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/*
* 3GPP TS 26.245 Timed Text decoder
* Copyright (c) 2012 Philip Langdale <philipl@overt.org>
*
* 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 "avcodec.h"
#include "ass.h"
#include "libavutil/avstring.h"
#include "libavutil/common.h"
#include "libavutil/bprint.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mem.h"
#define STYLE_FLAG_BOLD 1
#define STYLE_FLAG_ITALIC 2
#define STYLE_FLAG_UNDERLINE 4
static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end,
char **style_start, char **style_end,
uint8_t **style_flags, int style_entries)
{
int i = 0;
while (text < text_end) {
for (i = 0; i < style_entries; i++) {
if (*style_flags[i] && text == style_start[i]) {
if (*style_flags[i] & STYLE_FLAG_BOLD)
av_bprintf(buf, "{\\b1}");
if (*style_flags[i] & STYLE_FLAG_ITALIC)
av_bprintf(buf, "{\\i1}");
if (*style_flags[i] & STYLE_FLAG_UNDERLINE)
av_bprintf(buf, "{\\u1}");
}
}
switch (*text) {
case '\r':
break;
case '\n':
av_bprintf(buf, "\\N");
break;
default:
av_bprint_chars(buf, *text, 1);
break;
}
for (i = 0; i < style_entries; i++) {
if (*style_flags[i] && text == style_end[i]) {
if (*style_flags[i] & STYLE_FLAG_BOLD)
av_bprintf(buf, "{\\b0}");
if (*style_flags[i] & STYLE_FLAG_ITALIC)
av_bprintf(buf, "{\\i0}");
if (*style_flags[i] & STYLE_FLAG_UNDERLINE)
av_bprintf(buf, "{\\u0}");
}
}
text++;
}
return 0;
}
static int mov_text_init(AVCodecContext *avctx) {
/*
* TODO: Handle the default text style.
* NB: Most players ignore styles completely, with the result that
* it's very common to find files where the default style is broken
* and respecting it results in a worse experience than ignoring it.
*/
return ff_ass_subtitle_header_default(avctx);
}
static int mov_text_decode_frame(AVCodecContext *avctx,
void *data, int *got_sub_ptr, AVPacket *avpkt)
{
AVSubtitle *sub = data;
int ret, ts_start, ts_end;
AVBPrint buf;
char *ptr = avpkt->data;
char *end;
//char *ptr_temp;
int text_length, tsmb_type, style_entries;
uint64_t tsmb_size, tracksize;
char **style_start = { 0, };
char **style_end = { 0, };
uint8_t **style_flags = { 0, };
const uint8_t *tsmb;
int index, i, size_var;
uint8_t *flag;
char *style_pos;
if (!ptr || avpkt->size < 2)
return AVERROR_INVALIDDATA;
/*
* A packet of size two with value zero is an empty subtitle
* used to mark the end of the previous non-empty subtitle.
* We can just drop them here as we have duration information
* already. If the value is non-zero, then it's technically a
* bad packet.
*/
if (avpkt->size == 2)
return AV_RB16(ptr) == 0 ? 0 : AVERROR_INVALIDDATA;
/*
* The first two bytes of the packet are the length of the text string
* In complex cases, there are style descriptors appended to the string
* so we can't just assume the packet size is the string size.
*/
text_length = AV_RB16(ptr);
end = ptr + FFMIN(2 + text_length, avpkt->size);
ptr += 2;
ts_start = av_rescale_q(avpkt->pts,
avctx->time_base,
(AVRational){1,100});
ts_end = av_rescale_q(avpkt->pts + avpkt->duration,
avctx->time_base,
(AVRational){1,100});
tsmb_size = 0;
tracksize = 2 + text_length;
// Note that the spec recommends lines be no longer than 2048 characters.
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
if (text_length + 2 != avpkt->size) {
while (tracksize + 8 <= avpkt->size) {
// A box is a minimum of 8 bytes.
tsmb = ptr + tracksize - 2;
tsmb_size = AV_RB32(tsmb);
tsmb += 4;
tsmb_type = AV_RB32(tsmb);
tsmb += 4;
if (tsmb_size == 1) {
if (tracksize + 16 > avpkt->size)
break;
tsmb_size = AV_RB64(tsmb);
tsmb += 8;
size_var = 18;
} else
size_var = 10;
//size_var is equal to 10 or 18 depending on the size of box
if (tracksize + tsmb_size > avpkt->size)
break;
if (tsmb_type == MKBETAG('s','t','y','l')) {
if (tracksize + size_var > avpkt->size)
break;
style_entries = AV_RB16(tsmb);
tsmb += 2;
// A single style record is of length 12 bytes.
if (tracksize + size_var + style_entries * 12 > avpkt->size)
break;
for(i = 0; i < style_entries; i++) {
style_pos = ptr + AV_RB16(tsmb);
index = i;
av_dynarray_add(&style_start, &index, style_pos);
tsmb += 2;
style_pos = ptr + AV_RB16(tsmb);
index = i;
av_dynarray_add(&style_end, &index, style_pos);
tsmb += 2;
// fontID = AV_RB16(tsmb);
tsmb += 2;
flag = av_malloc(1);
if (!flag)
return AVERROR(ENOMEM);
*flag = AV_RB8(tsmb);
index = i;
av_dynarray_add(&style_flags, &index, flag);
//fontsize=AV_RB8(tsmb);
tsmb += 2;
// text-color-rgba
tsmb += 4;
}
text_to_ass(&buf, ptr, end, style_start, style_end, style_flags, style_entries);
for(i = 0; i < style_entries; i++) {
av_freep(&style_flags[i]);
}
av_freep(&style_start);
av_freep(&style_end);
av_freep(&style_flags);
}
tracksize = tracksize + tsmb_size;
}
} else
text_to_ass(&buf, ptr, end, NULL, NULL, 0, 0);
ret = ff_ass_add_rect_bprint(sub, &buf, ts_start, ts_end - ts_start);
av_bprint_finalize(&buf, NULL);
if (ret < 0)
return ret;
*got_sub_ptr = sub->num_rects > 0;
return avpkt->size;
}
AVCodec ff_movtext_decoder = {
.name = "mov_text",
.long_name = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = AV_CODEC_ID_MOV_TEXT,
.init = mov_text_init,
.decode = mov_text_decode_frame,
};
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