132 lines
4.7 KiB
C
132 lines
4.7 KiB
C
/*
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* Copyright 2010 S.N. Hemanth Meenakshisundaram <smeenaks ucsd edu>
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* Copyright 2010 Stefano Sabatini <stefano.sabatini-lala poste it>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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 "libavutil/opt.h"
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#include "audio.h"
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#include "avfilter.h"
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#include "filters.h"
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#include "formats.h"
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#include "internal.h"
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typedef struct ANullContext {
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const AVClass *class;
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AVChannelLayout ch_layout;
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int sample_rate;
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int64_t duration;
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int nb_samples; ///< number of samples per requested frame
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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(ch_layout), AV_OPT_TYPE_CHLAYOUT, {.str = "stereo"}, 0, 0, FLAGS },
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{ "cl", "set channel_layout", OFFSET(ch_layout), AV_OPT_TYPE_CHLAYOUT, {.str = "stereo"}, 0, 0, FLAGS },
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{ "sample_rate", "set sample rate", OFFSET(sample_rate) , AV_OPT_TYPE_INT, {.i64 = 44100}, 1, INT_MAX, FLAGS },
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{ "r", "set sample rate", OFFSET(sample_rate) , AV_OPT_TYPE_INT, {.i64 = 44100}, 1, INT_MAX, FLAGS },
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{ "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 1, UINT16_MAX, FLAGS },
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{ "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 1, UINT16_MAX, FLAGS },
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{ "duration", "set the audio duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64 = -1}, -1, INT64_MAX, FLAGS },
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{ "d", "set the audio duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64 = -1}, -1, INT64_MAX, FLAGS },
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{ NULL }
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};
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AVFILTER_DEFINE_CLASS(anullsrc);
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static int query_formats(AVFilterContext *ctx)
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{
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ANullContext *null = ctx->priv;
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const AVChannelLayout chlayouts[] = { null->ch_layout, { 0 } };
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int sample_rates[] = { null->sample_rate, -1 };
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int ret;
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if ((ret = ff_set_common_formats (ctx, ff_all_formats (AVMEDIA_TYPE_AUDIO))) < 0 ||
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(ret = ff_set_common_samplerates_from_list(ctx, sample_rates)) < 0)
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return ret;
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return ff_set_common_channel_layouts_from_list(ctx, chlayouts);
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}
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static av_cold int config_props(AVFilterLink *outlink)
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{
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ANullContext *null = outlink->src->priv;
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if (null->duration >= 0)
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null->duration = av_rescale(null->duration, null->sample_rate, AV_TIME_BASE);
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return 0;
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}
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static int activate(AVFilterContext *ctx)
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{
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ANullContext *null = ctx->priv;
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AVFilterLink *outlink = ctx->outputs[0];
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if (null->duration >= 0 && null->pts >= null->duration) {
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ff_outlink_set_status(outlink, AVERROR_EOF, null->pts);
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return 0;
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}
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if (ff_outlink_frame_wanted(outlink)) {
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AVFrame *samplesref = ff_get_audio_buffer(outlink, null->duration >= 0 ? FFMIN(null->nb_samples, null->duration - null->pts) : null->nb_samples);
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if (!samplesref)
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return AVERROR(ENOMEM);
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samplesref->pts = null->pts;
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null->pts += samplesref->nb_samples;
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return ff_filter_frame(outlink, samplesref);
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}
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return FFERROR_NOT_READY;
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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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},
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};
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const AVFilter ff_asrc_anullsrc = {
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.name = "anullsrc",
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.description = NULL_IF_CONFIG_SMALL("Null audio source, return empty audio frames."),
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.priv_size = sizeof(ANullContext),
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.inputs = NULL,
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FILTER_OUTPUTS(avfilter_asrc_anullsrc_outputs),
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FILTER_QUERY_FUNC(query_formats),
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.activate = activate,
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.priv_class = &anullsrc_class,
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};
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