[FFmpeg-devel] [PATCH] doc/general.texi: add note about 32-bit GCC builds of AviSynth+

Stephen Hutchinson qyot27 at gmail.com
Mon Apr 1 03:12:55 EEST 2019

The text has been updated to reflect that 32-bit builds of FFmpeg
in general don't default to AviSynth+GCC compatibility.
 doc/general.texi | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/doc/general.texi b/doc/general.texi
index bafa1e2ea2..6c1acb517c 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -51,6 +51,21 @@ For Windows, supported AviSynth variants are
 For Linux and OS X, the supported AviSynth variant is
 @url{https://github.com/avxsynth/avxsynth, AvxSynth}.
+ at float NOTE
+In 2016, AviSynth+ added support for building with GCC. However, due to
+the eccentricities of Windows' calling conventions, 32-bit GCC builds
+of AviSynth+ are not compatible with typical 32-bit builds of FFmpeg.
+By default, FFmpeg assumes compatibility with 32-bit MSVC builds of
+AviSynth+ since that is the most widely-used and entrenched build
+configuration.  Users can override this and enable support for 32-bit
+GCC builds of AviSynth+ by passing @code{-DAVSC_WIN32_GCC32} to
+ at code{--extra-cflags} when configuring FFmpeg.
+64-bit builds of FFmpeg are not affected, and can use either MSVC or
+GCC builds of AviSynth+ without any special flags.
+ at end float
 @float NOTE
 AviSynth and AvxSynth are loaded dynamically.  Distributors can build FFmpeg
 with @code{--enable-avisynth}, and the binaries will work regardless of the

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