/* * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; 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/channel_layout.h" #include "libavutil/internal.h" #include "libavutil/opt.h" #include "audio.h" #include "avfilter.h" #include "formats.h" #include "internal.h" typedef struct ChannelSplitContext { const AVClass *class; uint64_t channel_layout; char *channel_layout_str; } 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_str), AV_OPT_TYPE_STRING, { .str = "stereo" }, .flags = A|F }, { NULL }, }; AVFILTER_DEFINE_CLASS(channelsplit); static int init(AVFilterContext *ctx, const char *arg) { ChannelSplitContext *s = ctx->priv; int nb_channels; int ret = 0, i; s->class = &channelsplit_class; av_opt_set_defaults(s); if ((ret = av_set_options_string(s, arg, "=", ":")) < 0) return ret; if (!(s->channel_layout = av_get_channel_layout(s->channel_layout_str))) { av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout '%s'.\n", s->channel_layout_str); ret = AVERROR(EINVAL); goto fail; } nb_channels = av_get_channel_layout_nb_channels(s->channel_layout); for (i = 0; i < nb_channels; i++) { uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i); AVFilterPad pad = { 0 }; pad.type = AVMEDIA_TYPE_AUDIO; pad.name = av_get_channel_name(channel); ff_insert_outpad(ctx, i, &pad); } fail: av_opt_free(s); return ret; } static int query_formats(AVFilterContext *ctx) { ChannelSplitContext *s = ctx->priv; AVFilterChannelLayouts *in_layouts = NULL; int i; ff_set_common_formats (ctx, ff_planar_sample_fmts()); ff_set_common_samplerates(ctx, ff_all_samplerates()); ff_add_channel_layout(&in_layouts, s->channel_layout); ff_channel_layouts_ref(in_layouts, &ctx->inputs[0]->out_channel_layouts); for (i = 0; i < ctx->nb_outputs; i++) { AVFilterChannelLayouts *out_layouts = NULL; uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i); ff_add_channel_layout(&out_layouts, channel); ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->in_channel_layouts); } return 0; } static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *buf) { AVFilterContext *ctx = inlink->dst; int i, ret = 0; for (i = 0; i < ctx->nb_outputs; i++) { AVFilterBufferRef *buf_out = avfilter_ref_buffer(buf, ~AV_PERM_WRITE); if (!buf_out) { ret = AVERROR(ENOMEM); break; } buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[i]; buf_out->audio->channel_layout = av_channel_layout_extract_channel(buf->audio->channel_layout, i); ret = ff_filter_frame(ctx->outputs[i], buf_out); if (ret < 0) break; } avfilter_unref_buffer(buf); return ret; } static const AVFilterPad avfilter_af_channelsplit_inputs[] = { { .name = "default", .type = AVMEDIA_TYPE_AUDIO, .filter_frame = filter_frame, }, { NULL } }; AVFilter avfilter_af_channelsplit = { .name = "channelsplit", .description = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams"), .priv_size = sizeof(ChannelSplitContext), .init = init, .query_formats = query_formats, .inputs = avfilter_af_channelsplit_inputs, .outputs = NULL, .priv_class = &channelsplit_class, };