1/* 2 * Copyright (c) 2012 Michael Niedermayer 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21/** 22 * @file 23 * audio pad filter. 24 * 25 * Based on af_aresample.c 26 */ 27 28#include "libavutil/avstring.h" 29#include "libavutil/channel_layout.h" 30#include "libavutil/opt.h" 31#include "libavutil/samplefmt.h" 32#include "libavutil/avassert.h" 33#include "avfilter.h" 34#include "audio.h" 35#include "internal.h" 36 37typedef struct { 38 const AVClass *class; 39 int64_t next_pts; 40 41 int packet_size; 42 int64_t pad_len; 43 int64_t whole_len; 44} APadContext; 45 46#define OFFSET(x) offsetof(APadContext, x) 47#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM 48 49static const AVOption apad_options[] = { 50 { "packet_size", "set silence packet size", OFFSET(packet_size), AV_OPT_TYPE_INT, { .i64 = 4096 }, 0, INT_MAX, A }, 51 { "pad_len", "number of samples of silence to add", OFFSET(pad_len), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, A }, 52 { "whole_len", "target number of samples in the audio stream", OFFSET(whole_len), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, A }, 53 { NULL } 54}; 55 56AVFILTER_DEFINE_CLASS(apad); 57 58static av_cold int init(AVFilterContext *ctx) 59{ 60 APadContext *apad = ctx->priv; 61 62 apad->next_pts = AV_NOPTS_VALUE; 63 if (apad->whole_len && apad->pad_len) { 64 av_log(ctx, AV_LOG_ERROR, "Both whole and pad length are set, this is not possible\n"); 65 return AVERROR(EINVAL); 66 } 67 68 return 0; 69} 70 71static int filter_frame(AVFilterLink *inlink, AVFrame *frame) 72{ 73 AVFilterContext *ctx = inlink->dst; 74 APadContext *apad = ctx->priv; 75 76 if (apad->whole_len) 77 apad->whole_len -= frame->nb_samples; 78 79 apad->next_pts = frame->pts + av_rescale_q(frame->nb_samples, (AVRational){1, inlink->sample_rate}, inlink->time_base); 80 return ff_filter_frame(ctx->outputs[0], frame); 81} 82 83static int request_frame(AVFilterLink *outlink) 84{ 85 AVFilterContext *ctx = outlink->src; 86 APadContext *apad = ctx->priv; 87 int ret; 88 89 ret = ff_request_frame(ctx->inputs[0]); 90 91 if (ret == AVERROR_EOF && !ctx->is_disabled) { 92 int n_out = apad->packet_size; 93 AVFrame *outsamplesref; 94 95 if (apad->whole_len > 0) { 96 apad->pad_len = apad->whole_len; 97 apad->whole_len = 0; 98 } 99 if (apad->pad_len > 0) { 100 n_out = FFMIN(n_out, apad->pad_len); 101 apad->pad_len -= n_out; 102 } 103 104 if(!n_out) 105 return AVERROR_EOF; 106 107 outsamplesref = ff_get_audio_buffer(outlink, n_out); 108 if (!outsamplesref) 109 return AVERROR(ENOMEM); 110 111 av_assert0(outsamplesref->sample_rate == outlink->sample_rate); 112 av_assert0(outsamplesref->nb_samples == n_out); 113 114 av_samples_set_silence(outsamplesref->extended_data, 0, 115 n_out, 116 av_frame_get_channels(outsamplesref), 117 outsamplesref->format); 118 119 outsamplesref->pts = apad->next_pts; 120 if (apad->next_pts != AV_NOPTS_VALUE) 121 apad->next_pts += av_rescale_q(n_out, (AVRational){1, outlink->sample_rate}, outlink->time_base); 122 123 return ff_filter_frame(outlink, outsamplesref); 124 } 125 return ret; 126} 127 128static const AVFilterPad apad_inputs[] = { 129 { 130 .name = "default", 131 .type = AVMEDIA_TYPE_AUDIO, 132 .filter_frame = filter_frame, 133 }, 134 { NULL } 135}; 136 137static const AVFilterPad apad_outputs[] = { 138 { 139 .name = "default", 140 .request_frame = request_frame, 141 .type = AVMEDIA_TYPE_AUDIO, 142 }, 143 { NULL } 144}; 145 146AVFilter ff_af_apad = { 147 .name = "apad", 148 .description = NULL_IF_CONFIG_SMALL("Pad audio with silence."), 149 .init = init, 150 .priv_size = sizeof(APadContext), 151 .inputs = apad_inputs, 152 .outputs = apad_outputs, 153 .priv_class = &apad_class, 154 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL, 155}; 156