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assdec.c
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1 /*
2  * SSA/ASS decoder
3  * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <string.h>
23 
24 #include "avcodec.h"
25 #include "ass.h"
26 #include "ass_split.h"
27 #include "libavutil/internal.h"
28 #include "libavutil/mem.h"
29 
31 {
32  avctx->subtitle_header = av_malloc(avctx->extradata_size + 1);
33  if (!avctx->subtitle_header)
34  return AVERROR(ENOMEM);
35  memcpy(avctx->subtitle_header, avctx->extradata, avctx->extradata_size);
36  avctx->subtitle_header[avctx->extradata_size] = 0;
37  avctx->subtitle_header_size = avctx->extradata_size;
38  avctx->priv_data = ff_ass_split(avctx->extradata);
39  if(!avctx->priv_data)
40  return -1;
41  return 0;
42 }
43 
44 static int ass_decode_frame(AVCodecContext *avctx, void *data, int *got_sub_ptr,
45  AVPacket *avpkt)
46 {
47  const char *ptr = avpkt->data;
48  int len, size = avpkt->size;
49 
50  while (size > 0) {
51  int duration;
52  ASSDialog *dialog = ff_ass_split_dialog(avctx->priv_data, ptr, 0, NULL);
53  if (!dialog)
54  return AVERROR_INVALIDDATA;
55  duration = dialog->end - dialog->start;
56  len = ff_ass_add_rect(data, ptr, 0, duration, 1);
57  if (len < 0)
58  return len;
59  ptr += len;
60  size -= len;
61  }
62 
63  *got_sub_ptr = avpkt->size > 0;
64  return avpkt->size;
65 }
66 
67 static int ass_decode_close(AVCodecContext *avctx)
68 {
70  avctx->priv_data = NULL;
71  return 0;
72 }
73 
75  .name = "ass",
76  .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
77  .type = AVMEDIA_TYPE_SUBTITLE,
78  .id = AV_CODEC_ID_SSA,
79  .init = ass_decode_init,
80  .decode = ass_decode_frame,
81  .close = ass_decode_close,
82 };