yading@10: /*
yading@10:  * Copyright (c) 2002 Anders Johansson <ajh@atri.curtin.edu.au>
yading@10:  * Copyright (c) 2011 Clément Bœsch <ubitux@gmail.com>
yading@10:  * Copyright (c) 2011 Nicolas George <nicolas.george@normalesup.org>
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
yading@10:  * GNU Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Audio panning filter (channels mixing)
yading@10:  * Original code written by Anders Johansson for MPlayer,
yading@10:  * reimplemented for FFmpeg.
yading@10:  */
yading@10: 
yading@10: #include <stdio.h>
yading@10: #include "libavutil/avstring.h"
yading@10: #include "libavutil/channel_layout.h"
yading@10: #include "libavutil/opt.h"
yading@10: #include "libswresample/swresample.h"
yading@10: #include "audio.h"
yading@10: #include "avfilter.h"
yading@10: #include "formats.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: #define MAX_CHANNELS 63
yading@10: 
yading@10: typedef struct PanContext {
yading@10:     const AVClass *class;
yading@10:     char *args;
yading@10:     int64_t out_channel_layout;
yading@10:     double gain[MAX_CHANNELS][MAX_CHANNELS];
yading@10:     int64_t need_renorm;
yading@10:     int need_renumber;
yading@10:     int nb_input_channels;
yading@10:     int nb_output_channels;
yading@10: 
yading@10:     int pure_gains;
yading@10:     /* channel mapping specific */
yading@10:     int channel_map[SWR_CH_MAX];
yading@10:     struct SwrContext *swr;
yading@10: } PanContext;
yading@10: 
yading@10: static void skip_spaces(char **arg)
yading@10: {
yading@10:     int len = 0;
yading@10: 
yading@10:     sscanf(*arg, " %n", &len);
yading@10:     *arg += len;
yading@10: }
yading@10: 
yading@10: static int parse_channel_name(char **arg, int *rchannel, int *rnamed)
yading@10: {
yading@10:     char buf[8];
yading@10:     int len, i, channel_id = 0;
yading@10:     int64_t layout, layout0;
yading@10: 
yading@10:     skip_spaces(arg);
yading@10:     /* try to parse a channel name, e.g. "FL" */
yading@10:     if (sscanf(*arg, "%7[A-Z]%n", buf, &len)) {
yading@10:         layout0 = layout = av_get_channel_layout(buf);
yading@10:         /* channel_id <- first set bit in layout */
yading@10:         for (i = 32; i > 0; i >>= 1) {
yading@10:             if (layout >= (int64_t)1 << i) {
yading@10:                 channel_id += i;
yading@10:                 layout >>= i;
yading@10:             }
yading@10:         }
yading@10:         /* reject layouts that are not a single channel */
yading@10:         if (channel_id >= MAX_CHANNELS || layout0 != (int64_t)1 << channel_id)
yading@10:             return AVERROR(EINVAL);
yading@10:         *rchannel = channel_id;
yading@10:         *rnamed = 1;
yading@10:         *arg += len;
yading@10:         return 0;
yading@10:     }
yading@10:     /* try to parse a channel number, e.g. "c2" */
yading@10:     if (sscanf(*arg, "c%d%n", &channel_id, &len) &&
yading@10:         channel_id >= 0 && channel_id < MAX_CHANNELS) {
yading@10:         *rchannel = channel_id;
yading@10:         *rnamed = 0;
yading@10:         *arg += len;
yading@10:         return 0;
yading@10:     }
yading@10:     return AVERROR(EINVAL);
yading@10: }
yading@10: 
yading@10: static av_cold int init(AVFilterContext *ctx)
yading@10: {
yading@10:     PanContext *const pan = ctx->priv;
yading@10:     char *arg, *arg0, *tokenizer, *args = av_strdup(pan->args);
yading@10:     int out_ch_id, in_ch_id, len, named, ret;
yading@10:     int nb_in_channels[2] = { 0, 0 }; // number of unnamed and named input channels
yading@10:     double gain;
yading@10: 
yading@10:     if (!pan->args) {
yading@10:         av_log(ctx, AV_LOG_ERROR,
yading@10:                "pan filter needs a channel layout and a set "
yading@10:                "of channels definitions as parameter\n");
yading@10:         return AVERROR(EINVAL);
yading@10:     }
yading@10:     if (!args)
yading@10:         return AVERROR(ENOMEM);
yading@10:     arg = av_strtok(args, "|", &tokenizer);
yading@10:     ret = ff_parse_channel_layout(&pan->out_channel_layout, arg, ctx);
yading@10:     if (ret < 0)
yading@10:         goto fail;
yading@10:     pan->nb_output_channels = av_get_channel_layout_nb_channels(pan->out_channel_layout);
