Export settings bitrate & quality

The Computer Master File Share setting creates an h.264 video in an MP4 container. Apple has chosen a bit rate that they think is optimal for that kind of format. The difference between the two quality settings is how those bits are allocated throughout the movie; high quality does a first pass to determine where the most complex scenes are.

If you want more control, either use Compressor or MPEG Streamclip. Compressor will let you choose bit rates of up to 30 Mb per second. My guess is viewers won't detect any difference, lthough he file size will be 40% larger.

Russ

nevrozell wrote:

Hi everyone,

I am using the latest version of FCP X 10.1.1. I import AVCHD clips shot at 24p 24Mbit/s with my Sony A7 camera. I keep the native files, I do not use optimised media as I have good performance and do not apply effects to my movie.

When I export I made a new destination as follows:

- Format: Publishing > "Computer"

- Codec: H.264 Better Quality

- Resolution: 1920x1080

- Audio File Format: QuickTime Movie (AAC)

I have been using this export preset for a long time and I am used with its quality, I used to think its the best I could get. The thing lately I have found that is the final QuickTime movie has a bitrate of 20-21Mbit/s and never the maximum 24Mbit/s. I also tried to export a clip shot at 17Mbit/s same settings and the final QT movie also has a bitrate of 20-21Mbit/s. It seems FCP X locks the export bitrate at 20-21 when using this export preset?

I have also tried to export as Master File with ProRes 422 but the file is very large and the bitrate goes over 100Mbit/s which I think its artifical as my native clip is shot at 24Mbit/s.

So I would like to ask you two questions:

1. Why my QuickTime movie (using "Computer" preset) has a bitrate of only 20-21Mbit/s instead of the original 24Mbit/s?

2. Is my workflow (import native clips and export using "Computer" preset) giving me the best (identical to original AVCHD clip) image quality?

Thank you!

1)

The best export of H.264 you can get is to Export File or a Master File. FCPX will encode with the absolute highest quality you can expect (bitrate in the range of ~ 45 Mbps to about 55Mbps, give or take.) The setting you've been using is to export a "playable" version for Apple Devices. 20-21Mbps is still a very decent quality (YouTube max quality is 8Mbps for 1080). I seriously doubt you can tell the difference in quality between the original camera AVCHD and the output for Apple Devices. H.264 is a *highly* compressed storage format. ProRes is not. ProRes is a format best utilized in editing and not playing. No matter what you set the compression settings for with H.264, what you get will often surprise you (the compression scheme heavily relies on what pixels change from frame to frame -- not that much in the way of changes and the compression will be significant.)

2)

The significant quality of the ProRes codec is that it is "virtually" lossless (again - you would be very hard pressed to be able to tell the difference between the original and the ProRes version.) The simple act of importing with Transcode Optimized will create a ProRes 422 version of the video imported. You should find working with Optimized media would be enhance your workflow considerably. Upon Export/Sharing, FCPX will use the best quality media to create the output. The destination will determine how close to the original AVCHD quality you achieve.

For further control over output bandwidth, you will need Compressor or Quicktime 7 Pro or some other transcoding software that gives you control over the "particulars" (none of which I can recommend). FCPX (and Motion) always deliver "the best" quality for the codec chosen and the specific destination — you have no other control.