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Question

Render settings for CH puppet, 4k chromakeyed video and After Effects animations

Forum|Forum|6 years ago
April 20, 2019
3 replies
1096 views

This is really a cross-CH/AE question, but it pertains to both and there are bound to be other people trying similar things in the near future.

The first render I did took 22 hours, so I'm assuming there are several things I did wrong along the way. Hopefully the answers to these questions will save me and many others a lot of time.

Question 1: We're making ten 15 minute videos (without cuts--basically a "live" single camera shoot from the front). Practically speaking, they're the same as the "Just Dance" video game, except we aren't rotoscoping, we're just chromakeying and putting animated vectors in the background. In the videos there are eight or so 2 minute songs that have different choreography--the puppet, more or less, does the choreography, as well. My thought was that it would be less taxing on the system and easier to deal with the multiple dragger layers if I broke each song up into different scenes. Then I used Dynamic Link to bring them each into AE. Would it help render time if I compiled the CH scenes into one "master scene" so Dynamic Link is only rendering one scene instead of eight?

1a: Or would be faster to render each puppet scene into eight PNG sequences?

1b: Or compile a 15 minute master scene and render that as a single PNG sequence?

Question 2: The 4k video is 23.98fps. Does it matter what frame rate the CH scene is--as far as maximizing render efficiency is concerned?

2a: Are there other considerations to take in when choosing a frame rate for the CH scene as it relates to the final AE or Premiere comp?

Question 3: Probably an AE question, but you guys are way nicer to us noobs than the AE guys and why not have this question answered in the same place? Frame rate didn't even occur to me until I started reading about speeding up render times. Initially when I brought the 4k video into AE, the comp's frame rate said 59.97--I thought it was weird, but I'd never shot in 4k before and assumed that must have been how it was recorded (I read that shooting in 4k 4:2:2 10 bit color would be the easiest to key--it IS significantly easier to key than my old Canon 70D). Then I realized I could change the AE comp's frame rate, so I changed it to 29.97, which is what it was when I rendered it. As you already know from Question 2, I just checked the frame rate in VLC (Quicktime wouldn't even open the file) and it is, in fact, 23.98. So the question is: how important is it to make sure the comp's frame rates match?

My assumption is that when you set a comp's frame rate and it contains videos with different frame rates, the render time would be longer because it has to work harder to conform them all to the comp's frame rate, so...

3a: In terms of rendering speed, should all frame rates match the comp's frame rate? I also used some stock footage--haven't checked yet, but it's likely a different frame rate.

3b: I read in an older AE forum that AE has a harder time with certain file types, such as .MOV. Is that still the case?

3b1: If so, how do you easily remedy that? Bring the video into Quicktime or VLC and render it in another format? Which codec would be best for AE?

All the how-to's say "choose your favorite codec". We just want it to look as good as it can and render as fast as possible--isn't there one or two that fit that bill more than any others? All the choices make me extremely anxious (I'm sure I'm not the only one).

Question 4: Also AE--we're outputting the final product to 1080, so I just reduced the 4k video layer's size to 50%. For rendering efficiency, is there a better way to reduce it's size to 1080--keeping in mind that we shot it in 4K 10 bit so it could be more easily keyed?

Question 5: I have everything CH on the main hard drive (along with the applications), the video and AI files are on an SSD and the AE cache is on yet another SSD. Is that the best configuration? Maybe the CH files also be on the same SSD with the videos and AI files?

Question 6: I have a late 2014 Mac Mini with all the bells and whistles (16GB RAM 16MHz DDR3, 2TB hard drive, 3 GHz Intel Core i7), but is it already too old and slow to handle all that I'm throwing at it?

I know--it's lot of questions in one, but they all relate to speeding up render time, so hopefully your answers will help a lot of folks!

This topic has been closed for replies.

alank99101739

Legend

Nice! Yes, its not fast, but a lot better! Thanks for sharing all your findings here.

jonnymackjacksonAuthor

Known Participant

Thanks Alan for the tips---they helped IMMENSELY!

