[Libav-user] Using rematrix_maxval

Paul B Mahol onemda at gmail.com
Mon Dec 4 22:42:57 EET 2017

On 12/4/17, gaetan.dubreil at free.fr <gaetan.dubreil at free.fr> wrote:
> Hello,
> When I resample an audio file to the AV_SAMPLE_FMT_DBLP sample format with
> libswresample, I get some values out of the interval -1, 1. It happens when
> I resample from 44100 to 48000 for example. I tried to use the
> rematrix_maxval option like this :
>   SwrContext *ctx = swr_alloc();
>   ...
>   av_opt_set_double(ctx, "rematrix_maxval", 1, 0);
>   swr_init(ctx);
> but it have no effect.
> Does the way I use it are supposed to guarantee values between -1 and 1 or
> did I not understand its purpose?
> I can solve the problem by setting the rematrix_volume option to 0.96 but
> I'm not sure it will work in all cases.
> I wonder if being in 32 bits can be the cause of the problem.

I belive this is normal behaviour, to tell more we would need sample
that exhibits
this issue.

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