An article of mine from 2014 weighing the merits of shooting at 24 vs. 25 frames per second has recently been getting a lot of hits. I’m surprised that there’s still so much uncertainty around this issue, because for me it’s pretty clear-cut these days.
When I started out making films at the turn of the millennium, 25fps (or its interlaced variant, 50i) was the only option for video. The tapes ran at that speed and that was that. Cathode ray tube TVs were similarly inflexible, as was PAL DVD when it emerged.
Film could be shot at 24fps, and generally was for theatrical movies, since most cinema projectors only run at that speed, but film for television was shot at 25fps.
Three big technological shifts occurred in the late noughties: the delivery of video over the internet, flat-screen TVs and tapeless cameras. All of these support multiple frame rates, so gradually we found that we had a choice. At the start of a shoot, as a DP I would have to ask which frame rate to set.
Americans and others in NTSC regions are in a different situation. Their TV standard of 30fps has a discernibly different look to the international movie standard of 24fps, so the choice of frame rate is as much creative as it is technical. I don’t think anyone can tell the difference between 24 and 25fps, even on a subconscious level, so in Europe it seems we must decide on a purely technical basis.
But in fact, the decision is as much about what people are used to as anything else. I shot a feature film pilot once on 35mm at 25fps and it really freaked out the lab simply because they weren’t used to it.
And what people seem to be most used to and comfortable with in the UK today is 24fps. It offers the most compatibility with digital cinemas and Blu-ray without needing frame rate conversion. (Some cinemas can play 25fps DCPs, and Blu-rays support 25fps in a 50i wrapper which might not play in a lot of US machines, but 24 is always a safer bet for these formats.)
Historically, flickering of non-incandescent light sources and any TV screens in shot was a problem when shooting 24fps in the UK. These days it’s very easy to set your shutter to 172.8° (if your camera measures it as an angle) or 1/50th (if your camera measures it as an interval). This ensures that every frame – even though there are 24 of them per second – captures 1/50th of a second, in sync with the 50Hz mains supply.
The Times when 25fps is best
There are some situations in which 25fps is still the best or only option though, most notably when you’re shooting something intended primarily for broadcast on a traditional TV channel in the UK or Europe. The same goes if your primary distribution is on PAL DVD, which I know is still the case for certain types of corporate and educational videos.
Once I was puzzled by a director’s monitor not working on a short film shoot, and discovered that it didn’t support 24fps signals, so I had to choose 25 as my frame rate for that film. So it might be worth checking your monitors if you haven’t shot 24fps with them before.
Finally, if your film contains a lot of archive material or stock footage at 25fps, it makes sense to match that frame rate.
Whichever frame rate you ultimately choose, always discuss it with your postproduction team ahead of time to make sure that you’re all on the same page.
Today I thought I’d share the process I figured out for creating looping menus in Encore for DVD and Blu-ray. If, like me, you want to do it all from scratch rather than using any of the built-in templates, the process isn’t particularly intuitive, and was sufficiently different from DVD Studio Pro (the software I’m used to) to leave me scratching my head from time to time, but here’s how I did it in the end. I’ll use Stop/Eject‘s main menu as the example. I’m going to assume you already know the basics of Encore and can find your way around Photoshop.
First of all you have to understand how DVDs and Blu-rays (henceforth collectively referred to simply as “discs”) work. They’re not like websites or Flash movies where you can do anything you want; the specifications are quite narrow. A motion menu consists of two elements:
The background, which is a video (typically with audio) that you can create in Final Cut Pro, Premiere, or whatever.
The button highlights, which show the user which button is currently selected. The user will only ever see one of these at a time.
Hang on – background, button hightlights…. but what about the buttons themselves? These have to be part of the background. Yes, you can import your background movie as a Quicktime into Encore and then add buttons to it within Encore, but when you come to build your disc the software will render those buttons into the background movie. All the disc player can deal with is a background movie and the highlights.
I prefer to build my buttons into the background movie in my editing software (Final Cut) rather than add them in Encore, and that’s the approach I’ll outline here.
Another crucial point to understand is that each button highlight can only be one colour. So look at the Stop/Eject main menu below. The button highlights are the white rings. They could not be red-and-white striped rings, like life preservers; they can only be one solid colour.