After hours of research, trial and error, I found answers to most of the rest of my questions and was able to get the render time down to just over 4 hours!!

Answer to Questions 3 and 3a:

The most important lesson I learned is that keeping the frame rates the same for everything is key. This article does a fantastic job of explaining it fairly simply:

Frame Rates are Tricky Beasts | Larry Jordan

Answer to 3b: ???? (see answer to Question 4 below)

Answer to 3b1:

A lot of that is in Larry Jordan's article, but I did change the frame rate of some background videos and it doesn't make a difference, but for sure DO NOT change the frame rate of your primary video source, unless you want it to have an artistic look based on what happened to the video in the change. Alan's right---use the same FPS from shooting to comp settings to the final output settings to keep render time to a minimum and avoid jumpy video.

Answer (sort of) to Question 2:

I'm not sure it made much of a difference to match the CH puppet frame rate (I had it at 30fps and changed to 23.976), but exporting it as an Alpha channel MOV file (Animation preset) had to make rendering much faster.

Answer to Question 1 (and another question):

I also took Alan's advice on keeping the scenes separated, however I did have a problem with some of the scenes not exporting to AE the same length as they were in CH. For instance, the exact time of a song (scene) is 1:51:22, so I'd set the CH duration to that--but when I Dynamic Link it into AE, it might only be 1:51:20. I tried adding a whole second to the CH duration, but it would end up adding a half of second or so. The only way I could get it to be the exact length of the song was to change the export duration in Media Encoder. Anybody know what might be happening here?

Answer to Question 1a:

Compared to rendering PNG sequences, the MOV video rendered much faster and was a smaller file, as well. Definitely only use Dynamic Link for editing in AE--it slows everything down.

1b.---didn't try it, but it only took about 3-4 minutes to encode each 2 minute CH sequence, so making changes to one sequence is a lot faster than waiting for the whole 15 minute to encode again.

Answer to Question 4:

In Media Encoder, I used the ProResHQ preset and changed the pixel ratio to 1920x1080. The 15 minute video encoded in about 45 minutes, so add that to the 4 hours of rendering wait time, but it's still waaay less than 22 hours. I can't be sure that it didn't make keying a little more difficult, but I can only assume that not having a 4k video in the AE comp made my Mac a little happier.

Answer to Question 5:

Not sure what the answer is, but I did put all the CH .MOV Animation files on the same external SSD as all of my other video and AI files. So I had files on my fastest SSD, cache on a slower SSD and the Adobe apps running on my local drive. For the 22 hour render I had all the files on the slower SSD, the cache on an even slower HDD and the CH puppets in Dynamic Link from the local drive--so it's very likely that moving all the files to the fast SSD and eliminating the HDD from the mix also made a difference in speeding up the render time.

Answer to Question 6: I'd say for now, it's good enough for who it's for. By reducing the AE Preview setting to "skip 2 frames" and viewing it at half and screen size at 50%, I could even preview everything fairly well while working (make sure that you match those settings--if you choose 1/4, view at 25%; Full/100%, etc--apparently it makes a difference). And I'm fine with 4-5 hour render time for now.

Bonus tip: In Media Encoder Pref->General->uncheck Preview render. Everyone says it's a render time saver.

alank99101739

Legend

I don’t have answers to all your questions sorry, but a few points in case they help. I am not an AE expert.

I find it faster to export a video file from CH then work in AE using that file. Dynamic link brings across edits better, but if speed is a major issue try exporting a video file instead.

i export MOV files rather than PNG sequences. I think it stresses the file system less.

You can export movie files with an alpha channel.

If you render at 4k then downscale, that will take longer to render. 50% will be 4 times faster I suspect.

Using multiple scenes can make it more efficient because you just rerender one scene at a time. That is my default way of working

The FPS definitely affects render time. Use the same as final video for smoothest result

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