[deb_ffmpeg.git] / ffmpeg / libavfilter / af_pan.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 63

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 channels 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;

    pan->pure_gains = are_gains_pure(pan);
    /* libswr supports any sample and packing formats */
    ff_set_common_formats(ctx, ff_all_formats(AVMEDIA_TYPE_AUDIO));

    formats = ff_all_samplerates();
    if (!formats)
        return AVERROR(ENOMEM);
    ff_set_common_samplerates(ctx, formats);

    // inlink supports any channel layout
    layouts = ff_all_channel_counts();
    ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);

    // outlink supports only requested output channel layout
    layouts = NULL;
    ff_add_channel_layout(&layouts,
                          pan->out_channel_layout ? pan->out_channel_layout :
                          FF_COUNT2LAYOUT(pan->nb_output_channels));
    ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts);
    return 0;
}

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 support 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 += 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,
};
Commit	Line	Data
2ba45a60 DM	1	/*
	2	* Copyright (c) 2002 Anders Johansson <ajh@atri.curtin.edu.au>
	3	* Copyright (c) 2011 Clément Bœsch <u pkh me>
	4	* Copyright (c) 2011 Nicolas George <nicolas.george@normalesup.org>
	5	*
	6	* This file is part of FFmpeg.
	7	*
	8	* FFmpeg is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; either
	11	* version 2.1 of the License, or (at your option) any later version.
	12	*
	13	* FFmpeg is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with FFmpeg; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	21	*/
	22
	23	/**
	24	* @file
	25	* Audio panning filter (channels mixing)
	26	* Original code written by Anders Johansson for MPlayer,
	27	* reimplemented for FFmpeg.
	28	*/
	29
	30	#include <stdio.h>
	31	#include "libavutil/avstring.h"
	32	#include "libavutil/channel_layout.h"
	33	#include "libavutil/opt.h"
	34	#include "libswresample/swresample.h"
	35	#include "audio.h"
	36	#include "avfilter.h"
	37	#include "formats.h"
	38	#include "internal.h"
	39
	40	#define MAX_CHANNELS 63
	41
	42	typedef struct PanContext {
	43	const AVClass *class;
	44	char *args;
	45	int64_t out_channel_layout;
	46	double gain[MAX_CHANNELS][MAX_CHANNELS];
	47	int64_t need_renorm;
	48	int need_renumber;
	49	int nb_output_channels;
	50
	51	int pure_gains;
	52	/* channel mapping specific */
	53	int channel_map[MAX_CHANNELS];
	54	struct SwrContext *swr;
	55	} PanContext;
	56
	57	static void skip_spaces(char **arg)
	58	{
	59	int len = 0;
	60
	61	sscanf(*arg, " %n", &len);
	62	*arg += len;
	63	}
	64
65	static int parse_channel_name(char *arg, int rchannel, int *rnamed)
66	{
67	char buf[8];
68	int len, i, channel_id = 0;
69	int64_t layout, layout0;
70
71	skip_spaces(arg);
72	/* try to parse a channel name, e.g. "FL" */
73	if (sscanf(*arg, "%7[A-Z]%n", buf, &len)) {
74	layout0 = layout = av_get_channel_layout(buf);
75	/* channel_id <- first set bit in layout */
76	for (i = 32; i > 0; i >>= 1) {
77	if (layout >= (int64_t)1 << i) {
78	channel_id += i;
79	layout >>= i;
80	}
81	}
82	/* reject layouts that are not a single channel */
83	if (channel_id >= MAX_CHANNELS \|\| layout0 != (int64_t)1 << channel_id)
84	return AVERROR(EINVAL);
85	*rchannel = channel_id;
86	*rnamed = 1;
87	*arg += len;
88	return 0;
89	}
90	/* try to parse a channel number, e.g. "c2" */
