/* * Copyright (c) 2011 Stefano Sabatini * * 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 * eval audio source */ #include "libavutil/audioconvert.h" #include "libavutil/avassert.h" #include "libavutil/avstring.h" #include "libavutil/eval.h" #include "libavutil/opt.h" #include "libavutil/parseutils.h" #include "avfilter.h" #include "audio.h" #include "internal.h" static const char * const var_names[] = { "n", ///< number of frame "t", ///< timestamp expressed in seconds "s", ///< sample rate NULL }; enum var_name { VAR_N, VAR_T, VAR_S, VAR_VARS_NB }; typedef struct { const AVClass *class; char *sample_rate_str; int sample_rate; int64_t chlayout; char *chlayout_str; int nb_channels; int64_t pts; AVExpr *expr[8]; char *expr_str[8]; int nb_samples; ///< number of samples per requested frame char *duration_str; ///< total duration of the generated audio double duration; uint64_t n; double var_values[VAR_VARS_NB]; } EvalContext; #define OFFSET(x) offsetof(EvalContext, x) static const AVOption eval_options[]= { { "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.dbl = 1024}, 0, INT_MAX }, { "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.dbl = 1024}, 0, INT_MAX }, { "sample_rate", "set the sample rate", OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX }, { "s", "set the sample rate", OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX }, { "duration", "set audio duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0 }, { "d", "set audio duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0 }, { "channel_layout", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0 }, { "c", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0 }, {NULL}, }; static const char *eval_get_name(void *ctx) { return "aevalsrc"; } static const AVClass eval_class = { "AEvalSrcContext", eval_get_name, eval_options }; static int init(AVFilterContext *ctx, const char *args, void *opaque) { EvalContext *eval = ctx->priv; char *args1 = av_strdup(args); char *expr, *buf, *bufptr; int ret, i; eval->class = &eval_class; av_opt_set_defaults(eval); /* parse expressions */ buf = args1; i = 0; while (expr = av_strtok(buf, ":", &bufptr)) { ret = av_expr_parse(&eval->expr[i], expr, var_names, NULL, NULL, NULL, NULL, 0, ctx); if (ret < 0) goto end; i++; if (bufptr && *bufptr == ':') { /* found last expression */ bufptr++; break; } buf = NULL; } eval->nb_channels = i; if (bufptr && (ret = av_set_options_string(eval, bufptr, "=", ":")) < 0) goto end; if (eval->chlayout_str) { int n; ret = ff_parse_channel_layout(&eval->chlayout, eval->chlayout_str, ctx); if (ret < 0) goto end; n = av_get_channel_layout_nb_channels(eval->chlayout); if (n != eval->nb_channels) { av_log(ctx, AV_LOG_ERROR, "Mismatch between the specified number of channels '%d' " "and the number of channels '%d' in the specified channel layout '%s'\n", eval->nb_channels, n, eval->chlayout_str); ret = AVERROR(EINVAL); goto end; } } else { /* guess channel layout from nb expressions/channels */ eval->chlayout = av_get_default_channel_layout(eval->nb_channels); if (!eval->chlayout) { av_log(ctx, AV_LOG_ERROR, "Invalid number of channels '%d' provided\n", eval->nb_channels); ret = AVERROR(EINVAL); goto end; } } if ((ret = ff_parse_sample_rate(&eval->sample_rate, eval->sample_rate_str, ctx))) goto end; eval->duration = -1; if (eval->duration_str) { int64_t us = -1; if ((ret = av_parse_time(&us, eval->duration_str, 1)) < 0) { av_log(ctx, AV_LOG_ERROR, "Invalid duration: '%s'\n", eval->duration_str); goto end; } eval->duration = (double)us / 1000000; } eval->n = 0; end: av_free(args1); return ret; } static void uninit(AVFilterContext *ctx) { EvalContext *eval = ctx->priv; int i; for (i = 0; i < 8; i++) { av_expr_free(eval->expr[i]); eval->expr[i] = NULL; } av_freep(&eval->chlayout_str); av_freep(&eval->duration_str); av_freep(&eval->sample_rate_str); } static int config_props(AVFilterLink *outlink) { EvalContext *eval = outlink->src->priv; char buf[128]; outlink->time_base = (AVRational){1, eval->sample_rate}; outlink->sample_rate = eval->sample_rate; eval->var_values[VAR_S] = eval->sample_rate; av_get_channel_layout_string(buf, sizeof(buf), 0, eval->chlayout); av_log(outlink->src, AV_LOG_INFO, "sample_rate:%d chlayout:%s duration:%f\n", eval->sample_rate, buf, eval->duration); return 0; } static int query_formats(AVFilterContext *ctx) { EvalContext *eval = ctx->priv; enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_DBLP, AV_SAMPLE_FMT_NONE }; int64_t chlayouts[] = { eval->chlayout, -1 }; int sample_rates[] = { eval->sample_rate, -1 }; avfilter_set_common_sample_formats (ctx, avfilter_make_format_list(sample_fmts)); ff_set_common_channel_layouts(ctx, avfilter_make_format64_list(chlayouts)); ff_set_common_samplerates(ctx, avfilter_make_format_list(sample_rates)); return 0; } static int request_frame(AVFilterLink *outlink) { EvalContext *eval = outlink->src->priv; AVFilterBufferRef *samplesref; int i, j; double t = eval->var_values[VAR_N] * (double)1/eval->sample_rate; if (eval->duration >= 0 && t > eval->duration) return AVERROR_EOF; samplesref = ff_get_audio_buffer(outlink, AV_PERM_WRITE, eval->nb_samples); /* evaluate expression for each single sample and for each channel */ for (i = 0; i < eval->nb_samples; i++, eval->n++) { eval->var_values[VAR_N] = eval->n; eval->var_values[VAR_T] = eval->var_values[VAR_N] * (double)1/eval->sample_rate; for (j = 0; j < eval->nb_channels; j++) { *((double *) samplesref->extended_data[j] + i) = av_expr_eval(eval->expr[j], eval->var_values, NULL); } } samplesref->pts = eval->pts; samplesref->pos = -1; samplesref->audio->sample_rate = eval->sample_rate; eval->pts += eval->nb_samples; ff_filter_samples(outlink, samplesref); return 0; } AVFilter avfilter_asrc_aevalsrc = { .name = "aevalsrc", .description = NULL_IF_CONFIG_SMALL("Generate an audio signal generated by an expression."), .query_formats = query_formats, .init = init, .uninit = uninit, .priv_size = sizeof(EvalContext), .inputs = (const AVFilterPad[]) {{ .name = NULL}}, .outputs = (const AVFilterPad[]) {{ .name = "default", .type = AVMEDIA_TYPE_AUDIO, .config_props = config_props, .request_frame = request_frame, }, { .name = NULL}}, };