Peripheral I/O solutions

[Layton Hebert]

Professional film exhibition runs on DCP's. That's just the way that it is.

When you push that aside as "not up for debate", then you're immediatelly getting into second-tier solutions and stuff that might work (maybe, sometimes, depending) and anything beyond a simple picture on the screen and audio coming from the speakers is likely going to be next to impossible to accomplish.

Thanks for this response Frank! We definitely don't take it personally, and are very grateful for your opinion. I agree with you. Trust me, all the projectionists have pushed for more DCP standardization from the print-traffic/curatorial departments. Unfortunately, it's just not possible. We often exhibit films from amateur filmmakers, filmmakers' early work, student films, avant-garde shorts, and works-in-progress that we just don't have time to turn into DCP (putting aside the aesthetic and scientific variable-changing implications for a moment). It's ironic that our audiences expect professional exhibition of amateur work, but that's the institution's policy. Tough but fair. So when I say it's not up for debate, I really mean that DCP is not the precise subject of debate here. We are only interested in NON-DCP solutions.
However, your point is valid, and very much appreciated.
Thanks for weighing in and I hope to hear more!
Best regards,
Layton

[Scott Norwood]

I get the arguments above, but I don't buy "budget" as a reason not to require DCPs. They can be made for free by anyone with a home computer. This would be (by far) the cheapest part of any post-production process. There is really no excuse here. If all else fails, pay the 12-year-old down the street $10 to do it. Anyone who makes a movie should be able to afford that, and should be willing to do so in order to ensure proper exhibition at various venues.

In any case, if you are committed to Pro Res, I'll throw mplayer into consideration as playback software. Like ffmpeg, it is a command-line tool, but is somewhat friendlier. It seems to be particularly unpopular in the exhibition industry, but it's free to try and works well. I have had good luck with it. VLC would be another option. I'm personally averse to playing back movies from a computer (mostly because of the risk that the audience might be made aware of that if the computer or software crashes during playback), but I realize that it sometimes needs to happen.

One question about Pro Res: how do you plan to deal with different sound formats? The files typically are two-track Lt/Rt, but can be mono or multi-track as well. The only way that I know to properly exhibit a multi-channel Pro Res file is to output it to an SDI device, then dis-embed the sound from the SDI stream. Maybe there are other options. Thoughts?

[Carl Martin]

hi layton!

i only wish the pfa was so precious about all the film-originated work they show! most of that is dcp these days.

I don't buy "budget" as a reason not to require DCPs. They can be made for free by anyone with a home computer.

maybe so, but the results are often garbage! all too often the framerate is wrong, it's unnecessarily windowboxed, etc, etc. and of course poorly named and labeled.

The only way that I know to properly exhibit a multi-channel Pro Res file is to output it to an SDI device, then dis-embed the sound from the SDI stream. Maybe there are other options. Thoughts?

is an oppo an sdi device? i plug the hdmi from the mac into the oppo, which has analog 6-channel outputs to a dma8plus. in the tiny house the mac hdmi out goes directly into the christie projector, so up to 6 channels is all good. if it's lt/rt then the cp650 can slap some pro logic on there.

now, we mostly use vlc for playback (sometimes it trips up if the bitrate is too high and we have to use quicktime; conversely sometimes it will play what quicktime can't) and it seems to ignore how the channels are labeled so that has to be dealt with. vlc can remap the audio channels but i can't for the life of me figure out how to interpret the mapping interface so i just try different things until it works. vlc has to restart for the remapping to take so if you have more than one multichannel file in the same playlist and their channels aren't labeled the same then you are screwed. pain in the ass, it is. (in the plus column you can add subtitles, crop out letterboxing, and sometimes fix color and sync issues, but if you have a playlist the whole playlist is affected, not just the file. also you can rearrange the playlist live.)

[Carsten Kurz]

VLC can do everything, but it is a nightmare to configure properly, and a moving target.

- Carsten

[Carl Martin]

succinctly put!

also following this thread to see what we can do better (for little to no money). thanks for starting it, layton.

[Marcel Birgelen]

I get the arguments above, but I don't buy "budget" as a reason not to require DCPs. They can be made for free by anyone with a home computer. This would be (by far) the cheapest part of any post-production process. There is really no excuse here. If all else fails, pay the 12-year-old down the street $10 to do it. Anyone who makes a movie should be able to afford that, and should be willing to do so in order to ensure proper exhibition at various venues.

In any case, if you are committed to Pro Res, I'll throw mplayer into consideration as playback software. Like ffmpeg, it is a command-line tool, but is somewhat friendlier. It seems to be particularly unpopular in the exhibition industry, but it's free to try and works well. I have had good luck with it. VLC would be another option. I'm personally averse to playing back movies from a computer (mostly because of the risk that the audience might be made aware of that if the computer or software crashes during playback), but I realize that it sometimes needs to happen.

