Constant MAX_STRIPE_CAPACITY 

pub const MAX_STRIPE_CAPACITY: usize = 64;

Upper bound on the horizontal stripes the CPU encoder splits a frame into, so the persistent per-stripe state vector can be reserved to a fixed capacity once, up front.

With the vector reserved to this size at startup, the per-frame resize to the actual stripe count stays a cheap in-place adjustment that preserves each stripe’s reused encoder and scratch buffers, rather than a reallocation that would churn them whenever the count changes.