FFmpeg/libavfilter/af_pan.c
Moritz Barsnick efbc37a757 lavfi/pan: renormalize negative gain coefficients properly
The parser for the outdef will accept a negative value for the first
named channel's gain. As negative values effectively only invert the
phase of the signal, and not negate the level, the gains' absolute
values must be used to correctly accumulate the levels.

Signed-off-by: Moritz Barsnick <barsnick@gmx.net>
Reviewed-by: Nicolas George <george@nsup.org>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
2016-10-11 03:27:59 +02:00

434 lines
14 KiB
C

/*
* Copyright (c) 2002 Anders Johansson <ajh@atri.curtin.edu.au>
* Copyright (c) 2011 Clément Bœsch <u pkh me>
* Copyright (c) 2011 Nicolas George <nicolas.george@normalesup.org>
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Audio panning filter (channels mixing)
* Original code written by Anders Johansson for MPlayer,
* reimplemented for FFmpeg.
*/
#include <stdio.h>
#include "libavutil/avstring.h"
#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "libswresample/swresample.h"
#include "audio.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#define MAX_CHANNELS 64
typedef struct PanContext {
const AVClass *class;
char *args;
int64_t out_channel_layout;
double gain[MAX_CHANNELS][MAX_CHANNELS];
int64_t need_renorm;
int need_renumber;
int nb_output_channels;
int pure_gains;
/* channel mapping specific */
int channel_map[MAX_CHANNELS];
struct SwrContext *swr;
} PanContext;
static void skip_spaces(char **arg)
{
int len = 0;
sscanf(*arg, " %n", &len);
*arg += len;
}
static int parse_channel_name(char **arg, int *rchannel, int *rnamed)
{
char buf[8];
int len, i, channel_id = 0;
int64_t layout, layout0;
skip_spaces(arg);
/* try to parse a channel name, e.g. "FL" */
if (sscanf(*arg, "%7[A-Z]%n", buf, &len)) {
layout0 = layout = av_get_channel_layout(buf);
/* channel_id <- first set bit in layout */
for (i = 32; i > 0; i >>= 1) {
if (layout >= (int64_t)1 << i) {
channel_id += i;
layout >>= i;
}
}
/* reject layouts that are not a single channel */
if (channel_id >= MAX_CHANNELS || layout0 != (int64_t)1 << channel_id)
return AVERROR(EINVAL);
*rchannel = channel_id;
*rnamed = 1;
*arg += len;
return 0;
}
/* try to parse a channel number, e.g. "c2" */
if (sscanf(*arg, "c%d%n", &channel_id, &len) &&
channel_id >= 0 && channel_id < MAX_CHANNELS) {
*rchannel = channel_id;
*rnamed = 0;
*arg += len;
return 0;
}
return AVERROR(EINVAL);
}
static av_cold int init(AVFilterContext *ctx)
{
PanContext *const pan = ctx->priv;
char *arg, *arg0, *tokenizer, *args = av_strdup(pan->args);
int out_ch_id, in_ch_id, len, named, ret;
int nb_in_channels[2] = { 0, 0 }; // number of unnamed and named input channels
double gain;
if (!pan->args) {
av_log(ctx, AV_LOG_ERROR,
"pan filter needs a channel layout and a set "
"of channel definitions as parameter\n");
return AVERROR(EINVAL);
}
if (!args)
return AVERROR(ENOMEM);
arg = av_strtok(args, "|", &tokenizer);
ret = ff_parse_channel_layout(&pan->out_channel_layout,
&pan->nb_output_channels, arg, ctx);
if (ret < 0)
goto fail;
/* parse channel specifications */
while ((arg = arg0 = av_strtok(NULL, "|", &tokenizer))) {
/* channel name */
if (parse_channel_name(&arg, &out_ch_id, &named)) {
av_log(ctx, AV_LOG_ERROR,
"Expected out channel name, got \"%.8s\"\n", arg);
