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libavfilter/af_pan.c

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00001 /*
00002  * Copyright (c) 2002 Anders Johansson <ajh@atri.curtin.edu.au>
00003  * Copyright (c) 2011 Clément Bœsch <ubitux@gmail.com>
00004  * Copyright (c) 2011 Nicolas George <nicolas.george@normalesup.org>
00005  *
00006  * This file is part of FFmpeg.
00007  *
00008  * FFmpeg is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * FFmpeg is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00016  * GNU General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with FFmpeg; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00030 #include <stdio.h>
00031 #include "libavutil/avstring.h"
00032 #include "libavutil/opt.h"
00033 #include "libswresample/swresample.h"
00034 #include "avfilter.h"
00035 
00036 #define MAX_CHANNELS 63
00037 
00038 typedef struct PanContext {
00039     int64_t out_channel_layout;
00040     union {
00041         double d[MAX_CHANNELS][MAX_CHANNELS];
00042         // i is 1:7:8 fixed-point, i.e. in [-128*256; +128*256[
00043         int    i[MAX_CHANNELS][MAX_CHANNELS];
00044     } gain;
00045     int64_t need_renorm;
00046     int need_renumber;
00047     int nb_input_channels;
00048     int nb_output_channels;
00049 
00050     int pure_gains;
00051     void (*filter_samples)(struct PanContext*,
00052                            AVFilterBufferRef*,
00053                            AVFilterBufferRef*,
00054                            int);
00055 
00056     /* channel mapping specific */
00057     int channel_map[SWR_CH_MAX];
00058     struct SwrContext *swr;
00059 } PanContext;
00060 
00061 static int parse_channel_name(char **arg, int *rchannel, int *rnamed)
00062 {
00063     char buf[8];
00064     int len, i, channel_id;
00065     int64_t layout, layout0;
00066 
00067     if (sscanf(*arg, " %7[A-Z] %n", buf, &len)) {
00068         layout0 = layout = av_get_channel_layout(buf);
00069         for (i = 32; i > 0; i >>= 1) {
00070             if (layout >= (int64_t)1 << i) {
00071                 channel_id += i;
00072                 layout >>= i;
00073             }
00074         }
00075         if (channel_id >= MAX_CHANNELS || layout0 != (int64_t)1 << channel_id)
00076             return AVERROR(EINVAL);
00077         *rchannel = channel_id;
00078         *rnamed = 1;
00079         *arg += len;
00080         return 0;
00081     }
00082     if (sscanf(*arg, " c%d %n", &channel_id, &len) &&
00083         channel_id >= 0 && channel_id < MAX_CHANNELS) {
00084         *rchannel = channel_id;
00085         *rnamed = 0;
00086         *arg += len;
00087         return 0;
00088     }
00089     return AVERROR(EINVAL);
00090 }
00091 
00092 static void skip_spaces(char **arg)
00093 {
00094     int len = 0;
00095 
00096     sscanf(*arg, " %n", &len);
00097     *arg += len;
00098 }
00099 
00100 static av_cold int init(AVFilterContext *ctx, const char *args0, void *opaque)
00101 {
00102     PanContext *const pan = ctx->priv;
00103     char *arg, *arg0, *tokenizer, *args = av_strdup(args0);
00104     int out_ch_id, in_ch_id, len, named;
00105     int nb_in_channels[2] = { 0, 0 }; // number of unnamed and named input channels
00106     double gain;
00107 
00108     if (!args0) {
00109         av_log(ctx, AV_LOG_ERROR,
00110                "pan filter needs a channel layout and a set "
00111                "of channels definitions as parameter\n");
00112         return AVERROR(EINVAL);
00113     }
00114     if (!args)
00115         return AVERROR(ENOMEM);
00116     arg = av_strtok(args, ":", &tokenizer);
00117     pan->out_channel_layout = av_get_channel_layout(arg);
