchable.

I wasn't trying to edit or change anything (yet). I just wanted to see if I could play a DCP using VLC on this computer.

And now we know.

VLC will play a dcp and do it well and properly if there's enough horsepower available.

Now I guess I'll have to start looking at dcp-o-matic again. I think my computers were too underpowered before to really be able to use it "right" so when I looked at it before I just viewed a few menus and never really got back to doing anything with it.

[Randy Stankey]

...the tricky part is decoding the JPEG2000 quickly enough, and at the moment that's all done on the CPU, so your graphics card shouldn't really matter. ...

That's what I was thinking about and that's why I suggested looking at the video card. I did not understand that all the graphics processing was done in the CPU, not the graphics card.

When I was talking about getting a different graphics card for my computer, I got one that supports CUDA parallel processing. When I suggested checking configurations, I was talking about making sure that your operating system was set up to use CUDA. (I understand that CUDA is primarily an NVIDIA product and that AMD or other companies might have their own parallel processing architectures that do the same/similar thing but under a different name.)

I use Blender to do 3-D rendering. Blender can use CUDA to speed up rendering but you have to have your video card configured in your system to use it. Then, Blender has to be configured to access your video card's CUDA features. It's actually pretty simple to do. All you need to do is make a couple of selections in the preferences/setup menus. Still, it needs to be done or else CUDA won't work. If you are doing a complex render, it can slow your computer to a crawl. If that happens when you're not expecting it, you might spend some time scratching your head before you figure out what the solution is.

Other applications like Photoshop and Final Cut can also use your graphics card to speed up their work, as well. Both of those applications need to be told that you have a capable graphics card available to use, too.

If VLC and DCP-O-Matic don't use the graphics card like that or, if for some other reason, you don't have or can't use parallel processing capabilities in your graphics card, none of this counts. Does it?

[Ryan Gallagher]

Well, howzabout dat! Someone give that man a cigar!

Great picture, good sound that's in sync with the picture. Very watchable.

I wasn't trying to edit or change anything (yet). I just wanted to see if I could play a DCP using VLC on this computer.

And now we know.

VLC will play a dcp and do it well and properly if there's enough horsepower available.

Now I guess I'll have to start looking at dcp-o-matic again. I think my computers were too underpowered before to really be able to use it "right" so when I looked at it before I just viewed a few menus and never really got back to doing anything with it.

Neato discovery using VLC.

Most computers are pretty "underpowered" relative to doing anything with content longer than 5min (especially in 4K) in dcp-o-matic other than just trying to use the player. Dcp-o-matic transcodes projects with CPU but supports multi-thread. There is a beta that renders using GPU but have not tried it yet.

If you do a lot of DCP generation, especially feature length or 4K, the more cores the better. (think of beasts like AMD's ThreadRipper, or other high-core count server CPUs). If you can get DCP generation down to anywhere close to 1:1 real-time you are doing pretty good hardware wise. I have an older mac-pro tower dual Xenon 12 core running windows that still does a respectable job with 2K dcps... not quite 1:1 realtime but close. It certainly still beats modern lesser-core laptops and non-workstations PCs.

Note it can also job out DCP creation to multiple workstations/servers in a render farm context.

[Randy Stankey]

... There is a beta that renders using GPU but have not tried it yet. ...

... I have an older mac-pro tower dual Xenon 12 core running windows that still does a respectable job with 2K dcps... not quite 1:1 realtime but close. ...

... Note it can also job out DCP creation to multiple workstations/servers in a render farm context.

Things are making more sense, now.

My computer is a 2008 Mac Pro with 8 cores. Even at sixteen, going on seventeen years old, it still does everything I need it to do at respectable speed. The Compressor app that comes with Final Cut can farm out to multiple computers, too, but I haven't used it in a long time. Working at Mercyhurst, we had three different computers, all outfitted with FCP/Compressor that could work together. It worked well but I no longer have access to multiple machines and I don't have much call for that kind of work, anymore, either. I am planning to get a new computer, probably a Mac Studio, but that's going to have to wait until my budget improves. Until then, the computer I have will suffice for what I need it to do.

I just assumed that, since all the apps that I do video and graphics with can use GPU processing, most computers, today, are at least capable of it if not already configured for it.

Since my computer is fifteen-plus years old, I figured that technology would have progressed to the point where GPU processing would be a no-brainer.

[Ryan Gallagher]

My computer is a 2008 Mac Pro with 8 cores.

Yeah 8 core 16 thread is fairly respectable still for some CPU tasks, even at lower frequencies. Where we pay the penalty with these older machines is in power consumption/efficiency.

Mine is a 2012 dual 6core = 24 thread. The best/last of that generation. I even modded it to fit a very long workstation dual GPU card in it. (also older tech, but hey, works). In dcp-o-matic it outperforms my more modern i7 9700k 8 core 8 thread machine.