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aacenc: new default cutoff

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Improves subjective quality

Formula and testing by: kamedo2 <fujisakihir90@yahoo.co.jp>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2012-07-29 19:49:22 +02:00
parent 981d97f697
commit 72dabdfc58
3 changed files with 6 additions and 1 deletions
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2
libavcodec/aacpsy.c
View File

@ -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));

3
libavcodec/psymodel.c
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@ -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,

2
libavcodec/psymodel.h
View File

@ -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
*/