aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/aacenc.c
diff options
context:
space:
mode:
authorNathan Caldwell <saintdev@gmail.com>2011-07-29 14:49:04 -0600
committerAlex Converse <alex.converse@gmail.com>2011-08-13 19:40:33 -0700
commit24efdea7fd024431f8ddd2b08c9390eba08c91f1 (patch)
treeaff5a6b5c2660b0a8ac176d0022ce8d555269629 /libavcodec/aacenc.c
parent51a1d4d94afe536b46c96299f4b50ca26e471fef (diff)
downloadffmpeg-24efdea7fd024431f8ddd2b08c9390eba08c91f1.tar.gz
aacenc: Fix number of coefficients used in a LFE channel.
The spec states: * Only the lowest 12 spectral coefficients of any LFE may be non-zero We were using the 12 lowest *bands*.
Diffstat (limited to 'libavcodec/aacenc.c')
-rw-r--r--libavcodec/aacenc.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/libavcodec/aacenc.c b/libavcodec/aacenc.c
index 5a1fc94eb5..449b200b41 100644
--- a/libavcodec/aacenc.c
+++ b/libavcodec/aacenc.c
@@ -540,6 +540,12 @@ static int aac_encode_frame(AVCodecContext *avctx,
wi[ch].window_shape = 0;
wi[ch].num_windows = 1;
wi[ch].grouping[0] = 1;
+
+ /* Only the lowest 12 coefficients are used in a LFE channel.
+ * The expression below results in only the bottom 8 coefficients
+ * being used for 11.025kHz to 16kHz sample rates.
+ */
+ ics->num_swb = s->samplerate_index >= 8 ? 1 : 3;
} else {
wi[ch] = s->psy.model->window(&s->psy, samples2, la, cur_channel,
ics->window_sequence[0]);
@@ -550,7 +556,7 @@ static int aac_encode_frame(AVCodecContext *avctx,
ics->use_kb_window[0] = wi[ch].window_shape;
ics->num_windows = wi[ch].num_windows;
ics->swb_sizes = s->psy.bands [ics->num_windows == 8];
- ics->num_swb = tag == TYPE_LFE ? 12 : s->psy.num_bands[ics->num_windows == 8];
+ ics->num_swb = tag == TYPE_LFE ? ics->num_swb : s->psy.num_bands[ics->num_windows == 8];
for (w = 0; w < ics->num_windows; w++)
ics->group_len[w] = wi[ch].grouping[w];