eac3enc: use frame exponent strategy when applicable.

This checks if the set of selected exponent strategies for all blocks in a
channel are in the frame exponent strategy table, and if so, writes the
table index instead of each strategy. This saves up to 7 bits per channel per
frame, so the overall effect on quality is small.

1 files changed, 10 insertions, 0 deletions

diff --git a/libavcodec/eac3enc.h b/libavcodec/eac3enc.h
index eacb8cf164..a92a24c2fa 100644
--- a/libavcodec/eac3enc.h
+++ b/libavcodec/eac3enc.h
@@ -30,6 +30,16 @@
 #include "ac3enc.h"
 
 /**
+ * Initialize E-AC-3 exponent tables.
+ */
+void ff_eac3_exponent_init(void);
+
+/**
+ * Determine frame exponent strategy use and indices.
+ */
+void ff_eac3_get_frame_exp_strategy(AC3EncodeContext *s);
+
+/**
  * Set coupling states.
  * This determines whether certain flags must be written to the bitstream or
  * whether they will be implicitly already known by the decoder.