[FFmpeg-soc] [soc]: r4435 - aacenc/aacenc.c

Benjamin Larsson banan at ludd.ltu.se
Thu Jun 11 22:25:46 CEST 2009


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).

MvH
Benjamin Larsson


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