445 lines
14 KiB
C
445 lines
14 KiB
C
/*
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* Copyright (c) 2002 Anders Johansson <ajh@atri.curtin.edu.au>
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* Copyright (c) 2011 Clément Bœsch <u pkh me>
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* Copyright (c) 2011 Nicolas George <nicolas.george@normalesup.org>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Audio panning filter (channels mixing)
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* Original code written by Anders Johansson for MPlayer,
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* reimplemented for FFmpeg.
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*/
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#include <stdio.h>
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#include "libavutil/avstring.h"
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#include "libavutil/channel_layout.h"
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#include "libavutil/opt.h"
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#include "libswresample/swresample.h"
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#include "audio.h"
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#include "avfilter.h"
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#include "formats.h"
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#include "internal.h"
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#define MAX_CHANNELS 64
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typedef struct PanContext {
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const AVClass *class;
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char *args;
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int64_t out_channel_layout;
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double gain[MAX_CHANNELS][MAX_CHANNELS];
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int64_t need_renorm;
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int need_renumber;
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int nb_output_channels;
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int pure_gains;
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/* channel mapping specific */
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int channel_map[MAX_CHANNELS];
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struct SwrContext *swr;
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} PanContext;
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static void skip_spaces(char **arg)
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{
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int len = 0;
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sscanf(*arg, " %n", &len);
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*arg += len;
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}
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static int parse_channel_name(char **arg, int *rchannel, int *rnamed)
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{
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char buf[8];
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int len, i, channel_id = 0;
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int64_t layout, layout0;
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skip_spaces(arg);
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/* try to parse a channel name, e.g. "FL" */
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if (sscanf(*arg, "%7[A-Z]%n", buf, &len)) {
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layout0 = layout = av_get_channel_layout(buf);
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/* channel_id <- first set bit in layout */
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for (i = 32; i > 0; i >>= 1) {
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if (layout >= (int64_t)1 << i) {
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channel_id += i;
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layout >>= i;
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}
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}
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/* reject layouts that are not a single channel */
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if (channel_id >= MAX_CHANNELS || layout0 != (int64_t)1 << channel_id)
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return AVERROR(EINVAL);
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*rchannel = channel_id;
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*rnamed = 1;
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*arg += len;
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return 0;
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}
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/* try to parse a channel number, e.g. "c2" */
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if (sscanf(*arg, "c%d%n", &channel_id, &len) &&
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channel_id >= 0 && channel_id < MAX_CHANNELS) {
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*rchannel = channel_id;
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*rnamed = 0;
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*arg += len;
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return 0;
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}
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return AVERROR(EINVAL);
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}
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static av_cold int init(AVFilterContext *ctx)
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{
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PanContext *const pan = ctx->priv;
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char *arg, *arg0, *tokenizer, *args = av_strdup(pan->args);
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int out_ch_id, in_ch_id, len, named, ret, sign = 1;
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int nb_in_channels[2] = { 0, 0 }; // number of unnamed and named input channels
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double gain;
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if (!pan->args) {
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av_log(ctx, AV_LOG_ERROR,
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"pan filter needs a channel layout and a set "
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"of channel definitions as parameter\n");
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return AVERROR(EINVAL);
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}
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if (!args)
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return AVERROR(ENOMEM);
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arg = av_strtok(args, "|", &tokenizer);
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if (!arg) {
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av_log(ctx, AV_LOG_ERROR, "Channel layout not specified\n");
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ret = AVERROR(EINVAL);
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goto fail;
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}
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ret = ff_parse_channel_layout(&pan->out_channel_layout,
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&pan->nb_output_channels, arg, ctx);
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if (ret < 0)
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goto fail;
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/* parse channel specifications */
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while ((arg = arg0 = av_strtok(NULL, "|", &tokenizer))) {
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/* channel name */
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if (parse_channel_name(&arg, &out_ch_id, &named)) {
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av_log(ctx, AV_LOG_ERROR,
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"Expected out channel name, got \"%.8s\"\n", arg);
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ret = AVERROR(EINVAL);
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goto fail;
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}
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if (named) {
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if (!((pan->out_channel_layout >> out_ch_id) & 1)) {
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av_log(ctx, AV_LOG_ERROR,
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"Channel \"%.8s\" does not exist in the chosen layout\n", arg0);
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ret = AVERROR(EINVAL);
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goto fail;
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}
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/* get the channel number in the output channel layout:
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* out_channel_layout & ((1 << out_ch_id) - 1) are all the
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* channels that come before out_ch_id,
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* so their count is the index of out_ch_id */
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out_ch_id = av_get_channel_layout_nb_channels(pan->out_channel_layout & (((int64_t)1 << out_ch_id) - 1));
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}
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if (out_ch_id < 0 || out_ch_id >= pan->nb_output_channels) {
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av_log(ctx, AV_LOG_ERROR,
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"Invalid out channel name \"%.8s\"\n", arg0);
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ret = AVERROR(EINVAL);
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goto fail;
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}
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skip_spaces(&arg);