91	if (sscanf(*arg, "c%d%n", &channel_id, &len) &&
92	channel_id >= 0 && channel_id < MAX_CHANNELS) {
93	*rchannel = channel_id;
94	*rnamed = 0;
95	*arg += len;
96	return 0;
97	}
98	return AVERROR(EINVAL);
99	}
100
101	static av_cold int init(AVFilterContext *ctx)
102	{
103	PanContext *const pan = ctx->priv;
104	char arg, arg0, tokenizer, args = av_strdup(pan->args);
105	int out_ch_id, in_ch_id, len, named, ret;
106	int nb_in_channels[2] = { 0, 0 }; // number of unnamed and named input channels
107	double gain;
108
109	if (!pan->args) {
110	av_log(ctx, AV_LOG_ERROR,
111	"pan filter needs a channel layout and a set "
112	"of channels definitions as parameter\n");
113	return AVERROR(EINVAL);
114	}
115	if (!args)
116	return AVERROR(ENOMEM);
117	arg = av_strtok(args, "\|", &tokenizer);
118	ret = ff_parse_channel_layout(&pan->out_channel_layout,
119	&pan->nb_output_channels, arg, ctx);
120	if (ret < 0)
121	goto fail;
122
123	/* parse channel specifications */
124	while ((arg = arg0 = av_strtok(NULL, "\|", &tokenizer))) {
125	/* channel name */
126	if (parse_channel_name(&arg, &out_ch_id, &named)) {
127	av_log(ctx, AV_LOG_ERROR,
128	"Expected out channel name, got \"%.8s\"\n", arg);
129	ret = AVERROR(EINVAL);
130	goto fail;
131	}
132	if (named) {
133	if (!((pan->out_channel_layout >> out_ch_id) & 1)) {
134	av_log(ctx, AV_LOG_ERROR,
135	"Channel \"%.8s\" does not exist in the chosen layout\n", arg0);
136	ret = AVERROR(EINVAL);
137	goto fail;
138	}
139	/* get the channel number in the output channel layout:
140	* out_channel_layout & ((1 << out_ch_id) - 1) are all the
141	* channels that come before out_ch_id,
142	* so their count is the index of out_ch_id */
143	out_ch_id = av_get_channel_layout_nb_channels(pan->out_channel_layout & (((int64_t)1 << out_ch_id) - 1));
144	}
145	if (out_ch_id < 0 \|\| out_ch_id >= pan->nb_output_channels) {
146	av_log(ctx, AV_LOG_ERROR,
147	"Invalid out channel name \"%.8s\"\n", arg0);
148	ret = AVERROR(EINVAL);
149	goto fail;
150	}
151	skip_spaces(&arg);
152	if (*arg == '=') {
153	arg++;
154	} else if (*arg == '<') {
155	pan->need_renorm \|= (int64_t)1 << out_ch_id;
156	arg++;
157	} else {
158	av_log(ctx, AV_LOG_ERROR,
159	"Syntax error after channel name in \"%.8s\"\n", arg0);
160	ret = AVERROR(EINVAL);
161	goto fail;
162	}
163	/* gains */
164	while (1) {
165	gain = 1;
166	if (sscanf(arg, "%lf%n *%n", &gain, &len, &len))
167	arg += len;
168	if (parse_channel_name(&arg, &in_ch_id, &named)){
169	av_log(ctx, AV_LOG_ERROR,
170	"Expected in channel name, got \"%.8s\"\n", arg);
171	ret = AVERROR(EINVAL);
172	goto fail;
173	}
174	nb_in_channels[named]++;
175	if (nb_in_channels[!named]) {
176	av_log(ctx, AV_LOG_ERROR,
177	"Can not mix named and numbered channels\n");
178	ret = AVERROR(EINVAL);
179	goto fail;
180	}
181	pan->gain[out_ch_id][in_ch_id] = gain;
182	skip_spaces(&arg);
183	if (!*arg)
184	break;
185	if (*arg != '+') {
186	av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg);
187	ret = AVERROR(EINVAL);
188	goto fail;
189	}
190	arg++;
191	}
192	}
193	pan->need_renumber = !!nb_in_channels[1];
194
195	ret = 0;
196	fail:
197	av_free(args);
198	return ret;
199	}
200
201	static int are_gains_pure(const PanContext *pan)
202	{
203	int i, j;
204
205	for (i = 0; i < MAX_CHANNELS; i++) {
206	int nb_gain = 0;
207
208	for (j = 0; j < MAX_CHANNELS; j++) {
209	double gain = pan->gain[i][j];
210
211	/* channel mapping is effective only if 0% or 100% of a channel is
212	* selected... */
213	if (gain != 0. && gain != 1.)
