yading@10: /*
yading@10:  * Copyright (c) 2011 Stefano Sabatini
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * eval audio source
yading@10:  */
yading@10: 
yading@10: #include "libavutil/avassert.h"
yading@10: #include "libavutil/avstring.h"
yading@10: #include "libavutil/channel_layout.h"
yading@10: #include "libavutil/eval.h"
yading@10: #include "libavutil/opt.h"
yading@10: #include "libavutil/parseutils.h"
yading@10: #include "avfilter.h"
yading@10: #include "audio.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: static const char * const var_names[] = {
yading@10:     "n",            ///< number of frame
yading@10:     "t",            ///< timestamp expressed in seconds
yading@10:     "s",            ///< sample rate
yading@10:     NULL
yading@10: };
yading@10: 
yading@10: enum var_name {
yading@10:     VAR_N,
yading@10:     VAR_T,
yading@10:     VAR_S,
yading@10:     VAR_VARS_NB
yading@10: };
yading@10: 
yading@10: typedef struct {
yading@10:     const AVClass *class;
yading@10:     char *sample_rate_str;
yading@10:     int sample_rate;
yading@10:     int64_t chlayout;
yading@10:     char *chlayout_str;
yading@10:     int nb_channels;
yading@10:     int64_t pts;
yading@10:     AVExpr *expr[8];
yading@10:     char *exprs;
yading@10:     int nb_samples;             ///< number of samples per requested frame
yading@10:     char *duration_str;         ///< total duration of the generated audio
yading@10:     double duration;
yading@10:     uint64_t n;
yading@10:     double var_values[VAR_VARS_NB];
yading@10: } EvalContext;
yading@10: 
yading@10: #define OFFSET(x) offsetof(EvalContext, x)
yading@10: #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
yading@10: 
yading@10: static const AVOption aevalsrc_options[]= {
yading@10:     { "exprs",       "set the '|'-separated list of channels expressions", OFFSET(exprs), AV_OPT_TYPE_STRING, {.str = NULL}, .flags = FLAGS },
yading@10:     { "nb_samples",  "set the number of samples per requested frame", OFFSET(nb_samples),      AV_OPT_TYPE_INT,    {.i64 = 1024},    0,        INT_MAX, FLAGS },
yading@10:     { "n",           "set the number of samples per requested frame", OFFSET(nb_samples),      AV_OPT_TYPE_INT,    {.i64 = 1024},    0,        INT_MAX, FLAGS },
yading@10:     { "sample_rate", "set the sample rate",                           OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX, FLAGS },
yading@10:     { "s",           "set the sample rate",                           OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX, FLAGS },
yading@10:     { "duration",    "set audio duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
yading@10:     { "d",           "set audio duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
yading@10:     { "channel_layout", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
yading@10:     { "c",              "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
yading@10: {NULL},
yading@10: };
yading@10: 
yading@10: AVFILTER_DEFINE_CLASS(aevalsrc);
yading@10: 
yading@10: static int init(AVFilterContext *ctx)
yading@10: {
yading@10:     EvalContext *eval = ctx->priv;
yading@10:     char *args1 = av_strdup(eval->exprs);
yading@10:     char *expr, *buf;
yading@10:     int ret, i;
yading@10: 
yading@10:     if (!args1) {
yading@10:         av_log(ctx, AV_LOG_ERROR, "Channels expressions list is empty\n");
yading@10:         ret = eval->exprs ? AVERROR(ENOMEM) : AVERROR(EINVAL);
yading@10:         goto end;
yading@10:     }
yading@10: 
yading@10:     /* parse expressions */
yading@10:     buf = args1;
yading@10:     i = 0;
yading@10:     while (i < FF_ARRAY_ELEMS(eval->expr) && (expr = av_strtok(buf, "|", &buf))) {
yading@10:         ret = av_expr_parse(&eval->expr[i], expr, var_names,
yading@10:                             NULL, NULL, NULL, NULL, 0, ctx);
yading@10:         if (ret < 0)
yading@10:             goto end;
yading@10:         i++;
yading@10:     }
yading@10:     eval->nb_channels = i;
yading@10: 
yading@10:     if (eval->chlayout_str) {
yading@10:         int n;
yading@10:         ret = ff_parse_channel_layout(&eval->chlayout, eval->chlayout_str, ctx);
yading@10:         if (ret < 0)
yading@10:             goto end;
yading@10: 
yading@10:         n = av_get_channel_layout_nb_channels(eval->chlayout);
yading@10:         if (n != eval->nb_channels) {
yading@10:             av_log(ctx, AV_LOG_ERROR,
yading@10:                    "Mismatch between the specified number of channels '%d' "
yading@10:                    "and the number of channels '%d' in the specified channel layout '%s'\n",
yading@10:                    eval->nb_channels, n, eval->chlayout_str);
yading@10:             ret = AVERROR(EINVAL);
yading@10:             goto end;
yading@10:         }
yading@10:     } else {
yading@10:         /* guess channel layout from nb expressions/channels */
yading@10:         eval->chlayout = av_get_default_channel_layout(eval->nb_channels);
yading@10:         if (!eval->chlayout) {