One question about Pro Res: how do you plan to deal with different sound formats? The files typically are two-track Lt/Rt, but can be mono or multi-track as well. The only way that I know to properly exhibit a multi-channel Pro Res file is to output it to an SDI device, then dis-embed the sound from the SDI stream. Maybe there are other options. Thoughts?

Explaining all the intricacies of ffmpeg is really not something that can be done in a single post. The thing really is a massive tool, even the basic manual file is half a book worth of information, then there are the many modules you can use. In order to integrate ffmpeg into your project, I think you really need to read up and have a clear idea in mind what you want to do with it. If it's getting ProRes content to output on an SDI device, I think ffmpeg itself is not the thing you're looking for, but rather "mplayer".

Mplayer is essentially the "player frontend" for ffmpeg. The general rule of thumb is: if ffmpeg supports the file format, mplayer does so too. I'm sure you can play ProRes 422 with mplayer, because I've done so in the past (not for a screening though, just to preview the files), but ffmpeg needs to be compiled with the correct options. FFmpeg itself isn't really a playback-solution, it's a "swiss army knife" for recording, streaming and transcoding audio and video, so you'd probably be using mplayer to do the actual playback. You can use ffmpeg "directly" to do playback, but you'd need to tightly integrate it into something that lets you control it. Mplayer, at the very least, gives you keystroke inputs to control simple trick-play, to stop playback, etc. Although there are some GUI wrappers for mplayer, those generally defy the purpose of what you're trying to achieve: having playback controls independent from your output, so unless you build your own wrapper around it, you're stuck with command-line interfaces.

There is another player, called "mpv", based on mplayer, that's a little-bit more user-friendly, focuses more on high-quality playback and offers some very amazing filter options, but drops some lesser used functionality found in mplayer. We use "mpv" on Debian Linux using both an extra video card and two BlackMagic Design interfaces for alternative content playback with our own set of scripts in our screening room. Since it runs on a normal PC, we can send ethernet and serial commands to the automation this way. We've chosen "mpv" because it plays almost all consumer and semi-pro formats you can throw at it, it offers some very impressive filters to do some real-time corrections for content that needs it and it can easily split audio from the files into a separate HDMI output. It also supports using hardware acceleration on the video-card, while still running the output through the BlackMagicDesign HD-SDI card or 4K HDMI card we have installed. Alternatively, we also have a separate video card in there running a "silent" X-Server, which can also be used as an output for the stuff that doesn't support the BlackMagicDesign devices. We've done quite some quirky stuff with it, like mapping HDR10 content both to REC702 and DCI-P3 color space. It consumes a lot of my time though, since it doesn't come in a pre-fab playback container and it's all based on a bunch of more or less convoluted scripts of which I'm the only one who exactly knows what they do.

We never screen ProRes this way though and I'm not sure if mpv supports ProRes, the few times we've done so, we've done this using a Mac and QuickTime...

[Jesse Crooks]

I really don't buy the arguments against converting to DCP. The formats you're struggling to reproduce in accordance with the filmmaker's original intent were created for consumer-grade playback. When you do the side-by-side QC screenings, do you ever actually observe problems? If so, do they really compromise the content in a way that would be observable by the viewers? You might take the money you would otherwise spend on the hardware and instead pay someone to do the DCP conversion in-house.

[Ian Freer]

Q-Lab might be something to look at? https://qlab.app/
I worked a Festival several years ago where we used for it to run a non-DCP shorts program. We didn't use anywhere near the full potential of it (it's a pretty full featured show-control software, so it can automate have some level of automation programmed into it I think. We only used it for basic playback, but it worked well. Other than that I don't have any experience with it to be of any use, but there are some tutorials on their website.

[Marcel Birgelen]

I really don't buy the arguments against converting to DCP. The formats you're struggling to reproduce in accordance with the filmmaker's original intent were created for consumer-grade playback. When you do the side-by-side QC screenings, do you ever actually observe problems? If so, do they really compromise the content in a way that would be observable by the viewers? You might take the money you would otherwise spend on the hardware and instead pay someone to do the DCP conversion in-house.

Maybe you're going to buy them when you face the reality of he real world, where you may want to dictate how it works, but people keep ignoring you anyway. Meanwhile, those same people end up paying a substantial parts of your bills.

ProRes was never intended as a consumer-grade playback format, it's an intermediate format invented by Apple and introduced with FinalCut 2, it's being used by many editors as a result. I wouldn't call it consumer-grade by any means. In broadcast, ProRes is actually often considered to be a final delivery format.

Furthermore, while we generally expect stuff to be delivered in DCP format, in reality, you simply can't rely on that. The DCP format is too much of an outlier for all kinds of independents, as people often have zero to no knowledge about it. And for stuff that arrives last-minute, it's just impossible to convert and QC on-the-fly.

