aacenc: psy_3gpp_init(): Fix ath for the first line in each sfb.

Fix the MDCT line to frequency calculation for the first line in each sfb.
Use this value to calculate ATH.

Originally committed as revision 24231 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/libavcodec/aacpsy.c b/libavcodec/aacpsy.c
index 7a2a37f4aefc75b4948f1280ef53db9bd24a903b..78f4f08823e0b22d64f6405261da67f93a8bedc3 100644 (file)
--- a/libavcodec/aacpsy.c
+++ b/libavcodec/aacpsy.c
@@ -138,7 +138,7 @@ static av_cold int psy_3gpp_init(FFPsyContext *ctx) {
         }
         start = 0;
         for (g = 0; g < ctx->num_bands[j]; g++) {
-            minscale = ath(ctx->avctx->sample_rate * start / 1024.0, ATH_ADD);
+            minscale = ath(ctx->avctx->sample_rate * start / 1024.0 / 2.0, ATH_ADD);
             for (i = 1; i < ctx->bands[j][g]; i++)
                 minscale = FFMIN(minscale, ath(ctx->avctx->sample_rate * (start + i) / 1024.0 / 2.0, ATH_ADD));
             coeffs->ath[g] = minscale - minath;