From patchwork Thu Oct 21 03:19:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Soft Works X-Patchwork-Id: 31183 Delivered-To: ffmpegpatchwork2@gmail.com Received: by 2002:a05:6602:2084:0:0:0:0 with SMTP id a4csp128364ioa; Wed, 20 Oct 2021 20:22:02 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxMmFoy38XS78ylJ05as7sPRErRvJfsL/GJs3kPAjh93hk4soOEaj28KJDh/rzU/hTduJ4o X-Received: by 2002:a05:6402:3512:: with SMTP id b18mr3976708edd.15.1634786522146; Wed, 20 Oct 2021 20:22:02 -0700 (PDT) Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org. [79.124.17.100]) by mx.google.com with ESMTP id y13si8609658eda.344.2021.10.20.20.22.01; Wed, 20 Oct 2021 20:22:02 -0700 (PDT) Received-SPF: pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) client-ip=79.124.17.100; Authentication-Results: mx.google.com; dkim=neutral (body hash did not verify) header.i=@hotmail.com header.s=selector1 header.b=tDpYXQ7v; arc=fail (body hash mismatch); spf=pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) smtp.mailfrom=ffmpeg-devel-bounces@ffmpeg.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=hotmail.com Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 22BA068A8A1; Thu, 21 Oct 2021 06:20:01 +0300 (EEST) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from NAM10-MW2-obe.outbound.protection.outlook.com (mail-mw2nam10olkn2026.outbound.protection.outlook.com [40.92.42.26]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 6330368A12D for ; Thu, 21 Oct 2021 06:19:58 +0300 (EEST) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=eDr9AFQe6vQigCbOWBTrYfChM2vogDBdDfY17Yy3jtT/aPsdMOPAX2BMpGFRcXeSqkinp2wrZ+9gDKgrM8VMRhNbn2FaQXfEkn6k+WWizqrtYcs91OehGbuluDTdKTdY90zgmZykjE69CGT/5+Yfx8c8DwNasKHpWVWLxlH2zeyIwcb6qTHG76xv1j//92SKed3HgbtpfPCu1mKFEVSfmUXZWJAAPXbXVSzJQ6j8kGZD2ky4i1QwSSaxesiUdyp+8lBvynOsIrf5aAWyQVKrGITMwRIobi38XvueVAC7bNPg8kOd/MdhFDdtzYbCSnTkg68fWzwH+rRKH/LKx0oscw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=sjAiYC1yrYwutoXF8e5YKG9rTvFGkjfN6fFRlm3NCYM=; b=LEAnqitQXDEPv6/DsLBIEiD2x9c/JSHaUeZLhayvgWz/e1jrTs6G1gVeUd8Xthoa0xpFDPnYgzYpqMilfwjq9Q4Y+e79+EbHpP94qwnuLB4NUEIOd9GCPuzWvIfSsHUccI3wIDJztdxrGJXlmjx6U4U57W3PJ3uXPE5uoG6j2TpCC2HZUAV526i1qGvutx3QkO+yjF08dC1B8UbQvt+UxQkN3XKFabLrYAmA3JhUuIQeiXBTwZbddAwQg5z8OUupzxQIY6izdyFg+RzMHpbK2+75dQMbKee8GZae2g+Y/mfgipWCUncEt/U14977urVSeP73x7y3XtIh4l0rVuXKvA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=none; dmarc=none; dkim=none; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=hotmail.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=sjAiYC1yrYwutoXF8e5YKG9rTvFGkjfN6fFRlm3NCYM=; b=tDpYXQ7v5swbaDjRoHZlQL98vRtcV2F8OOXUvoFj80owhLSfTWYrsVeYOu+GXCT6xfGv4JnlDg3GA1HWaHcXvnbElWrkoCi1bMcHB4qQGPERhs8qw3P3Owh+iBnsCnojVflNT8EFp642pfzqhZrjqnNfqI/0vtJKCWnhGtTJ58hK/aldRIgDkHY0QMIrLg7mUU8Pw/ETP6SA8uXXrzEU+2h7b22WTGk8PGa6Gr6dwVOxLZSNdZ1hvoQoGi9ftSWoibeI5b0vaNkRRQL/qbsixA1pcvu26aEOn2SK2+ymLq7xL5Iqaw96sFGb4+ngXoZbu7GlBR/VGi23lJ0cFa7hrw== Received: from MN2PR04MB5981.namprd04.prod.outlook.com (2603:10b6:208:da::10) by MN2PR04MB5984.namprd04.prod.outlook.com (2603:10b6:208:d9::33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4608.16; Thu, 21 Oct 2021 03:19:55 +0000 Received: from MN2PR04MB5981.namprd04.prod.outlook.com ([fe80::ecfe:2528:2012:22cb]) by MN2PR04MB5981.namprd04.prod.outlook.com ([fe80::ecfe:2528:2012:22cb%5]) with mapi id 15.20.4608.018; Thu, 21 Oct 2021 03:19:55 +0000 From: Soft Works To: "ffmpeg-devel@ffmpeg.org" Thread-Topic: [PATCH v14 13/14] avfilter/graphicsub2text: Add new graphicsub2text filter (OCR) Thread-Index: AQHXxiqF+5ERbC4/z0ayHKHK04c4hw== Date: Thu, 21 Oct 2021 03:19:55 +0000 Message-ID: References: <4f225627a420d32b8766306e418c45bc8af41c47.1634785894.git.softworkz@hotmail.com> <4d6c9a34829586c3ad247e2423faa0d763fa01c4.1634785894.git.softworkz@hotmail.com> <541cf61d503ee53b51ebccada8f9cb087ae3c549.1634785895.git.softworkz@hotmail.com> <55d8df19375a269c01802b3ab9b0e4c30d9654eb.1634785895.git.softworkz@hotmail.