ret = AVERROR(EINVAL);
goto fail;
}
if (named) {
if (!((pan->out_channel_layout >> out_ch_id) & 1)) {
av_log(ctx, AV_LOG_ERROR,
"Channel \"%.8s\" does not exist in the chosen layout\n", arg0);
ret = AVERROR(EINVAL);
goto fail;
}
/* get the channel number in the output channel layout:
* out_channel_layout & ((1 << out_ch_id) - 1) are all the
* channels that come before out_ch_id,
* so their count is the index of out_ch_id */
out_ch_id = av_get_channel_layout_nb_channels(pan->out_channel_layout & (((int64_t)1 << out_ch_id) - 1));
}
if (out_ch_id < 0 || out_ch_id >= pan->nb_output_channels) {
av_log(ctx, AV_LOG_ERROR,
"Invalid out channel name \"%.8s\"\n", arg0);
ret = AVERROR(EINVAL);
goto fail;
}
skip_spaces(&arg);
if (*arg == '=') {
arg++;
} else if (*arg == '<') {
pan->need_renorm |= (int64_t)1 << out_ch_id;
arg++;
} else {
av_log(ctx, AV_LOG_ERROR,
"Syntax error after channel name in \"%.8s\"\n", arg0);
ret = AVERROR(EINVAL);
goto fail;
}
/* gains */
while (1) {
gain = 1;
if (sscanf(arg, "%lf%n *%n", &gain, &len, &len))
arg += len;
if (parse_channel_name(&arg, &in_ch_id, &named)){
av_log(ctx, AV_LOG_ERROR,
"Expected in channel name, got \"%.8s\"\n", arg);
ret = AVERROR(EINVAL);
goto fail;
}
nb_in_channels[named]++;
if (nb_in_channels[!named]) {
av_log(ctx, AV_LOG_ERROR,
"Can not mix named and numbered channels\n");
ret = AVERROR(EINVAL);
goto fail;
}
pan->gain[out_ch_id][in_ch_id] = gain;
skip_spaces(&arg);
if (!*arg)
break;
if (*arg != '+') {
av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg);
ret = AVERROR(EINVAL);
goto fail;
}
arg++;
}
}
pan->need_renumber = !!nb_in_channels[1];
ret = 0;
fail:
av_free(args);
return ret;
}
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[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;
AVFilterLink *inlink = ctx->inputs[0];
AVFilterLink *outlink = ctx->outputs[0];
AVFilterFormats *formats = NULL;
AVFilterChannelLayouts *layouts;
int ret;
pan->pure_gains = are_gains_pure(pan);
/* libswr supports any sample and packing formats */
if ((ret = ff_set_common_formats(ctx, ff_all_formats(AVMEDIA_TYPE_AUDIO))) < 0)
return ret;
formats = ff_all_samplerates();
if ((ret = ff_set_common_samplerates(ctx, formats)) < 0)
return ret;
// inlink supports any channel layout
layouts = ff_all_channel_counts();
if ((ret = ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts)) < 0)
return ret;
// outlink supports only requested output channel layout
layouts = NULL;
if ((ret = ff_add_channel_layout(&layouts,
pan->out_channel_layout ? pan->out_channel_layout :
FF_COUNT2LAYOUT(pan->nb_output_channels))) < 0)
return ret;
return ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts);
}
static int config_props(AVFilterLink *link)
{
AVFilterContext *ctx = link->dst;
PanContext *pan = ctx->priv;
char buf[1024], *cur;
int i, j, k, r;
double t;
if (pan->need_renumber) {
// input channels were given by their name: renumber them
for (i = j = 0; i < MAX_CHANNELS; i++) {
if ((link->channel_layout >> i) & 1) {
for (k = 0; k < pan->nb_output_channels; k++)
pan->gain[k][j] = pan->gain[k][i];
j++;
}
}
}
// sanity check; can't be done in query_formats since the inlink
// channel layout is unknown at that time
if (link->channels > MAX_CHANNELS ||
pan->nb_output_channels > MAX_CHANNELS) {
av_log(ctx, AV_LOG_ERROR,
