Change #264735

Comments

swscale/ops_dispatch: fix and generalize tail buffer size calculation
This code had two issues:

1. It was over-allocating bytes for the input offset map case, and
2. It was hard-coding the assumption that there is only a single tail block

We can fix both of these issues by rewriting the way the tail size is derived.

In the non-offset case, and assuming only 1 tail block:
    aligned_w - safe_width
  = num_blocks * block_size - (num_blocks - 1) * block_size
  = block_size

Additionally, the FFMAX(tail_size_in/out) is unnecessary, because:
    tail_size = pass->width - safe_width <= aligned_w - safe_width

In the input offset case, we instead realize that the input kernel already
never over-reads the input due to the filter size adjustment/clamping, so
the only thing we need to ensure is that we allocate extra bytes for the
input over-read.

Signed-off-by: Niklas Haas <git@haasn.dev>

Changed files

• libswscale/ops_dispatch.c