This IS the Avid L2: Re: [Avid-L2] Speed Ramps of converted 23.98 clips in a 59.94i project don't match offline? [2 Attachments]

Saturday, January 17, 2015

Re: [Avid-L2] Speed Ramps of converted 23.98 clips in a 59.94i project don't match offline? [2 Attachments]

So here are some of the Avid performance charts for Media Net 5.1. Are these the appropriate charts for our 4 chassis 64 drive allocation group with 2 spares per chassis?

---In avid-l2@yahoogroups.com, <bigfish@...> wrote :

Good to know for future projects. Unfortunately I never get consulted until there is a problem and the AEs don't anticipate issues ahead of time. Given we use big 10 plus multi groups and medianet 5 unity storage for offline how does performance and bandwidth compare with our current 10:1, 14:1 and sometimes 10:1m media when using dnx 36? I'm going to google but if anybody has experience with big dnx 36 multi groups in offline I'd appreciate an info.

---In avid-l2@yahoogroups.com, <cutandcover@...> wrote :

Staying at 23.98 throughout would avoid all this pain. I never touch 29.97 until the end, especially in an offline/online workflow, post MC around v4 or so. As soon as DNxHD 36 and ProRes Proxy arrived, we said goodbye to NTSC 23.976 projects entirely.

On Saturday, January 17, 2015, bigfish@... [Avid-L2] <Avid-L2@yahoogroups.com> wrote:

Yes we can't relink back to the originals but that's not an issue for us as my sequence is the final and it typically is only a dozen or so shots in a show. I agree about staying in a frame rate but that is not possible with this series. They shot 23.98 to DVCProHD tape. The Panny -1400 deck was set to add pulldown on capture to a 29.97 project. We also have a lot of 29.97 acquired footage. It's just the file based media that they also shoot 23.98 that we have to treat in a 23.98 project and bring that bin into the offline 29.97 project. Without the speed ramps we generally have no issues other than bumping things a frame or two to get them visually in sync. Those frame bumps again feel like this sort of mismatched metadata of 24 vs. 30 frame time code. It's just all the motion effect keyframe jiggering that is difficult. It's always harder to try and match something than just create it they way you would do it.

Unfortunately there are still learning curves for changing into the 23.98 world of post and we are feeling the pain of starting the process without all the frame rate ducks in line. In the future we may opt to not add pull down in the Panny decks but that will depend on how much stock footage is involved in a particular project and if it only exists at 30 frame. I don't care for taking 30 back to 24 visually but sometimes we have to bite the bullet.

---In avid-l2@yahoogroups.com, <domqsilverio@...> wrote :

My usual recommendation is to maintain the original base frame rate to the entire offline and online process. Do not change frame rates. Mix it down and bring the mixdown version to delivery frame rate. This will result in a consist 2:3 pulldown. Or have Symphony do the conversion during baseband SDI output.

I think the problem is you transcoded to the target frame rate in the uprez process. I am unsure how you even relinked back to your sequence.

Dom Q. Silverio

On Sat, Jan 17, 2015 at 3:24 PM, John Moore bigfish@... [Avid-L2] <Avid-L2@yahoogroups.com> wrote:

We are experiencing a very annoy problem where the speed ramped shots from the 30i offline don't line up when the 23.98 source clips are converted during uprez.

Here is the AE workflow that was explained to me:
The main offline project is an SD 30i project. For the file based 23.98 media they bring that into a 1080p/23.976 HD project and they add a tape name, I'm told they can't add a tape name to these clips while in an SD project. Once the tape name is added then they toggle the project format to 23.976o NTSC project. The clips are then transcoded to 14:1, 10:1 or 10:1m. I think they mostly go to 14:1. These clips are broll and are not grouped. The offline cuts in the 23.98 sd clips. At uprezz the AE ama links to the 23.98 media and adds the tape name then they transcode while in the final delivery 59.94i 1080 project choosing to convert the clips. This is what I get in my online sequence. These converted clips aren't matching the offline speed ramp moves. They are usually close to the shot but have to manipulated to match. The best workaround they have come up with is to manually figure out the time code range needed and manually convert a clip containing all the necessary frames. They save the motion effect to a bin then cut in the converted clip matching the first frame visually then dropping the saved motion effect onto the converted clip. I'm told this has worked in the past but it doesn't seem to be working of late and they are having to manually go in an tinker with the speed ramps.

I think the crux of the problem stems from the added tape name which tell Avid the source is tape based. Now when the toggle back to the 23.076p NTSC project I'm speculating that the project only knows tape machines that were 29.97 from the traditional telecine work flows. I'm thinking when they transcode to SD media Avid is confusing the source 24 frame time code with 30 frame code. If I look at the motion effect editor window I can see for example that parking on an anchor point at the beginning of the effect shows a time code ending in :17 in motion effect window while in the timeline the clips time code reads ending in :24. These is one of the reasons I thing there is a 24 frame vs 30 timecode misinterpretation that is shifting the shots. I think this combined with motion effects that get trimmed so the original anchor point is well outside the actual frame range that is visible is also contributing to the mis synced pictures.

Anybody seen this before? I haven't had time to really experiment with the material do to deadlines but I think I've got the issue surrounded.

John Moore
Barking Trout Productions
Studio City, CA
bigfish@...