108 lines
3.0 KiB
C
108 lines
3.0 KiB
C
/*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* null audio source
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*/
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#include <inttypes.h>
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#include <stdio.h>
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#include "libavutil/channel_layout.h"
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#include "libavutil/internal.h"
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#include "avfilter.h"
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#include "internal.h"
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typedef struct {
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uint64_t channel_layout;
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int64_t sample_rate;
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} ANullContext;
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static int init(AVFilterContext *ctx, const char *args)
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{
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ANullContext *priv = ctx->priv;
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char channel_layout_str[128] = "";
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priv->sample_rate = 44100;
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priv->channel_layout = AV_CH_LAYOUT_STEREO;
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if (args)
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sscanf(args, "%"PRId64":%s", &priv->sample_rate, channel_layout_str);
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if (priv->sample_rate < 0) {
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av_log(ctx, AV_LOG_ERROR, "Invalid negative sample rate: %"PRId64"\n", priv->sample_rate);
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return AVERROR(EINVAL);
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}
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if (*channel_layout_str)
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if (!(priv->channel_layout = av_get_channel_layout(channel_layout_str))
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&& sscanf(channel_layout_str, "%"PRId64, &priv->channel_layout) != 1) {
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av_log(ctx, AV_LOG_ERROR, "Invalid value '%s' for channel layout\n",
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channel_layout_str);
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return AVERROR(EINVAL);
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}
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return 0;
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}
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static int config_props(AVFilterLink *outlink)
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{
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ANullContext *priv = outlink->src->priv;
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char buf[128];
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int chans_nb;
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outlink->sample_rate = priv->sample_rate;
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outlink->channel_layout = priv->channel_layout;
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chans_nb = av_get_channel_layout_nb_channels(priv->channel_layout);
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av_get_channel_layout_string(buf, sizeof(buf), chans_nb, priv->channel_layout);
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av_log(outlink->src, AV_LOG_VERBOSE,
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"sample_rate:%"PRId64 " channel_layout:%"PRId64 " channel_layout_description:'%s'\n",
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priv->sample_rate, priv->channel_layout, buf);
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return 0;
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}
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static int request_frame(AVFilterLink *link)
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{
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return -1;
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}
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static const AVFilterPad avfilter_asrc_anullsrc_outputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_AUDIO,
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.config_props = config_props,
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.request_frame = request_frame,
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},
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{ NULL }
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};
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AVFilter avfilter_asrc_anullsrc = {
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.name = "anullsrc",
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.description = NULL_IF_CONFIG_SMALL("Null audio source, never return audio frames."),
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.init = init,
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.priv_size = sizeof(ANullContext),
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.inputs = NULL,
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.outputs = avfilter_asrc_anullsrc_outputs,
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};
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