| 1 | /* |
| 2 | * Copyright (c) 2013 Nicolas George |
| 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 License |
| 8 | * 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 |
| 14 | * GNU Lesser General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Lesser General Public License |
| 17 | * along with FFmpeg; if not, write to the Free Software Foundation, Inc., |
| 18 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 19 | */ |
| 20 | |
| 21 | #include "libavutil/opt.h" |
| 22 | #include "avfilter.h" |
| 23 | #include "internal.h" |
| 24 | |
| 25 | typedef struct { |
| 26 | const AVClass *class; |
| 27 | int sample_rate; |
| 28 | int rescale_pts; |
| 29 | } ASetRateContext; |
| 30 | |
| 31 | #define CONTEXT ASetRateContext |
| 32 | #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM |
| 33 | |
| 34 | #define OPT_GENERIC(name, field, def, min, max, descr, type, deffield, ...) \ |
| 35 | { name, descr, offsetof(CONTEXT, field), AV_OPT_TYPE_ ## type, \ |
| 36 | { .deffield = def }, min, max, FLAGS, __VA_ARGS__ } |
| 37 | |
| 38 | #define OPT_INT(name, field, def, min, max, descr, ...) \ |
| 39 | OPT_GENERIC(name, field, def, min, max, descr, INT, i64, __VA_ARGS__) |
| 40 | |
| 41 | static const AVOption asetrate_options[] = { |
| 42 | OPT_INT("sample_rate", sample_rate, 44100, 1, INT_MAX, "set the sample rate"), |
| 43 | OPT_INT("r", sample_rate, 44100, 1, INT_MAX, "set the sample rate"), |
| 44 | {NULL}, |
| 45 | }; |
| 46 | |
| 47 | AVFILTER_DEFINE_CLASS(asetrate); |
| 48 | |
| 49 | static av_cold int query_formats(AVFilterContext *ctx) |
| 50 | { |
| 51 | ASetRateContext *sr = ctx->priv; |
| 52 | int sample_rates[] = { sr->sample_rate, -1 }; |
| 53 | |
| 54 | ff_formats_ref(ff_make_format_list(sample_rates), |
| 55 | &ctx->outputs[0]->in_samplerates); |
| 56 | return 0; |
| 57 | } |
| 58 | |
| 59 | static av_cold int config_props(AVFilterLink *outlink) |
| 60 | { |
| 61 | AVFilterContext *ctx = outlink->src; |
| 62 | ASetRateContext *sr = ctx->priv; |
| 63 | AVFilterLink *inlink = ctx->inputs[0]; |
| 64 | AVRational intb = ctx->inputs[0]->time_base; |
| 65 | int inrate = inlink->sample_rate; |
| 66 | |
| 67 | if (intb.num == 1 && intb.den == inrate) { |
| 68 | outlink->time_base.num = 1; |
| 69 | outlink->time_base.den = outlink->sample_rate; |
| 70 | } else { |
| 71 | outlink->time_base = intb; |
| 72 | sr->rescale_pts = 1; |
| 73 | if (av_q2d(intb) > 1.0 / FFMAX(inrate, outlink->sample_rate)) |
| 74 | av_log(ctx, AV_LOG_WARNING, "Time base is inaccurate\n"); |
| 75 | } |
| 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | static int filter_frame(AVFilterLink *inlink, AVFrame *frame) |
| 80 | { |
| 81 | AVFilterContext *ctx = inlink->dst; |
| 82 | ASetRateContext *sr = ctx->priv; |
| 83 | AVFilterLink *outlink = ctx->outputs[0]; |
| 84 | |
| 85 | frame->sample_rate = outlink->sample_rate; |
| 86 | if (sr->rescale_pts) |
| 87 | frame->pts = av_rescale(frame->pts, inlink->sample_rate, |
| 88 | outlink->sample_rate); |
| 89 | return ff_filter_frame(outlink, frame); |
| 90 | } |
| 91 | |
| 92 | static const AVFilterPad asetrate_inputs[] = { |
| 93 | { |
| 94 | .name = "default", |
| 95 | .type = AVMEDIA_TYPE_AUDIO, |
| 96 | .filter_frame = filter_frame, |
| 97 | }, |
| 98 | { NULL } |
| 99 | }; |
| 100 | |
| 101 | static const AVFilterPad asetrate_outputs[] = { |
| 102 | { |
| 103 | .name = "default", |
| 104 | .type = AVMEDIA_TYPE_AUDIO, |
| 105 | .config_props = config_props, |
| 106 | }, |
| 107 | { NULL } |
| 108 | }; |
| 109 | |
| 110 | AVFilter ff_af_asetrate = { |
| 111 | .name = "asetrate", |
| 112 | .description = NULL_IF_CONFIG_SMALL("Change the sample rate without " |
| 113 | "altering the data."), |
| 114 | .query_formats = query_formats, |
| 115 | .priv_size = sizeof(ASetRateContext), |
| 116 | .inputs = asetrate_inputs, |
| 117 | .outputs = asetrate_outputs, |
| 118 | .priv_class = &asetrate_class, |
| 119 | }; |