| /* |
| * 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, const char *args) |
| { |
| int ret; |
| APadContext *apad = ctx->priv; |
| |
| apad->class = &apad_class; |
| apad->next_pts = AV_NOPTS_VALUE; |
| |
| av_opt_set_defaults(apad); |
| |
| if ((ret = av_opt_set_from_string(apad, args, NULL, "=", ":")) < 0) |
| return ret; |
| |
| 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, AVFilterBufferRef *frame) |
| { |
| AVFilterContext *ctx = inlink->dst; |
| APadContext *apad = ctx->priv; |
| |
| if (apad->whole_len) |
| apad->whole_len -= frame->audio->nb_samples; |
| |
| 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 = apad->packet_size; |
| AVFilterBufferRef *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, 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, |
| .priv_class = &apad_class, |
| }; |