[pulseaudio-discuss] [PATCH v2] resampler: Support speex resampler compiled with FIXED_POINT

[Peter Meerwald]

> When Speex is compiled with FIXED_POINT defined, it scales float input
> to ±32768 instead of ±1. In order to make floating point resampler
> work with speex compiled with FIXED_POINT, we need to rescale the input
> to speex. This rescaling does not hurt normal speex, so we do it
> unconditionally.

floating point multiplication is quite costly on some platforms, I'd 
rather not force everyone to scale every sample twice for no good reason

p.

> Signed-off-by: Alexander E. Patrakov <patrakov at gmail.com>
> Reported-by: Fahad Arslan <fahad_arslan at mentor.com>
> Original-author: Peter Meerwald <pmeerw at pmeerw.net>
> Cc: Damir Jelić <poljarinho at gmail.com>
> Cc: Peter Meerwald <pmeerw at pmeerw.net>
> ---
>  src/pulsecore/resampler.c | 25 ++++++++++++++++++++++---
>  1 file changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/src/pulsecore/resampler.c b/src/pulsecore/resampler.c
> index 1153281..fca6887 100644
> --- a/src/pulsecore/resampler.c
> +++ b/src/pulsecore/resampler.c
> @@ -1473,9 +1473,11 @@ static int libsamplerate_init(pa_resampler *r) {
>  /*** speex based implementation ***/
>  
>  static unsigned speex_resample_float(pa_resampler *r, const pa_memchunk *input, unsigned in_n_frames, pa_memchunk *output, unsigned *out_n_frames) {
> -    float *in, *out;
> +    pa_memblock *b;
> +    float *in, *out, *t;
>      uint32_t inf = in_n_frames, outf = *out_n_frames;
>      SpeexResamplerState *state;
> +    unsigned i, nsamples;
>  
>      pa_assert(r);
>      pa_assert(input);
> @@ -1484,12 +1486,29 @@ static unsigned speex_resample_float(pa_resampler *r, const pa_memchunk *input,
>  
>      state = r->impl.data;
>  
> +    nsamples = r->work_channels * in_n_frames;
> +    b = pa_memblock_new(r->mempool, nsamples * sizeof(float));
> +    t = pa_memblock_acquire(b);
> +
>      in = pa_memblock_acquire_chunk(input);
> -    out = pa_memblock_acquire_chunk(output);
>  
> -    pa_assert_se(speex_resampler_process_interleaved_float(state, in, &inf, out, &outf) == 0);
> +    for (i = 0; i < nsamples; i++)
> +        t[i] = 32768.0f * in[i];
>  
>      pa_memblock_release(input->memblock);
> +
> +    out = pa_memblock_acquire_chunk(output);
> +
> +    pa_assert_se(speex_resampler_process_interleaved_float(state, t, &inf, out, &outf) == 0);
> +
> +    pa_memblock_release(b);
> +    pa_memblock_unref(b);
> +
> +    nsamples = r->work_channels * outf;
> +
> +    for (i = 0; i < nsamples; i++)
> +        out[i] = out[i] * (1.0f / 32768.0f);
> +
>      pa_memblock_release(output->memblock);
>  
>      pa_assert(inf == in_n_frames);
> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)