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/* |
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* Copyright 2010 S.N. Hemanth Meenakshisundaram <smeenaks ucsd edu>
* Copyright 2010 Stefano Sabatini <stefano.sabatini-lala poste it>
* |
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* 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
*/
|
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#include <inttypes.h>
#include <stdio.h> |
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|
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#include "libavutil/channel_layout.h"
#include "libavutil/internal.h" |
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#include "libavutil/opt.h" |
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#include "audio.h" |
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#include "avfilter.h"
#include "internal.h" |
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typedef struct { |
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const AVClass *class;
char *channel_layout_str; |
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uint64_t channel_layout; |
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char *sample_rate_str;
int sample_rate; |
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int nb_samples; ///< number of samples per requested frame
int64_t pts; |
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} ANullContext;
|
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#define OFFSET(x) offsetof(ANullContext, x) |
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#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM |
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static const AVOption anullsrc_options[]= { |
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{ "channel_layout", "set channel_layout", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, {.str = "stereo"}, 0, 0, FLAGS },
{ "cl", "set channel_layout", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, {.str = "stereo"}, 0, 0, FLAGS },
{ "sample_rate", "set sample rate", OFFSET(sample_rate_str) , AV_OPT_TYPE_STRING, {.str = "44100"}, 0, 0, FLAGS },
{ "r", "set sample rate", OFFSET(sample_rate_str) , AV_OPT_TYPE_STRING, {.str = "44100"}, 0, 0, FLAGS }, |
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{ "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS },
{ "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS }, |
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{ NULL } |
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};
|
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AVFILTER_DEFINE_CLASS(anullsrc); |
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|
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static av_cold int init(AVFilterContext *ctx) |
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{ |
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ANullContext *null = ctx->priv; |
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int ret; |
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|
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if ((ret = ff_parse_sample_rate(&null->sample_rate,
null->sample_rate_str, ctx)) < 0) |
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return ret;
|
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if ((ret = ff_parse_channel_layout(&null->channel_layout, NULL, |
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null->channel_layout_str, ctx)) < 0) |
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return ret; |
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return 0;
}
|
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static int query_formats(AVFilterContext *ctx)
{
ANullContext *null = ctx->priv;
int64_t chlayouts[] = { null->channel_layout, -1 };
int sample_rates[] = { null->sample_rate, -1 }; |
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int ret; |
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|
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if ((ret = ff_set_common_formats (ctx, ff_all_formats (AVMEDIA_TYPE_AUDIO))) < 0 ||
(ret = ff_set_common_channel_layouts (ctx, avfilter_make_format64_list (chlayouts ))) < 0 ||
(ret = ff_set_common_samplerates (ctx, ff_make_format_list (sample_rates ))) < 0)
return ret; |
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return 0;
}
|
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static int config_props(AVFilterLink *outlink)
{ |
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ANullContext *null = outlink->src->priv; |
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char buf[128];
|
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av_get_channel_layout_string(buf, sizeof(buf), 0, null->channel_layout); |
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av_log(outlink->src, AV_LOG_VERBOSE, |
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"sample_rate:%d channel_layout:'%s' nb_samples:%d\n", |
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null->sample_rate, buf, null->nb_samples); |
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return 0;
}
|
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static int request_frame(AVFilterLink *outlink) |
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{ |
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int ret; |
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ANullContext *null = outlink->src->priv; |
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AVFrame *samplesref; |
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|
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samplesref = ff_get_audio_buffer(outlink, null->nb_samples); |
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if (!samplesref)
return AVERROR(ENOMEM);
|
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samplesref->pts = null->pts; |
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samplesref->channel_layout = null->channel_layout;
samplesref->sample_rate = outlink->sample_rate; |
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|
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ret = ff_filter_frame(outlink, av_frame_clone(samplesref)); |
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av_frame_free(&samplesref); |
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if (ret < 0)
return ret; |
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null->pts += null->nb_samples; |
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return ret; |
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}
|
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static const AVFilterPad avfilter_asrc_anullsrc_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.config_props = config_props,
.request_frame = request_frame,
},
{ NULL }
};
|
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AVFilter ff_asrc_anullsrc = { |
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.name = "anullsrc",
.description = NULL_IF_CONFIG_SMALL("Null audio source, return empty audio frames."),
.init = init, |
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.query_formats = query_formats, |
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.priv_size = sizeof(ANullContext),
.inputs = NULL,
.outputs = avfilter_asrc_anullsrc_outputs,
.priv_class = &anullsrc_class, |
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}; |