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-tmn: [VGr7GDlaKBNi5pNg3itGywaJb6WVqzix] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: e0550490-f91d-4d2e-2c84-08d99441a7b6 x-ms-traffictypediagnostic: MN2PR04MB5984: x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: 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 x-ms-exchange-antispam-messagedata-chunkcount: 1 x-ms-exchange-antispam-messagedata-0: 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 MIME-Version: 1.0 X-OriginatorOrg: sct-15-20-3174-20-msonline-outlook-529c7.templateTenant X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: MN2PR04MB5981.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg: 00000000-0000-0000-0000-000000000000 X-MS-Exchange-CrossTenant-Network-Message-Id: e0550490-f91d-4d2e-2c84-08d99441a7b6 X-MS-Exchange-CrossTenant-originalarrivaltime: 21 Oct 2021 03:19:55.6295 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa X-MS-Exchange-CrossTenant-userprincipalname: softworkz@hotmail.com X-MS-Exchange-CrossTenant-rms-persistedconsumerorg: 00000000-0000-0000-0000-000000000000 X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR04MB5984 Subject: [FFmpeg-devel] [PATCH v14 13/14] avfilter/graphicsub2text: Add new graphicsub2text filter (OCR) X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" X-TUID: phXp3hioB1Os Signed-off-by: softworkz --- configure | 1 + doc/filters.texi | 55 ++++++ libavfilter/Makefile | 2 + libavfilter/allfilters.c | 1 + libavfilter/sf_graphicsub2text.c | 323 +++++++++++++++++++++++++++++++ 5 files changed, 382 insertions(+) create mode 100644 libavfilter/sf_graphicsub2text.c diff --git a/configure b/configure index 31092ab38b..3276264c0c 100755 --- a/configure +++ b/configure @@ -3605,6 +3605,7 @@ frei0r_deps_any="libdl LoadLibrary" frei0r_filter_deps="frei0r" frei0r_src_filter_deps="frei0r" fspp_filter_deps="gpl" +graphicsub2text_filter_deps="libtesseract" histeq_filter_deps="gpl" hqdn3d_filter_deps="gpl" interlace_filter_deps="gpl" diff --git a/doc/filters.texi b/doc/filters.texi index 7f7ccc3f2a..e75d095ea4 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -25502,6 +25502,61 @@ ffmpeg -i "https://streams.videolan.org/ffmpeg/mkv_subtitles.mkv" -filter_comple @end example @end itemize +@section graphicsub2text + +Converts graphic subtitles to text subtitles by performing OCR. + +For this filter to be available, ffmpeg needs to be compiled with libtesseract (see https://github.com/tesseract-ocr/tesseract). +Language models need to be downloaded from https://github.com/tesseract-ocr/tessdata and put into as subfolder named 'tessdata' or into a folder specified via the environment variable 'TESSDATA_PREFIX'. +The path can also be specified via filter option (see below). + +Note: These models are including the data for both OCR modes. + +Inputs: +- 0: Subtitles [bitmap] + +Outputs: +- 0: Subtitles [text] + +It accepts the following parameters: + +@table @option +@item ocr_mode +The character recognition mode to use. + +Supported OCR modes are: + +@table @var +@item 0, tesseract +This is the classic libtesseract operation mode. It is fast