Do Fcpx proxies created from double system audio synced clips retain audio?

[Joe Marler]

[Mauricio Lleras] “wondered if proxies created after having sync done would retain the audio or if they are necessarily image only..”

Proxies contain the original camera audio but there’s no such thing as “audio proxies” for double system audio. If distributing a proxy-only library, the original audio files must also be included and the recipient must relink them. Same situation with photos or graphics.

However if you are only distributing lower-res dailies for viewing (not editing), this isn’t an issue because those exported files will contain whatever double system sound you chose to export. Typically this would be a mixdown of the the selected “high quality” channels in a stereo track, but it’s also possible to export an MXF with multichannel audio.

[Mauricio Lleras]

[Joe Marler] “However if you are only distributing lower-res dailies for viewing (not editing), this isn’t an issue because those exported files will contain whatever double system sound you chose to export. Typically this would be a mixdown of the the selected “high quality” channels in a stereo track, but it’s also possible to export an MXF with multichannel audio.”

Right, so essentially this would create two sets of files, the Fcpx image proxies and then low res exports.
I was wondering if I could use the fcpx create proxies command to get review dailies with sync sound in just one step…
Well; I guess it would’ve been just too easy…
But thanks

[Joe Marler]

[Mauricio Lleras] “Right, so essentially this would create two sets of files, the Fcpx image proxies and then low res exports.
I was wondering if I could use the fcpx create proxies command to get review dailies with sync sound in just one step…”

Proxies are ProRes 422 so they are about 50-60% the size of H264 originals, even though they are 1/4 the pixel resolution. Depending on clip size and bandwidth, not necessarily easy to distribute. By contrast dailies at 1080p or 720p H264 are much smaller and easier to distribute, plus they can include whatever double system audio you want.

My 2017 iMac can export 60 sec of 720p H264 from a 4k timeline in about 34 sec, so that’s pretty fast. Sizes for 60 sec clip:

4k H264 original: 646 MB
Proxy: 334 MB
1080p/29.97: 150.4 MB, export time: 38 sec
720p/29.97: 90.5 MB, export time: 34 sec

[Mauricio Lleras]

Thanks for the input Joe, did some tests exporting H264 at 1080p from the 4K Red files in Resolve and times were similar to yours (I also have a 2017 Imac), so pretty good all in all. Exports from Fcpx were surprisingly slow in comparison…