yading@10: 
yading@10:     /* parse channel specifications */
yading@10:     while ((arg = arg0 = av_strtok(NULL, "|", &tokenizer))) {
yading@10:         /* channel name */
yading@10:         if (parse_channel_name(&arg, &out_ch_id, &named)) {
yading@10:             av_log(ctx, AV_LOG_ERROR,
yading@10:                    "Expected out channel name, got \"%.8s\"\n", arg);
yading@10:             ret = AVERROR(EINVAL);
yading@10:             goto fail;
yading@10:         }
yading@10:         if (named) {
yading@10:             if (!((pan->out_channel_layout >> out_ch_id) & 1)) {
yading@10:                 av_log(ctx, AV_LOG_ERROR,
yading@10:                        "Channel \"%.8s\" does not exist in the chosen layout\n", arg0);
yading@10:                 ret = AVERROR(EINVAL);
yading@10:                 goto fail;
yading@10:             }
yading@10:             /* get the channel number in the output channel layout:
yading@10:              * out_channel_layout & ((1 << out_ch_id) - 1) are all the
yading@10:              * channels that come before out_ch_id,
yading@10:              * so their count is the index of out_ch_id */
yading@10:             out_ch_id = av_get_channel_layout_nb_channels(pan->out_channel_layout & (((int64_t)1 << out_ch_id) - 1));
yading@10:         }
yading@10:         if (out_ch_id < 0 || out_ch_id >= pan->nb_output_channels) {
yading@10:             av_log(ctx, AV_LOG_ERROR,
yading@10:                    "Invalid out channel name \"%.8s\"\n", arg0);
yading@10:             ret = AVERROR(EINVAL);
yading@10:             goto fail;
yading@10:         }
yading@10:         skip_spaces(&arg);
yading@10:         if (*arg == '=') {
yading@10:             arg++;
yading@10:         } else if (*arg == '<') {
yading@10:             pan->need_renorm |= (int64_t)1 << out_ch_id;
yading@10:             arg++;
yading@10:         } else {
yading@10:             av_log(ctx, AV_LOG_ERROR,
yading@10:                    "Syntax error after channel name in \"%.8s\"\n", arg0);
yading@10:             ret = AVERROR(EINVAL);
yading@10:             goto fail;
yading@10:         }
yading@10:         /* gains */
yading@10:         while (1) {
yading@10:             gain = 1;
yading@10:             if (sscanf(arg, "%lf%n *%n", &gain, &len, &len))
yading@10:                 arg += len;
yading@10:             if (parse_channel_name(&arg, &in_ch_id, &named)){
yading@10:                 av_log(ctx, AV_LOG_ERROR,
yading@10:                        "Expected in channel name, got \"%.8s\"\n", arg);
yading@10:                  ret = AVERROR(EINVAL);
yading@10:                  goto fail;
yading@10:             }
yading@10:             nb_in_channels[named]++;
yading@10:             if (nb_in_channels[!named]) {
yading@10:                 av_log(ctx, AV_LOG_ERROR,
yading@10:                        "Can not mix named and numbered channels\n");
yading@10:                 ret = AVERROR(EINVAL);
yading@10:                 goto fail;
yading@10:             }
yading@10:             pan->gain[out_ch_id][in_ch_id] = gain;
yading@10:             skip_spaces(&arg);
yading@10:             if (!*arg)
yading@10:                 break;
yading@10:             if (*arg != '+') {
yading@10:                 av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg);
yading@10:                 ret = AVERROR(EINVAL);
yading@10:                 goto fail;
yading@10:             }
yading@10:             arg++;
yading@10:         }
yading@10:     }
yading@10:     pan->need_renumber = !!nb_in_channels[1];
yading@10: 
yading@10:     ret = 0;
yading@10: fail:
yading@10:     av_free(args);
yading@10:     return ret;
yading@10: }
yading@10: 
yading@10: static int are_gains_pure(const PanContext *pan)
yading@10: {
yading@10:     int i, j;
yading@10: 
yading@10:     for (i = 0; i < MAX_CHANNELS; i++) {
yading@10:         int nb_gain = 0;
yading@10: 
yading@10:         for (j = 0; j < MAX_CHANNELS; j++) {
yading@10:             double gain = pan->gain[i][j];
yading@10: 
yading@10:             /* channel mapping is effective only if 0% or 100% of a channel is
yading@10:              * selected... */
yading@10:             if (gain != 0. && gain != 1.)
