Ever since an update of either Final Cut Pro, QuickTIme or Pro Apps (no-one really knows) Final Cut Pro has a nasty bug when exporting a self contained quicktime movie from a DVCPRO HD (720p & perhaps 1080i) timeline. The aspect ratio and frame size of the resulting self contained movie is incorrect and therefore requires render when brought back in a native DVCPRO HD sequence - even the same sequence the movie was exported from.

For some of us, this is a big issue. Each re-render takes up to 2 hours per hour show. In our case, we are currently in post on a 13 part History Channel series, 1 two-hour documentary, 3 one-hour Biography Channel programs, 2 one-hour documentary specials and 1 two-hour History Channel documentary special. The network requires up to 14 deliverables per show (HD, SD, Texted, Textless, Short Forms, Cut Downs, Previews, etc.) - Add it up ; that's nearly 280 deliverables (20 shows X 14) each needing render - we're looking at 560 hours of unnecessary renders. Without mentioning the concern on what the re-renders are doing to the visual integrity of the programs.

Why use DVCPRO HD?

It's a fair question, especially since the release of the very promising Apple ProRes codec. Our reasons are simple:

• All our shows are shot with the Varicam and we'd like to stay native
• Prores has issues of its own (wrong timecode and other bugs)
• Editors started editing months back in DVCPRO HD (Media manager from DVCPRO HD to Prores isn't reliable)
• AJA and Black Magic ingesting to Prores has been unreliable (dropped frames on SATA RAIDs)

Why the need for exporting self contained and reimporting them?

This on the other hand isn't a valid question but I've heard it - so I'll address it. It isn't a valid question in my opinion
because questioning why a user is utilizing a feature of the software is silly (The mechanic responds: why are you using
the fifth gear on your car? stay in fourth...)

Our reasons are the following:

• Editors deliver a complete online self contained version of the shows which we use to master to HDCAM & Digibeta
• We sometime have to redo a master based on failing the network's tech review (audio hit, video hit, etc.)
• We archive self contained quicktimes on LTO tapes and would like to reimport them in the future, if needed, without
  requiring a render

Bug Description

A copy of a FCP 6 project with media (44 MB) which was used to write this document is available to download at:

http://LumiereMedia.com/dvcprohdbug/DVCPROHD_BUG_TEST.zip

The bug is simple (Illustrations below)

• Import a perfectly fine DVCPRO HD 720p60 clip into FCP
• Drop it on a timeline - it doesn't require a render (which is good)
• Place an IN and OUT point to cover the total clip
• Choose File/Export QuickTime Movie (use current settings/self contained/no recompress)
• Import the clip in FCP and it requires a render (Figure 1 - Figure 4):

-Aspect ratio is square / should be HD (960X720)
- Resolution is 1280 X 720 / should be 960 X 720

Figure 1: Reimported Clips from incorrect OUT points have the wrong Pixel Aspect Ratio and Frame Size

Work Around

Although the following aren't legitimate workarounds they do shed some light on the nature of the bug.

Place a correct OUT point (The Out Point Inclusive rule):

A frequently used method to place IN and OUT points on a timeline is to use the up arrow (or Home button) to find your
IN point to the left and press 'I' and use the down arrow (or End button) to find your OUT point to the right and press 'O'.
Although it is an OK means to find your IN point, it is an inaccurate way to find your OUT point because it will include one
extra frame to the right of the end of the clip in the timeline. Zoom in to the frame and you will clearly see the extra empty
frame (Figure 2).

Figure 2: This OUT point includes on blank frame after the clip.

It is by using this method to place the IN and OUT points on a single clip that the bug manifests itself. Place a correct
OUT point on the end of the clip (one frame back) and the resulting self contained movie will not have the issue described
above (Figure 3).

Figure 3: This OUT point includes the end of the clip without an empty frame.

Figure 4: Clip with the wrong Aspect Ratio and Frame Size requires a render, the other doesn't.

So it looks like FCP gets confused on the settings of the exported clip if any included frames from the sequence does not
include a clip (duplicating the working clip and exporting it as one self contained with correct IN and OUT points works
fine). Including Slugs, FCP text, etc... doesn't.

Placing a correct OUT point and moving the IN point back a frame to include an empty frame does trigger the bug as
well.

This workaround would work great for solid clips in a timeline but unfortunately, slugs, bars, text are often necessary in a
sequence.

Recompress All Frames:

This workaround is even less desirable than the above but it works. Check the 'Recompress All Frames' checkbox in the
export window and the resulting movie will have the correct settings. The problem is that this defeats the purpose of
exporting a self contained movie since your material will go through an additional compression degrading the quality of
your material.

Rendering Non DVCPRO HD Assets to DVCPRO HD Movie Doesn't work:

Rendering all your non DVCPRO HD assets (Text, Slugs, etc...) to DVCPRO HD and reimporting does not solve the issue.

Additional Findings (Some Clips Don't Have Problems)

It seems that the issue starts with the quicktime movie. In the exact same circumstances (same timeline) some generate
the bug, others don't, even with 2 clips which seemingly have the exact same settings (Figure 5):

Figure 5: Although the BUG CLIP & NO BUG CLIPS both seem to have identical settings and play without render in the
DVCPRO HD 59.94 Timeline, they generate different results when exported with an empty frame from the sequence

- BUG CLIP
- NO BUG CLIP

(click the clips above to download them)

They both don't need rendering in a DVCPRO HD 720p 59.94 timeline but one will generate a wrong aspect ratio self
contained the other won't.

All reported settings in the FCP browser are identical (Figure 6 & 7).

Figure 6 (Part 1): All reported settings in the FCP Browser seem identical between BUG CLIP & NO BUG CLIP but they
generate different results when exported.

Figure 7 (Part 2): All reported settings in the FCP Browser seem identical between BUG CLIP & NO BUG CLIP but they
generate different results when exported.

Conclusion

The issue is definitely with the clips. What is different between these clips that makes FCP behave differently when
exporting them? The answer to this question will lead to resolving this bug.

copyright © Frederic Lumiere2007 All rights reserved

A PDF version of this article is available for download by clicking HERE