| /* |
| * 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_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} |
| }, |
| }; |
