97 lines
3.0 KiB
C
97 lines
3.0 KiB
C
/*
|
|
* 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
|
|
* null audio source
|
|
*/
|
|
|
|
#include "avfilter.h"
|
|
#include "libavutil/audioconvert.h"
|
|
|
|
typedef struct {
|
|
int64_t channel_layout;
|
|
int64_t sample_rate;
|
|
} ANullContext;
|
|
|
|
static int init(AVFilterContext *ctx, const char *args, void *opaque)
|
|
{
|
|
ANullContext *priv = ctx->priv;
|
|
char channel_layout_str[128] = "";
|
|
|
|
priv->sample_rate = 44100;
|
|
priv->channel_layout = AV_CH_LAYOUT_STEREO;
|
|
|
|
if (args)
|
|
sscanf(args, "%"PRId64":%s", &priv->sample_rate, channel_layout_str);
|
|
|
|
if (priv->sample_rate < 0) {
|
|
av_log(ctx, AV_LOG_ERROR, "Invalid negative sample rate: %"PRId64"\n", priv->sample_rate);
|
|
return AVERROR(EINVAL);
|
|
}
|
|
|
|
if (*channel_layout_str)
|
|
if (!(priv->channel_layout = av_get_channel_layout(channel_layout_str))
|
|
&& sscanf(channel_layout_str, "%"PRId64, &priv->channel_layout) != 1) {
|
|
av_log(ctx, AV_LOG_ERROR, "Invalid value '%s' for channel layout\n",
|
|
channel_layout_str);
|
|
return AVERROR(EINVAL);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int config_props(AVFilterLink *outlink)
|
|
{
|
|
ANullContext *priv = outlink->src->priv;
|
|
char buf[128];
|
|
int chans_nb;
|
|
|
|
outlink->sample_rate = priv->sample_rate;
|
|
outlink->channel_layout = priv->channel_layout;
|
|
|
|
chans_nb = av_get_channel_layout_nb_channels(priv->channel_layout);
|
|
av_get_channel_layout_string(buf, sizeof(buf), chans_nb, priv->channel_layout);
|
|
av_log(outlink->src, AV_LOG_INFO,
|
|
"sample_rate:%"PRId64 " channel_layout:%"PRId64 " channel_layout_description:'%s'\n",
|
|
priv->sample_rate, priv->channel_layout, buf);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int request_frame(AVFilterLink *link)
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
AVFilter avfilter_asrc_anullsrc = {
|
|
.name = "anullsrc",
|
|
.description = NULL_IF_CONFIG_SMALL("Null audio source, never return audio frames."),
|
|
|
|
.init = init,
|
|
.priv_size = sizeof(ANullContext),
|
|
|
|
.inputs = (AVFilterPad[]) {{ .name = NULL}},
|
|
|
|
.outputs = (AVFilterPad[]) {{ .name = "default",
|
|
.type = AVMEDIA_TYPE_AUDIO,
|
|
.config_props = config_props,
|
|
.request_frame = request_frame, },
|
|
{ .name = NULL}},
|
|
};
|