diff options
Diffstat (limited to 'libavfilter/af_channelsplit.c')
-rw-r--r-- | libavfilter/af_channelsplit.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/libavfilter/af_channelsplit.c b/libavfilter/af_channelsplit.c new file mode 100644 index 0000000..c9b31fa --- /dev/null +++ b/libavfilter/af_channelsplit.c @@ -0,0 +1,146 @@ +/* + * 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/audioconvert.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 +static const AVOption options[] = { + { "channel_layout", "Input channel layout.", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, { .str = "stereo" }, .flags = A }, + { NULL }, +}; + +static const AVClass channelsplit_class = { + .class_name = "channelsplit filter", + .item_name = av_default_item_name, + .option = options, + .version = LIBAVUTIL_VERSION_INT, +}; + +static int init(AVFilterContext *ctx, const char *arg, void *opaque) +{ + 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) { + av_log(ctx, AV_LOG_ERROR, "Error parsing options string '%s'.\n", arg); + 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 void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *buf) +{ + AVFilterContext *ctx = inlink->dst; + int i; + + for (i = 0; i < ctx->nb_outputs; i++) { + AVFilterBufferRef *buf_out = avfilter_ref_buffer(buf, ~AV_PERM_WRITE); + + if (!buf_out) + return; + + 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); + + ff_filter_samples(ctx->outputs[i], buf_out); + } + avfilter_unref_buffer(buf); +} + +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 = (const AVFilterPad[]){{ .name = "default", + .type = AVMEDIA_TYPE_AUDIO, + .filter_samples = filter_samples, }, + { NULL }}, + .outputs = (const AVFilterPad[]){{ NULL }}, +}; |