af: use af_lavrresample for format conversions, if possible

Refactor to remove the duplicated format filter insertion code. Allow
other format converting filters to be inserted on format mismatches.
af_info.test_conversion checks whether conversion between two formats
would work with the given filter; do this to avoid having to insert
multiple conversion filters at once and such things. (Although this
isn't ideal: what if we want to avoid af_format for some conversions?
What if we want to split af_format in endian-swapping filters etc.?)

Prefer af_lavrresample for conversions that it supports natively,
otherwise let af_format handle the full conversion.

1 files changed, 1 insertions, 0 deletions

diff --git a/audio/filter/af.h b/audio/filter/af.h
index e4a329abea..50719c4d1b 100644
--- a/audio/filter/af.h
+++ b/audio/filter/af.h
@@ -60,6 +60,7 @@ struct af_info {
     const char *comment;
     const int flags;
     int (*open)(struct af_instance *vf);
+    bool (*test_conversion)(int src_format, int dst_format);
 };
 
 // Linked list of audio filters