Many independently produced DCPs we've tried to screen ended up being defective, so we had to fall-back on that USB stick with that MP4 or MOV file on it... Many times, you can give people instructions to deliver a DCP and they deliver whatever format they want anyway, or as indicated, the DCP ends up being unplayable. Also, keep in mind: If they're not going to pay for DCP conversion, I don't really feel like to do the work for them.

[Alan Butterfield]

Layton,

I've been doing exactly what you are talking about for the last decade (at least) for the Australian Film, Television and Radio School (AFTRS) and as a freelancer for various film festivals (incl Sydney FF and Flickerfest). Customers include students, short filmmakers and productions who want to screen works in progress. Our system has evolved after all sorts of hiccups so I thought the following might help

Firstly you and your curators are correct to not want to convert everything to DCP as its unnecessary, takes a reasonable amount of time and can potentially introduce artefacts ("Is that **** in the original?" I hear them say).

In both situations we use surprisingly old Macs running Adobe Premiere Pro with Aja output cards playing (for the most part) movies encoded in one of the Apple ProRes codecs. Yes I know editing software sounds like overkill but the reasoning runs like this -

We want to display the movie as its ORIGINAL frames, not as some interpolated version of them.

One of the supreme advantages of the DCP format is that it is, like film, a frame-based display with each frame having a defined duration on the screen - sort of like a very fast slide projector. Many computer-based display systems might show the original frames this way but its not common. In the US much of your content will be either at 24fps or 29.97fps. Most computer connect to the screen at 60Hz so straight up you've got an issue. With editing software we can set the timeline to that of the movie and the Aja card and projector follow. For this reason I reject Quicktime, Playback Pro, VLC etc. They connect to the projector via an extended desktop scenario which while adequate fails to meet this requirement.

Editing software however can make use of video output cards like Aja or Blackmagic to display your movie exactly as created. But why Premiere Pro?

Editors will normally set their software up to deliver the output at some previously specified spec (frame rate, resolution, colour space extra). Premiere is no different but UNLIKE any other software I've found only Premiere allow us the vary the frame rate WITHIN the project by setting multiple timelines to different sequence settings. Can't see what an editor would use this for but in a festival/short film situation its a godsend. When confronted by a bunch of titles at different frame rates I can set multiple timelines for each frame rate required and switch between them as required. Sequence settings are also used to match the output to the movie's resolution, colour space and soundtrack format.

We want to display movies with all sorts of colour spaces, resolutions and soundtrack formats. The playout solution has to be flexible and yet obey the important rules for these variables.

Premiere is ready to import movies from any source imaginable. Some "fool" invents H265 and Premiere is ready for it. Even (un-encrypted) DCPs can be imported into Premiere and will display with the correct colour and gamma. ProRes, H264 and MKV are easily imported.

Soundtracks can be stereo, two mono tracks, a single 5.1 track or up to eight mono tracks to achieve discreet 5.1 or even 7.1. Output resolution can be any standard understood by the Aja card.

Premiere is very common. So there are lots of bright young things ready to teach this old dog some new tricks. Its very flexible so you can make your show as you wish (cross-fades to a logo, a bit of black between each work, pre-adjust the audio volume etc)

At AFTRS we use 2008! Mac Pros with a large RAID, lots of memory and a KONA 4 I/O card. For my own (mobile) work I use a 2015 Macbook Pro with a AJA Io XT unit connected by Thunderbolt 1 with a RAID 0 SSD for carrying the content. Anything you buy today will far exceed the spec of either of these so I don't think you really need to wait for the forthcoming Mac Pro. Several older limitations on Macbook Pros are now gone as they now have good GPUs and enough fast SSD storage to hold several programmes of material.

I used the Aja product because -

Aja products have a good control panel interface that I can park in the corner of my screen and be sure that its doing what I want it to do. Blackmagic make their control interface (such as it is) a System Preference which makes it hard to access.

It has both embedded audio (into the HDMI or HD-SDI video) as well as an eight channel balanced audio output which gives me options for different setups such as working in another cinema with minimal "adjustment" to their wiring.

It enacts playback buffering offered by Premiere in their Mercury replay engine to help with slow systems that can cause image stuttering. BM doesn't seem to know that this improvement by Adobe happened.

It "seems" to act as a co-processor if you've made use of Premiere's facility to "Scale to output resolution". This is used if some young bright thing delivers a movie at an odd resolution such as 2048x1080 - we try to keep the output at 1920x1080.

I always try to connect via HD-SDI as HDMI can be flaky with its copy protection facility but if you want to perhaps work at resolutions above 2K you'll be forced towards HDMI.

Of course all of this assumes that you actually have projectionists in the bio box to operate the system. Automation is not really an option.

