avcodec/ac3enc: Avoid allocation for windowed_samples

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/ac3enc.c

@@ -2184,7 +2184,6 @@ av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
     AC3EncodeContext *s = avctx->priv_data;
 
     av_freep(&s->mdct_window);
-    av_freep(&s->windowed_samples);
     if (s->planar_samples)
         for (ch = 0; ch < s->channels; ch++)
             av_freep(&s->planar_samples[ch]);
@@ -2459,9 +2458,6 @@ static av_cold int allocate_buffers(AC3EncodeContext *s)
     int total_coefs    = AC3_MAX_COEFS * channel_blocks;
     const unsigned sampletype_size = SAMPLETYPE_SIZE(s);
 
-    if (!(s->windowed_samples = av_malloc(sampletype_size * AC3_WINDOW_SIZE)))
-        return AVERROR(ENOMEM);
-
     if (!FF_ALLOCZ_TYPED_ARRAY(s->planar_samples,  s->channels))
         return AVERROR(ENOMEM);
 

libavcodec/ac3enc.h

@@ -30,6 +30,7 @@
 
 #include <stdint.h>
 
+#include "libavutil/mem_internal.h"
 #include "libavutil/opt.h"
 #include "libavutil/tx.h"
 
@@ -232,7 +233,6 @@ typedef struct AC3EncodeContext {
     int frame_bits;                         ///< all frame bits except exponents and mantissas
     int exponent_bits;                      ///< number of bits used for exponents
 
-    void *windowed_samples;
     uint8_t **planar_samples;
     uint8_t *bap_buffer;
     uint8_t *bap1_buffer;
@@ -259,6 +259,11 @@ typedef struct AC3EncodeContext {
 
     /* AC-3 vs. E-AC-3 function pointers */
     void (*output_frame_header)(struct AC3EncodeContext *s);
+
+    union {
+        DECLARE_ALIGNED(32, float,   windowed_samples_float)[AC3_WINDOW_SIZE];
+        DECLARE_ALIGNED(32, int32_t, windowed_samples_fixed)[AC3_WINDOW_SIZE];
+    };
 } AC3EncodeContext;
 
 extern const AVChannelLayout ff_ac3_ch_layouts[19];

libavcodec/ac3enc_template.c

@@ -37,6 +37,11 @@
 #include "ac3enc.h"
 #include "eac3enc.h"
 
+#if AC3ENC_FLOAT
+#define RENAME(element) element ## _float
+#else
+#define RENAME(element) element ## _fixed
+#endif
 
 /*
  * Apply the MDCT to input samples to generate frequency coefficients.
@@ -51,15 +56,16 @@ static void apply_mdct(AC3EncodeContext *s)
         for (blk = 0; blk < s->num_blocks; blk++) {
             AC3Block *block = &s->blocks[blk];
             const SampleType *input_samples = (SampleType*)s->planar_samples[ch] + blk * AC3_BLOCK_SIZE;
+            SampleType *windowed_samples = s->RENAME(windowed_samples);
 
-            s->fdsp->vector_fmul(s->windowed_samples, input_samples,
+            s->fdsp->vector_fmul(windowed_samples, input_samples,
                                  s->mdct_window, AC3_BLOCK_SIZE);
-            s->fdsp->vector_fmul_reverse((SampleType*)s->windowed_samples + AC3_BLOCK_SIZE,
+            s->fdsp->vector_fmul_reverse(windowed_samples + AC3_BLOCK_SIZE,
                                          &input_samples[AC3_BLOCK_SIZE],
                                          s->mdct_window, AC3_BLOCK_SIZE);
 
             s->tx_fn(s->tx, block->mdct_coef[ch+1],
-                     s->windowed_samples, sizeof(float));
+                     windowed_samples, sizeof(*windowed_samples));
         }
     }
 }