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if (*arg == '=') {
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arg++;
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} else if (*arg == '<') {
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pan->need_renorm |= (int64_t)1 << out_ch_id;
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arg++;
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} else {
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av_log(ctx, AV_LOG_ERROR,
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"Syntax error after channel name in \"%.8s\"\n", arg0);
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ret = AVERROR(EINVAL);
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goto fail;
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}
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/* gains */
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while (1) {
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gain = 1;
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if (sscanf(arg, "%lf%n *%n", &gain, &len, &len))
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arg += len;
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if (parse_channel_name(&arg, &in_ch_id, &named)){
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av_log(ctx, AV_LOG_ERROR,
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"Expected in channel name, got \"%.8s\"\n", arg);
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ret = AVERROR(EINVAL);
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goto fail;
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}
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nb_in_channels[named]++;
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if (nb_in_channels[!named]) {
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av_log(ctx, AV_LOG_ERROR,
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"Can not mix named and numbered channels\n");
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ret = AVERROR(EINVAL);
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goto fail;
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}
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pan->gain[out_ch_id][in_ch_id] = sign * gain;
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skip_spaces(&arg);
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if (!*arg)
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break;
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if (*arg == '-') {
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sign = -1;
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} else if (*arg != '+') {
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av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg);
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ret = AVERROR(EINVAL);
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goto fail;
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} else {
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sign = 1;
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}
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arg++;
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}
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}
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pan->need_renumber = !!nb_in_channels[1];
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ret = 0;
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fail:
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av_free(args);
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return ret;
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}
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static int are_gains_pure(const PanContext *pan)
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{
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int i, j;
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for (i = 0; i < MAX_CHANNELS; i++) {
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int nb_gain = 0;
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for (j = 0; j < MAX_CHANNELS; j++) {
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double gain = pan->gain[i][j];
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/* channel mapping is effective only if 0% or 100% of a channel is
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* selected... */
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if (gain != 0. && gain != 1.)
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return 0;
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/* ...and if the output channel is only composed of one input */
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if (gain && nb_gain++)
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return 0;
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}
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}
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return 1;
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}
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static int query_formats(AVFilterContext *ctx)
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{
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PanContext *pan = ctx->priv;
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AVFilterLink *inlink = ctx->inputs[0];
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AVFilterLink *outlink = ctx->outputs[0];
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AVFilterFormats *formats = NULL;
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AVFilterChannelLayouts *layouts;
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int ret;
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pan->pure_gains = are_gains_pure(pan);
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/* libswr supports any sample and packing formats */
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if ((ret = ff_set_common_formats(ctx, ff_all_formats(AVMEDIA_TYPE_AUDIO))) < 0)
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return ret;
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formats = ff_all_samplerates();
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if ((ret = ff_set_common_samplerates(ctx, formats)) < 0)
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return ret;
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// inlink supports any channel layout
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layouts = ff_all_channel_counts();
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if ((ret = ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts)) < 0)
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return ret;
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// outlink supports only requested output channel layout
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layouts = NULL;
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if ((ret = ff_add_channel_layout(&layouts,
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pan->out_channel_layout ? pan->out_channel_layout :
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FF_COUNT2LAYOUT(pan->nb_output_channels))) < 0)
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return ret;
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return ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts);
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}
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static int config_props(AVFilterLink *link)
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{
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AVFilterContext *ctx = link->dst;
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PanContext *pan = ctx->priv;
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char buf[1024], *cur;
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int i, j, k, r;
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double t;
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if (pan->need_renumber) {
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// input channels were given by their name: renumber them
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for (i = j = 0; i < MAX_CHANNELS; i++) {
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if ((link->channel_layout >> i) & 1) {
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for (k = 0; k < pan->nb_output_channels; k++)
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pan->gain[k][j] = pan->gain[k][i];
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j++;
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}
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}
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}
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// sanity check; can't be done in query_formats since the inlink
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// channel layout is unknown at that time
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if (link->channels > MAX_CHANNELS ||
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pan->nb_output_channels > MAX_CHANNELS) {
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av_log(ctx, AV_LOG_ERROR,
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"af_pan supports a maximum of %d channels. "
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"Feel free to ask for a higher limit.\n", MAX_CHANNELS);
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return AVERROR_PATCHWELCOME;
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}
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// init libswresample context
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pan->swr = swr_alloc_set_opts(pan->swr,
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pan->out_channel_layout, link->format, link->sample_rate,
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link->channel_layout, link->format, link->sample_rate,
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0, ctx);
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if (!pan->swr)
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return AVERROR(ENOMEM);
