[FFmpeg-devel] [PATCH] ac3_parser type punning fix
David DeHaven
dave
Sun Oct 19 07:44:16 CEST 2008
> Nothing major, I just applied the same fix that was applied to
> aac_parser.c recently...
>
> -DrD-
> <ac3_parser.patch>
I think there was confusion about the whole point of this patch...
On the four x86 based machine/OS combos I built and tested on (i686-pc-
mingw32, 2x i686-pc-linux, i686-apple-darwin), gcc with optimizations
at more than -O0 would produce machine code that would *only* byteswap
32 of the 64 bits in the "state" variable passed to both aac_sync and
ac3_sync leading to complete and utter misinterpretation of the header
information. The result: at the *least* would be that it reported the
wrong information to stdout, at worst it would crash due to having the
wrong codec parameters. I can't honestly believe that noone else has
seen this problem, especially considering aac_sync has been already
fixed unless that was simply a "compiler warning" fix.
I can provide disassembly snippets if you need further convincing...
-DrD-
More information about the ffmpeg-devel
mailing list