214	return 0;
215	/* ...and if the output channel is only composed of one input */
216	if (gain && nb_gain++)
217	return 0;
218	}
219	}
220	return 1;
221	}
222
223	static int query_formats(AVFilterContext *ctx)
224	{
225	PanContext *pan = ctx->priv;
226	AVFilterLink *inlink = ctx->inputs[0];
227	AVFilterLink *outlink = ctx->outputs[0];
228	AVFilterFormats *formats = NULL;
229	AVFilterChannelLayouts *layouts;
230
231	pan->pure_gains = are_gains_pure(pan);
232	/* libswr supports any sample and packing formats */
233	ff_set_common_formats(ctx, ff_all_formats(AVMEDIA_TYPE_AUDIO));
234
235	formats = ff_all_samplerates();
236	if (!formats)
237	return AVERROR(ENOMEM);
238	ff_set_common_samplerates(ctx, formats);
239
240	// inlink supports any channel layout
241	layouts = ff_all_channel_counts();
242	ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);
243
244	// outlink supports only requested output channel layout
245	layouts = NULL;
246	ff_add_channel_layout(&layouts,
247	pan->out_channel_layout ? pan->out_channel_layout :
248	FF_COUNT2LAYOUT(pan->nb_output_channels));
249	ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts);
250	return 0;
251	}
252
253	static int config_props(AVFilterLink *link)
254	{
255	AVFilterContext *ctx = link->dst;
256	PanContext *pan = ctx->priv;
257	char buf[1024], *cur;
258	int i, j, k, r;
259	double t;
260
261	if (pan->need_renumber) {
262	// input channels were given by their name: renumber them
263	for (i = j = 0; i < MAX_CHANNELS; i++) {
264	if ((link->channel_layout >> i) & 1) {
265	for (k = 0; k < pan->nb_output_channels; k++)
266	pan->gain[k][j] = pan->gain[k][i];
267	j++;
268	}
269	}
270	}
271
272	// sanity check; can't be done in query_formats since the inlink
273	// channel layout is unknown at that time
274	if (link->channels > MAX_CHANNELS \|\|
275	pan->nb_output_channels > MAX_CHANNELS) {
276	av_log(ctx, AV_LOG_ERROR,
277	"af_pan support a maximum of %d channels. "
278	"Feel free to ask for a higher limit.\n", MAX_CHANNELS);
279	return AVERROR_PATCHWELCOME;
280	}
281
282	// init libswresample context
283	pan->swr = swr_alloc_set_opts(pan->swr,
284	pan->out_channel_layout, link->format, link->sample_rate,
285	link->channel_layout, link->format, link->sample_rate,
286	0, ctx);
287	if (!pan->swr)
288	return AVERROR(ENOMEM);
289	if (!link->channel_layout) {
290	if (av_opt_set_int(pan->swr, "ich", link->channels, 0) < 0)
291	return AVERROR(EINVAL);
292	}
293	if (!pan->out_channel_layout) {
294	if (av_opt_set_int(pan->swr, "och", pan->nb_output_channels, 0) < 0)
295	return AVERROR(EINVAL);
296	}
297
298	// gains are pure, init the channel mapping
299	if (pan->pure_gains) {
300
301	// get channel map from the pure gains
302	for (i = 0; i < pan->nb_output_channels; i++) {
303	int ch_id = -1;
304	for (j = 0; j < link->channels; j++) {
305	if (pan->gain[i][j]) {
306	ch_id = j;
307	break;
308	}
309	}
310	pan->channel_map[i] = ch_id;
311	}
312
313	av_opt_set_int(pan->swr, "icl", pan->out_channel_layout, 0);
314	av_opt_set_int(pan->swr, "uch", pan->nb_output_channels, 0);
315	swr_set_channel_mapping(pan->swr, pan->channel_map);
316	} else {
317	// renormalize
318	for (i = 0; i < pan->nb_output_channels; i++) {
319	if (!((pan->need_renorm >> i) & 1))
