fft: avoid a signed overflow

[ffmpeg] / libavcodec / ac3enc_float.c

diff --git a/libavcodec/ac3enc_float.c b/libavcodec/ac3enc_float.c
index deec79ce8f35ce4f04857538e6998ad2eef09206..598c69db1b68272b12e99ede21025ed254c07601 100644 (file)
--- a/libavcodec/ac3enc_float.c
+++ b/libavcodec/ac3enc_float.c
@@ -35,8 +35,8 @@
 #if CONFIG_AC3_ENCODER
 #define AC3ENC_TYPE AC3ENC_TYPE_AC3
 #include "ac3enc_opts_template.c"
-static AVClass ac3enc_class = { "AC-3 Encoder", av_default_item_name,
-                                ac3_options, LIBAVUTIL_VERSION_INT };
+static const AVClass ac3enc_class = { "AC-3 Encoder", av_default_item_name,
+                                      ac3_options, LIBAVUTIL_VERSION_INT };
 #endif
 
 #include "ac3enc_template.c"
@@ -103,10 +103,11 @@ static int normalize_samples(AC3EncodeContext *s)
  */
 static void scale_coefficients(AC3EncodeContext *s)
 {
-    int chan_size = AC3_MAX_COEFS * AC3_MAX_BLOCKS;
-    s->ac3dsp.float_to_fixed24(s->fixed_coef_buffer + chan_size,
-                               s->mdct_coef_buffer  + chan_size,
-                               chan_size * s->channels);
+    int chan_size = AC3_MAX_COEFS * s->num_blocks;
+    int cpl       = s->cpl_on;
+    s->ac3dsp.float_to_fixed24(s->fixed_coef_buffer + (chan_size * !cpl),
+                               s->mdct_coef_buffer  + (chan_size * !cpl),
+                               chan_size * (s->channels + cpl));
 }
 
 
@@ -119,16 +120,27 @@ static void clip_coefficients(DSPContext *dsp, float *coef, unsigned int len)
 }
 
 
+/**
+ * Calculate a single coupling coordinate.
+ */
+static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
+{
+    float coord = 0.125;
+    if (energy_cpl > 0)
+        coord *= sqrtf(energy_ch / energy_cpl);
+    return FFMIN(coord, COEF_MAX);
+}
+
+
 #if CONFIG_AC3_ENCODER
 AVCodec ff_ac3_encoder = {
-    "ac3",
-    AVMEDIA_TYPE_AUDIO,
-    CODEC_ID_AC3,
-    sizeof(AC3EncodeContext),
-    ff_ac3_encode_init,
-    ff_ac3_float_encode_frame,
-    ff_ac3_encode_close,
-    NULL,
+    .name           = "ac3",
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = CODEC_ID_AC3,
+    .priv_data_size = sizeof(AC3EncodeContext),
+    .init           = ff_ac3_encode_init,
+    .encode         = ff_ac3_float_encode_frame,
+    .close          = ff_ac3_encode_close,
     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_FLT,AV_SAMPLE_FMT_NONE},
     .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
     .priv_class = &ac3enc_class,