/* * 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 * Channel split filter * * Split an audio stream into per-channel streams. */ #include "libavutil/attributes.h" #include "libavutil/channel_layout.h" #include "libavutil/internal.h" #include "libavutil/mem.h" #include "libavutil/opt.h" #include "audio.h" #include "avfilter.h" #include "filters.h" #include "formats.h" #include "internal.h" #define MAX_CH 64 typedef struct ChannelSplitContext { const AVClass *class; AVChannelLayout channel_layout; char *channels_str; int map[64]; } ChannelSplitContext; #define OFFSET(x) offsetof(ChannelSplitContext, x) #define A AV_OPT_FLAG_AUDIO_PARAM #define F AV_OPT_FLAG_FILTERING_PARAM static const AVOption channelsplit_options[] = { { "channel_layout", "Input channel layout.", OFFSET(channel_layout), AV_OPT_TYPE_CHLAYOUT, { .str = "stereo" }, .flags = A|F }, { "channels", "Channels to extract.", OFFSET(channels_str), AV_OPT_TYPE_STRING, { .str = "all" }, .flags = A|F }, { NULL } }; AVFILTER_DEFINE_CLASS(channelsplit); static av_cold int init(AVFilterContext *ctx) { ChannelSplitContext *s = ctx->priv; AVChannelLayout channel_layout = { 0 }; int all = 0, ret = 0, i; if (!strcmp(s->channels_str, "all")) { if ((ret = av_channel_layout_copy(&channel_layout, &s->channel_layout)) < 0) goto fail; all = 1; } else { if ((ret = av_channel_layout_from_string(&channel_layout, s->channels_str)) < 0) goto fail; } if (channel_layout.nb_channels > MAX_CH) { av_log(ctx, AV_LOG_ERROR, "Too many channels\n"); goto fail; } for (i = 0; i < channel_layout.nb_channels; i++) { enum AVChannel channel = av_channel_layout_channel_from_index(&channel_layout, i); char buf[64]; AVFilterPad pad = { .flags = AVFILTERPAD_FLAG_FREE_NAME }; av_channel_name(buf, sizeof(buf), channel); pad.type = AVMEDIA_TYPE_AUDIO; pad.name = av_strdup(buf); if (!pad.name) { ret = AVERROR(ENOMEM); goto fail; } if (all) { s->map[i] = i; } else { char buf[128]; av_channel_layout_describe(&s->channel_layout, buf, sizeof(buf)); if ((ret = av_channel_layout_index_from_channel(&s->channel_layout, channel)) < 0) { av_log(ctx, AV_LOG_ERROR, "Channel name '%s' not present in channel layout '%s'.\n", pad.name, buf); av_freep(&pad.name); goto fail; } s->map[i] = ret; } if ((ret = ff_append_outpad(ctx, &pad)) < 0) goto fail; } fail: av_channel_layout_uninit(&channel_layout); return ret; } static av_cold void uninit(AVFilterContext *ctx) { ChannelSplitContext *s = ctx->priv; av_channel_layout_uninit(&s->channel_layout); } static int query_formats(AVFilterContext *ctx) { ChannelSplitContext *s = ctx->priv; AVFilterChannelLayouts *in_layouts = NULL; int i, ret; if ((ret = ff_set_common_formats(ctx, ff_planar_sample_fmts())) < 0 || (ret = ff_set_common_all_samplerates(ctx)) < 0) return ret; if ((ret = ff_add_channel_layout(&in_layouts, &s->channel_layout)) < 0 || (ret = ff_channel_layouts_ref(in_layouts, &ctx->inputs[0]->outcfg.channel_layouts)) < 0) return ret; for (i = 0; i < ctx->nb_outputs; i++) { AVChannelLayout channel_layout = { 0 }; AVFilterChannelLayouts *out_layouts = NULL; enum AVChannel channel = av_channel_layout_channel_from_index(&s->channel_layout, s->map[i]); if ((ret = av_channel_layout_from_mask(&channel_layout, 1ULL << channel)) < 0 || (ret = ff_add_channel_layout(&out_layouts, &channel_layout)) < 0 || (ret = ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->incfg.channel_layouts)) < 0) return ret; } return 0; } static int filter_frame(AVFilterLink *outlink, AVFrame *buf) { AVFilterContext *ctx = outlink->src; ChannelSplitContext *s = ctx->priv; const int i = FF_OUTLINK_IDX(outlink); enum AVChannel channel = av_channel_layout_channel_from_index(&buf->ch_layout, s->map[i]); int ret; AVFrame *buf_out = av_frame_clone(buf); if (!buf_out) return AVERROR(ENOMEM); buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[s->map[i]]; ret = av_channel_layout_from_mask(&buf_out->ch_layout, 1ULL << channel); if (ret < 0) return ret; return ff_filter_frame(ctx->outputs[i], buf_out); } static int activate(AVFilterContext *ctx) { AVFilterLink *inlink = ctx->inputs[0]; int status, ret; AVFrame *in; int64_t pts; for (int i = 0; i < ctx->nb_outputs; i++) { FF_FILTER_FORWARD_STATUS_BACK_ALL(ctx->outputs[i], ctx); } ret = ff_inlink_consume_frame(inlink, &in); if (ret < 0) return ret; if (ret > 0) { for (int i = 0; i < ctx->nb_outputs; i++) { if (ff_outlink_get_status(ctx->outputs[i])) continue; ret = filter_frame(ctx->outputs[i], in); if (ret < 0) break; } av_frame_free(&in); if (ret < 0) return ret; } if (ff_inlink_acknowledge_status(inlink, &status, &pts)) { for (int i = 0; i < ctx->nb_outputs; i++) { if (ff_outlink_get_status(ctx->outputs[i])) continue; ff_outlink_set_status(ctx->outputs[i], status, pts); } return 0; } for (int i = 0; i < ctx->nb_outputs; i++) { if (ff_outlink_get_status(ctx->outputs[i])) continue; if (ff_outlink_frame_wanted(ctx->outputs[i])) { ff_inlink_request_frame(inlink); return 0; } } return FFERROR_NOT_READY; } const AVFilter ff_af_channelsplit = { .name = "channelsplit", .description = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams."), .priv_size = sizeof(ChannelSplitContext), .priv_class = &channelsplit_class, .init = init, .activate = activate, .uninit = uninit, FILTER_INPUTS(ff_audio_default_filterpad), .outputs = NULL, FILTER_QUERY_FUNC(query_formats), .flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS, };