1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
/*
* Copyright (c) 2015 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 <tesseract/capi.h>
#include "libavutil/opt.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
typedef struct OCRContext {
const AVClass *class;
char *datapath;
char *language;
char *whitelist;
char *blacklist;
TessBaseAPI *tess;
} OCRContext;
#define OFFSET(x) offsetof(OCRContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption ocr_options[] = {
{ "datapath", "set datapath", OFFSET(datapath), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
{ "language", "set language", OFFSET(language), AV_OPT_TYPE_STRING, {.str="eng"}, 0, 0, FLAGS },
{ "whitelist", "set character whitelist", OFFSET(whitelist), AV_OPT_TYPE_STRING, {.str="0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.:;,-+_!?\"'[]{}()<>|/\\=*&%$#@!~ "}, 0, 0, FLAGS },
{ "blacklist", "set character blacklist", OFFSET(blacklist), AV_OPT_TYPE_STRING, {.str=""}, 0, 0, FLAGS },
{ NULL }
};
static av_cold int init(AVFilterContext *ctx)
{
OCRContext *s = ctx->priv;
s->tess = TessBaseAPICreate();
if (TessBaseAPIInit3(s->tess, s->datapath, s->language) == -1) {
av_log(ctx, AV_LOG_ERROR, "failed to init tesseract\n");
return AVERROR(EINVAL);
}
if (!TessBaseAPISetVariable(s->tess, "tessedit_char_whitelist", s->whitelist)) {
av_log(ctx, AV_LOG_ERROR, "failed to set whitelist\n");
return AVERROR(EINVAL);
}
if (!TessBaseAPISetVariable(s->tess, "tessedit_char_blacklist", s->blacklist)) {
av_log(ctx, AV_LOG_ERROR, "failed to set blacklist\n");
return AVERROR(EINVAL);
}
av_log(ctx, AV_LOG_DEBUG, "Tesseract version: %s\n", TessVersion());
return 0;
}
static int query_formats(AVFilterContext *ctx)
{
static const enum AVPixelFormat pix_fmts[] = {
AV_PIX_FMT_GRAY8,
AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
AV_PIX_FMT_YUVJ411P,
AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
AV_PIX_FMT_NONE
};
return ff_set_common_formats_from_list(ctx, pix_fmts);
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVDictionary **metadata = &in->metadata;
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
OCRContext *s = ctx->priv;
char *result;
int *confs;
result = TessBaseAPIRect(s->tess, in->data[0], 1,
in->linesize[0], 0, 0, in->width, in->height);
confs = TessBaseAPIAllWordConfidences(s->tess);
av_dict_set(metadata, "lavfi.ocr.text", result, 0);
for (int i = 0; confs[i] != -1; i++) {
char number[256];
snprintf(number, sizeof(number), "%d ", confs[i]);
av_dict_set(metadata, "lavfi.ocr.confidence", number, AV_DICT_APPEND);
}
TessDeleteText(result);
TessDeleteIntArray(confs);
return ff_filter_frame(outlink, in);
}
static av_cold void uninit(AVFilterContext *ctx)
{
OCRContext *s = ctx->priv;
TessBaseAPIEnd(s->tess);
TessBaseAPIDelete(s->tess);
}
AVFILTER_DEFINE_CLASS(ocr);
static const AVFilterPad ocr_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
},
};
static const AVFilterPad ocr_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
};
const AVFilter ff_vf_ocr = {
.name = "ocr",
.description = NULL_IF_CONFIG_SMALL("Optical Character Recognition."),
.priv_size = sizeof(OCRContext),
.priv_class = &ocr_class,
.query_formats = query_formats,
.init = init,
.uninit = uninit,
FILTER_INPUTS(ocr_inputs),
FILTER_OUTPUTS(ocr_outputs),
};
|