yading@10:                 return 0;
yading@10:             /* ...and if the output channel is only composed of one input */
yading@10:             if (gain && nb_gain++)
yading@10:                 return 0;
yading@10:         }
yading@10:     }
yading@10:     return 1;
yading@10: }
yading@10: 
yading@10: static int query_formats(AVFilterContext *ctx)
yading@10: {
yading@10:     PanContext *pan = ctx->priv;
yading@10:     AVFilterLink *inlink  = ctx->inputs[0];
yading@10:     AVFilterLink *outlink = ctx->outputs[0];
yading@10:     AVFilterFormats *formats = NULL;
yading@10:     AVFilterChannelLayouts *layouts;
yading@10: 
yading@10:     pan->pure_gains = are_gains_pure(pan);
yading@10:     /* libswr supports any sample and packing formats */
yading@10:     ff_set_common_formats(ctx, ff_all_formats(AVMEDIA_TYPE_AUDIO));
yading@10: 
yading@10:     formats = ff_all_samplerates();
yading@10:     if (!formats)
yading@10:         return AVERROR(ENOMEM);
yading@10:     ff_set_common_samplerates(ctx, formats);
yading@10: 
yading@10:     // inlink supports any channel layout
yading@10:     layouts = ff_all_channel_layouts();
yading@10:     ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);
yading@10: 
yading@10:     // outlink supports only requested output channel layout
yading@10:     layouts = NULL;
yading@10:     ff_add_channel_layout(&layouts, pan->out_channel_layout);
yading@10:     ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts);
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int config_props(AVFilterLink *link)
yading@10: {
yading@10:     AVFilterContext *ctx = link->dst;
yading@10:     PanContext *pan = ctx->priv;
yading@10:     char buf[1024], *cur;
yading@10:     int i, j, k, r;
yading@10:     double t;
yading@10: 
yading@10:     pan->nb_input_channels = av_get_channel_layout_nb_channels(link->channel_layout);
yading@10:     if (pan->need_renumber) {
yading@10:         // input channels were given by their name: renumber them
yading@10:         for (i = j = 0; i < MAX_CHANNELS; i++) {
yading@10:             if ((link->channel_layout >> i) & 1) {
yading@10:                 for (k = 0; k < pan->nb_output_channels; k++)
yading@10:                     pan->gain[k][j] = pan->gain[k][i];
yading@10:                 j++;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     // sanity check; can't be done in query_formats since the inlink
yading@10:     // channel layout is unknown at that time
yading@10:     if (pan->nb_input_channels > SWR_CH_MAX ||
yading@10:         pan->nb_output_channels > SWR_CH_MAX) {
yading@10:         av_log(ctx, AV_LOG_ERROR,
yading@10:                "libswresample support a maximum of %d channels. "
yading@10:                "Feel free to ask for a higher limit.\n", SWR_CH_MAX);
yading@10:         return AVERROR_PATCHWELCOME;
yading@10:     }
yading@10: 
yading@10:     // init libswresample context
yading@10:     pan->swr = swr_alloc_set_opts(pan->swr,
yading@10:                                   pan->out_channel_layout, link->format, link->sample_rate,
yading@10:                                   link->channel_layout,    link->format, link->sample_rate,
yading@10:                                   0, ctx);
yading@10:     if (!pan->swr)
yading@10:         return AVERROR(ENOMEM);
yading@10: 
yading@10:     // gains are pure, init the channel mapping
yading@10:     if (pan->pure_gains) {
yading@10: 
yading@10:         // get channel map from the pure gains
yading@10:         for (i = 0; i < pan->nb_output_channels; i++) {
yading@10:             int ch_id = -1;
yading@10:             for (j = 0; j < pan->nb_input_channels; j++) {
yading@10:                 if (pan->gain[i][j]) {
yading@10:                     ch_id = j;
yading@10:                     break;
yading@10:                 }
yading@10:             }
yading@10:             pan->channel_map[i] = ch_id;
yading@10:         }
yading@10: 
yading@10:         av_opt_set_int(pan->swr, "icl", pan->out_channel_layout, 0);
yading@10:         av_opt_set_int(pan->swr, "uch", pan->nb_output_channels, 0);
yading@10:         swr_set_channel_mapping(pan->swr, pan->channel_map);
yading@10:     } else {
yading@10:         // renormalize
yading@10:         for (i = 0; i < pan->nb_output_channels; i++) {
yading@10:             if (!((pan->need_renorm >> i) & 1))
yading@10:                 continue;
yading@10:             t = 0;