00118     if (!pan->out_channel_layout) {
00119         av_log(ctx, AV_LOG_ERROR, "Unknown channel layout \"%s\"\n", arg);
00120         return AVERROR(EINVAL);
00121     }
00122     pan->nb_output_channels = av_get_channel_layout_nb_channels(pan->out_channel_layout);
00123 
00124     /* parse channel specifications */
00125     while ((arg = arg0 = av_strtok(NULL, ":", &tokenizer))) {
00126         /* channel name */
00127         if (parse_channel_name(&arg, &out_ch_id, &named)) {
00128             av_log(ctx, AV_LOG_ERROR,
00129                    "Expected out channel name, got \"%.8s\"\n", arg);
00130             return AVERROR(EINVAL);
00131         }
00132         if (named) {
00133             if (!((pan->out_channel_layout >> out_ch_id) & 1)) {
00134                 av_log(ctx, AV_LOG_ERROR,
00135                        "Channel \"%.8s\" does not exist in the chosen layout\n", arg0);
00136                 return AVERROR(EINVAL);
00137             }
00138             /* get the channel number in the output channel layout:
00139              * out_channel_layout & ((1 << out_ch_id) - 1) are all the
00140              * channels that come before out_ch_id,
00141              * so their count is the index of out_ch_id */
00142             out_ch_id = av_get_channel_layout_nb_channels(pan->out_channel_layout & (((int64_t)1 << out_ch_id) - 1));
00143         }
00144         if (out_ch_id < 0 || out_ch_id >= pan->nb_output_channels) {
00145             av_log(ctx, AV_LOG_ERROR,
00146                    "Invalid out channel name \"%.8s\"\n", arg0);
00147             return AVERROR(EINVAL);
00148         }
00149         if (*arg == '=') {
00150             arg++;
00151         } else if (*arg == '<') {
00152             pan->need_renorm |= (int64_t)1 << out_ch_id;
00153             arg++;
00154         } else {
00155             av_log(ctx, AV_LOG_ERROR,
00156                    "Syntax error after channel name in \"%.8s\"\n", arg0);
00157             return AVERROR(EINVAL);
00158         }
00159         /* gains */
00160         while (1) {
00161             gain = 1;
00162             if (sscanf(arg, " %lf %n* %n", &gain, &len, &len))
00163                 arg += len;
00164             if (parse_channel_name(&arg, &in_ch_id, &named)){
00165                 av_log(ctx, AV_LOG_ERROR,
00166                        "Expected in channel name, got \"%.8s\"\n", arg);
00167                 return AVERROR(EINVAL);
00168             }
00169             nb_in_channels[named]++;
00170             if (nb_in_channels[!named]) {
00171                 av_log(ctx, AV_LOG_ERROR,
00172                        "Can not mix named and numbered channels\n");
00173                 return AVERROR(EINVAL);
00174             }
00175             pan->gain.d[out_ch_id][in_ch_id] = gain;
00176             if (!*arg)
00177                 break;
00178             if (*arg != '+') {
00179                 av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg);
00180                 return AVERROR(EINVAL);
00181             }
00182             arg++;
00183             skip_spaces(&arg);
00184         }
00185     }
00186     pan->need_renumber = !!nb_in_channels[1];
00187 
00188     av_free(args);
00189     return 0;
00190 }
00191 
00192 static int are_gains_pure(const PanContext *pan)
00193 {
00194     int i, j;
00195 
00196     for (i = 0; i < MAX_CHANNELS; i++) {
00197         int nb_gain = 0;
00198 
00199         for (j = 0; j < MAX_CHANNELS; j++) {
00200             double gain = pan->gain.d[i][j];
00201 
00202             /* channel mapping is effective only if 0% or 100% of a channel is
00203              * selected... */
00204             if (gain != 0. && gain != 1.)
