libavcodec/assenc.c

   1 /*
   2  * SSA/ASS encoder
   3  * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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 "libavutil/avstring.h"
  26 #include "libavutil/internal.h"
  27 #include "libavutil/mem.h"
  28
  29 static av_cold int ass_encode_init(AVCodecContext *avctx)
  30 {
  31     avctx->extradata = av_malloc(avctx->subtitle_header_size);
  32     if (!avctx->extradata)
  33         return AVERROR(ENOMEM);
  34     memcpy(avctx->extradata, avctx->subtitle_header, avctx->subtitle_header_size);
  35     avctx->extradata_size = avctx->subtitle_header_size;
  36     return 0;
  37 }
  38
  39 static int ass_encode_frame(AVCodecContext *avctx,
  40                             unsigned char *buf, int bufsize,
  41                             const AVSubtitle *sub)
  42 {
  43     int i, len, total_len = 0;
  44
  45     for (i=0; i<sub->num_rects; i++) {
  46         if (sub->rects[i]->type != SUBTITLE_ASS) {
  47             av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
  48             return -1;
  49         }
  50
  51         len = av_strlcpy(buf+total_len, sub->rects[i]->ass, bufsize-total_len);
  52
  53         if (len > bufsize-total_len-1) {
  54             av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
  55             return -1;
  56         }
  57
  58         total_len += len;
  59     }
  60
  61     return total_len;
  62 }
  63
  64 AVCodec ff_ass_encoder = {
  65     .name         = "ass",
  66     .long_name    = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
  67     .type         = AVMEDIA_TYPE_SUBTITLE,
  68     .id           = AV_CODEC_ID_SSA,
  69     .init         = ass_encode_init,
  70     .encode_sub   = ass_encode_frame,
  71 };