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Diffstat (limited to 'libavfilter/af_apad.c')
| -rw-r--r-- | libavfilter/af_apad.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/libavfilter/af_apad.c b/libavfilter/af_apad.c new file mode 100644 index 0000000000..eafc7050e8 --- /dev/null +++ b/libavfilter/af_apad.c @@ -0,0 +1,161 @@ +/* + * 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, +}; |