but less accurate than LSTM. +@item 1, lstm +Newer OCR implementation based on ML models. Provides usually better results, requires more processing resources. +@item 2, both +Use a combination of both modes. +@end table + +@item tessdata_path +The path to a folder containing the language models to be used. + +@item language +The recognition language. It needs to match the first three characters of a language model file in the tessdata path. + +@end table + + +@subsection Examples + +@itemize +@item +Convert DVB graphic subtitles to ASS (text) subtitles + +Note: For this to work, you need to have the data file 'eng.traineddata' in a 'tessdata' subfolder (see above). +@example +ffmpeg ffmpeg -loglevel verbose -i "https://streams.videolan.org/streams/ts/video_subs_ttxt%2Bdvbsub.ts" -filter_complex "[0:13]graphicsub2text=ocr_mode=both" -c:s ass -y output.mkv +@end example +@end itemize + + @section graphicsub2video Renders graphic subtitles as video frames. diff --git a/libavfilter/Makefile b/libavfilter/Makefile index 302bdaf416..6e5b04c250 100644 --- a/libavfilter/Makefile +++ b/libavfilter/Makefile @@ -293,6 +293,8 @@ OBJS-$(CONFIG_GBLUR_FILTER) += vf_gblur.o OBJS-$(CONFIG_GEQ_FILTER) += vf_geq.o OBJS-$(CONFIG_GRADFUN_FILTER) += vf_gradfun.o OBJS-$(CONFIG_GRAPHICSUB2VIDEO_FILTER) += vf_overlaygraphicsubs.o framesync.o +OBJS-$(CONFIG_GRAPHICSUB2TEXT_FILTER) += sf_graphicsub2text.o +OBJS-$(CONFIG_GRAPHICSUB2VIDEO_FILTER) += vf_overlaygraphicsubs.o framesync.o OBJS-$(CONFIG_GRAPHMONITOR_FILTER) += f_graphmonitor.o OBJS-$(CONFIG_GRAYWORLD_FILTER) += vf_grayworld.o OBJS-$(CONFIG_GREYEDGE_FILTER) += vf_colorconstancy.o diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c index f0eccbacd4..70399a77f4 100644 --- a/libavfilter/allfilters.c +++ b/libavfilter/allfilters.c @@ -535,6 +535,7 @@ extern const AVFilter ff_avf_showwaves; extern const AVFilter ff_avf_showwavespic; extern const AVFilter ff_vaf_spectrumsynth; extern const AVFilter ff_sf_censor; +extern const AVFilter ff_sf_graphicsub2text; extern const AVFilter ff_sf_showspeaker; extern const AVFilter ff_sf_splitcc; extern const AVFilter ff_sf_stripstyles; diff --git a/libavfilter/sf_graphicsub2text.c b/libavfilter/sf_graphicsub2text.c new file mode 100644 index 0000000000..c963ba4384 --- /dev/null +++ b/libavfilter/sf_graphicsub2text.c @@ -0,0 +1,323 @@ +/* + * Copyright (c) 2021 softworkz + * + * 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 + */ + +/** + * @file + * subtitle filter to convert graphical subs to text subs via OCR + */ + +#include +#include + +#include "libavutil/opt.h" +#include "subtitles.h" + +typedef struct SubOcrContext { + const AVClass *class; + int w, h; + + TessBaseAPI *tapi; + TessOcrEngineMode ocr_mode; + char *tessdata_path; + char *language; + + int readorder_counter; + + AVFrame *pending_frame; +} SubOcrContext; + + +static int init(AVFilterContext *ctx) +{ + SubOcrContext *s = ctx->priv; + const char* tver = TessVersion(); + int ret; + + s->tapi = TessBaseAPICreate(); + + if (!s->tapi || !tver || !strlen(tver)) { + av_log(ctx, AV_LOG_ERROR, "Failed to access libtesseract\n"); + return AVERROR(ENOSYS); + } + + av_log(ctx, AV_LOG_VERBOSE, "Initializing libtesseract, version: %s\n", tver); + + ret = TessBaseAPIInit4(s->tapi, s->tessdata_path, s->language, s->ocr_mode, NULL, 0, NULL, NULL, 0, 1); + if (ret < 0 ) { + av_log(ctx, AV_LOG_ERROR, "Failed to initialize libtesseract. Error: %d\n", ret); + return AVERROR(ENOSYS); + } + + ret = TessBaseAPISetVariable(s->tapi, "tessedit_char_blacklist", "|"); + if (ret < 0 ) { + av_log(ctx, AV_LOG_ERROR, "Failed to set 'tessedit_char_blacklist'. Error: %d\n", ret); + return AVERROR(EINVAL); + } + + return 0; +} + +static void uninit(AVFilterContext *ctx) +{ + SubOcrContext *s = ctx->priv; + + if (s->tapi) { + TessBaseAPIEnd(s->tapi); + TessBaseAPIDelete(s->tapi); + } +} + +static int query_formats(AVFilterContext *ctx) +{ + AVFilterFormats *formats, *formats2; + AVFilterLink *inlink = ctx->inputs[0]; + AVFilterLink *outlink = ctx->outputs[0]; + static const enum AVSubtitleType in_fmts[] = { AV_SUBTITLE_FMT_BITMAP, AV_SUBTITLE_FMT_NONE }; + static const enum AVSubtitleType out_fmts[] = { AV_SUBTITLE_FMT_ASS, AV_SUBTITLE_FMT_NONE }; + int ret; + + /* set input format */ + formats = ff_make_format_list(in_fmts); + if ((ret = ff_formats_ref(formats, &inlink->outcfg.formats)) < 0) + return ret; + + /* set output format */ + formats2 = ff_make_format_list(out_fmts); + if ((ret = ff_formats_ref(formats2, &outlink->incfg.formats)) < 0) + return ret; + + return 0; +} + +static int config_input(AVFilterLink *inlink) +{ + AVFilterContext *ctx = inlink->dst; + SubOcrContext *s = ctx->priv; + + if (s->w <= 0 || s->h <= 0) { + s->w = inlink->w; + s->h = inlink->h; + } + return 0; +} + +static int config_output(AVFilterLink *outlink) +{ + const AVFilterContext *ctx = outlink->src; + SubOcrContext *s = ctx->priv; + + outlink->format = AV_SUBTITLE_FMT_ASS; + outlink->w = s->w; + outlink->h = s->h; + + return 0; +} + +static uint8_t* create_grayscale_image(AVFilterContext *ctx, AVSubtitleArea *area) +{ + uint8_t gray_pal[256]; + const size_t img_size = area->buf[0]->size; + const uint8_t* img = area->buf[0]->data; + uint8_t* gs_img = av_malloc(img_size); + + if (!gs_img) + return NULL; + + for (unsigned i = 0; i < 256; i++) { + const uint8_t *col = (uint8_t*)&area->pal[i]; + const int val = (int)col[3] * FFMAX3(col[0], col[1], col[2]); + gray_pal[i] = (uint8_t)(val >> 8); + } + + for (unsigned i = 0; i < img_size; i++) + gs_img[i] = 255 - gray_pal[img[i]]; + + return gs_img; +} + +static int convert_area(AVFilterContext *ctx, AVSubtitleArea *area) +{ + SubOcrContext *s = ctx->priv; + char *ocr_text = NULL; + int ret; + uint8_t *gs_img = create_grayscale_image(ctx, area); + + if (!gs_img) + return AVERROR(ENOMEM); + + area->type = AV_SUBTITLE_FMT_ASS; + TessBaseAPISetImage(s->tapi, gs_img, area->w, area->h, 1, area->linesize[0]); + TessBaseAPISetSourceResolution(s->tapi, 70); + + ret = TessBaseAPIRecognize(s->tapi, NULL); + if (ret == 0) + ocr_text = TessBaseAPIGetUTF8Text(s->tapi); + + if (!ocr_text) { + av_log(ctx, AV_LOG_WARNING, "OCR didn't return a text. ret=%d\n", ret); + area->ass = NULL; + } + else { + const size_t len = strlen(ocr_text); + + if (len > 0 && ocr_text[len - 1] == '\n') + ocr_text[len - 1] = 0; + + av_log(ctx, AV_LOG_VERBOSE, "OCR Result: %s\n", ocr_text); + + area->ass = av_strdup(ocr_text); + + TessDeleteText(ocr_text); + } + + av_freep(&gs_img); + av_buffer_unref(&area->buf[0]); + area->type = AV_SUBTITLE_FMT_ASS; + + return 0; +} + +static int filter_frame(AVFilterLink *inlink, AVFrame *frame) +{ + AVFilterContext *ctx = inlink->dst; + SubOcrContext *s = ctx->priv; + AVFilterLink *outlink = inlink->dst->outputs[0]; + int ret, frame_sent = 0; + + if (s->pending_frame) { + const uint64_t pts_diff = frame->subtitle_pts - s->pending_frame->subtitle_pts; + s->pending_frame->subtitle_end_time = (uint32_t)(pts_diff / 1000); + + ret = ff_filter_frame(outlink, s->pending_frame); + s->pending_frame = NULL; + if (ret < 0) + return