mirror of
https://github.com/FFmpeg/FFmpeg.git
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255 lines
8.1 KiB
C
255 lines
8.1 KiB
C
/*
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* Copyright (c) 2011 Stefano Sabatini
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* eval audio source
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*/
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#include "libavutil/audioconvert.h"
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#include "libavutil/avassert.h"
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#include "libavutil/avstring.h"
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#include "libavutil/eval.h"
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#include "libavutil/opt.h"
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#include "libavutil/parseutils.h"
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#include "avfilter.h"
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#include "audio.h"
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#include "internal.h"
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static const char * const var_names[] = {
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"n", ///< number of frame
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"t", ///< timestamp expressed in seconds
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"s", ///< sample rate
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NULL
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};
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enum var_name {
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VAR_N,
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VAR_T,
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VAR_S,
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VAR_VARS_NB
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};
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typedef struct {
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const AVClass *class;
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char *sample_rate_str;
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int sample_rate;
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int64_t chlayout;
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char *chlayout_str;
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int nb_channels;
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int64_t pts;
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AVExpr *expr[8];
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char *expr_str[8];
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int nb_samples; ///< number of samples per requested frame
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char *duration_str; ///< total duration of the generated audio
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double duration;
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uint64_t n;
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double var_values[VAR_VARS_NB];
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} EvalContext;
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#define OFFSET(x) offsetof(EvalContext, x)
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static const AVOption aevalsrc_options[]= {
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{ "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.dbl = 1024}, 0, INT_MAX },
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{ "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.dbl = 1024}, 0, INT_MAX },
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{ "sample_rate", "set the sample rate", OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX },
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{ "s", "set the sample rate", OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX },
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{ "duration", "set audio duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0 },
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{ "d", "set audio duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0 },
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{ "channel_layout", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0 },
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{ "c", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0 },
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{NULL},
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};
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AVFILTER_DEFINE_CLASS(aevalsrc);
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static int init(AVFilterContext *ctx, const char *args)
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{
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EvalContext *eval = ctx->priv;
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char *args1 = av_strdup(args);
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char *expr, *buf, *bufptr;
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int ret, i;
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eval->class = &aevalsrc_class;
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av_opt_set_defaults(eval);
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/* parse expressions */
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buf = args1;
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i = 0;
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while (expr = av_strtok(buf, ":", &bufptr)) {
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ret = av_expr_parse(&eval->expr[i], expr, var_names,
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NULL, NULL, NULL, NULL, 0, ctx);
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if (ret < 0)
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goto end;
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i++;
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if (bufptr && *bufptr == ':') { /* found last expression */
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bufptr++;
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break;
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}
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buf = NULL;
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}
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eval->nb_channels = i;
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if (bufptr && (ret = av_set_options_string(eval, bufptr, "=", ":")) < 0)
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goto end;
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if (eval->chlayout_str) {
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int n;
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ret = ff_parse_channel_layout(&eval->chlayout, eval->chlayout_str, ctx);
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if (ret < 0)
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goto end;
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n = av_get_channel_layout_nb_channels(eval->chlayout);
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if (n != eval->nb_channels) {
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av_log(ctx, AV_LOG_ERROR,
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"Mismatch between the specified number of channels '%d' "
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"and the number of channels '%d' in the specified channel layout '%s'\n",
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eval->nb_channels, n, eval->chlayout_str);
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ret = AVERROR(EINVAL);
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goto end;
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}
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} else {
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/* guess channel layout from nb expressions/channels */
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eval->chlayout = av_get_default_channel_layout(eval->nb_channels);
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if (!eval->chlayout) {
