Unifying the way the EBML unknown length is signaled, rather than using two
incompatible values. UINT64_MAX cannot be read as a valid EBML length with the
current code.
Co-authored-by: Steve Lhomme <robux4@ycbcr.xyz>
Co-authored-by: Dale Curtis <dalecurtis@chromium.org>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>