Hey time lapse enthusiasts, I'm calling upon your expertise to help me fix an annoying problem I've been having. I've been having a frustrating experience (for some time now) with severe degradation of quality when uploading my videos (time lapse and regular) to the web (youtube and vimeo) and I'm hoping you can take a minute and offer any advice on how to tweak my workflow for optimal results. I watch others work on the web all the time, which looks great so I must be doing something wrong.

I just recently finished editing a long overdue demo reel of some of my time lapse stuff. For this edit, I wanted to export at higher than HD resolutions to match the displays of my new mobile platforms (Dell M3800@ 3200x1800 and Galaxy Note Pro @ 2560x1440) so I can show potential clients the video in the best quality possible. This seems to be accomplished but as I said, once uploaded to the web it looks terrible.

Here's the workflow I used for this project:
All the time lapse sequences I used were processed with LRTimelapse 3.3 and Lightroom 5 before being edited and exported in Premiere Pro. After doing the LR+LRT workflow, I exported the temporary stills from LR as 10-bit (lossless) TIFF's. Then, rendered the sequences from LRT as 5K ProRes (444) UHQ .mov files and imported them into Premiere. In Premiere I made a sequence preset for the footage, here's the settings I used.

General
Editing mode: DSLR
Timebase: 29.97fps
Video Settings
Frame size: 3200h 1800v (1.0000)
Frame rate: 29.97 frames/second
Pixel Aspect Ratio: Square Pixels (1.0)
Fields: No Fields (Progressive Scan)
Audio Settings
Sample rate: 48000 samples/second
Default Sequence
Total video tracks: 3
Master track type: Stereo
Audio Tracks:
Audio 1: Standard
Audio 2: Standard
Audio 3: Standard

I did all of my editing within this sequence and once done imported that 3200X1800 sequence into both 2560x1440 and 1920x1080 sequences (other than frame size all other setting the same) so I could export it in multiple resolutions.
Upon exporting, I made a couple of presets for exporting the custom resolutions, here's the settings I used.
Format: H.264, 3200x1800, 29.97 fps, Progressive, VBR, 2 pass, Target 60 Mbps, Max 80 Mbps, AAC, 160 kbps, 48 kHz, Stereo, Aspect: Square Pixels (1.0), NTSC, Profile: High, Level: 5.1, "Render at Maximum Depth & Use Maximum Render Quality" both un-checked. (For the 2560x1440 preset everything was the same with the exception of the frame size and Target Bitrate (40 Mbps) ).

For the HD version, I used Premiere's H.264 HD 1080p 29.97 preset.
I then exported three versions (3200x1800, 2560x1440, 1920x1080) which all play and look great on their respective device.

So far everything is fine and I'm happy but after uploading to YouTube and Vimeo, it all falls apart. Besides the fuzzy/soft look, the uploaded version looks flatter, brighter/overexposed and there is all kinds of noise/artifacts that I can see. Aliasing??? IDK.

On YouTube, I uploaded both a 3200x1800 and a 1920x1080 version and on Vimeo just the 1080 version. I can't really say one looks better than the others, they all look poor to me when compared to the original. In the past, I have exported videos using Premiere's H.264 YouTube and Vimeo presets but that never seemed to yield better results either so I ditched using them.

After all this typing, basically what I am getting at is: What export setting do you guys use for the best results when uploading to YouTube and/or Vimeo? I appreciate any help you have to offer.

Here's the 3200x1440 version uploaded to YouTube:
https://www.youtube.com/watch?v=D2MCsfBpE3E

Here's the 1920x1080 version uploaded to YouTube:
https://www.youtube.com/watch?v=1Syp88EUspc

Here's the 1920x1080 version uploaded to Vimeo:
https://vimeo.com/93686523

Thank you for your help,
Will

Just check the vimeo compression guidelines. Same goes for youtube in my experience.
https://vimeo.com/help/compression