From 5eae7f8f35500b88382619bff3cd01f2e1e0b1ea Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Tue, 18 Dec 2012 05:13:59 +0100 Subject: avfilter: add apad filter This filter pads an audio stream with silence It can together with -shortest be used to extend audio streams to the same length as video. Signed-off-by: Michael Niedermayer --- libavfilter/af_apad.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100644 libavfilter/af_apad.c (limited to 'libavfilter/af_apad.c') diff --git a/libavfilter/af_apad.c b/libavfilter/af_apad.c new file mode 100644 index 0000000000..55c65e2015 --- /dev/null +++ b/libavfilter/af_apad.c @@ -0,0 +1,116 @@ +/* + * 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 { + int64_t next_pts; +} APadContext; + +static av_cold int init(AVFilterContext *ctx, const char *args) +{ + APadContext *apad = ctx->priv; + + apad->next_pts = AV_NOPTS_VALUE; + + return 0; +} + +static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *frame) +{ + AVFilterContext *ctx = inlink->dst; + APadContext *apad = ctx->priv; + apad->next_pts = frame->pts + av_rescale_q(frame->audio->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) { + int n_out = 4096; + AVFilterBufferRef *outsamplesref = ff_get_audio_buffer(outlink, AV_PERM_WRITE, n_out); + if (!outsamplesref) + return AVERROR(ENOMEM); + + av_assert0(outsamplesref->audio->sample_rate == outlink->sample_rate); + av_assert0(outsamplesref->audio->nb_samples == n_out); + + av_samples_set_silence(outsamplesref->extended_data, 0, + n_out, + outsamplesref->audio->channels, + 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, + .min_perms = AV_PERM_READ, + }, + { NULL }, +}; + +static const AVFilterPad apad_outputs[] = { + { + .name = "default", + .request_frame = request_frame, + .type = AVMEDIA_TYPE_AUDIO, + }, + { NULL }, +}; + +AVFilter avfilter_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, +}; -- cgit v1.2.3