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/*
* Copyright (c) 2012 Michael Niedermayer
*
* 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
* audio pad filter.
*
* Based on af_aresample.c
*/
#include "libavutil/avstring.h"
#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "libavutil/samplefmt.h"
#include "libavutil/avassert.h"
#include "avfilter.h"
#include "audio.h"
#include "internal.h"
typedef struct {
const AVClass *class;
int64_t next_pts;
int packet_size;
int64_t pad_len, pad_len_left;
int64_t whole_len, whole_len_left;
} APadContext;
#define OFFSET(x) offsetof(APadContext, x)
#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption apad_options[] = {
{ "packet_size", "set silence packet size", OFFSET(packet_size), AV_OPT_TYPE_INT, { .i64 = 4096 }, 0, INT_MAX, A },
{ "pad_len", "set number of samples of silence to add", OFFSET(pad_len), AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, A },
{ "whole_len", "set minimum target number of samples in the audio stream", OFFSET(whole_len), AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, A },
{ NULL }
};
AVFILTER_DEFINE_CLASS(apad);
static av_cold int init(AVFilterContext *ctx)
{
APadContext *apad = ctx->priv;
apad->next_pts = AV_NOPTS_VALUE;
if (apad->whole_len >= 0 && apad->pad_len >= 0) {
av_log(ctx, AV_LOG_ERROR, "Both whole and pad length are set, this is not possible\n");
return AVERROR(EINVAL);
}
apad->pad_len_left = apad->pad_len;
apad->whole_len_left = apad->whole_len;
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
{
AVFilterContext *ctx = inlink->dst;
APadContext *apad = ctx->priv;
if (apad->whole_len >= 0) {
apad->whole_len_left = FFMAX(apad->whole_len_left - frame->nb_samples, 0);
av_log(ctx, AV_LOG_DEBUG,
"n_out:%d whole_len_left:%"PRId64"\n", frame->nb_samples, apad->whole_len_left);
}
apad->next_pts = frame->pts + av_rescale_q(frame->nb_samples, (AVRational){1, inlink->sample_rate}, inlink->time_base);
return ff_filter_frame(ctx->outputs[0], frame);
}
static int request_frame(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
APadContext *apad = ctx->priv;
int ret;
ret = ff_request_frame(ctx->inputs[0]);
if (ret == AVERROR_EOF && !ctx->is_disabled) {
int n_out = apad->packet_size;
AVFrame *outsamplesref;
if (apad->whole_len >= 0 && apad->pad_len < 0) {
apad->pad_len = apad->pad_len_left = apad->whole_len_left;
}
if (apad->pad_len >=0 || apad->whole_len >= 0) {
n_out = FFMIN(n_out, apad->pad_len_left);
apad->pad_len_left -= n_out;
av_log(ctx, AV_LOG_DEBUG,
"padding n_out:%d pad_len_left:%"PRId64"\n", n_out, apad->pad_len_left);
}
if (!n_out)
return AVERROR_EOF;
outsamplesref = ff_get_audio_buffer(outlink, n_out);
if (!outsamplesref)
return AVERROR(ENOMEM);
av_assert0(outsamplesref->sample_rate == outlink->sample_rate);
av_assert0(outsamplesref->nb_samples == n_out);
av_samples_set_silence(outsamplesref->extended_data, 0,
n_out,
av_frame_get_channels(outsamplesref),
outsamplesref->format);
outsamplesref->pts = apad->next_pts;
if (apad->next_pts != AV_NOPTS_VALUE)
apad->next_pts += av_rescale_q(n_out, (AVRational){1, outlink->sample_rate}, outlink->time_base);
return ff_filter_frame(outlink, outsamplesref);
}
return ret;
}
static const AVFilterPad apad_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad apad_outputs[] = {
{
.name = "default",
.request_frame = request_frame,
.type = AVMEDIA_TYPE_AUDIO,
},
{ NULL }
};
AVFilter ff_af_apad = {
.name = "apad",
.description = NULL_IF_CONFIG_SMALL("Pad audio with silence."),
.init = init,
.priv_size = sizeof(APadContext),
.inputs = apad_inputs,
.outputs = apad_outputs,
.priv_class = &apad_class,
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,
};
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