2 * Copyright (c) 2011 Stefano Sabatini
4 * This file is part of FFmpeg.
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.
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.
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
26 #include "libavutil/avassert.h"
27 #include "libavutil/avstring.h"
28 #include "libavutil/channel_layout.h"
29 #include "libavutil/eval.h"
30 #include "libavutil/opt.h"
31 #include "libavutil/parseutils.h"
36 static const char * const var_names[] = {
37 "n", ///< number of frame
38 "t", ///< timestamp expressed in seconds
52 char *sample_rate_str;
60 int nb_samples; ///< number of samples per requested frame
63 double var_values[VAR_VARS_NB];
66 #define OFFSET(x) offsetof(EvalContext, x)
67 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
69 static const AVOption aevalsrc_options[]= {
70 { "exprs", "set the '|'-separated list of channels expressions", OFFSET(exprs), AV_OPT_TYPE_STRING, {.str = NULL}, .flags = FLAGS },
71 { "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS },
72 { "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS },
73 { "sample_rate", "set the sample rate", OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX, FLAGS },
74 { "s", "set the sample rate", OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX, FLAGS },
75 { "duration", "set audio duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64 = -1}, -1, INT64_MAX, FLAGS },
76 { "d", "set audio duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64 = -1}, -1, INT64_MAX, FLAGS },
77 { "channel_layout", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
78 { "c", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
82 AVFILTER_DEFINE_CLASS(aevalsrc);
84 static int init(AVFilterContext *ctx)
86 EvalContext *eval = ctx->priv;
87 char *args1 = av_strdup(eval->exprs);
92 av_log(ctx, AV_LOG_ERROR, "Channels expressions list is empty\n");
93 ret = eval->exprs ? AVERROR(ENOMEM) : AVERROR(EINVAL);
97 /* parse expressions */
99 while (expr = av_strtok(buf, "|", &buf)) {
100 if (!av_dynarray2_add((void **)&eval->expr, &eval->nb_channels, sizeof(*eval->expr), NULL)) {
101 ret = AVERROR(ENOMEM);
104 ret = av_expr_parse(&eval->expr[eval->nb_channels - 1], expr, var_names,
105 NULL, NULL, NULL, NULL, 0, ctx);
110 if (eval->chlayout_str) {
112 ret = ff_parse_channel_layout(&eval->chlayout, eval->chlayout_str, ctx);
116 n = av_get_channel_layout_nb_channels(eval->chlayout);
117 if (n != eval->nb_channels) {
118 av_log(ctx, AV_LOG_ERROR,
119 "Mismatch between the specified number of channels '%d' "
120 "and the number of channels '%d' in the specified channel layout '%s'\n",
121 eval->nb_channels, n, eval->chlayout_str);
122 ret = AVERROR(EINVAL);
126 /* guess channel layout from nb expressions/channels */
127 eval->chlayout = av_get_default_channel_layout(eval->nb_channels);
128 if (!eval->chlayout && eval->nb_channels <= 0) {
129 av_log(ctx, AV_LOG_ERROR, "Invalid number of channels '%d' provided\n",
131 ret = AVERROR(EINVAL);
136 if ((ret = ff_parse_sample_rate(&eval->sample_rate, eval->sample_rate_str, ctx)))
145 static av_cold void uninit(AVFilterContext *ctx)
147 EvalContext *eval = ctx->priv;
150 for (i = 0; i < eval->nb_channels; i++) {
151 av_expr_free(eval->expr[i]);
152 eval->expr[i] = NULL;
154 av_freep(&eval->expr);
157 static int config_props(AVFilterLink *outlink)
159 EvalContext *eval = outlink->src->priv;
162 outlink->time_base = (AVRational){1, eval->sample_rate};
163 outlink->sample_rate = eval->sample_rate;
165 eval->var_values[VAR_S] = eval->sample_rate;
167 av_get_channel_layout_string(buf, sizeof(buf), 0, eval->chlayout);
169 av_log(outlink->src, AV_LOG_VERBOSE,
170 "sample_rate:%d chlayout:%s duration:%"PRId64"\n",
171 eval->sample_rate, buf, eval->duration);
176 static int query_formats(AVFilterContext *ctx)
178 EvalContext *eval = ctx->priv;
179 static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_DBLP, AV_SAMPLE_FMT_NONE };
180 int64_t chlayouts[] = { eval->chlayout ? eval->chlayout : FF_COUNT2LAYOUT(eval->nb_channels) , -1 };
181 int sample_rates[] = { eval->sample_rate, -1 };
183 ff_set_common_formats (ctx, ff_make_format_list(sample_fmts));
184 ff_set_common_channel_layouts(ctx, avfilter_make_format64_list(chlayouts));
185 ff_set_common_samplerates(ctx, ff_make_format_list(sample_rates));
190 static int request_frame(AVFilterLink *outlink)
192 EvalContext *eval = outlink->src->priv;
195 int64_t t = av_rescale(eval->n, AV_TIME_BASE, eval->sample_rate);
197 if (eval->duration >= 0 && t >= eval->duration)
200 samplesref = ff_get_audio_buffer(outlink, eval->nb_samples);
202 return AVERROR(ENOMEM);
204 /* evaluate expression for each single sample and for each channel */
205 for (i = 0; i < eval->nb_samples; i++, eval->n++) {
206 eval->var_values[VAR_N] = eval->n;
207 eval->var_values[VAR_T] = eval->var_values[VAR_N] * (double)1/eval->sample_rate;
209 for (j = 0; j < eval->nb_channels; j++) {
210 *((double *) samplesref->extended_data[j] + i) =
211 av_expr_eval(eval->expr[j], eval->var_values, NULL);
215 samplesref->pts = eval->pts;
216 samplesref->sample_rate = eval->sample_rate;
217 eval->pts += eval->nb_samples;
219 return ff_filter_frame(outlink, samplesref);
222 static const AVFilterPad aevalsrc_outputs[] = {
225 .type = AVMEDIA_TYPE_AUDIO,
226 .config_props = config_props,
227 .request_frame = request_frame,
232 AVFilter avfilter_asrc_aevalsrc = {
234 .description = NULL_IF_CONFIG_SMALL("Generate an audio signal generated by an expression."),
235 .query_formats = query_formats,
238 .priv_size = sizeof(EvalContext),
240 .outputs = aevalsrc_outputs,
241 .priv_class = &aevalsrc_class,