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if (!link->channel_layout) {
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if (av_opt_set_int(pan->swr, "ich", link->channels, 0) < 0)
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return AVERROR(EINVAL);
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}
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if (!pan->out_channel_layout) {
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if (av_opt_set_int(pan->swr, "och", pan->nb_output_channels, 0) < 0)
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return AVERROR(EINVAL);
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}
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// gains are pure, init the channel mapping
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if (pan->pure_gains) {
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// get channel map from the pure gains
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for (i = 0; i < pan->nb_output_channels; i++) {
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int ch_id = -1;
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for (j = 0; j < link->channels; j++) {
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if (pan->gain[i][j]) {
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ch_id = j;
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break;
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}
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}
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pan->channel_map[i] = ch_id;
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}
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av_opt_set_int(pan->swr, "icl", pan->out_channel_layout, 0);
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av_opt_set_int(pan->swr, "uch", pan->nb_output_channels, 0);
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swr_set_channel_mapping(pan->swr, pan->channel_map);
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} else {
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// renormalize
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for (i = 0; i < pan->nb_output_channels; i++) {
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if (!((pan->need_renorm >> i) & 1))
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continue;
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t = 0;
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for (j = 0; j < link->channels; j++)
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t += fabs(pan->gain[i][j]);
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if (t > -1E-5 && t < 1E-5) {
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// t is almost 0 but not exactly, this is probably a mistake
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if (t)
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av_log(ctx, AV_LOG_WARNING,
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"Degenerate coefficients while renormalizing\n");
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continue;
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}
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for (j = 0; j < link->channels; j++)
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pan->gain[i][j] /= t;
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}
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av_opt_set_int(pan->swr, "icl", link->channel_layout, 0);
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av_opt_set_int(pan->swr, "ocl", pan->out_channel_layout, 0);
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swr_set_matrix(pan->swr, pan->gain[0], pan->gain[1] - pan->gain[0]);
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}
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r = swr_init(pan->swr);
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if (r < 0)
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return r;
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// summary
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for (i = 0; i < pan->nb_output_channels; i++) {
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cur = buf;
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for (j = 0; j < link->channels; j++) {
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r = snprintf(cur, buf + sizeof(buf) - cur, "%s%.3g i%d",
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j ? " + " : "", pan->gain[i][j], j);
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cur += FFMIN(buf + sizeof(buf) - cur, r);
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}
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av_log(ctx, AV_LOG_VERBOSE, "o%d = %s\n", i, buf);
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}
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// add channel mapping summary if possible
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if (pan->pure_gains) {
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av_log(ctx, AV_LOG_INFO, "Pure channel mapping detected:");
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for (i = 0; i < pan->nb_output_channels; i++)
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if (pan->channel_map[i] < 0)
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av_log(ctx, AV_LOG_INFO, " M");
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else
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av_log(ctx, AV_LOG_INFO, " %d", pan->channel_map[i]);
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av_log(ctx, AV_LOG_INFO, "\n");
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return 0;
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}
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return 0;
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}
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static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
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{
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int ret;
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int n = insamples->nb_samples;
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AVFilterLink *const outlink = inlink->dst->outputs[0];
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AVFrame *outsamples = ff_get_audio_buffer(outlink, n);
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PanContext *pan = inlink->dst->priv;
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if (!outsamples) {
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av_frame_free(&insamples);
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return AVERROR(ENOMEM);
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}
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swr_convert(pan->swr, outsamples->extended_data, n,
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(void *)insamples->extended_data, n);
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av_frame_copy_props(outsamples, insamples);
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outsamples->channel_layout = outlink->channel_layout;
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outsamples->channels = outlink->channels;
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ret = ff_filter_frame(outlink, outsamples);
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av_frame_free(&insamples);
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return ret;
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}
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static av_cold void uninit(AVFilterContext *ctx)
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{
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PanContext *pan = ctx->priv;
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swr_free(&pan->swr);
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}
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#define OFFSET(x) offsetof(PanContext, x)
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static const AVOption pan_options[] = {
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{ "args", NULL, OFFSET(args), AV_OPT_TYPE_STRING, { .str = NULL }, CHAR_MIN, CHAR_MAX, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM },
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{ NULL }
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};
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AVFILTER_DEFINE_CLASS(pan);
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static const AVFilterPad pan_inputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_AUDIO,
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.config_props = config_props,
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.filter_frame = filter_frame,
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},
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{ NULL }
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};
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static const AVFilterPad pan_outputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_AUDIO,
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},
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{ NULL }
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};
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AVFilter ff_af_pan = {
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.name = "pan",
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.description = NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."),
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.priv_size = sizeof(PanContext),
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.priv_class = &pan_class,
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.init = init,
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.uninit = uninit,
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.query_formats = query_formats,
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.inputs = pan_inputs,
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.outputs = pan_outputs,
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};
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