ret; + + frame_sent = 1; + + if (frame->num_subtitle_areas == 0) { + // No need to forward this empty frame + av_frame_free(&frame); + return 0; + } + } + + ret = av_frame_make_writable(frame); + + if (ret < 0) { + av_frame_free(&frame); + return ret; + } + + frame->format = AV_SUBTITLE_FMT_ASS; + + av_log(ctx, AV_LOG_DEBUG, "filter_frame sub_pts: %"PRIu64", start_time: %d, end_time: %d, num_areas: %d\n", + frame->subtitle_pts, frame->subtitle_start_time, frame->subtitle_end_time, frame->num_subtitle_areas); + + if (frame->num_subtitle_areas > 1 && + frame->subtitle_areas[0]->y > frame->subtitle_areas[frame->num_subtitle_areas - 1]->y) { + + for (unsigned i = 0; i < frame->num_subtitle_areas / 2; i++) + FFSWAP(AVSubtitleArea*, frame->subtitle_areas[i], frame->subtitle_areas[frame->num_subtitle_areas - i - 1]); + } + + for (unsigned i = 0; i < frame->num_subtitle_areas; i++) { + AVSubtitleArea *area = frame->subtitle_areas[i]; + + ret = convert_area(ctx, area); + if (ret < 0) + return ret; + + if (area->ass && area->ass[0] != '\0') { + char *tmp = area->ass; + + if (i == 0) + area->ass = avpriv_ass_get_dialog(s->readorder_counter++, 0, "Default", NULL, tmp); + else + area->ass = av_asprintf("\\N%s", tmp); + + av_free(tmp); + } + } + + // When decoders can't determine the end time, they are setting it either to UINT32_NAX + // or 30s (dvbsub). + if (frame->num_subtitle_areas > 0 && frame->subtitle_end_time >= 30000) { + // Can't send it without end time, wait for the next frame to determine the end_display time + s->pending_frame = frame; + + if (frame_sent) + return 0; + + // To keep all going, send an empty frame instead + frame = ff_get_subtitles_buffer(outlink, AV_SUBTITLE_FMT_ASS); + if (!frame) + return AVERROR(ENOMEM); + + av_frame_copy_props(frame, s->pending_frame); + frame->subtitle_end_time = 1; + } + + return ff_filter_frame(outlink, frame); +} + +#define OFFSET(x) offsetof(SubOcrContext, x) +#define FLAGS (AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_FILTERING_PARAM) + +static const AVOption graphicsub2text_options[] = { + { "ocr_mode", "set ocr mode", OFFSET(ocr_mode), AV_OPT_TYPE_INT, {.i64=OEM_TESSERACT_ONLY}, OEM_TESSERACT_ONLY, 2, FLAGS, "ocr_mode" }, + { "tesseract", "classic tesseract ocr", 0, AV_OPT_TYPE_CONST, {.i64=OEM_TESSERACT_ONLY}, 0, 0, FLAGS, "ocr_mode" }, + { "lstm", "lstm (ML based)", 0, AV_OPT_TYPE_CONST, {.i64=OEM_LSTM_ONLY}, 0, 0, FLAGS, "ocr_mode" }, + { "both", "use both models combined", 0, AV_OPT_TYPE_CONST, {.i64=OEM_TESSERACT_LSTM_COMBINED}, 0, 0, FLAGS, "ocr_mode" }, + { "tessdata_path", "path to tesseract data", OFFSET(tessdata_path), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS, NULL }, + { "language", "ocr language", OFFSET(language), AV_OPT_TYPE_STRING, {.str = "eng"}, 0, 0, FLAGS, NULL }, + { NULL }, +}; + +AVFILTER_DEFINE_CLASS(graphicsub2text); + +static const AVFilterPad inputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_SUBTITLE, + .filter_frame = filter_frame, + .config_props = config_input, + }, +}; + +static const AVFilterPad outputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_SUBTITLE, + .config_props = config_output, + }, +}; + +const AVFilter ff_sf_graphicsub2text = { + .name = "graphicsub2text", + .description = NULL_IF_CONFIG_SMALL("Convert graphical subtitles to text subtitles via OCR"), + .init = init, + .uninit = uninit, + .priv_size = sizeof(SubOcrContext), + .priv_class = &graphicsub2text_class, + FILTER_INPUTS(inputs), + FILTER_OUTPUTS(outputs), + FILTER_QUERY_FUNC(query_formats), +};