Blackmagic Forum

Hi all.

I'm a pretty new user. I've done a couple short videos on my late 2017 MacBook Pro (10.15.2) with its Radeon Pro 560 (4 GB) card. it was hard to work with, since even at 24 FPS and using non-fancy cell phone video the playback goes all choppy any time there's a lot going on onscreen. And rendering was pretty slow, down to 4 fps at times.

So I got a Radeon Pro W5700 and put it in a Sonnet Breakaway Box 550. I re-rendered some of the old videos and it took half the time it did before, yay! But playback is still unbearably, unusably choppy, boo. Even at half or quarter resolution it stutters and freezes and jumps.

I have not yet upgraded to Studio to try to use both GPUs at once. It's currently using the laptop GPU for GUI only and the EGPU for Metal, whatever that means. I have "Use GPU Scopes" off and GPU processing mode set to auto.

My questions:
1. if I spent the money and upgraded to Studio, would the dual GPUs make playback less choppy?
or
2. did I just flush a thousand bucks down the toilet?

Grateful for any guidance and happy to provide more specifics.

A thousand bucks would have bought you a nice new MB Air M1 and ended your troubles.
That said, are you sure that phone footage is CFR? Many have no constant frame rate, which can cause all kinds of problems, with or without an eGPU.

I have no experience with eGPUs but I'd imagine shuffling data through thunderbolt and the MBP's internal bus to the display GPU would stall playback. Are you getting the green playback light but it's still choppy?

Sent from my Mi 9T using Tapatalk

Optimize footage to ProRes and see if that helps with playback.

eGPU would help you with rendering of effects, color corrections, graphics and image transformations, but it does not speed up image decoding for all codecs, so it might not help you with the phone footage playback at all.

Hm.

@Mario Kalogjera Maybe I got the terminology wrong when I said playback. Once I export the file to MP4 or whatever, it plays back fine. I'm talking about being in the Edit window and trying to work on it. I hit the spacebar to play and it goes all choppy. The light goes red and the number drops down to as low as 11 or 12 fps.

The phone footage is from a variety of places, mostly iPhones but probably some Android. Formats are .mov, .mp4 and m4v. When I dump the clips into the bin, I say yes to the dialog that asks if I want to conform it to the project settings.

@Uli Plank How would I be able to tell whether a given clip is CFR, and is there any way to fix it if it isn't CFR?

@Dejan Špagnut is optimizing to ProRes something I would do while still working on the file, or only at the end when I export?

@PDXHoly:

I understood you well. I also meant playback while editing.

You can download https://mediaarea.net/en/MediaInfo to see if its vfr or cfr and whether therin lies your problem.

@Mario Kalogjera I will do that, thank you very much!

Optimizing media is basically converting the hard to playback files to some easier to playback format, such as Apple ProRes. It is done at the beginning of editing process to avoid playback problems such as yours.

Oh! I'm so green!

Thank you folks. I got MediaInfo and a bunch of the iPhone clips are variable frame rate. I bet that's it.

So that makes me wonder something else: I exported this particular video (Mp4, H.264, 1920x1080 HD, 24, quality restricted to 6300 KB/S to fit his file size requirements) to someone and he streamed it live on YouTube and it played back choppy in some parts. The file played back perfectly on my machine so it may be a YouTube or streaming issue.

If I optimize the individual clips, before working on them, do you think that sort of issue would be lessened? Working on the file was frustrating but I thought once it was exported all the problems went away.

Would exporting the final project using ProRes instead of H.264 be a good idea in general?

I'm off to study that part of the manual. Thank you all so much for your help. I have a friend who's having similar issues, so you're directly making two lives better, and indirectly so many more!

PDXHolly wrote:If I optimize the individual clips, before working on them, do you think that sort of issue would be lessened?

Yes.

PDXHolly wrote:Would exporting the final project using ProRes instead of H.264 be a good idea in general?

YouTube can ingest either and will always recompress it again to h264/h265/whatever they decide. ProRes 422 HQ or 4444 is going to be a larger file size (and longer render / upload) but you do get a better final result if you upload ProRes since it's only compressed once, by YT. ProRes is especially important if you have banding issues (due to subtle color gradients), which cannot withstand multiple h264 recompressions.

Comes down to time, storage space, length of piece, content, and quality standards.

PDXHolly wrote:Oh! I'm so green!

Thank you folks. I got MediaInfo and a bunch of the iPhone clips are variable frame rate. I bet that's it.

So that makes me wonder something else: I exported this particular video (Mp4, H.264, 1920x1080 HD, 24, quality restricted to 6300 KB/S to fit his file size requirements) to someone and he streamed it live on YouTube and it played back choppy in some parts. The file played back perfectly on my machine so it may be a YouTube or streaming issue.

If you gave him 24 fps and he was streaming at 30 fps, it can results in grave "choppiness". 24fps input only works perfect with 24 fps output, it's passable with 60 fps and (a bit less) with 25 fps.

Innnnteresting. Thank you all so much for your insight. I've got a lot to learn.