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filter-graph: add min plugin

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Output the lowest sample value of a number of inputs.
This commit is contained in:
Niklas Carlsson 2026-03-27 15:56:42 +01:00 • committed by Wim Taymans
parent ecc85f2959
commit a9d7023ec3
2 changed files with 94 additions and 0 deletions
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85
spa/plugins/filter-graph/plugin_builtin.c
View file

@ -2562,6 +2562,89 @@ static const struct spa_fga_descriptor max_desc = {
.cleanup = builtin_cleanup,
};
/** min */
static void min_run(void * Instance, unsigned long SampleCount)
{
struct builtin *impl = Instance;
float *out = impl->port[0];
float *src[8];
unsigned long n, p, n_srcs = 0;
if (out == NULL)
return;
for (p = 1; p < 9; p++) {
if (impl->port[p] != NULL)
src[n_srcs++] = impl->port[p];
}
if (n_srcs == 0) {
spa_memzero(out, SampleCount * sizeof(float));
} else if (n_srcs == 1) {
spa_memcpy(out, src[0], SampleCount * sizeof(float));
} else {
for (n = 0; n < SampleCount; n++)
out[n] = SPA_MIN(src[0][n], src[1][n]);
for (p = 2; p < n_srcs; p++) {
for (n = 0; n < SampleCount; n++)
out[n] = SPA_MIN(out[n], src[p][n]);
}
}
}
static struct spa_fga_port min_ports[] = {
{ .index = 0,
.name = "Out",
.flags = SPA_FGA_PORT_OUTPUT | SPA_FGA_PORT_AUDIO,
},
{ .index = 1,
.name = "In 1",
.flags = SPA_FGA_PORT_INPUT | SPA_FGA_PORT_AUDIO,
},
{ .index = 2,
.name = "In 2",
.flags = SPA_FGA_PORT_INPUT | SPA_FGA_PORT_AUDIO,
},
{ .index = 3,
.name = "In 3",
.flags = SPA_FGA_PORT_INPUT | SPA_FGA_PORT_AUDIO,
},
{ .index = 4,
.name = "In 4",
.flags = SPA_FGA_PORT_INPUT | SPA_FGA_PORT_AUDIO,
},
{ .index = 5,
.name = "In 5",
.flags = SPA_FGA_PORT_INPUT | SPA_FGA_PORT_AUDIO,
},
{ .index = 6,
.name = "In 6",
.flags = SPA_FGA_PORT_INPUT | SPA_FGA_PORT_AUDIO,
},
{ .index = 7,
.name = "In 7",
.flags = SPA_FGA_PORT_INPUT | SPA_FGA_PORT_AUDIO,
},
{ .index = 8,
.name = "In 8",
.flags = SPA_FGA_PORT_INPUT | SPA_FGA_PORT_AUDIO,
},
};
static const struct spa_fga_descriptor min_desc = {
.name = "min",
.flags = SPA_FGA_DESCRIPTOR_SUPPORTS_NULL_DATA,
.n_ports = SPA_N_ELEMENTS(min_ports),
.ports = min_ports,
.instantiate = builtin_instantiate,
.connect_port = builtin_connect_port,
.run = min_run,
.cleanup = builtin_cleanup,
};
/* DC blocking */
struct dcblock {
float xm1;
@ -3367,6 +3450,8 @@ static const struct spa_fga_descriptor * builtin_descriptor(unsigned long Index)
return &null_desc;
case 32:
return &convolver2_desc;
case 33:
return &min_desc;
}
return NULL;
}

9
src/modules/module-filter-chain.c
View file

@ -604,6 +604,15 @@ extern struct spa_handle_factory spa_filter_graph_factory;
* All input ports samples are checked to find the maximum value per sample. Unused
* input ports will be ignored and not cause overhead.
*
* ### Min
*
* Use the `min` plugin if you need to select the minimum value of a number of input ports.
*
* It has 8 input ports named "In 1" to "In 8" and one output port "Out".
*
* All input ports samples are checked to find the minimum value per sample. Unused
* input ports will be ignored and not cause overhead.
*
* ### dcblock
*
* Use the `dcblock` plugin implements a [DC blocker](https://www.dsprelated.com/freebooks/filters/DC_Blocker.html).