yading@10:             av_log(ctx, AV_LOG_ERROR, "Invalid number of channels '%d' provided\n",
yading@10:                    eval->nb_channels);
yading@10:             ret = AVERROR(EINVAL);
yading@10:             goto end;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     if ((ret = ff_parse_sample_rate(&eval->sample_rate, eval->sample_rate_str, ctx)))
yading@10:         goto end;
yading@10: 
yading@10:     eval->duration = -1;
yading@10:     if (eval->duration_str) {
yading@10:         int64_t us = -1;
yading@10:         if ((ret = av_parse_time(&us, eval->duration_str, 1)) < 0) {
yading@10:             av_log(ctx, AV_LOG_ERROR, "Invalid duration: '%s'\n", eval->duration_str);
yading@10:             goto end;
yading@10:         }
yading@10:         eval->duration = (double)us / 1000000;
yading@10:     }
yading@10:     eval->n = 0;
yading@10: 
yading@10: end:
yading@10:     av_free(args1);
yading@10:     return ret;
yading@10: }
yading@10: 
yading@10: static void uninit(AVFilterContext *ctx)
yading@10: {
yading@10:     EvalContext *eval = ctx->priv;
yading@10:     int i;
yading@10: 
yading@10:     for (i = 0; i < 8; i++) {
yading@10:         av_expr_free(eval->expr[i]);
yading@10:         eval->expr[i] = NULL;
yading@10:     }
yading@10:     av_freep(&eval->chlayout_str);
yading@10:     av_freep(&eval->duration_str);
yading@10:     av_freep(&eval->sample_rate_str);
yading@10: }
yading@10: 
yading@10: static int config_props(AVFilterLink *outlink)
yading@10: {
yading@10:     EvalContext *eval = outlink->src->priv;
yading@10:     char buf[128];
yading@10: 
yading@10:     outlink->time_base = (AVRational){1, eval->sample_rate};
yading@10:     outlink->sample_rate = eval->sample_rate;
yading@10: 
yading@10:     eval->var_values[VAR_S] = eval->sample_rate;
yading@10: 
yading@10:     av_get_channel_layout_string(buf, sizeof(buf), 0, eval->chlayout);
yading@10: 
yading@10:     av_log(outlink->src, AV_LOG_VERBOSE,
yading@10:            "sample_rate:%d chlayout:%s duration:%f\n",
yading@10:            eval->sample_rate, buf, eval->duration);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int query_formats(AVFilterContext *ctx)
yading@10: {
yading@10:     EvalContext *eval = ctx->priv;
yading@10:     static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_DBLP, AV_SAMPLE_FMT_NONE };
yading@10:     int64_t chlayouts[] = { eval->chlayout, -1 };
yading@10:     int sample_rates[] = { eval->sample_rate, -1 };
yading@10: 
yading@10:     ff_set_common_formats (ctx, ff_make_format_list(sample_fmts));
yading@10:     ff_set_common_channel_layouts(ctx, avfilter_make_format64_list(chlayouts));
yading@10:     ff_set_common_samplerates(ctx, ff_make_format_list(sample_rates));
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int request_frame(AVFilterLink *outlink)
yading@10: {
yading@10:     EvalContext *eval = outlink->src->priv;
yading@10:     AVFrame *samplesref;
yading@10:     int i, j;
yading@10:     double t = eval->n * (double)1/eval->sample_rate;
yading@10: 
yading@10:     if (eval->duration >= 0 && t >= eval->duration)
yading@10:         return AVERROR_EOF;
yading@10: 
yading@10:     samplesref = ff_get_audio_buffer(outlink, eval->nb_samples);
yading@10:     if (!samplesref)
yading@10:         return AVERROR(ENOMEM);
yading@10: 
yading@10:     /* evaluate expression for each single sample and for each channel */
yading@10:     for (i = 0; i < eval->nb_samples; i++, eval->n++) {
yading@10:         eval->var_values[VAR_N] = eval->n;
yading@10:         eval->var_values[VAR_T] = eval->var_values[VAR_N] * (double)1/eval->sample_rate;
yading@10: 
yading@10:         for (j = 0; j < eval->nb_channels; j++) {
yading@10:             *((double *) samplesref->extended_data[j] + i) =
yading@10:                 av_expr_eval(eval->expr[j], eval->var_values, NULL);
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     samplesref->pts = eval->pts;
yading@10:     samplesref->sample_rate = eval->sample_rate;
yading@10:     eval->pts += eval->nb_samples;
yading@10: 
yading@10:     return ff_filter_frame(outlink, samplesref);
yading@10: }
yading@10: 
yading@10: static const AVFilterPad aevalsrc_outputs[] = {
yading@10:     {
yading@10:         .name          = "default",
yading@10:         .type          = AVMEDIA_TYPE_AUDIO,
yading@10:         .config_props  = config_props,
yading@10:         .request_frame = request_frame,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: AVFilter avfilter_asrc_aevalsrc = {
yading@10:     .name        = "aevalsrc",
yading@10:     .description = NULL_IF_CONFIG_SMALL("Generate an audio signal generated by an expression."),
yading@10: 
yading@10:     .query_formats = query_formats,
yading@10:     .init        = init,
yading@10:     .uninit      = uninit,
yading@10:     .priv_size   = sizeof(EvalContext),
yading@10:     .inputs      = NULL,
yading@10:     .outputs     = aevalsrc_outputs,
yading@10:     .priv_class  = &aevalsrc_class,
yading@10: };