feat: add VAE encoding tiling support and adaptive overlap (#484)

* implement  tiling vae encode support

* Tiling (vae/upscale): adaptative overlap

* Tiling: fix edge case

* Tiling: fix crash when less than 2 tiles per dim

* remove extra dot

* Tiling: fix edge cases for adaptative overlap

* tiling: fix edge case

* set vae tile size via env var

* vae tiling: refactor again, base on smaller buffer for alignment

* Use bigger tiles for encode (to match compute buffer size)

* Fix edge case when tile is bigger than latent

* non-square VAE tiling (#3)

* refactor tile number calculation

* support non-square tiles

* add env var to change tile overlap

* add safeguards and better error messages for SD_TILE_OVERLAP

* add safeguards and include overlapping factor for SD_TILE_SIZE

* avoid rounding issues when specifying SD_TILE_SIZE as a factor

* lower SD_TILE_OVERLAP limit

* zero-init empty output buffer

* Fix decode latent size

* fix encode

* tile size params instead of env

* Tiled vae parameter validation (#6)

* avoid crash with invalid tile sizes, use 0 for default

* refactor default tile size, limit overlap factor

* remove explicit parameter for relative tile size

* limit encoding tile to latent size

* unify code style and format code

* update docs

* fix get_tile_sizes in decode_first_stage

---------

Co-authored-by: Wagner Bruna <wbruna@users.noreply.github.com>
Co-authored-by: leejet <leejet714@gmail.com>

README.md

@@ -356,6 +356,9 @@ arguments:
   --clip-skip N                      ignore last_dot_pos layers of CLIP network; 1 ignores none, 2 ignores one layer (default: -1)
                                      <= 0 represents unspecified, will be 1 for SD1.x, 2 for SD2.x
   --vae-tiling                       process vae in tiles to reduce memory usage
+  --vae-tile-size [X]x[Y]            tile size for vae tiling (default: 32x32)
+  --vae-relative-tile-size [X]x[Y]   relative tile size for vae tiling, in fraction of image size if < 1, in number of tiles per dim if >=1 (overrides --vae-tile-size)
+  --vae-tile-overlap OVERLAP         tile overlap for vae tiling, in fraction of tile size (default: 0.5)
   --vae-on-cpu                       keep vae in cpu (for low vram)
   --clip-on-cpu                      keep clip in cpu (for low vram)
   --diffusion-fa                     use flash attention in the diffusion model (for low vram)