aacenc: replace scale factor warning by assert

The code would crash after printing the warning

Fixes CID717903, CID717904
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/aacenc.c

@@ -385,8 +385,7 @@ static void encode_scale_factors(AVCodecContext *avctx, AACEncContext *s,
         for (i = 0; i < sce->ics.max_sfb; i++) {
             if (!sce->zeroes[w*16 + i]) {
                 diff = sce->sf_idx[w*16 + i] - off + SCALE_DIFF_ZERO;
-                if (diff < 0 || diff > 120)
-                    av_log(avctx, AV_LOG_ERROR, "Scalefactor difference is too big to be coded\n");
+                av_assert0(diff >= 0 && diff <= 120);
                 off = sce->sf_idx[w*16 + i];
                 put_bits(&s->pb, ff_aac_scalefactor_bits[diff], ff_aac_scalefactor_code[diff]);
             }