/* * Copyright (c) 2002 Anders Johansson <ajh@atri.curtin.edu.au> * Copyright (c) 2011 Clément Bœsch <ubitux@gmail.com> * 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 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/opt.h" #include "libswresample/swresample.h" #include "avfilter.h" #define MAX_CHANNELS 63 typedef struct PanContext { int64_t out_channel_layout; union { double d[MAX_CHANNELS][MAX_CHANNELS]; // i is 1:7:8 fixed-point, i.e. in [-128*256; +128*256[ int i[MAX_CHANNELS][MAX_CHANNELS]; } gain; int64_t need_renorm; int need_renumber; int nb_input_channels; int nb_output_channels; int pure_gains; void (*filter_samples)(struct PanContext*, AVFilterBufferRef*, AVFilterBufferRef*, int); /* channel mapping specific */ int channel_map[SWR_CH_MAX]; struct SwrContext *swr; } PanContext; static int parse_channel_name(char **arg, int *rchannel, int *rnamed) { char buf[8]; int len, i, channel_id; int64_t layout, layout0; if (sscanf(*arg, " %7[A-Z] %n", buf, &len)) { layout0 = layout = av_get_channel_layout(buf); for (i = 32; i > 0; i >>= 1) { if (layout >= (int64_t)1 << i) { channel_id += i; layout >>= i; } } if (channel_id >= MAX_CHANNELS || layout0 != (int64_t)1 << channel_id) return AVERROR(EINVAL); *rchannel = channel_id; *rnamed = 1; *arg += len; return 0; } 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 void skip_spaces(char **arg) { int len = 0; sscanf(*arg, " %n", &len); *arg += len; } static av_cold int init(AVFilterContext *ctx, const char *args0, void *opaque) { PanContext *const pan = ctx->priv; char *arg, *arg0, *tokenizer, *args = av_strdup(args0); int out_ch_id, in_ch_id, len, named; int nb_in_channels[2] = { 0, 0 }; // number of unnamed and named input channels double gain; if (!args0) { av_log(ctx, AV_LOG_ERROR, "pan filter needs a channel layout and a set " "of channels definitions as parameter\n"); return AVERROR(EINVAL); } if (!args) return AVERROR(ENOMEM); arg = av_strtok(args, ":", &tokenizer); pan->out_channel_layout = av_get_channel_layout(arg); if (!pan->out_channel_layout) { av_log(ctx, AV_LOG_ERROR, "Unknown channel layout \"%s\"\n", arg); return AVERROR(EINVAL); } pan->nb_output_channels = av_get_channel_layout_nb_channels(pan->out_channel_layout); /* 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); return AVERROR(EINVAL); } 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); return AVERROR(EINVAL); } /* 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); return AVERROR(EINVAL); } 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); return AVERROR(EINVAL); } /* 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); return AVERROR(EINVAL); } nb_in_channels[named]++; if (nb_in_channels[!named]) { av_log(ctx, AV_LOG_ERROR, "Can not mix named and numbered channels\n"); return AVERROR(EINVAL); } pan->gain.d[out_ch_id][in_ch_id] = gain; if (!*arg) break; if (*arg != '+') { av_log(ctx, AV_LOG_ERROR, "Syntax error near \"%.8s\"\n", arg); return AVERROR(EINVAL); } arg++; skip_spaces(&arg); } } pan->need_renumber = !!nb_in_channels[1]; av_free(args); return 0; } 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.d[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 config_props(AVFilterLink *link) { AVFilterContext *ctx = link->dst; PanContext *pan = ctx->priv; char buf[1024], *cur; int i, j, k, r; double t; pan->nb_input_channels = av_get_channel_layout_nb_channels(link->channel_layout); 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.d[k][j] = pan->gain.d[k][i]; j++; } } } // gains are pure, init the channel mapping if (pan->pure_gains) { // sanity check; can't be done in query_formats since the inlink // channel layout is unknown at that time if (pan->nb_input_channels > SWR_CH_MAX) { av_log(ctx, AV_LOG_ERROR, "libswresample support a maximum of %d channels. " "Feel free to ask for a higher limit.\n", SWR_CH_MAX); return AVERROR_PATCHWELCOME; } // get channel map from the pure gains for (i = 0; i < pan->nb_output_channels; i++) { int ch_id = -1; for (j = 0; j < pan->nb_input_channels; j++) { if (pan->gain.d[i][j]) { ch_id = j; break; } } pan->channel_map[i] = ch_id; } // 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); 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); r = swr_init(pan->swr); if (r < 0) return r; } else { // renormalize for (i = 0; i < pan->nb_output_channels; i++) { if (!