mirror of https://git.ffmpeg.org/ffmpeg.git
126 lines
4.5 KiB
C
126 lines
4.5 KiB
C
/*
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* Copyright (c) 2012 Clément Bœsch
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Raw subtitles decoder
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*/
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#include "avcodec.h"
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#include "ass.h"
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#include "libavutil/bprint.h"
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#include "libavutil/opt.h"
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typedef struct {
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AVClass *class;
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char *linebreaks;
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int keep_ass_markup;
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} TextContext;
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#define OFFSET(x) offsetof(TextContext, x)
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#define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
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static const AVOption options[] = {
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{ "linebreaks", "Extra line breaks characters", OFFSET(linebreaks), AV_OPT_TYPE_STRING, {.str=NULL}, .flags=SD },
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{ "keep_ass_markup", "Set if ASS tags must be escaped", OFFSET(keep_ass_markup), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, .flags=SD },
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{ NULL }
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};
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static const AVClass text_decoder_class = {
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.class_name = "text decoder",
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.item_name = av_default_item_name,
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.option = options,
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.version = LIBAVUTIL_VERSION_INT,
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};
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static int text_event_to_ass(const AVCodecContext *avctx, AVBPrint *buf,
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const char *p, const char *p_end)
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{
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const TextContext *text = avctx->priv_data;
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for (; p < p_end && *p; p++) {
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/* forced custom line breaks, not accounted as "normal" EOL */
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if (text->linebreaks && strchr(text->linebreaks, *p)) {
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av_bprintf(buf, "\\N");
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/* standard ASS escaping so random characters don't get mis-interpreted
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* as ASS */
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} else if (!text->keep_ass_markup && strchr("{}\\", *p)) {
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av_bprintf(buf, "\\%c", *p);
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/* some packets might end abruptly (no \0 at the end, like for example
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* in some cases of demuxing from a classic video container), some
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* might be terminated with \n or \r\n which we have to remove (for
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* consistency with those who haven't), and we also have to deal with
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* evil cases such as \r at the end of the buffer (and no \0 terminated
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* character) */
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} else if (p[0] == '\n') {
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/* some stuff left so we can insert a line break */
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if (p < p_end - 1)
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av_bprintf(buf, "\\N");
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} else if (p[0] == '\r' && p < p_end - 1 && p[1] == '\n') {
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/* \r followed by a \n, we can skip it. We don't insert the \N yet
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* because we don't know if it is followed by more text */
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continue;
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/* finally, a sane character */
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} else {
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av_bprint_chars(buf, *p, 1);
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}
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}
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av_bprintf(buf, "\r\n");
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return 0;
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}
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static int text_decode_frame(AVCodecContext *avctx, void *data,
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int *got_sub_ptr, AVPacket *avpkt)
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{
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AVBPrint buf;
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AVSubtitle *sub = data;
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const char *ptr = avpkt->data;
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const int ts_start = av_rescale_q(avpkt->pts, avctx->time_base, (AVRational){1,100});
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const int ts_duration = avpkt->duration != -1 ?
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av_rescale_q(avpkt->duration, avctx->time_base, (AVRational){1,100}) : -1;
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av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
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if (ptr && avpkt->size > 0 && *ptr &&
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!text_event_to_ass(avctx, &buf, ptr, ptr + avpkt->size)) {
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if (!av_bprint_is_complete(&buf)) {
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av_bprint_finalize(&buf, NULL);
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return AVERROR(ENOMEM);
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}
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ff_ass_add_rect(sub, buf.str, ts_start, ts_duration, 0);
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}
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*got_sub_ptr = sub->num_rects > 0;
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av_bprint_finalize(&buf, NULL);
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return avpkt->size;
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}
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AVCodec ff_text_decoder = {
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.name = "text",
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.priv_data_size = sizeof(TextContext),
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.long_name = NULL_IF_CONFIG_SMALL("Raw text subtitle"),
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.type = AVMEDIA_TYPE_SUBTITLE,
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.id = AV_CODEC_ID_TEXT,
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.decode = text_decode_frame,
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.init = ff_ass_subtitle_header_default,
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.priv_class = &text_decoder_class,
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};
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