lpc: Reduce stack usage by allocating LLSModel in context.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

libavcodec/lpc.c

@@ -208,7 +208,7 @@ int ff_lpc_calc_coefs(LPCContext *s,
     }
 
     if (lpc_type == FF_LPC_TYPE_CHOLESKY) {
-        LLSModel m[2];
+        LLSModel *m = s->lls_models;
         LOCAL_ALIGNED(32, double, var, [FFALIGN(MAX_LPC_ORDER+1,4)]);
         double av_uninit(weight);
         memset(var, 0, FFALIGN(MAX_LPC_ORDER+1,4)*sizeof(*var));

libavcodec/lpc.h

@@ -24,6 +24,7 @@
 
 #include <stdint.h>
 #include "libavutil/avassert.h"
+#include "libavutil/lls.h"
 
 #define ORDER_METHOD_EST     0
 #define ORDER_METHOD_2LEVEL  1
@@ -79,6 +80,9 @@ typedef struct LPCContext {
      */
     void (*lpc_compute_autocorr)(const double *data, int len, int lag,
                                  double *autoc);
+
+    // TODO: these should be allocated to reduce ABI compatibility issues
+    LLSModel lls_models[2];
 } LPCContext;