lavfi: add avfilter_all_channel_layouts public symbol

This list is mainly useful to be directly used as a parameter by the
audio sink buffer, when there is no need to force a specific channel
layout.

The list of formats is generated programmatically, and avoids channel
layouts not supported by libavfilter (with more than 8 channels).

We preferred to avoid compile-time generation in order to avoid some
unnecessary complexity (build hacks, generating code maintainance
etc.).

A more compact way to express this list through the use of macros
should be possible when libavfilter will support more than 8 channels,
as there will be no need to filter out channel layouts with more than
8 channels.

See thread:
Subject: [FFmpeg-devel] [PATCH] lavfi: add ff_all_channel_layouts internal symbol
Date: Sat, 20 Aug 2011 15:33:16 +0200

1 files changed, 6 insertions, 1 deletions

diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index a8426fea53..f1ebd09735 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -29,7 +29,7 @@
 #include "libavutil/rational.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  2
-#define LIBAVFILTER_VERSION_MINOR 41
+#define LIBAVFILTER_VERSION_MINOR 42
 #define LIBAVFILTER_VERSION_MICRO  0
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
@@ -275,6 +275,11 @@ AVFilterFormats *avfilter_all_formats(enum AVMediaType type);
 AVFilterFormats *avfilter_make_all_formats(enum AVMediaType type);
 
 /**
+ * A list of all channel layouts supported by libavfilter.
+ */
+extern const int64_t avfilter_all_channel_layouts[];
+
+/**
  * Return a list of all channel layouts supported by FFmpeg.
  */
 AVFilterFormats *avfilter_make_all_channel_layouts(void);