320	continue;
321	t = 0;
322	for (j = 0; j < link->channels; j++)
323	t += pan->gain[i][j];
324	if (t > -1E-5 && t < 1E-5) {
325	// t is almost 0 but not exactly, this is probably a mistake
326	if (t)
327	av_log(ctx, AV_LOG_WARNING,
328	"Degenerate coefficients while renormalizing\n");
329	continue;
330	}
331	for (j = 0; j < link->channels; j++)
332	pan->gain[i][j] /= t;
333	}
334	av_opt_set_int(pan->swr, "icl", link->channel_layout, 0);
335	av_opt_set_int(pan->swr, "ocl", pan->out_channel_layout, 0);
336	swr_set_matrix(pan->swr, pan->gain[0], pan->gain[1] - pan->gain[0]);
337	}
338
339	r = swr_init(pan->swr);
340	if (r < 0)
341	return r;
342
343	// summary
344	for (i = 0; i < pan->nb_output_channels; i++) {
345	cur = buf;
346	for (j = 0; j < link->channels; j++) {
347	r = snprintf(cur, buf + sizeof(buf) - cur, "%s%.3g i%d",
348	j ? " + " : "", pan->gain[i][j], j);
349	cur += FFMIN(buf + sizeof(buf) - cur, r);
350	}
351	av_log(ctx, AV_LOG_VERBOSE, "o%d = %s\n", i, buf);
352	}
353	// add channel mapping summary if possible
354	if (pan->pure_gains) {
355	av_log(ctx, AV_LOG_INFO, "Pure channel mapping detected:");
356	for (i = 0; i < pan->nb_output_channels; i++)
357	if (pan->channel_map[i] < 0)
358	av_log(ctx, AV_LOG_INFO, " M");
359	else
360	av_log(ctx, AV_LOG_INFO, " %d", pan->channel_map[i]);
361	av_log(ctx, AV_LOG_INFO, "\n");
362	return 0;
363	}
364	return 0;
365	}
366
367	static int filter_frame(AVFilterLink inlink, AVFrame insamples)
368	{
369	int ret;
370	int n = insamples->nb_samples;
371	AVFilterLink *const outlink = inlink->dst->outputs[0];
372	AVFrame *outsamples = ff_get_audio_buffer(outlink, n);
373	PanContext *pan = inlink->dst->priv;
374
375	if (!outsamples)
376	return AVERROR(ENOMEM);
377	swr_convert(pan->swr, outsamples->extended_data, n,
378	(void *)insamples->extended_data, n);
379	av_frame_copy_props(outsamples, insamples);
380	outsamples->channel_layout = outlink->channel_layout;
381	av_frame_set_channels(outsamples, outlink->channels);
382
383	ret = ff_filter_frame(outlink, outsamples);
384	av_frame_free(&insamples);
385	return ret;
386	}
387
388	static av_cold void uninit(AVFilterContext *ctx)
389	{
390	PanContext *pan = ctx->priv;
391	swr_free(&pan->swr);
392	}
393
394	#define OFFSET(x) offsetof(PanContext, x)
395
396	static const AVOption pan_options[] = {
397	{ "args", NULL, OFFSET(args), AV_OPT_TYPE_STRING, { .str = NULL }, CHAR_MIN, CHAR_MAX, AV_OPT_FLAG_AUDIO_PARAM \| AV_OPT_FLAG_FILTERING_PARAM },
398	{ NULL }
399	};
400
401	AVFILTER_DEFINE_CLASS(pan);
402
403	static const AVFilterPad pan_inputs[] = {
404	{
405	.name = "default",
406	.type = AVMEDIA_TYPE_AUDIO,
407	.config_props = config_props,
408	.filter_frame = filter_frame,
409	},
410	{ NULL }
411	};
412
413	static const AVFilterPad pan_outputs[] = {
414	{
415	.name = "default",
416	.type = AVMEDIA_TYPE_AUDIO,
417	},
418	{ NULL }
419	};
420
421	AVFilter ff_af_pan = {
422	.name = "pan",
423	.description = NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."),
424	.priv_size = sizeof(PanContext),
425	.priv_class = &pan_class,
426	.init = init,
427	.uninit = uninit,
428	.query_formats = query_formats,
429	.inputs = pan_inputs,
430	.outputs = pan_outputs,
431	};