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>
6 * This file is part of FFmpeg.
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.
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.
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
25 * Audio panning filter (channels mixing)
26 * Original code written by Anders Johansson for MPlayer,
27 * reimplemented for FFmpeg.
31 #include "libavutil/avstring.h"
32 #include "libavutil/channel_layout.h"
33 #include "libavutil/opt.h"
34 #include "libswresample/swresample.h"
40 #define MAX_CHANNELS 63
42 typedef struct PanContext
{
45 int64_t out_channel_layout
;
46 double gain
[MAX_CHANNELS
][MAX_CHANNELS
];
49 int nb_output_channels
;
52 /* channel mapping specific */
53 int channel_map
[MAX_CHANNELS
];
54 struct SwrContext
*swr
;
57 static void skip_spaces(char **arg
)
61 sscanf(*arg
, " %n", &len
);
65 static int parse_channel_name(char **arg
, int *rchannel
, int *rnamed
)
68 int len
, i
, channel_id
= 0;
69 int64_t layout
, layout0
;
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
) {
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
;
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
;
98 return AVERROR(EINVAL
);
101 static av_cold
int init(AVFilterContext
*ctx
)
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
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
);
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
);
123 /* parse channel specifications */
124 while ((arg
= arg0
= av_strtok(NULL
, "|", &tokenizer
))) {
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
);
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
);
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));
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
);
154 } else if (*arg
== '<') {
155 pan
->need_renorm
|= (int64_t)1 << out_ch_id
;
158 av_log(ctx
, AV_LOG_ERROR
,
159 "Syntax error after channel name in \"%.8s\"\n", arg0
);
160 ret
= AVERROR(EINVAL
);
166 if (sscanf(arg
, "%lf%n *%n", &gain
, &len
, &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
);
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
);
181 pan
->gain
[out_ch_id
][in_ch_id
] = gain
;
186 av_log(ctx
, AV_LOG_ERROR
, "Syntax error near \"%.8s\"\n", arg
);
187 ret
= AVERROR(EINVAL
);
193 pan
->need_renumber
= !!nb_in_channels
[1];
201 static int are_gains_pure(const PanContext
*pan
)
205 for (i
= 0; i
< MAX_CHANNELS
; i
++) {
208 for (j
= 0; j
< MAX_CHANNELS
; j
++) {
209 double gain
= pan
->gain
[i
][j
];
211 /* channel mapping is effective only if 0% or 100% of a channel is
213 if (gain
!= 0. && gain
!= 1.)
215 /* ...and if the output channel is only composed of one input */
216 if (gain
&& nb_gain
++)
223 static int query_formats(AVFilterContext
*ctx
)
225 PanContext
*pan
= ctx
->priv
;
226 AVFilterLink
*inlink
= ctx
->inputs
[0];
227 AVFilterLink
*outlink
= ctx
->outputs
[0];
228 AVFilterFormats
*formats
= NULL
;
229 AVFilterChannelLayouts
*layouts
;
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
));
235 formats
= ff_all_samplerates();
237 return AVERROR(ENOMEM
);
238 ff_set_common_samplerates(ctx
, formats
);
240 // inlink supports any channel layout
241 layouts
= ff_all_channel_counts();
242 ff_channel_layouts_ref(layouts
, &inlink
->out_channel_layouts
);
244 // outlink supports only requested output channel layout
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
);
253 static int config_props(AVFilterLink
*link
)
255 AVFilterContext
*ctx
= link
->dst
;
256 PanContext
*pan
= ctx
->priv
;
257 char buf
[1024], *cur
;
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
];
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
;
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
,
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
);
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
);
298 // gains are pure, init the channel mapping
299 if (pan
->pure_gains
) {
301 // get channel map from the pure gains
302 for (i
= 0; i
< pan
->nb_output_channels
; i
++) {
304 for (j
= 0; j
< link
->channels
; j
++) {
305 if (pan
->gain
[i
][j
]) {
310 pan
->channel_map
[i
] = ch_id
;
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
);
318 for (i
= 0; i
< pan
->nb_output_channels
; i
++) {
319 if (!((pan
->need_renorm
>> i
) & 1))
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
327 av_log(ctx
, AV_LOG_WARNING
,
328 "Degenerate coefficients while renormalizing\n");
331 for (j
= 0; j
< link
->channels
; j
++)
332 pan
->gain
[i
][j
] /= t
;
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]);
339 r
= swr_init(pan
->swr
);
344 for (i
= 0; i
< pan
->nb_output_channels
; i
++) {
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
);
351 av_log(ctx
, AV_LOG_VERBOSE
, "o%d = %s\n", i
, buf
);
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");
360 av_log(ctx
, AV_LOG_INFO
, " %d", pan
->channel_map
[i
]);
361 av_log(ctx
, AV_LOG_INFO
, "\n");
367 static int filter_frame(AVFilterLink
*inlink
, AVFrame
*insamples
)
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
;
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
);
383 ret
= ff_filter_frame(outlink
, outsamples
);
384 av_frame_free(&insamples
);
388 static av_cold
void uninit(AVFilterContext
*ctx
)
390 PanContext
*pan
= ctx
->priv
;
394 #define OFFSET(x) offsetof(PanContext, x)
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
},
401 AVFILTER_DEFINE_CLASS(pan
);
403 static const AVFilterPad pan_inputs
[] = {
406 .type
= AVMEDIA_TYPE_AUDIO
,
407 .config_props
= config_props
,
408 .filter_frame
= filter_frame
,
413 static const AVFilterPad pan_outputs
[] = {
416 .type
= AVMEDIA_TYPE_AUDIO
,
421 AVFilter ff_af_pan
= {
423 .description
= NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."),
424 .priv_size
= sizeof(PanContext
),
425 .priv_class
= &pan_class
,
428 .query_formats
= query_formats
,
429 .inputs
= pan_inputs
,
430 .outputs
= pan_outputs
,