diff options
Diffstat (limited to 'libavfilter/af_pan.c')
| -rw-r--r-- | libavfilter/af_pan.c | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/libavfilter/af_pan.c b/libavfilter/af_pan.c new file mode 100644 index 0000000..753522b --- /dev/null +++ b/libavfilter/af_pan.c @@ -0,0 +1,390 @@ +/* + * 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 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/audioconvert.h" +#include "libavutil/avstring.h" +#include "libavutil/opt.h" +#include "libswresample/swresample.h" +#include "audio.h" +#include "avfilter.h" +#include "formats.h" +#include "internal.h" + +#define MAX_CHANNELS 63 + +typedef struct PanContext { + int64_t out_channel_layout; + double gain[MAX_CHANNELS][MAX_CHANNELS]; + int64_t need_renorm; + int need_renumber; + int nb_input_channels; + int nb_output_channels; + + int pure_gains; + /* 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 = 0; + int64_t layout, layout0; + + /* 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 void skip_spaces(char **arg) +{ + int len = 0; + + sscanf(*arg, " %n", &len); + *arg += len; +} + +static av_cold int init(AVFilterContext *ctx, const char *args0) +{ + PanContext *const pan = ctx->priv; + char *arg, *arg0, *tokenizer, *args = av_strdup(args0); + int out_ch_id, in_ch_id, len, named, ret; + 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); + ret = ff_parse_channel_layout(&pan->out_channel_layout, arg, ctx); + if (ret < 0) + return ret; + 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[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[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; + + pan->pure_gains = are_gains_pure(pan); + /* libswr supports any sample and packing formats */ + ff_set_common_formats(ctx, ff_all_formats(AVMEDIA_TYPE_AUDIO)); + + formats = ff_all_samplerates(); + if (!formats) + return AVERROR(ENOMEM); + ff_set_common_samplerates(ctx, formats); + + // inlink supports any channel layout + layouts = ff_all_channel_layouts(); + ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts); + + // outlink supports only requested output channel layout + layouts = NULL; + ff_add_channel_layout(&layouts, pan->out_channel_layout); + ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts); + return 0; +} + +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[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 (pan->nb_input_channels > SWR_CH_MAX || + pan->nb_output_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; + } + + // 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); + + // 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 < pan->nb_input_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 < pan->nb_input_channels; j++) + t += 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 < pan->nb_input_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 < pan->nb_input_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_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples) +{ + int ret; + int n = insamples->audio->nb_samples; + AVFilterLink *const outlink = inlink->dst->outputs[0]; + AVFilterBufferRef *outsamples = ff_get_audio_buffer(outlink, AV_PERM_WRITE, n); + PanContext *pan = inlink->dst->priv; + + swr_convert(pan->swr, outsamples->data, n, (void *)insamples->data, n); + avfilter_copy_buffer_ref_props(outsamples, insamples); + outsamples->audio->channel_layout = outlink->channel_layout; + + ret = ff_filter_samples(outlink, outsamples); + avfilter_unref_buffer(insamples); + return ret; +} + +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} + }, +}; |