00205                 return 0;
00206             /* ...and if the output channel is only composed of one input */
00207             if (gain && nb_gain++)
00208                 return 0;
00209         }
00210     }
00211     return 1;
00212 }
00213 
00214 static int config_props(AVFilterLink *link)
00215 {
00216     AVFilterContext *ctx = link->dst;
00217     PanContext *pan = ctx->priv;
00218     char buf[1024], *cur;
00219     int i, j, k, r;
00220     double t;
00221 
00222     pan->nb_input_channels = av_get_channel_layout_nb_channels(link->channel_layout);
00223     if (pan->need_renumber) {
00224         // input channels were given by their name: renumber them
00225         for (i = j = 0; i < MAX_CHANNELS; i++) {
00226             if ((link->channel_layout >> i) & 1) {
00227                 for (k = 0; k < pan->nb_output_channels; k++)
00228                     pan->gain.d[k][j] = pan->gain.d[k][i];
00229                 j++;
00230             }
00231         }
00232     }
00233     // gains are pure, init the channel mapping
00234     if (pan->pure_gains) {
00235 
00236         // sanity check; can't be done in query_formats since the inlink
00237         // channel layout is unknown at that time
00238         if (pan->nb_input_channels > SWR_CH_MAX) {
00239             av_log(ctx, AV_LOG_ERROR,
00240                    "libswresample support a maximum of %d channels. "
00241                    "Feel free to ask for a higher limit.\n", SWR_CH_MAX);
00242             return AVERROR_PATCHWELCOME;
00243         }
00244 
00245         // get channel map from the pure gains
00246         for (i = 0; i < pan->nb_output_channels; i++) {
00247             int ch_id = -1;
00248             for (j = 0; j < pan->nb_input_channels; j++) {
00249                 if (pan->gain.d[i][j]) {
00250                     ch_id = j;
00251                     break;
00252                 }
00253             }
00254             pan->channel_map[i] = ch_id;
00255         }
00256 
00257         // init libswresample context
00258         pan->swr = swr_alloc_set_opts(pan->swr,
00259                                       pan->out_channel_layout, link->format, link->sample_rate,
00260                                       link->channel_layout,    link->format, link->sample_rate,
00261                                       0, ctx);
00262         if (!pan->swr)
00263             return AVERROR(ENOMEM);
00264         av_opt_set_int(pan->swr, "icl", pan->out_channel_layout, 0);
00265         av_opt_set_int(pan->swr, "uch", pan->nb_output_channels, 0);
00266         swr_set_channel_mapping(pan->swr, pan->channel_map);
00267         r = swr_init(pan->swr);
00268         if (r < 0)
00269             return r;
00270     } else {
00271         // renormalize
00272         for (i = 0; i < pan->nb_output_channels; i++) {
00273             if (!((pan->need_renorm >> i) & 1))
00274                 continue;
00275             t = 0;
00276             for (j = 0; j < pan->nb_input_channels; j++)
00277                 t += pan->gain.d[i][j];
00278             if (t > -1E-5 && t < 1E-5) {
00279                 // t is almost 0 but not exactly, this is probably a mistake
00280                 if (t)
00281                     av_log(ctx, AV_LOG_WARNING,
00282                            "Degenerate coefficients while renormalizing\n");
00283                 continue;
00284             }
00285             for (j = 0; j < pan->nb_input_channels; j++)
00286                 pan->gain.d[i][j] /= t;
00287         }
00288     }
00289     // summary
00290     for (i = 0; i < pan->nb_output_channels; i++) {
00291         cur = buf;
00292         for (j = 0; j < pan->nb_input_channels; j++) {
00293             r = snprintf(cur, buf + sizeof(buf) - cur, "%s%.3g i%d",
00294                          j ? " + " : "", pan->gain.d[i][j], j);
00295             cur += FFMIN(buf + sizeof(buf) - cur, r);
00296         }
00297         av_log(ctx, AV_LOG_INFO, "o%d = %s\n", i, buf);
00298     }
00299     // add channel mapping summary if possible
00300     if (pan->pure_gains) {
00301         av_log(ctx, AV_LOG_INFO, "Pure channel mapping detected:");
00302         for (i = 0; i < pan->nb_output_channels; i++)
00303             if (pan->channel_map[i] < 0)
00304                 av_log(ctx, AV_LOG_INFO, " M");
00305             else
00306                 av_log(ctx, AV_LOG_INFO, " %d", pan->channel_map[i]);
00307         av_log(ctx, AV_LOG_INFO, "\n");
00308         return 0;
00309     }
00310     // convert to integer
00311     for (i = 0; i < pan->nb_output_channels; i++) {
00312         for (j = 0; j < pan->nb_input_channels; j++) {
00313             if (pan->gain.d[i][j] < -128 || pan->gain.d[i][j] > 128)