yading@10:             for (j = 0; j < pan->nb_input_channels; j++)
yading@10:                 t += pan->gain[i][j];
yading@10:             if (t > -1E-5 && t < 1E-5) {
yading@10:                 // t is almost 0 but not exactly, this is probably a mistake
yading@10:                 if (t)
yading@10:                     av_log(ctx, AV_LOG_WARNING,
yading@10:                            "Degenerate coefficients while renormalizing\n");
yading@10:                 continue;
yading@10:             }
yading@10:             for (j = 0; j < pan->nb_input_channels; j++)
yading@10:                 pan->gain[i][j] /= t;
yading@10:         }
yading@10:         av_opt_set_int(pan->swr, "icl", link->channel_layout, 0);
yading@10:         av_opt_set_int(pan->swr, "ocl", pan->out_channel_layout, 0);
yading@10:         swr_set_matrix(pan->swr, pan->gain[0], pan->gain[1] - pan->gain[0]);
yading@10:     }
yading@10: 
yading@10:     r = swr_init(pan->swr);
yading@10:     if (r < 0)
yading@10:         return r;
yading@10: 
yading@10:     // summary
yading@10:     for (i = 0; i < pan->nb_output_channels; i++) {
yading@10:         cur = buf;
yading@10:         for (j = 0; j < pan->nb_input_channels; j++) {
yading@10:             r = snprintf(cur, buf + sizeof(buf) - cur, "%s%.3g i%d",
yading@10:                          j ? " + " : "", pan->gain[i][j], j);
yading@10:             cur += FFMIN(buf + sizeof(buf) - cur, r);
yading@10:         }
yading@10:         av_log(ctx, AV_LOG_VERBOSE, "o%d = %s\n", i, buf);
yading@10:     }
yading@10:     // add channel mapping summary if possible
yading@10:     if (pan->pure_gains) {
yading@10:         av_log(ctx, AV_LOG_INFO, "Pure channel mapping detected:");
yading@10:         for (i = 0; i < pan->nb_output_channels; i++)
yading@10:             if (pan->channel_map[i] < 0)
yading@10:                 av_log(ctx, AV_LOG_INFO, " M");
yading@10:             else
yading@10:                 av_log(ctx, AV_LOG_INFO, " %d", pan->channel_map[i]);
yading@10:         av_log(ctx, AV_LOG_INFO, "\n");
yading@10:         return 0;
yading@10:     }
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
yading@10: {
yading@10:     int ret;
yading@10:     int n = insamples->nb_samples;
yading@10:     AVFilterLink *const outlink = inlink->dst->outputs[0];
yading@10:     AVFrame *outsamples = ff_get_audio_buffer(outlink, n);
yading@10:     PanContext *pan = inlink->dst->priv;
yading@10: 
yading@10:     if (!outsamples)
yading@10:         return AVERROR(ENOMEM);
yading@10:     swr_convert(pan->swr, outsamples->data, n, (void *)insamples->data, n);
yading@10:     av_frame_copy_props(outsamples, insamples);
yading@10:     outsamples->channel_layout = outlink->channel_layout;
yading@10:     av_frame_set_channels(outsamples, outlink->channels);
yading@10: 
yading@10:     ret = ff_filter_frame(outlink, outsamples);
yading@10:     av_frame_free(&insamples);
yading@10:     return ret;
yading@10: }
yading@10: 
yading@10: static av_cold void uninit(AVFilterContext *ctx)
yading@10: {
yading@10:     PanContext *pan = ctx->priv;
yading@10:     swr_free(&pan->swr);
yading@10: }
yading@10: 
yading@10: #define OFFSET(x) offsetof(PanContext, x)
yading@10: 
yading@10: static const AVOption pan_options[] = {
yading@10:     { "args", NULL, OFFSET(args), AV_OPT_TYPE_STRING, { .str = NULL }, CHAR_MIN, CHAR_MAX, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: AVFILTER_DEFINE_CLASS(pan);
yading@10: 
yading@10: 
yading@10: static const AVFilterPad pan_inputs[] = {
yading@10:     {
yading@10:         .name         = "default",
yading@10:         .type         = AVMEDIA_TYPE_AUDIO,
yading@10:         .config_props = config_props,
yading@10:         .filter_frame = filter_frame,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: static const AVFilterPad pan_outputs[] = {
yading@10:     {
yading@10:         .name = "default",
yading@10:         .type = AVMEDIA_TYPE_AUDIO,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: AVFilter avfilter_af_pan = {
yading@10:     .name          = "pan",
yading@10:     .description   = NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."),
yading@10:     .priv_size     = sizeof(PanContext),
yading@10:     .priv_class    = &pan_class,
yading@10:     .init          = init,
yading@10:     .uninit        = uninit,
yading@10:     .query_formats = query_formats,
yading@10:     .inputs        = pan_inputs,
yading@10:     .outputs       = pan_outputs,
yading@10: };