Combining SD and HD footage
Posted by Dan Israel on Apr 15, 2013 in Video
During a recent post session, I was struggling with combining footage from multiple cameras (and eras). I had three basic formats: SD, HDV, and AVCHD. The SD and HDV were LOWER field interlacing, while the AVCHD was UPPER. (I also had a small amount of progressive footage from another source – though it didn’t present a problem.) I elected to have the Final Cut Sequence setting to UPPER as most of the footage was AVCHD. Therefore all SD & HDV footage received a SHIFT FIELDS filter with a value of -1. This seem to work fine, until I rendered (or output) the footage.
What I discovered was this: Apparently, Final Cut Pro 7 cannot accurately render footage that has both the SHIFT FIELDS filter and a SPEED change applied. All footage at 100% rendered appropriately. But any footage with a speed variation applied, suddenly began to render with the fields out of order. I experimented with various settings on the SHIFT FIELDS filter as well as some other filters, including DE-INTERLACE.
I was unwilling to simply DE-INTERLACE the footage, because I didn’t want to further reduce the resolution of footage that was low resolution already. I’ve also seen it suggested that the sequence be set to LOWER and the High Def footage be DE-INTERLACED, as the effect isn’t as noticeable on HD footage. However, I did not feel either of these was the proper solution. Throwing away half a field of data every frame is simply lazy. I also tried to nest the sequences so that the math was occurring in a different way. However, this did not work in my case.
SOLUTION:
- Since the footage would play properly without rendering, I made my cut decisions regarding speed changes in my main timeline.
- Once I was pleased, creatively, I copied the footage with the speed changes applied to a new sequence (Called “My Footage Conformed).
- I then set the Sequence Settings to match the footage and rendered it. It should play perfectly. Properly interlaced with smooth speed ramps – no flicker – no jerking.
- Using EXPORT, I output the footage using the CURRENT SETTINGS. (It’s up to you if you want to expand the front and back to leave yourself some editing wiggle room later).
- Then, IMPORT the footage back into the Project and replace the original footage in your Main Timeline with the imported conformed footage. It will still get the SHIFT FIELDS applied to it, but it will play smoothly.
Remember, it is the combination of SPEED and SHIFT FIELDS that don’t work together. And if you want, keep the sub-sequence in case you need to change. You can then re-Export and re-Import.
