lavu/channel_layout: change av_get_channel_layout() behavior at the next bump

The new syntax is preferred since it allows backward syntax compatibility
with libswr when switching to the new option handling code with
AV_OPT_TYPE_CHANNEL_LAYOUT.

With the new parser the string:
1234

is interpreted as a channel layout mask, rather than as a number of
channels, and thus it's compatible with the current way to set a channel
layout as an integer (e.g. for the icl and ocl options) making use of
integer option values.

ff_get_channel_layout() with compat=0 will be used in the
AV_OPT_TYPE_CHANNEL handler code.

The user is encouraged to switch to the new forward compatible syntax,
which requires to put a trailing "c" when specifying a layout as a number
of channels.

1 files changed, 3 insertions, 0 deletions

diff --git a/libavutil/version.h b/libavutil/version.h
index 41e479cce7..001b612d4e 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -138,6 +138,9 @@
 #ifndef FF_API_VDPAU
 #define FF_API_VDPAU                    (LIBAVUTIL_VERSION_MAJOR < 53)
 #endif
+#ifndef FF_API_GET_CHANNEL_LAYOUT_COMPAT
+#define FF_API_GET_CHANNEL_LAYOUT_COMPAT (LIBAVUTIL_VERSION_MAJOR < 53)
+#endif
 
 /**
  * @}