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av_log(ctx, AV_LOG_ERROR, "Invalid number of channels '%d' provided\n",
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eval->nb_channels);
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ret = AVERROR(EINVAL);
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goto end;
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}
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}
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if ((ret = ff_parse_sample_rate(&eval->sample_rate, eval->sample_rate_str, ctx)))
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goto end;
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eval->duration = -1;
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if (eval->duration_str) {
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int64_t us = -1;
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if ((ret = av_parse_time(&us, eval->duration_str, 1)) < 0) {
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av_log(ctx, AV_LOG_ERROR, "Invalid duration: '%s'\n", eval->duration_str);
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goto end;
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}
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eval->duration = (double)us / 1000000;
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}
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eval->n = 0;
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end:
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av_free(args1);
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return ret;
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}
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static void uninit(AVFilterContext *ctx)
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{
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EvalContext *eval = ctx->priv;
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int i;
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for (i = 0; i < 8; i++) {
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av_expr_free(eval->expr[i]);
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eval->expr[i] = NULL;
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}
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av_freep(&eval->chlayout_str);
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av_freep(&eval->duration_str);
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av_freep(&eval->sample_rate_str);
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}
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static int config_props(AVFilterLink *outlink)
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{
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EvalContext *eval = outlink->src->priv;
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char buf[128];
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outlink->time_base = (AVRational){1, eval->sample_rate};
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outlink->sample_rate = eval->sample_rate;
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eval->var_values[VAR_S] = eval->sample_rate;
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av_get_channel_layout_string(buf, sizeof(buf), 0, eval->chlayout);
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av_log(outlink->src, AV_LOG_VERBOSE,
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"sample_rate:%d chlayout:%s duration:%f\n",
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eval->sample_rate, buf, eval->duration);
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return 0;
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}
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static int query_formats(AVFilterContext *ctx)
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{
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EvalContext *eval = ctx->priv;
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enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_DBLP, AV_SAMPLE_FMT_NONE };
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int64_t chlayouts[] = { eval->chlayout, -1 };
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int sample_rates[] = { eval->sample_rate, -1 };
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ff_set_common_formats (ctx, ff_make_format_list(sample_fmts));
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ff_set_common_channel_layouts(ctx, avfilter_make_format64_list(chlayouts));
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ff_set_common_samplerates(ctx, ff_make_format_list(sample_rates));
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return 0;
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}
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static int request_frame(AVFilterLink *outlink)
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{
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EvalContext *eval = outlink->src->priv;
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AVFilterBufferRef *samplesref;
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int i, j;
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double t = eval->var_values[VAR_N] * (double)1/eval->sample_rate;
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if (eval->duration >= 0 && t > eval->duration)
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return AVERROR_EOF;
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samplesref = ff_get_audio_buffer(outlink, AV_PERM_WRITE, eval->nb_samples);
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/* evaluate expression for each single sample and for each channel */
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for (i = 0; i < eval->nb_samples; i++, eval->n++) {
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eval->var_values[VAR_N] = eval->n;
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eval->var_values[VAR_T] = eval->var_values[VAR_N] * (double)1/eval->sample_rate;
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for (j = 0; j < eval->nb_channels; j++) {
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*((double *) samplesref->extended_data[j] + i) =
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av_expr_eval(eval->expr[j], eval->var_values, NULL);
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}
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}
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samplesref->pts = eval->pts;
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samplesref->pos = -1;
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samplesref->audio->sample_rate = eval->sample_rate;
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eval->pts += eval->nb_samples;
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ff_filter_samples(outlink, samplesref);
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return 0;
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}
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AVFilter avfilter_asrc_aevalsrc = {
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.name = "aevalsrc",
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.description = NULL_IF_CONFIG_SMALL("Generate an audio signal generated by an expression."),
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.query_formats = query_formats,
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.init = init,
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.uninit = uninit,
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.priv_size = sizeof(EvalContext),
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.inputs = (const AVFilterPad[]) {{ .name = NULL}},
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.outputs = (const AVFilterPad[]) {{ .name = "default",
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.type = AVMEDIA_TYPE_AUDIO,
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.config_props = config_props,
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.request_frame = request_frame, },
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{ .name = NULL}},
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};
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