[Libquicktime-devel] Patch to improve handling of Arri Alexa

[Erik J. <eri...@gm...>]

Hello,

Apparently newer versions of the SDK for Arri Alexa cameras produce
files with large blocks of NULL bytes not contained in atoms. In the
example file I've seen there were about 35Mbytes worth right after the
moov atom. This causes quicktime_read_info(), and hence do_open(), to
step through this block byte by byte trying to interpret the contents
at each step as an atom.

The attached patch tries to detect that we've hit a block of NULL
bytes and skips until the next non-NULL byte is encountered. On my
test machine this speeds up the opening of the movie from about 20
seconds to 0.04 seconds.

Kind regards,
Erik