So, now you appreciate all of the above you can get started on your menu. The first step for me was shooting and editing the background movie, although for most people this will be a computer-generated graphic rather than something shot with a camera. It’s important to think about where your loop point is going to be so that the menu will loop smoothly.
The following video shows my edited background movie. The buttons were created in Photoshop and added to the movie in Final Cut, before exporting as a ProRes Quicktime (with these buttons now baked in) ready to be imported into Encore.
In Encore I can now create a new menu and use the pick-whip in the properties panel to select my Quicktime file as the source for both the video and the audio. I can also set the loop point in the same panel.
I need to make sure that the loop point is at a place in the video where the audio track is silent or at least is playing a constant background noise – e.g. an air conditioning hum – that will not jump unpleasantly when the menu loops. You’ll notice that my menu’s audio track has a beat or two of silence around the loop point. If you’re using music, don’t start it immediately at the loop point as many players take a fraction of a second to kick in the audio after they loop.
I also need to ensure that all of the buttons have appeared before the loop point. This is because the loop point is the place at which the player will start displaying the button highlight. If your menu loops back to a point before the buttons have appeared, the user will momentarily see the highlight without the corresponding button.
To create the button highlights, right-click (or ctrl-click if you’re using a single button mouse) on the menu and choose “edit menu in Photoshop” from the contextual menu. Photoshop will open with a still of your menu as it appears at the loop point. Annoyingly, this still will be in standard definition even if you’re creating a Blu-ray disc, so the first thing you’ll need to do in Photoshop is to change the pixel aspect ratio to square and re-size the image to 1920×1080.
For each button, create a new group in the layers palette and give it a name that starts with (+). When you go back to Encore it will recognise this folder as pertaining to a button. Within the group, make a new layer and call it (=1)highlight. Draw your button highlight on this layer, remembering that it can only be one colour.
Now we need to pause a moment and consider hit areas. When your disc is played in a computer, the user can select buttons with the mouse. The hit area determines what part of the screen the user must hover the mouse pointer over for the button to be considered selected. This area MUST be rectangular. For each button, Encore will look at all the layers within the relevant group and draw the smallest possible rectangle that will completely enclose all those layers; that will be your button’s hit area.
In my case, right now the only layers in my groups are the white rings which are the button highlights themselves. But what if someone hovers the mouse over the words “special features”? I want the button to be selected then too, so in the (+)special features group I’ll create a second layer (critically, it must be below the highlight layer) and draw a rectangle where I want my hit area to be. I can then click the eye icon next to this in the layer palette so it becomes invisible and doesn’t ruin the look of my menu.
Another restriction of the DVD/Blu-ray specs is that button hit areas can’t overlap. Given the restriction I mentioned earlier, that they must be rectangular, you can see from the layout of my menu that it isn’t possible for the hit areas of Play Movie and Scene Selection to include the text for those buttons without overlapping each other. I choose not to compromise the design of the menu and trust that users will soon find the hit area with a quick sweep of the mouse over the whole image.
I save the image in Photoshop and return to Encore. I can now see the button hit areas outlined on the menu. If I click the icon for “show selected subpicture highlights” (see below image) I can see the highlights too. It’s now simply a case of setting the target for each button using the pick-whip in the properties panel.
When users return to the main menu, after they’ve visited the special features menu, for example, I don’t want them to have to sit through the intro part of the menu again; I want them to go straight to the loop point. So I’ll go to the main menu button in the special features menu and set the target – not using the pick-whip, but through the pull-down menu. I’ll select “specifiy link” and in the dialogue box which appears I make sure to tick the “set to loop point” checkbox.
One final point. The version of Encore I used (CS5.1) has a bug whereby any motion menu longer than 70 seconds will not loop smoothly; a second or so of black will appear each time the player gets to the end of the loop. This issue does not occur in Encore’s preview, only when you’ve burnt the disc. There’s no workaround that I can find other than shortening the menu.
I hope this has been some help to those of you out there who are still burning your films onto physical discs. Let me know if you’d like to hear more about any part of the disc authoring process.