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pan: add channel mapping capability.

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This commit is contained in:
Clément Bœsch
2012-01-18 12:00:16 +01:00
committed by Clément Bœsch
parent 66fdbcbbc9
commit 6728dd37ac
4 changed files with 175 additions and 8 deletions
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135
libavfilter/af_pan.c
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@ -30,12 +30,14 @@
#include <stdio.h>
#include "libavutil/audioconvert.h"
#include "libavutil/avstring.h"
#include "libavutil/opt.h"
#include "libswresample/swresample.h"
#include "avfilter.h"
#include "internal.h"
#define MAX_CHANNELS 63
typedef struct {
typedef struct PanContext {
int64_t out_channel_layout;
union {
double d[MAX_CHANNELS][MAX_CHANNELS];
@ -46,6 +48,16 @@ typedef struct {
int need_renumber;
int nb_input_channels;
int nb_output_channels;
int pure_gains;
void (*filter_samples)(struct PanContext*,
AVFilterBufferRef*,
AVFilterBufferRef*,
int);
/* channel mapping specific */
int channel_map[SWR_CH_MAX];
struct SwrContext *swr;
} PanContext;
static int parse_channel_name(char **arg, int *rchannel, int *rnamed)
@ -179,6 +191,31 @@ static av_cold int init(AVFilterContext *ctx, const char *args0, void *opaque)
return 0;
}
static void filter_samples_channel_mapping(PanContext *pan, AVFilterBufferRef *outsamples, AVFilterBufferRef *insamples, int n);
static void filter_samples_panning (PanContext *pan, AVFilterBufferRef *outsamples, AVFilterBufferRef *insamples, int n);
static int are_gains_pure(const PanContext *pan)
{
int i, j;
for (i = 0; i < MAX_CHANNELS; i++) {
int nb_gain = 0;
for (j = 0; j < MAX_CHANNELS; j++) {
double gain = pan->gain.d[i][j];
/* channel mapping is effective only if 0% or 100% of a channel is
* selected... */
if (gain != 0. && gain != 1.)
return 0;
/* ...and if the output channel is only composed of one input */
if (gain && nb_gain++)
return 0;
}
}
return 1;
}
static int query_formats(AVFilterContext *ctx)
{
PanContext *pan = ctx->priv;
@ -186,11 +223,21 @@ static int query_formats(AVFilterContext *ctx)
AVFilterLink *outlink = ctx->outputs[0];
AVFilterFormats *formats;
if (pan->nb_output_channels <= SWR_CH_MAX)
pan->pure_gains = are_gains_pure(pan);
if (pan->pure_gains) {
/* libswr supports any sample and packing formats */
avfilter_set_common_sample_formats(ctx, avfilter_make_all_formats(AVMEDIA_TYPE_AUDIO));
avfilter_set_common_packing_formats(ctx, avfilter_make_all_packing_formats());
pan->filter_samples = filter_samples_channel_mapping;
} else {
const enum AVSampleFormat sample_fmts[] = {AV_SAMPLE_FMT_S16, -1};
const int packing_fmts[] = {AVFILTER_PACKED, -1};
avfilter_set_common_sample_formats (ctx, avfilter_make_format_list(sample_fmts));
avfilter_set_common_packing_formats(ctx, avfilter_make_format_list(packing_fmts));
pan->filter_samples = filter_samples_panning;
}
// inlink supports any channel layout
formats = avfilter_make_all_channel_layouts();
@ -222,6 +269,44 @@ static int config_props(AVFilterLink *link)
}
}
}
// gains are pure, init the channel mapping
if (pan->pure_gains) {
// sanity check; can't be done in query_formats since the inlink
// channel layout is unknown at that time
if (pan->nb_input_channels > SWR_CH_MAX) {
av_log(ctx, AV_LOG_ERROR,
"libswresample support a maximum of %d channels. "
"Feel free to ask for a higher limit.\n", SWR_CH_MAX);
