/* * 3GPP TS 26.245 Timed Text decoder * Copyright (c) 2012 Philip Langdale * * 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, };