00314                 av_log(ctx, AV_LOG_WARNING,
00315                     "Gain #%d->#%d too large, clamped\n", j, i);
00316             pan->gain.i[i][j] = av_clipf(pan->gain.d[i][j], -128, 128) * 256.0;
00317         }
00318     }
00319     return 0;
00320 }
00321 
00322 static void filter_samples_channel_mapping(PanContext *pan,
00323                                            AVFilterBufferRef *outsamples,
00324                                            AVFilterBufferRef *insamples,
00325                                            int n)
00326 {
00327     swr_convert(pan->swr, outsamples->data, n, (void *)insamples->data, n);
00328 }
00329 
00330 static void filter_samples_panning(PanContext *pan,
00331                                    AVFilterBufferRef *outsamples,
00332                                    AVFilterBufferRef *insamples,
00333                                    int n)
00334 {
00335     int i, o;
00336 
00337     /* input */
00338     const int16_t *in     = (int16_t *)insamples->data[0];
00339     const int16_t *in_end = in + n * pan->nb_input_channels;
00340 
00341     /* output */
00342     int16_t *out = (int16_t *)outsamples->data[0];
00343 
00344     for (; in < in_end; in += pan->nb_input_channels) {
00345         for (o = 0; o < pan->nb_output_channels; o++) {
00346             int v = 0;
00347             for (i = 0; i < pan->nb_input_channels; i++)
00348                 v += pan->gain.i[o][i] * in[i];
00349             *(out++) = v >> 8;
00350         }
00351     }
00352 }
00353 
00354 static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples)
00355 {
00356     int n = insamples->audio->nb_samples;
00357     AVFilterLink *const outlink = inlink->dst->outputs[0];
00358     AVFilterBufferRef *outsamples = avfilter_get_audio_buffer(outlink, AV_PERM_WRITE, n);
00359     PanContext *pan = inlink->dst->priv;
00360 
00361     pan->filter_samples(pan, outsamples, insamples, n);
00362 
00363     avfilter_filter_samples(outlink, outsamples);
00364     avfilter_unref_buffer(insamples);
00365 }
00366 
00367 static int query_formats(AVFilterContext *ctx)
00368 {
00369     PanContext *pan = ctx->priv;
00370     AVFilterLink *inlink  = ctx->inputs[0];
00371     AVFilterLink *outlink = ctx->outputs[0];
00372     AVFilterFormats *formats;
00373 
00374     if (pan->nb_output_channels <= SWR_CH_MAX)
00375         pan->pure_gains = are_gains_pure(pan);
00376     if (pan->pure_gains) {
00377         /* libswr supports any sample and packing formats */
00378         avfilter_set_common_sample_formats(ctx, avfilter_make_all_formats(AVMEDIA_TYPE_AUDIO));
00379         avfilter_set_common_packing_formats(ctx, avfilter_make_all_packing_formats());
00380         pan->filter_samples = filter_samples_channel_mapping;
00381     } else {
00382         const enum AVSampleFormat sample_fmts[] = {AV_SAMPLE_FMT_S16, -1};
00383         const int                packing_fmts[] = {AVFILTER_PACKED,   -1};
00384 
00385         avfilter_set_common_sample_formats (ctx, avfilter_make_format_list(sample_fmts));
00386         avfilter_set_common_packing_formats(ctx, avfilter_make_format_list(packing_fmts));
00387         pan->filter_samples = filter_samples_panning;
00388     }
00389 
00390     // inlink supports any channel layout
00391     formats = avfilter_make_all_channel_layouts();
00392     avfilter_formats_ref(formats, &inlink->out_chlayouts);
00393 
00394     // outlink supports only requested output channel layout
00395     formats = NULL;
00396     avfilter_add_format(&formats, pan->out_channel_layout);
00397     avfilter_formats_ref(formats, &outlink->in_chlayouts);
00398     return 0;
00399 }
00400 
00401 static av_cold void uninit(AVFilterContext *ctx)
00402 {
00403     PanContext *pan = ctx->priv;
00404     swr_free(&pan->swr);
00405 }
00406 
00407 AVFilter avfilter_af_pan = {
00408     .name          = "pan",
00409     .description   = NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."),
00410     .priv_size     = sizeof(PanContext),
00411     .init          = init,
00412     .uninit        = uninit,
00413     .query_formats = query_formats,
00414 
00415     .inputs    = (const AVFilterPad[]) {
00416         { .name             = "default",
00417           .type             = AVMEDIA_TYPE_AUDIO,
00418           .config_props     = config_props,
00419           .filter_samples   = filter_samples,
00420           .min_perms        = AV_PERM_READ, },
00421         { .name = NULL}
00422     },
00423     .outputs   = (const AVFilterPad[]) {
00424         { .name             = "default",
00425           .type             = AVMEDIA_TYPE_AUDIO, },
00426         { .name = NULL}
00427     },
00428 };
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