We can't predict if the quality is going to be below the threshold
eventually, so we might as well enable it always.
Change-Id: I30aedecc8c6d4daf159f6ef152697df0206d1e93
This fixes some color smearing due to heavy quantization.
This is only enabled for q <= 30 (cf ERROR_DIFFUSION_QUALITY)
Change-Id: I07e83a4d38461357a32c9e214f7eadc6db73baa9
If "exact" is false, we can modify the luma samples in fully transparent
areas to facilitate lossy compression. Experiments on some PNG images
show compression improvement of more than 20%.
Change-Id: I1a728cfa920a6652bc1f600d87c01f7f648c4942
this avoids duplicates between these trees and dsp/, e.g., enc/tree.c,
dec/tree.c, making pulling the whole library source tree into one target
possible
BUG=webp:279
Change-Id: I060a614833c7c24ddd37bf641702ae6a5eef1775
