[FFmpeg-devel] CONFIG_W64_DEMUXER and dead-code elimination

Bruce Dawson brucedawson at google.com
Wed May 11 16:19:11 CEST 2016

The error is:

    wavdec.obj : error LNK2001: unresolved external symbol _ff_w64_guid_data

This happens because the compiler does not recognize early enough
that _ff_w64_guid_data is never actually needed, so it creates a reference
to it.

I am adding a temporary fix to Chromium's ffmpeg repo so that we can test
with the new compiler. It is not known whether the official VS 2015 Update
3 will have this issue or not. The fix/hack is here:


On Wed, May 11, 2016 at 10:04 AM, Michael Niedermayer <
michael at niedermayer.cc> wrote:

> On Tue, May 10, 2016 at 01:22:53PM -0400, Bruce Dawson wrote:
> > BTW, the reason I suggested the CONFIG_W64_DEMUXER patch that started
> this
> > email thread is because the pre-release version of VS 2015 Update 3 can't
> > handle that code as-is. Microsoft might change their compiler before the
> > officially release of Update 3, but currently ffmpeg (in Chromium at
> least)
> > doesn't build with VS 2015 Update 3 pre-release without some sort of
> > workaround for the reference to a symbol from w64.c.
> what exactly happens? what error does the compiler produce ?
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> No human being will ever know the Truth, for even if they happen to say it
> by chance, they would not even known they had done so. -- Xenophanes
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel

Bruce Dawson

More information about the ffmpeg-devel mailing list