Drop in image quality when exporting from FCPX

I recently exported a video from FCPX and when watching the finished video, I noticed a slight drop in image quality. At first, I assumed it was because I was working with proxy media, but after some troubleshooting, I found it was FCPX that was dropping the quality on output. I wanted to be sure of what, where, and when the downgrading was happening, and in making sure I also found that QuickTime X plays files at a lower quality than QuickTime 7.

To test it, I selected a particular .mov file with some contrasted edges and watched it in QuickTime X.





Then I watched it in QuickTime 7. The exact same file looks better in the older app.





So I knew there was nothing wrong with the file itself. It was just different apps playing at different quality, and QuickTime 7 played it at a higher quality.

I made a new project and event in FCPX. The event had only this .mov file. I had FCPX automatically copy this file to Final Cut Events folder too. I dropped the entire clip into the timeline and did a simple "Command E" export using the same settings. When I watched the exported file in QuickTime 7, it was of a lower quality than the original .mov file.





I tried exporting again using Compressor's Pro Res settings, among others, but the result is always a slightly more pixelated version than the original.

What can I do to minimize the drop in quality on export?

Every time you encode something there is a quality loss. Unless you use lossless.

ProRes 4444 and Animation codec are called lossless but there is still compression going on. Prores422 and others are considered broadcast codecs because the are near lossless and work great to edit with. My guess is your original video is h.264 and the issue you are seeing is the transcoding, to all I-frame codec.

The only lossless codec is None (really on export from AE, FCP7, Motion 4) you can choose not to compress the file.

The only time I had to use that was with an effects teacher in college, he was trying to drive home a point about compression.

Even on effects for broadcast if a composite wasn't completed in AE and it was to be finished in FCP, we would usually just render out to the animation codec with an alpha channel.

Hopefully this helps. Maybe BenB can give you some more info.

Oh a second note. A quick way to see what has changed. Take both clips into FCPX or motion, then stack them on top of each other, and change the top layers composite/blend mode to subtract. This will leave behind anything that is different.