| 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 | |
| 37 | typedef struct { |
| 38 | const AVClass *class; |
| 39 | int64_t next_pts; |
| 40 | |
| 41 | int packet_size; |
| 42 | int64_t pad_len, pad_len_left; |
| 43 | int64_t whole_len, whole_len_left; |
| 44 | } APadContext; |
| 45 | |
| 46 | #define OFFSET(x) offsetof(APadContext, x) |
| 47 | #define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM |
| 48 | |
| 49 | static 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", "set number of samples of silence to add", OFFSET(pad_len), AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, A }, |
| 52 | { "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 }, |
| 53 | { NULL } |
| 54 | }; |
| 55 | |
| 56 | AVFILTER_DEFINE_CLASS(apad); |
| 57 | |
| 58 | static 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 >= 0 && apad->pad_len >= 0) { |
| 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 | apad->pad_len_left = apad->pad_len; |
| 68 | apad->whole_len_left = apad->whole_len; |
| 69 | |
| 70 | return 0; |
| 71 | } |
| 72 | |
| 73 | static int filter_frame(AVFilterLink *inlink, AVFrame *frame) |
| 74 | { |
| 75 | AVFilterContext *ctx = inlink->dst; |
| 76 | APadContext *apad = ctx->priv; |
| 77 | |
| 78 | if (apad->whole_len >= 0) { |
| 79 | apad->whole_len_left = FFMAX(apad->whole_len_left - frame->nb_samples, 0); |
| 80 | av_log(ctx, AV_LOG_DEBUG, |
| 81 | "n_out:%d whole_len_left:%"PRId64"\n", frame->nb_samples, apad->whole_len_left); |
| 82 | } |
| 83 | |
| 84 | apad->next_pts = frame->pts + av_rescale_q(frame->nb_samples, (AVRational){1, inlink->sample_rate}, inlink->time_base); |
| 85 | return ff_filter_frame(ctx->outputs[0], frame); |
| 86 | } |
| 87 | |
| 88 | static int request_frame(AVFilterLink *outlink) |
| 89 | { |
| 90 | AVFilterContext *ctx = outlink->src; |
| 91 | APadContext *apad = ctx->priv; |
| 92 | int ret; |
| 93 | |
| 94 | ret = ff_request_frame(ctx->inputs[0]); |
| 95 | |
| 96 | if (ret == AVERROR_EOF && !ctx->is_disabled) { |
| 97 | int n_out = apad->packet_size; |
| 98 | AVFrame *outsamplesref; |
| 99 | |
| 100 | if (apad->whole_len >= 0 && apad->pad_len < 0) { |
| 101 | apad->pad_len = apad->pad_len_left = apad->whole_len_left; |
| 102 | } |
| 103 | if (apad->pad_len >=0 || apad->whole_len >= 0) { |
| 104 | n_out = FFMIN(n_out, apad->pad_len_left); |
| 105 | apad->pad_len_left -= n_out; |
| 106 | av_log(ctx, AV_LOG_DEBUG, |
| 107 | "padding n_out:%d pad_len_left:%"PRId64"\n", n_out, apad->pad_len_left); |
| 108 | } |
| 109 | |
| 110 | if (!n_out) |
| 111 | return AVERROR_EOF; |
| 112 | |
| 113 | outsamplesref = ff_get_audio_buffer(outlink, n_out); |
| 114 | if (!outsamplesref) |
| 115 | return AVERROR(ENOMEM); |
| 116 | |
| 117 | av_assert0(outsamplesref->sample_rate == outlink->sample_rate); |
| 118 | av_assert0(outsamplesref->nb_samples == n_out); |
| 119 | |
| 120 | av_samples_set_silence(outsamplesref->extended_data, 0, |
| 121 | n_out, |
| 122 | av_frame_get_channels(outsamplesref), |
| 123 | outsamplesref->format); |
| 124 | |
| 125 | outsamplesref->pts = apad->next_pts; |
| 126 | if (apad->next_pts != AV_NOPTS_VALUE) |
| 127 | apad->next_pts += av_rescale_q(n_out, (AVRational){1, outlink->sample_rate}, outlink->time_base); |
| 128 | |
| 129 | return ff_filter_frame(outlink, outsamplesref); |
| 130 | } |
| 131 | return ret; |
| 132 | } |
| 133 | |
| 134 | static const AVFilterPad apad_inputs[] = { |
| 135 | { |
| 136 | .name = "default", |
| 137 | .type = AVMEDIA_TYPE_AUDIO, |
| 138 | .filter_frame = filter_frame, |
| 139 | }, |
| 140 | { NULL } |
| 141 | }; |
| 142 | |
| 143 | static const AVFilterPad apad_outputs[] = { |
| 144 | { |
| 145 | .name = "default", |
| 146 | .request_frame = request_frame, |
| 147 | .type = AVMEDIA_TYPE_AUDIO, |
| 148 | }, |
| 149 | { NULL } |
| 150 | }; |
| 151 | |
| 152 | AVFilter ff_af_apad = { |
| 153 | .name = "apad", |
| 154 | .description = NULL_IF_CONFIG_SMALL("Pad audio with silence."), |
| 155 | .init = init, |
| 156 | .priv_size = sizeof(APadContext), |
| 157 | .inputs = apad_inputs, |
| 158 | .outputs = apad_outputs, |
| 159 | .priv_class = &apad_class, |
| 160 | .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL, |
| 161 | }; |