Archive for August, 2016

48fps Editing

Sunday, August 21st, 2016

render4k_logo2.jpg

One of the new features that came in Media Composer 8.3 (December 2014) was the ability to edit at higher frame rates (up to 60.000p). Combined with the resolution/frame rate independence of the DNxHR codec, this provides solutions for content being produced for specialized venues, experience, etc.

Recently I was approached with the question of how well did 48fps editing work for a feature length production.  I contacted my friends at RED to provide me with a clip shot at 48.000fps with project rate at 48.000 fps so it would not be tagged as a 2x slomo clip. All testing so far as been done with this one single clip.

The good news is that you can edit 48fps (and 47.952) at their native rate.
The bad news is that several of the common workflows expected with the process do not.

Once you click “custom” in the Media Composer projects, you will see the additional frame rates not available with the preset project templates:

hfr-projects.png

One thing you will notice here is that there are no film settings available once you click custom. It is not so much for tracking KeyKode and film elements that is the issue (although it could since film itself as no defined film rate), it is the fact that one cannot create a project to able to use 1/4 frame sync with double system audio workflows.

no-film-settings.png

Trying to open the project in a 24fps project as a workaround did not work either, and even if it did, you would only see every other frame defeating the purpose of 1/4 frame sync. The issue is most likely related to the fact that audio being “addressed” for 1/4 frame sync is tagged as 96fps upon import into a 35mm/4-perf project (4 x 24) or 72fps in a 3-perf project (3×72). Something like 192fps might have to be done to support 48fps. This is the reason why you don’t see it in 30fps projects (4 x 30 = 120fps).

AMA linking to the material worked just fine. One thing to note here is that even when selecting a 48fps project, the project defaults to 24fps editing timebase, what Avid calls “2 frame safety” to protect for tape outputs. Since this is a file based world, and editors like to edit on every frame, be sure to change it to 48fps.

The START timecode of the clip displays 24fps NDF, it uses the field indicators to designate 48fps counts with either a : or . right before the frame portion of the timecode. The same applies to the RECORD side timecode for sequence position. Unfortunately there is no 48fps counter available as seen in other applications as a guide only, even when selecting 48fps at the timebase.

start-timecode.png

Once issue that I have not gotten to the bottom of yet, is that Media Composer’s TC does not match either the Red Player or DaVinci Resolve’s TC START for the same clip, while Red Player and Resolve match each other:

Red Player:

rcx-player.png

Resolve:

resolve-48fps.png

ALE importing and merging is an important part of any feature based workflow from dailies onward, and the easiest way to test that is via a simple roundtrip of an ALE exported from Media Composer, add a custom column, or change NAME and see if it merges back. In this case, the NAME was changed from the camera file name to scene_take.

As exported:

ale-export.png

As modified for import:

ale-import.png

No success. There is a mismatch error raised:

ale-merge.png

Perhaps it is due to the fact that exporting an ALE does not reflect the : or . field indicators. I edit the ALE timecode to reflect it as seen in the bin from 22:39:25:05 to 22:39:25.05. Same error. Changing fps in the header to 24 instead of 48 does  not work either and there is a fps mismatch error message. So no ALE import merge support available. I was able to import an ALE file, but the 22:39:25.05 in the ALE was changed to 22:39:25:05 which is a +/-1 frame offset from actual image. And while on the topic of ALE import, you need to select “Import Media” which is a very non-intuitive menu name for non-media import.