return AVERROR_PATCHWELCOME;
}
// get channel map from the pure gains
for (i = 0; i < pan->nb_output_channels; i++) {
int ch_id = -1;
for (j = 0; j < pan->nb_input_channels; j++) {
if (pan->gain.d[i][j]) {
ch_id = j;
break;
}
}
pan->channel_map[i] = ch_id;
}
// init libswresample context
pan->swr = swr_alloc_set_opts(pan->swr,
pan->out_channel_layout, link->format, link->sample_rate,
link->channel_layout, link->format, link->sample_rate,
0, ctx);
if (!pan->swr)
return AVERROR(ENOMEM);
av_opt_set_int(pan->swr, "icl", pan->out_channel_layout, 0);
av_opt_set_int(pan->swr, "uch", pan->nb_output_channels, 0);
swr_set_channel_mapping(pan->swr, pan->channel_map);
r = swr_init(pan->swr);
if (r < 0)
return r;
} else {
// renormalize
for (i = 0; i < pan->nb_output_channels; i++) {
if (!((pan->need_renorm >> i) & 1))
@ -239,6 +324,7 @@ static int config_props(AVFilterLink *link)
for (j = 0; j < pan->nb_input_channels; j++)
pan->gain.d[i][j] /= t;
}
}
// summary
for (i = 0; i < pan->nb_output_channels; i++) {
cur = buf;
@ -249,6 +335,17 @@ static int config_props(AVFilterLink *link)
}
av_log(ctx, AV_LOG_INFO, "o%d = %s\n", i, buf);
}
// add channel mapping summary if possible
if (pan->pure_gains) {
av_log(ctx, AV_LOG_INFO, "Pure channel mapping detected:");
for (i = 0; i < pan->nb_output_channels; i++)
if (pan->channel_map[i] < 0)
av_log(ctx, AV_LOG_INFO, " M");
else
av_log(ctx, AV_LOG_INFO, " %d", pan->channel_map[i]);
av_log(ctx, AV_LOG_INFO, "\n");
return 0;
}
// convert to integer
for (i = 0; i < pan->nb_output_channels; i++) {
for (j = 0; j < pan->nb_input_channels; j++) {
@ -261,19 +358,26 @@ static int config_props(AVFilterLink *link)
return 0;
}
static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples)
static void filter_samples_channel_mapping(PanContext *pan,
AVFilterBufferRef *outsamples,
AVFilterBufferRef *insamples,
int n)
{
PanContext *const pan = inlink->dst->priv;
int i, o, n = insamples->audio->nb_samples;
swr_convert(pan->swr, outsamples->data, n, (void *)insamples->data, n);
}
static void filter_samples_panning(PanContext *pan,
AVFilterBufferRef *outsamples,
AVFilterBufferRef *insamples,
int n)
{
int i, o;
/* input */
const int16_t *in = (int16_t *)insamples->data[0];
const int16_t *in_end = in + n * pan->nb_input_channels;
/* output */
AVFilterLink *const outlink = inlink->dst->outputs[0];
AVFilterBufferRef *outsamples = avfilter_get_audio_buffer(outlink, AV_PERM_WRITE, n);
int16_t *out = (int16_t *)outsamples->data[0];
for (; in < in_end; in += pan->nb_input_channels) {
@ -284,16 +388,33 @@ static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples)
*(out++) = v >> 8;
}
}
}
static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples)
{
int n = insamples->audio->nb_samples;
AVFilterLink *const outlink = inlink->dst->outputs[0];
AVFilterBufferRef *outsamples = avfilter_get_audio_buffer(outlink, AV_PERM_WRITE, n);
PanContext *pan = inlink->dst->priv;
pan->filter_samples(pan, outsamples, insamples, n);
avfilter_filter_samples(outlink, outsamples);
avfilter_unref_buffer(insamples);
}
static av_cold void uninit(AVFilterContext *ctx)
{
PanContext *pan = ctx->priv;
swr_free(&pan->swr);
}
AVFilter avfilter_af_pan = {
.name = "pan",
.description = NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."),
.priv_size = sizeof(PanContext),
.init = init,
.uninit = uninit,
.query_formats = query_formats,
.inputs = (const AVFilterPad[]) {