[FFmpeg-cvslog] aacenc: new default cutoff

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Sun Jul 29 19:49:22 2012 +0200| [72dabdfc58064fcb249f26fc7afca2221f18a832] | committer: Michael Niedermayer

aacenc: new default cutoff

Improves subjective quality

Formula and testing by: kamedo2 <fujisakihir90 at yahoo.co.jp>
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=72dabdfc58064fcb249f26fc7afca2221f18a832
---

 libavcodec/aacpsy.c   |    2 +-
 libavcodec/psymodel.c |    3 +++
 libavcodec/psymodel.h |    2 ++
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/libavcodec/aacpsy.c b/libavcodec/aacpsy.c
index 585a249..a9a8988 100644
--- a/libavcodec/aacpsy.c
+++ b/libavcodec/aacpsy.c
@@ -292,7 +292,7 @@ static av_cold int psy_3gpp_init(FFPsyContext *ctx) {
     int i, j, g, start;
     float prev, minscale, minath, minsnr, pe_min;
     const int chan_bitrate = ctx->avctx->bit_rate / ctx->avctx->channels;
-    const int bandwidth    = ctx->avctx->cutoff ? ctx->avctx->cutoff : ctx->avctx->sample_rate / 2;
+    const int bandwidth    = ctx->avctx->cutoff ? ctx->avctx->cutoff : AAC_CUTOFF(ctx->avctx);
     const float num_bark   = calc_bark((float)bandwidth);
 
     ctx->model_priv_data = av_mallocz(sizeof(AacPsyContext));
diff --git a/libavcodec/psymodel.c b/libavcodec/psymodel.c
index a17aecc..bdd2509 100644
--- a/libavcodec/psymodel.c
+++ b/libavcodec/psymodel.c
@@ -100,6 +100,9 @@ av_cold struct FFPsyPreprocessContext* ff_psy_preprocess_init(AVCodecContext *av
     if (avctx->cutoff > 0)
         cutoff_coeff = 2.0 * avctx->cutoff / avctx->sample_rate;
 
+    if (!cutoff_coeff && avctx->codec_id == CODEC_ID_AAC)
+        cutoff_coeff = 2.0 * AAC_CUTOFF(avctx) / avctx->sample_rate;
+
     if (cutoff_coeff)
     ctx->fcoeffs = ff_iir_filter_init_coeffs(avctx, FF_FILTER_TYPE_BUTTERWORTH,
                                              FF_FILTER_MODE_LOWPASS, FILT_ORDER,
diff --git a/libavcodec/psymodel.h b/libavcodec/psymodel.h
index 317974b..37c8191 100644
--- a/libavcodec/psymodel.h
+++ b/libavcodec/psymodel.h
@@ -29,6 +29,8 @@
 /** maximum number of channels */
 #define PSY_MAX_CHANS 20
 
+#define AAC_CUTOFF(s) (s->bit_rate ? FFMIN3(4000 + s->bit_rate/8, 12000 + s->bit_rate/32, s->sample_rate / 2) : (s->sample_rate / 2))
+
 /**
  * single band psychoacoustic information
  */