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/***
This file is part of PulseAudio.
Copyright 2014 David Henningsson, Canonical Ltd.
PulseAudio is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 2.1 of the License,
or (at your option) any later version.
PulseAudio is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "lfe-filter.h"
#include <pulse/xmalloc.h>
#include <pulsecore/flist.h>
#include <pulsecore/llist.h>
#include <pulsecore/filter/biquad.h>
#include <pulsecore/filter/crossover.h>
struct saved_state {
PA_LLIST_FIELDS(struct saved_state);
pa_memchunk chunk;
int64_t index;
struct lr4 lr4[PA_CHANNELS_MAX];
};
PA_STATIC_FLIST_DECLARE(lfe_state, 0, pa_xfree);
/* An LR4 filter, implemented as a chain of two Butterworth filters.
Currently the channel map is fixed so that a highpass filter is applied to all
channels except for the LFE channel, where a lowpass filter is applied.
This works well for e g stereo to 2.1/5.1/7.1 scenarios, where the remap engine
has calculated the LFE channel to be the average of all source channels.
*/
struct pa_lfe_filter {
int64_t index;
PA_LLIST_HEAD(struct saved_state, saved);
float crossover;
pa_channel_map cm;
pa_sample_spec ss;
size_t maxrewind;
bool active;
struct lr4 lr4[PA_CHANNELS_MAX];
};
static void remove_state(pa_lfe_filter_t *f, struct saved_state *s) {
PA_LLIST_REMOVE(struct saved_state, f->saved, s);
pa_memblock_unref(s->chunk.memblock);
pa_xfree(s);
}
pa_lfe_filter_t * pa_lfe_filter_new(const pa_sample_spec* ss, const pa_channel_map* cm, float crossover_freq, size_t maxrewind) {
pa_lfe_filter_t *f = pa_xnew0(struct pa_lfe_filter, 1);
f->crossover = crossover_freq;
f->cm = *cm;
f->ss = *ss;
f->maxrewind = maxrewind;
pa_lfe_filter_update_rate(f, ss->rate);
return f;
}
void pa_lfe_filter_free(pa_lfe_filter_t *f) {
while (f->saved)
remove_state(f, f->saved);
pa_xfree(f);
}
void pa_lfe_filter_reset(pa_lfe_filter_t *f) {
pa_lfe_filter_update_rate(f, f->ss.rate);
}
static void process_block(pa_lfe_filter_t *f, pa_memchunk *buf, bool store_result) {
int samples = buf->length / pa_frame_size(&f->ss);
void *garbage = store_result ? NULL : pa_xmalloc(buf->length);
if (f->ss.format == PA_SAMPLE_FLOAT32NE) {
int i;
float *data = pa_memblock_acquire_chunk(buf);
for (i = 0; i < f->cm.channels; i++)
lr4_process_float32(&f->lr4[i], samples, f->cm.channels, &data[i], garbage ? garbage : &data[i]);
pa_memblock_release(buf->memblock);
}
else if (f->ss.format == PA_SAMPLE_S16NE) {
int i;
short *data = pa_memblock_acquire_chunk(buf);
for (i = 0; i < f->cm.channels; i++)
lr4_process_s16(&f->lr4[i], samples, f->cm.channels, &data[i], garbage ? garbage : &data[i]);
pa_memblock_release(buf->memblock);
}
else pa_assert_not_reached();
pa_xfree(garbage);
f->index += samples;
}
pa_memchunk * pa_lfe_filter_process(pa_lfe_filter_t *f, pa_memchunk *buf) {
struct saved_state *s, *s2;
void *data;
if (!f->active)
return buf;
/* Remove old states (FIXME: we could do better than searching the entire array here?) */
PA_LLIST_FOREACH_SAFE(s, s2, f->saved)
if (s->index + (int64_t) (s->chunk.length / pa_frame_size(&f->ss) + f->maxrewind) < f->index)
remove_state(f, s);
/* Insert our existing state into the flist */
if ((s = pa_flist_pop(PA_STATIC_FLIST_GET(lfe_state))) == NULL)
s = pa_xnew(struct saved_state, 1);
PA_LLIST_INIT(struct saved_state, s);
/* TODO: This actually memcpys the entire chunk into a new allocation, because we need to retain the original
in case of rewinding. Investigate whether this can be avoided. */
data = pa_memblock_acquire_chunk(buf);
s->chunk.memblock = pa_memblock_new_malloced(pa_memblock_get_pool(buf->memblock), pa_xmemdup(data, buf->length), buf->length);
s->chunk.length = buf->length;
s->chunk.index = 0;
pa_memblock_release(buf->memblock);
s->index = f->index;
memcpy(s->lr4, f->lr4, sizeof(struct lr4) * f->cm.channels);
PA_LLIST_PREPEND(struct saved_state, f->saved, s);
process_block(f, buf, true);
return buf;
}
void pa_lfe_filter_update_rate(pa_lfe_filter_t *f, uint32_t new_rate) {
int i;
float biquad_freq = f->crossover / (new_rate / 2);
while (f->saved)
remove_state(f, f->saved);
f->index = 0;
f->ss.rate = new_rate;
if (biquad_freq <= 0 || biquad_freq >= 1) {
pa_log_warn("Crossover frequency (%f) outside range for sample rate %d", f->crossover, new_rate);
f->active = false;
return;
}
for (i = 0; i < f->cm.channels; i++)
lr4_set(&f->lr4[i], f->cm.map[i] == PA_CHANNEL_POSITION_LFE ? BQ_LOWPASS : BQ_HIGHPASS, biquad_freq);
f->active = true;
}
void pa_lfe_filter_rewind(pa_lfe_filter_t *f, size_t amount) {
struct saved_state *i, *s = NULL;
size_t samples = amount / pa_frame_size(&f->ss);
f->index -= samples;
/* Find the closest saved position */
PA_LLIST_FOREACH(i, f->saved) {
if (i->index > f->index)
continue;
if (s == NULL || i->index > s->index)
s = i;
}
if (s == NULL) {
pa_log_debug("Rewinding LFE filter %lu samples to position %lli. No saved state found", samples, (long long) f->index);
pa_lfe_filter_update_rate(f, f->ss.rate);
return;
}
pa_log_debug("Rewinding LFE filter %lu samples to position %lli. Found saved state at position %lli",
samples, (long long) f->index, (long long) s->index);
memcpy(f->lr4, s->lr4, sizeof(struct lr4) * f->cm.channels);
/* now fast forward to the actual position */
if (f->index > s->index) {
pa_memchunk x = s->chunk;
x.length = (f->index - s->index) * pa_frame_size(&f->ss);
if (x.length > s->chunk.length) {
pa_log_error("Hole in stream, cannot fast forward LFE filter");
return;
}
f->index = s->index;
process_block(f, &x, false);
}
}
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