[pulseaudio-discuss] [PATCH] remap: Add 4-channel to mono channel rearrangement

[Peter Meerwald]

> Signed-off-by: Peter Meerwald <pmeerw at pmeerw.net>
> ---
>  src/pulsecore/remap.c |   36 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 35 insertions(+), 1 deletion(-)
> 
> diff --git a/src/pulsecore/remap.c b/src/pulsecore/remap.c
> index 37213d5..09d4837 100644
> --- a/src/pulsecore/remap.c
> +++ b/src/pulsecore/remap.c
> @@ -239,9 +239,12 @@ static void remap_channels_matrix_float32ne_c(pa_remap_t *m, float *dst, const f
>      }
>  }
>  
> +/* Produce an array containing input channel indices to map to output channels.
> + * If the output channel is empty, the array element is -1. */
>  bool pa_setup_remap_arrange(const pa_remap_t *m, int8_t arrange[PA_CHANNELS_MAX]) {
>      unsigned ic, oc;
>      unsigned n_ic, n_oc;
> +    unsigned count_output = 0;
>  
>      pa_assert(m);
>  
> @@ -262,10 +265,22 @@ bool pa_setup_remap_arrange(const pa_remap_t *m, int8_t arrange[PA_CHANNELS_MAX]
>                  return false;
>  
>              arrange[oc] = ic;
> +            count_output++;
>          }
>      }
>  
> -    return true;
> +    return count_output > 0;
> +}
> +
> +static void remap_arrange_mono_s16ne_c(pa_remap_t *m, int16_t *dst, const int16_t *src, unsigned n) {
> +    const unsigned n_ic = m->i_ss.channels;
> +    const int8_t *arrange = m->state;
> +
> +    src += arrange[0];
> +    for (; n > 0; n--) {
> +        *dst++ = *src;
> +        src += n_ic;
> +    }
>  }
>  
>  static void remap_arrange_stereo_s16ne_c(pa_remap_t *m, int16_t *dst, const int16_t *src, unsigned n) {
> @@ -295,6 +310,17 @@ static void remap_arrange_ch4_s16ne_c(pa_remap_t *m, int16_t *dst, const int16_t
>      }
>  }
>  
> +static void remap_arrange_mono_float32ne_c(pa_remap_t *m, float *dst, const float *src, unsigned n) {
> +    const unsigned n_ic = m->i_ss.channels;
> +    const int8_t *arrange = m->state;
> +
> +    src += arrange[0];
> +    for (; n > 0; n--) {
> +        *dst++ = *src;
> +        src += n_ic;
> +    }
> +}
> +
>  static void remap_arrange_stereo_float32ne_c(pa_remap_t *m, float *dst, const float *src, unsigned n) {
>      const unsigned n_ic = m->i_ss.channels;
>      const int8_t *arrange = m->state;
> @@ -370,6 +396,14 @@ static void init_remap_c(pa_remap_t *m) {
>          pa_log_info("Using 4-channel to mono remapping");
>          pa_set_remap_func(m, (pa_do_remap_func_t) remap_ch4_to_mono_s16ne_c,
>              (pa_do_remap_func_t) remap_ch4_to_mono_float32ne_c);
> +    } else if (pa_setup_remap_arrange(m, arrange) && n_oc == 1) {
> +
> +        pa_log_info("Using mono arrange remapping");
> +        pa_set_remap_func(m, (pa_do_remap_func_t) remap_arrange_mono_s16ne_c,
> +            (pa_do_remap_func_t) remap_arrange_mono_float32ne_c);
> +
> +        /* setup state */
> +        m->state = pa_xnewdup(int8_t, arrange, PA_CHANNELS_MAX);
>      } else if (pa_setup_remap_arrange(m, arrange) && n_oc == 2) {
>  
>          pa_log_info("Using stereo arrange remapping");
> 

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-- 

Peter Meerwald
+43-664-2444418 (mobile)