[FFmpeg-cvslog] psymodel: dont apply lowpass filters with a cutoff close to the nyquist
Michael Niedermayer
git at videolan.org
Thu Mar 7 19:41:31 CET 2013
ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Thu Mar 7 19:28:30 2013 +0100| [fee5da6b0a79bed9dc849f216b6da1e03132b668] | committer: Michael Niedermayer
psymodel: dont apply lowpass filters with a cutoff close to the nyquist
The IIR filter numerically diverges in such cases, this could easily be
fixed but would make the filter slower on some platforms
Fixes Ticket2246
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=fee5da6b0a79bed9dc849f216b6da1e03132b668
---
libavcodec/psymodel.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libavcodec/psymodel.c b/libavcodec/psymodel.c
index a4a7cbb..09dd83d 100644
--- a/libavcodec/psymodel.c
+++ b/libavcodec/psymodel.c
@@ -106,7 +106,7 @@ av_cold struct FFPsyPreprocessContext* ff_psy_preprocess_init(AVCodecContext *av
if (!cutoff_coeff && avctx->codec_id == AV_CODEC_ID_AAC)
cutoff_coeff = 2.0 * AAC_CUTOFF(avctx) / avctx->sample_rate;
- if (cutoff_coeff)
+ if (cutoff_coeff && cutoff_coeff < 0.98)
ctx->fcoeffs = ff_iir_filter_init_coeffs(avctx, FF_FILTER_TYPE_BUTTERWORTH,
FF_FILTER_MODE_LOWPASS, FILT_ORDER,
cutoff_coeff, 0.0, 0.0);
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