"af_pan supports a maximum of %d channels. "
"Feel free to ask for a higher limit.\n", MAX_CHANNELS);
return AVERROR_PATCHWELCOME;
}
// 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);
if (!link->channel_layout) {
if (av_opt_set_int(pan->swr, "ich", link->channels, 0) < 0)
return AVERROR(EINVAL);
}
if (!pan->out_channel_layout) {
if (av_opt_set_int(pan->swr, "och", pan->nb_output_channels, 0) < 0)
return AVERROR(EINVAL);
}
// gains are pure, init the channel mapping
if (pan->pure_gains) {
// get channel map from the pure gains
for (i = 0; i < pan->nb_output_channels; i++) {
int ch_id = -1;
for (j = 0; j < link->channels; j++) {
if (pan->gain[i][j]) {
ch_id = j;
break;
}
}
pan->channel_map[i] = ch_id;
}
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);
} else {
// renormalize
for (i = 0; i < pan->nb_output_channels; i++) {
if (!((pan->need_renorm >> i) & 1))
continue;
t = 0;
for (j = 0; j < link->channels; j++)
t += fabs(pan->gain[i][j]);
if (t > -1E-5 && t < 1E-5) {
// t is almost 0 but not exactly, this is probably a mistake
if (t)
av_log(ctx, AV_LOG_WARNING,
"Degenerate coefficients while renormalizing\n");
continue;
}
for (j = 0; j < link->channels; j++)
pan->gain[i][j] /= t;
}
av_opt_set_int(pan->swr, "icl", link->channel_layout, 0);
av_opt_set_int(pan->swr, "ocl", pan->out_channel_layout, 0);
swr_set_matrix(pan->swr, pan->gain[0], pan->gain[1] - pan->gain[0]);
}
r = swr_init(pan->swr);
if (r < 0)
return r;
// summary
for (i = 0; i < pan->nb_output_channels; i++) {
cur = buf;
for (j = 0; j < link->channels; j++) {
r = snprintf(cur, buf + sizeof(buf) - cur, "%s%.3g i%d",
j ? " + " : "", pan->gain[i][j], j);
cur += FFMIN(buf + sizeof(buf) - cur, r);
}
av_log(ctx, AV_LOG_VERBOSE, "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;
}
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
{
int ret;
int n = insamples->nb_samples;
AVFilterLink *const outlink = inlink->dst->outputs[0];
AVFrame *outsamples = ff_get_audio_buffer(outlink, n);
PanContext *pan = inlink->dst->priv;
if (!outsamples)
return AVERROR(ENOMEM);
swr_convert(pan->swr, outsamples->extended_data, n,
(void *)insamples->extended_data, n);
av_frame_copy_props(outsamples, insamples);
outsamples->channel_layout = outlink->channel_layout;
av_frame_set_channels(outsamples, outlink->channels);
ret = ff_filter_frame(outlink, outsamples);
av_frame_free(&insamples);
return ret;
}
static av_cold void uninit(AVFilterContext *ctx)
{
PanContext *pan = ctx->priv;
swr_free(&pan->swr);
}
#define OFFSET(x) offsetof(PanContext, x)
static const AVOption pan_options[] = {
{ "args", NULL, OFFSET(args), AV_OPT_TYPE_STRING, { .str = NULL }, CHAR_MIN, CHAR_MAX, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM },
{ NULL }
};
AVFILTER_DEFINE_CLASS(pan);
static const AVFilterPad pan_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.config_props = config_props,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad pan_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
},
{ NULL }
};
AVFilter ff_af_pan = {
.name = "pan",
.description = NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."),
.priv_size = sizeof(PanContext),
.priv_class = &pan_class,
.init = init,
.uninit = uninit,
.query_formats = query_formats,
.inputs = pan_inputs,
.outputs = pan_outputs,
};