/* * 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, sign = 1;    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);    if (!arg) {        av_log(ctx, AV_LOG_ERROR, "Channel layout not specified\n");        ret = AVERROR(EINVAL);        goto fail;    }    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] = sign * gain;            skip_spaces(&arg);            if (!*arg)                break;            if (*arg == '-') {                sign = -1;            } else if (*arg != '+') {                av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg);                ret = AVERROR(EINVAL);                goto fail;            } else {                sign = 1;            }            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,};