I've tried all the possible ways to parallelize the uploads. Nothing works. Uploads should be done one after the other. And it takes about one hour to get the job done through an optical fiber network.
Each of my single app is localized in 20 languages, for iPhone and iPad.
So, 40 hours in front of the computer to upload app previews, because if you don't save right after the upload, you're diconnected and must redo the job.
So, 4 days per app.
I have 15 apps.
So, 60 days overall.
I work 20 days per month.
So, 3 months just doing the uploads.
That's a BIG TROUBLE !!!
Thanks for your answer. On my side I could get things better:
1) I did a test to see if I had to upload a video for each language. The answer is NO. These days, the default language app preview is taken if you don't upload an app preview for a given localized language.
2) I realized that the "ProRes 422 HQ only" Codec generates files about 400-600 MB ... So, within Final Cut Pro X, I went through the Destination entry menu, to change the "Master Files" Codec to H.264. Then the video weight 20-40MB and it takes about 3 minutes to upload on iTunes Connect.
Hope this will help someone. Tell it if so.
Thanks.