diff options
Diffstat (limited to 'libavfilter/af_apad.c')
| -rw-r--r-- | libavfilter/af_apad.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/libavfilter/af_apad.c b/libavfilter/af_apad.c new file mode 100644 index 0000000000..88a3a77a19 --- /dev/null +++ b/libavfilter/af_apad.c @@ -0,0 +1,156 @@ +/* + * 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; + int64_t whole_len; +} 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", "number of samples of silence to add", OFFSET(pad_len), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, A }, + { "whole_len", "target number of samples in the audio stream", OFFSET(whole_len), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, 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 && apad->pad_len) { + av_log(ctx, AV_LOG_ERROR, "Both whole and pad length are set, this is not possible\n"); + return AVERROR(EINVAL); + } + + return 0; +} + +static int filter_frame(AVFilterLink *inlink, AVFrame *frame) +{ + AVFilterContext *ctx = inlink->dst; + APadContext *apad = ctx->priv; + + if (apad->whole_len) + apad->whole_len -= frame->nb_samples; + + 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 = apad->whole_len; + apad->whole_len = 0; + } + if (apad->pad_len > 0) { + n_out = FFMIN(n_out, apad->pad_len); + apad->pad_len -= n_out; + } + + 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, +}; |