I believe the whole :/. is also the basis for EDL’s not being correct. Another test here is checking EDL to make sure counting is correct. For the test I synced a BWF file to reflect typical double system workflows. AuxTC and SoundTC columns all have the same behavior and EDL’s are all the same. My test sequence is to reflect frame accuracy when editing 48fps so the sequence starts with a 1 frame event, then 2 frames, then 3, 4, 5, etc. up to 24 (1/2 second) as seen here:

48fps-timeline.png

The EDL looks like (click for full size):

48fps-edl.png

Just looking at the EDL, you can tell there will be issues:

  • No indication of it being a 48fps EDL - this can be done in the FCM command line at the top rather than having to name the sequence as such as a reminder.
  • The first line is a 0 duration despite it being a 1 frame event.
  • If you look down the record side out point, you would expect to see, 1, 2, 3, 4, but you do not.
  • According to this EDL, even if you thought it as a 48fps EDL without the :/. indicators, the half second is event 009 rather than 024 as edited.
  • No support for the :/. indicators for frame precision. None of the available templates support it.

Using the soon to be available AAF Reporting service, it sees the timecodes as 48fp as seen in this screenshot.

aaf-report-48fps.png

So, as with the ALE roundtrip test, what does an EDL roundtrip look like? When importing the EDL, I do get prompted for frame rate, but not the project rate. Then a message about 24 events having to be modified, then an empty timeline.

48fps-edl-import.png

The good news here is that an AAF did roundtrip correctly as long as you remember to set your project edit timebase to 48fps. If you leave it at 24, import the AAF and export an EDL, it is a very different looking one with additional events as seen here (click to see full size):

edl-compare.png

Conforming the 48fps AAF (picture only) in DaVinci Resolve was also correct, but as you can see, the EDL view of the timeline counts as 48fps, not 24 with field indicators. Click image to see full resolution:

48fps-in-resolve.png

A conform check was frame accurate which is good. It would seem that the difference in timecode noted above is not affecting the conform process and may be a display issue in Media Composer?

Another test was the audio post workflow and taking an AAF to Pro Tools. The import failed right away:

pro-tools-48fps.JPG

Part of any feature workflow with Pro Tools is the ability to manage changes, The change list tool does not work at all with 48fps projects. I do not know whether it is because of the frame rate, or the fact that it is not a film project. Change management is needed regardless of acquisition format.

First this:

change-list-error-1.png

Then:

change-list-error-2.png

The one thing I could not test was the 48fps monitoring. Avid’s own DNxIO box does not support 47.952/48 fps monitoring. I am told that AJA does, but nothing on their website indicates that frame rate. Perhaps it will be part of an upcoming update. In any case it will be relagated to certain project formats so some form of letterboxing/pillarboxing and scaling will be included depending on project resolution/aspect ratio to match the monitor being used.

OP1a, DPX, and Same as Source QuickTime worked fine.

Answering what seemed to be a simple question; “does 48fps works with Media Composer for feature production?”, needs to be vetted to the expected workflow of a production. In some cases “yes”, in others no, but mostly “it depends”. It is a feature, but not a complete solution.

Update 9/10/2016:

Scott Freeman reminded me of the fps setting in “General Settings” and setting that to 48 rather than 24 allows the TC counts to be 48 as seen here:

48fps-tn.jpg

Doing so, also allowed an ALE file to be merged into the existing clip that does not work when project is set to 24. There is no need for this project type to default to 24 frame (two frame safety) and the selection for TC should be part of the Format window along with fps edit rate.

format-tab.png

If anything, the general setting should be “TC rate matches edit rate” as an option and the user should always have access to both counting types in the TC viewers as a choice.

With 48fps active, EDLs are now “frame accurate” as 48fps but the FCM command should still indicate frame rate along with “NON-DROP FRAME”. For the same sequence above, the EDL is now:

48fps-as-48-edl.png

I then tried importing this EDL back into the project. I selected the EDL and was greeted with the parameters of the EDL but was not able to select any “project type”:

edl-import-1.png

The EDL imports with no further messages until I tried loading it and got:

edl-import-2.png

The rate was defined in the first window that popped up, but did not seem to apply to the sequence.  I clicked “Yes” and when it loaded, there were no events.

So selecting 48fs in the General settings allows for more workflow operations to work, but some are still missing such as 1/4 frame sync, and Pro Tools post.