((pan->need_renorm >> i) & 1)) continue; t = 0; for (j = 0; j < pan->nb_input_channels; j++) t += pan->gain.d[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 < pan->nb_input_channels; j++) pan->gain.d[i][j] /= t; } } // summary for (i = 0; i < pan->nb_output_channels; i++) { cur = buf; for (j = 0; j < pan->nb_input_channels; j++) { r = snprintf(cur, buf + sizeof(buf) - cur, "%s%.3g i%d", j ? " + " : "", pan->gain.d[i][j], j); cur += FFMIN(buf + sizeof(buf) - cur, r); } av_log(ctx, AV_LOG_INFO, "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; } // convert to integer for (i = 0; i < pan->nb_output_channels; i++) { for (j = 0; j < pan->nb_input_channels; j++) { if (pan->gain.d[i][j] < -128 || pan->gain.d[i][j] > 128) av_log(ctx, AV_LOG_WARNING, "Gain #%d->#%d too large, clamped\n", j, i); pan->gain.i[i][j] = av_clipf(pan->gain.d[i][j], -128, 128) * 256.0; } } return 0; } static void filter_samples_channel_mapping(PanContext *pan, AVFilterBufferRef *outsamples, AVFilterBufferRef *insamples, int n) { swr_convert(pan->swr, outsamples->data, n, (void *)insamples->data, n); } static void filter_samples_panning(PanContext *pan, AVFilterBufferRef *outsamples, AVFilterBufferRef *insamples, int n) { int i, o; /* input */ const int16_t *in = (int16_t *)insamples->data[0]; const int16_t *in_end = in + n * pan->nb_input_channels; /* output */ int16_t *out = (int16_t *)outsamples->data[0]; for (; in < in_end; in += pan->nb_input_channels) { for (o = 0; o < pan->nb_output_channels; o++) { int v = 0; for (i = 0; i < pan->nb_input_channels; i++) v += pan->gain.i[o][i] * in[i]; *(out++) = v >> 8; } } } static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples) { int n = insamples->audio->nb_samples; AVFilterLink *const outlink = inlink->dst->outputs[0]; AVFilterBufferRef *outsamples = avfilter_get_audio_buffer(outlink, AV_PERM_WRITE, n); PanContext *pan = inlink->dst->priv; pan->filter_samples(pan, outsamples, insamples, n); avfilter_copy_buffer_ref_props(outsamples, insamples); outsamples->audio->channel_layout = outlink->channel_layout; outsamples->audio->planar = outlink->planar; avfilter_filter_samples(outlink, outsamples); avfilter_unref_buffer(insamples); } static int query_formats(AVFilterContext *ctx) { PanContext *pan = ctx->priv; AVFilterLink *inlink = ctx->inputs[0]; AVFilterLink *outlink = ctx->outputs[0]; AVFilterFormats *formats; if (pan->nb_output_channels <= SWR_CH_MAX) pan->pure_gains = are_gains_pure(pan); if (pan->pure_gains) { /* libswr supports any sample and packing formats */ avfilter_set_common_sample_formats(ctx, avfilter_make_all_formats(AVMEDIA_TYPE_AUDIO)); avfilter_set_common_packing_formats(ctx, avfilter_make_all_packing_formats()); pan->filter_samples = filter_samples_channel_mapping; } else { const enum AVSampleFormat sample_fmts[] = {AV_SAMPLE_FMT_S16, -1}; const int packing_fmts[] = {AVFILTER_PACKED, -1}; avfilter_set_common_sample_formats (ctx, avfilter_make_format_list(sample_fmts)); avfilter_set_common_packing_formats(ctx, avfilter_make_format_list(packing_fmts)); pan->filter_samples = filter_samples_panning; } // inlink supports any channel layout formats = avfilter_make_all_channel_layouts(); avfilter_formats_ref(formats, &inlink->out_chlayouts); // outlink supports only requested output channel layout formats = NULL; avfilter_add_format(&formats, pan->out_channel_layout); avfilter_formats_ref(formats, &outlink->in_chlayouts); return 0; } static av_cold void uninit(AVFilterContext *ctx) { PanContext *pan = ctx->priv; swr_free(&pan->swr); } AVFilter avfilter_af_pan = { .name = "pan", .description = NULL_IF_CONFIG_SMALL("Remix channels with coefficients (panning)."), .priv_size = sizeof(PanContext), .init = init, .uninit = uninit, .query_formats = query_formats, .inputs = (const AVFilterPad[]) { { .name = "default", .type = AVMEDIA_TYPE_AUDIO, .config_props = config_props, .filter_samples = filter_samples, .min_perms = AV_PERM_READ, }, { .name = NULL} }, .outputs = (const AVFilterPad[]) { { .name = "default", .type = AVMEDIA_TYPE_AUDIO, }, { .name = NULL} }, };