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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 APadContext {
- 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 *s = ctx->priv;
-
- s->next_pts = AV_NOPTS_VALUE;
- if (s->whole_len >= 0 && s->pad_len >= 0) {
- av_log(ctx, AV_LOG_ERROR, "Both whole and pad length are set, this is not possible\n");
- return AVERROR(EINVAL);
- }
- s->pad_len_left = s->pad_len;
- s->whole_len_left = s->whole_len;
-
- return 0;
- }
-
- static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
- {
- AVFilterContext *ctx = inlink->dst;
- APadContext *s = ctx->priv;
-
- if (s->whole_len >= 0) {
- s->whole_len_left = FFMAX(s->whole_len_left - frame->nb_samples, 0);
- av_log(ctx, AV_LOG_DEBUG,
- "n_out:%d whole_len_left:%"PRId64"\n", frame->nb_samples, s->whole_len_left);
- }
-
- s->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 *s = ctx->priv;
- int ret;
-
- ret = ff_request_frame(ctx->inputs[0]);
-
- if (ret == AVERROR_EOF && !ctx->is_disabled) {
- int n_out = s->packet_size;
- AVFrame *outsamplesref;
-
- if (s->whole_len >= 0 && s->pad_len < 0) {
- s->pad_len = s->pad_len_left = s->whole_len_left;
- }
- if (s->pad_len >=0 || s->whole_len >= 0) {
- n_out = FFMIN(n_out, s->pad_len_left);
- s->pad_len_left -= n_out;
- av_log(ctx, AV_LOG_DEBUG,
- "padding n_out:%d pad_len_left:%"PRId64"\n", n_out, s->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,
- outsamplesref->channels,
- outsamplesref->format);
-
- outsamplesref->pts = s->next_pts;
- if (s->next_pts != AV_NOPTS_VALUE)
- s->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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