On Thu, Jun 11, 2009 at 10:25:46PM +0200, Benjamin Larsson wrote: > alexc wrote: > > Author: alexc > > Date: Thu Jun 11 19:23:53 2009 > > New Revision: 4435 > > > > Log: > > Use scaled MDCT initializer (trunk r18855). > > > > Modified: > > aacenc/aacenc.c > > > > Modified: aacenc/aacenc.c > > ============================================================================== > > --- aacenc/aacenc.c Thu Jun 11 18:53:44 2009 (r4434) > > +++ aacenc/aacenc.c Thu Jun 11 19:23:53 2009 (r4435) > > @@ -173,8 +173,8 @@ static av_cold int aac_encode_init(AVCod > > s->samplerate_index = i; > > > > dsputil_init(&s->dsp, avctx); > > - ff_mdct_init(&s->mdct1024, 11, 0); > > - ff_mdct_init(&s->mdct128, 8, 0); > > + ff_mdct_init(&s->mdct1024, 11, 0, 1.0); > > + ff_mdct_init(&s->mdct128, 8, 0, 1.0); > > // window init > > Hi, at least when doing the inverse transform the sign is flipped > compared to what most codecs usually use, for example the aac decoder > is/was adding a - to a scalefactor somewhere. So I just wonder if you > are sure that it should be 1.0 instead of -1.0? While it shouldn't > matter to the actual encode it might produce strange results for > synthetic metrics (psnr, rms, sse).
It's the same with AAC decoder - sign flipping is long incorporated into other place along with scaling. The right constant is either -512.0 or -1.0/512.0 but who cares. > MvH > Benjamin Larsson _______________________________________________ FFmpeg-soc mailing list [email protected] https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-soc