If you want more detail I'm happy to help.

Alan Butterfield (really old projectionist)

[Carsten Kurz]

There is certainly a lack in computer playback software to adjust screen refresh rates to content. I know one windows player, MPC-HC, that has interface options to allow to switch output frame rates with every piece of content (as far as the graphics card allows). That said, not every display/projector deals with spontaneous refresh rate changes nicely. Macs are able to adjust frame rates to common types if the display allows it, but I don't know any OS X player software that is able to automate the process from within a running playlist.

I guess everyone has to decide based on his actual working scheme how he deals with it. I know a couple of smaller festivals that use Playback Pro, often they do not use DCI gear, or, may have one DCI venue, and the others using notebooks, media players, etc.

Admittedly, an application like VLC is the only one being capable of playing 99.9% of all incoming codecs and codec varieties, of which there are very many. Not every MP4 or Prores is the same.

Sometimes it is advisable to conform everything to DCP. I know one festival doing it, and they use laptops with NeoDCP in those venues which do not support 'proper' DCI. But they spent a lot of time doing the conversions, and often they struggle with non-compliant frame rates.

Sometimes you simply want to play everything in exactly the format you receive it. Very often now, you get smartphone videos, edited on the smartphone/tablet with variable frame rates. This certainly is not cinema, but I think it would be wrong to enforce pro formats and complications on people who never intended to play a 'proper' cinema with their work. I you strictly enforce DCP for each and every festival, you lose many interesting submissions.

Maybe at some point, VLC will receive an option to support decklink cards for output?


Video formats remain a moving target, and with all implication mentioned, it is not possible to solve the problem with suitable hard- and software only. Knowledge is the third necessary component.

[Carl Martin]

alan,

this is very interesting! i attribute what grey hairs i have to trying to deal with videos of different framerates. when, say, student shorts are compiled into one file and delivered to us that way, they all get converted to a single framerate, and the ones that are not natively that framerate of course look stuttery. so i always ask for (don't always get) an individual file for each short. they always look better if the file is at the native framerate. it has been my assumption that the mac (no special output card that i'm aware of) will actually output the correct framerate if the output device supports it. it doesn't always look perfect, but it's better than the framerate-converted file, and i figured whatever remaining glitchiness was simply baked into the short.

that said, i had wondered why, in our tiny house where the mac plugs directly into the server hdmi input, the server always shows playback speed as 60hz, regardless of whatever framerate quicktime claims. (and quicktime will sometimes claim some bizarre framerates!)

whatever live framerate conversion the mac is performing during playback is so much better than what results when a file is converted to a new file with a different framerate, presumably because stuttering is less glaring at a higher rate. but i'm mad that it does this.

i doubt we'd be able to afford this aja card though, and with editing software to boot!

[Jesse Crooks]

Marcel, I was not suggesting that they request the content to be delivered as a DCP. We always convert them ourselves to ensure it's done correctly, even for film festivals rentals that are not part of our programming. With regard to ProRes, there have been a number of good suggestions and I can see supporting that in addition to DCP. It's the desire to support any number of other formats that I think is probably more trouble than it's worth.

[Marcel Birgelen]

Marcel, I was not suggesting that they request the content to be delivered as a DCP. We always convert them ourselves to ensure it's done correctly, even for film festivals rentals that are not part of our programming. With regard to ProRes, there have been a number of good suggestions and I can see supporting that in addition to DCP. It's the desire to support any number of other formats that I think is probably more trouble than it's worth.

The point I'm trying to make is: We actually request content to be delivered as DCP, but in practice, this often goes wrong, because people don't really understand the DCP format and all besides a handful of production studios do actually have the resources to do a QC on a DCP. So, if you get an independently created DCP, chances are, there's something wrong with it, which you usually only discover when it's practically too late.

Also, depending on what business you're in, you may need to adjust to the realities of that field. If you're running a screening room that runs a lot of dailies or broadcast content, you may see a lot of non-DCP formats and ProRes is one of them. ProRes has become, over the years, somewhat of a defacto deliverable for broadcasting. If we screen in-production content, we seldomly use automation, but we have a dedicated PC running Avid Media Composer and Adobe Premiere and an old Mac tower running FinalCut Pro, so we can screen content right from there. In some cases, you even see people making edits on-the-fly...

[Scott Norwood]

I'm a bit out of touch with this. I've done screenings for film crews on film, DVD, and videotape, but it has been half a decade or more since I have done any of this stuff. Pro Res is a thing now for dailies screenings? How does that work? You get a bunch of files and someone says "play this"? Do the files have sound? Do you need a full Avid system to properly play them? I've fumbled around a bit with Avid's software, but never in the context of file playback. I can imagine that DCPs wouldn't be used for this purpose, but hadn't really thought about what would be,