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/*
* Copyright (c) 2019 Paul B Mahol
*
* 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
*/
#include <pocketsphinx/pocketsphinx.h>
#include "libavutil/avstring.h"
#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "audio.h"
#include "avfilter.h"
#include "internal.h"
typedef struct ASRContext {
const AVClass *class;
int rate;
char *hmm;
char *dict;
char *lm;
char *lmctl;
char *lmname;
char *logfn;
ps_decoder_t *ps;
cmd_ln_t *config;
int utt_started;
} ASRContext;
#define OFFSET(x) offsetof(ASRContext, x)
#define FLAGS AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
static const AVOption asr_options[] = {
{ "rate", "set sampling rate", OFFSET(rate), AV_OPT_TYPE_INT, {.i64=16000}, 0, INT_MAX, .flags = FLAGS },
{ "hmm", "set directory containing acoustic model files", OFFSET(hmm), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
{ "dict", "set pronunciation dictionary", OFFSET(dict), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
{ "lm", "set language model file", OFFSET(lm), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
{ "lmctl", "set language model set", OFFSET(lmctl), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
{ "lmname","set which language model to use", OFFSET(lmname), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
{ "logfn", "set output for log messages", OFFSET(logfn), AV_OPT_TYPE_STRING, {.str="/dev/null"}, .flags = FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(asr);
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
AVDictionary **metadata = &in->metadata;
ASRContext *s = ctx->priv;
int have_speech;
const char *speech;
ps_process_raw(s->ps, (const int16_t *)in->data[0], in->nb_samples, 0, 0);
have_speech = ps_get_in_speech(s->ps);
if (have_speech && !s->utt_started)
s->utt_started = 1;
if (!have_speech && s->utt_started) {
ps_end_utt(s->ps);
speech = ps_get_hyp(s->ps, NULL);
if (speech != NULL)
av_dict_set(metadata, "lavfi.asr.text", speech, 0);
ps_start_utt(s->ps);
s->utt_started = 0;
}
return ff_filter_frame(ctx->outputs[0], in);
}
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
ASRContext *s = ctx->priv;
ps_start_utt(s->ps);
return 0;
}
static av_cold int asr_init(AVFilterContext *ctx)
{
ASRContext *s = ctx->priv;
const float frate = s->rate;
char *rate = av_asprintf("%f", frate);
const char *argv[] = { "-logfn", s->logfn,
"-hmm", s->hmm,
"-lm", s->lm,
"-lmctl", s->lmctl,
"-lmname", s->lmname,
"-dict", s->dict,
"-samprate", rate,
NULL };
s->config = cmd_ln_parse_r(NULL, ps_args(), 14, (char **)argv, 0);
av_free(rate);
if (!s->config)
return AVERROR(ENOMEM);
ps_default_search_args(s->config);
s->ps = ps_init(s->config);
if (!s->ps)
return AVERROR(ENOMEM);
return 0;
}
static int query_formats(AVFilterContext *ctx)
{
ASRContext *s = ctx->priv;
int sample_rates[] = { s->rate, -1 };
int ret;
AVFilterFormats *formats = NULL;
AVFilterChannelLayouts *layout = NULL;
if ((ret = ff_add_format (&formats, AV_SAMPLE_FMT_S16 )) < 0 ||
(ret = ff_set_common_formats (ctx , formats )) < 0 ||
(ret = ff_add_channel_layout (&layout , AV_CH_LAYOUT_MONO )) < 0 ||
(ret = ff_set_common_channel_layouts (ctx , layout )) < 0 ||
(ret = ff_set_common_samplerates_from_list(ctx, sample_rates )) < 0)
return ret;
return 0;
}
static av_cold void asr_uninit(AVFilterContext *ctx)
{
ASRContext *s = ctx->priv;
ps_free(s->ps);
s->ps = NULL;
cmd_ln_free_r(s->config);
s->config = NULL;
}
static const AVFilterPad asr_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.filter_frame = filter_frame,
.config_props = config_input,
},
};
static const AVFilterPad asr_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
},
};
const AVFilter ff_af_asr = {
.name = "asr",
.description = NULL_IF_CONFIG_SMALL("Automatic Speech Recognition."),
.priv_size = sizeof(ASRContext),
.priv_class = &asr_class,
.init = asr_init,
.uninit = asr_uninit,
.flags = AVFILTER_FLAG_METADATA_ONLY,
FILTER_INPUTS(asr_inputs),
FILTER_OUTPUTS(asr_outputs),
FILTER_QUERY_FUNC(query_formats),
};
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