diff options
Diffstat (limited to 'libavfilter/vf_ocr.c')
-rw-r--r-- | libavfilter/vf_ocr.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/libavfilter/vf_ocr.c b/libavfilter/vf_ocr.c new file mode 100644 index 0000000000..870dd68841 --- /dev/null +++ b/libavfilter/vf_ocr.c @@ -0,0 +1,151 @@ +/* + * 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 + }; + + AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts); + if (!fmts_list) + return AVERROR(ENOMEM); + ff_set_common_formats(ctx, fmts_list); + + return 0; +} + +static int filter_frame(AVFilterLink *inlink, AVFrame *in) +{ + AVDictionary **metadata = avpriv_frame_get_metadatap(in); + AVFilterContext *ctx = inlink->dst; + AVFilterLink *outlink = ctx->outputs[0]; + OCRContext *s = ctx->priv; + char *result; + + result = TessBaseAPIRect(s->tess, in->data[0], 1, + in->linesize[0], 0, 0, in->width, in->height); + av_dict_set(metadata, "lavfi.ocr.text", result, 0); + TessDeleteText(result); + + 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, + }, + { NULL } +}; + +static const AVFilterPad ocr_outputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_VIDEO, + }, + { NULL } +}; + +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, + .inputs = ocr_inputs, + .outputs = ocr_outputs, +}; |