Video geekery aside ;), the Dithering option in Blender’s Post-Processing section seems to be the ticket to much cleaner final videos. I put a little clip up on Viimeo to demonstrate:
The video is native 720p, and uses a split-screen produced in the Compositor to illustrate the benefits of using Dithering for certain subjects. Left half of the screen is un-dithered imagery, and shows considerable banding in the gradients of light scattered about the setting. On the right I’ve swapped in imagery of the setting made with Dithering set to its max of 2.0 – almost no banding is visible, and the perceived depth of the setting is enhanced considerably to my eyes, a little side benefit of the de-banding process.
The Vimeo conversion may introduce a measure of tonal distortion itself, so for the best look at the comparison, download the original from the Vimeo page while it’s still available.
The .mp4 video was made in Handbrake using the h.264 video codec set for an average bitrate of 5Mbps, not atypical for web-delivered video material. I’ll also be making a comparable version in the .avi container using Blender, just to see how that pathway pans out.
PS. The .avi version written out from Blender using the MPEG/h.264 options @ 5Mbps also looks immeasurably better in the dithered portions. This is good because while most artifacts like banding are produced during compression and thus are codec-dependent, the choice of container format often determines which players can actual play the videos. Always good to have options.
Having played both the .mp4 and the .avi versions in a handful of players, the benefits of using the Dithering option are very obvious. Just wish I’d tried it earlier.
EDIT: I just discovered that the video that is linked-to for downloading on the Vimeo page is yet another damn transcoding of my original upload. Don’t know why they do that! But it does not reflect at all the quality of the original, since it not only introduced more (and more severe) banding but also seems to have changed the entire luma and chroma structure. I’ll try to find somewhere to upload the original test video for direct download.