We use three years of data from the Supernova Legacy Survey (SNLS) to study
the general properties of core-collapse and type Ia supernovae. This is the
first such study using the "rolling search" technique which guarantees
well-sampled SNLS light curves and good efficiency for supernovae brighter than
$i^\prime\sim24$. Using host photometric redshifts, we measure the supernova
absolute magnitude distribution down to luminosities $4.5 {\rm mag}$ fainter
than normal SNIa. Using spectroscopy and light-curve fitting to discriminate
against SNIa, we find a sample of 117 core-collapse supernova candidates with
redshifts $z<0.4$ (median redshift of 0.29) and measure their rate to be larger
than the type Ia supernova rate by a factor $4.5\pm0.8(stat.) \pm0.6 (sys.)$.
This corresponds to a core-collapse rate at $z=0.3$ of $[1.42\pm 0.3(stat.)
\pm0.3(sys.)]\times10^{-4}\yr^{-1}(h_{70}^{-1}\Mpc)^{-3}$.
