1/* 2 * 3GPP TS 26.245 Timed Text encoder 3 * Copyright (c) 2012 Philip Langdale <philipl@overt.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 <stdarg.h> 23#include "avcodec.h" 24#include "libavutil/avassert.h" 25#include "libavutil/avstring.h" 26#include "libavutil/intreadwrite.h" 27#include "ass_split.h" 28#include "ass.h" 29 30typedef struct { 31 ASSSplitContext *ass_ctx; 32 char buffer[2048]; 33 char *ptr; 34 char *end; 35} MovTextContext; 36 37 38static av_cold int mov_text_encode_init(AVCodecContext *avctx) 39{ 40 /* 41 * For now, we'll use a fixed default style. When we add styling 42 * support, this will be generated from the ASS style. 43 */ 44 static uint8_t text_sample_entry[] = { 45 0x00, 0x00, 0x00, 0x00, // uint32_t displayFlags 46 0x01, // int8_t horizontal-justification 47 0xFF, // int8_t vertical-justification 48 0x00, 0x00, 0x00, 0x00, // uint8_t background-color-rgba[4] 49 // BoxRecord { 50 0x00, 0x00, // int16_t top 51 0x00, 0x00, // int16_t left 52 0x00, 0x00, // int16_t bottom 53 0x00, 0x00, // int16_t right 54 // }; 55 // StyleRecord { 56 0x00, 0x00, // uint16_t startChar 57 0x00, 0x00, // uint16_t endChar 58 0x00, 0x01, // uint16_t font-ID 59 0x00, // uint8_t face-style-flags 60 0x12, // uint8_t font-size 61 0xFF, 0xFF, 0xFF, 0xFF, // uint8_t text-color-rgba[4] 62 // }; 63 // FontTableBox { 64 0x00, 0x00, 0x00, 0x12, // uint32_t size 65 'f', 't', 'a', 'b', // uint8_t name[4] 66 0x00, 0x01, // uint16_t entry-count 67 // FontRecord { 68 0x00, 0x01, // uint16_t font-ID 69 0x05, // uint8_t font-name-length 70 'S', 'e', 'r', 'i', 'f',// uint8_t font[font-name-length] 71 // }; 72 // }; 73 }; 74 75 MovTextContext *s = avctx->priv_data; 76 77 avctx->extradata_size = sizeof text_sample_entry; 78 avctx->extradata = av_mallocz(avctx->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE); 79 if (!avctx->extradata) 80 return AVERROR(ENOMEM); 81 82 memcpy(avctx->extradata, text_sample_entry, avctx->extradata_size); 83 84 s->ass_ctx = ff_ass_split(avctx->subtitle_header); 85 return s->ass_ctx ? 0 : AVERROR_INVALIDDATA; 86} 87 88static void mov_text_text_cb(void *priv, const char *text, int len) 89{ 90 MovTextContext *s = priv; 91 av_assert0(s->end >= s->ptr); 92 av_strlcpy(s->ptr, text, FFMIN(s->end - s->ptr, len + 1)); 93 s->ptr += FFMIN(s->end - s->ptr, len); 94} 95 96static void mov_text_new_line_cb(void *priv, int forced) 97{ 98 MovTextContext *s = priv; 99 av_assert0(s->end >= s->ptr); 100 av_strlcpy(s->ptr, "\n", FFMIN(s->end - s->ptr, 2)); 101 if (s->end > s->ptr) 102 s->ptr++; 103} 104 105static const ASSCodesCallbacks mov_text_callbacks = { 106 .text = mov_text_text_cb, 107 .new_line = mov_text_new_line_cb, 108}; 109 110static int mov_text_encode_frame(AVCodecContext *avctx, unsigned char *buf, 111 int bufsize, const AVSubtitle *sub) 112{ 113 MovTextContext *s = avctx->priv_data; 114 ASSDialog *dialog; 115 int i, len, num; 116 117 s->ptr = s->buffer; 118 s->end = s->ptr + sizeof(s->buffer); 119 120 for (i = 0; i < sub->num_rects; i++) { 121 122 if (sub->rects[i]->type != SUBTITLE_ASS) { 123 av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n"); 124 return AVERROR(ENOSYS); 125 } 126 127 dialog = ff_ass_split_dialog(s->ass_ctx, sub->rects[i]->ass, 0, &num); 128 for (; dialog && num--; dialog++) { 129 ff_ass_split_override_codes(&mov_text_callbacks, s, dialog->text); 130 } 131 } 132 133 if (s->ptr == s->buffer) 134 return 0; 135 136 AV_WB16(buf, strlen(s->buffer)); 137 buf += 2; 138 139 len = av_strlcpy(buf, s->buffer, bufsize - 2); 140 141 if (len > bufsize-3) { 142 av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n"); 143 return AVERROR(EINVAL); 144 } 145 146 return len + 2; 147} 148 149static int mov_text_encode_close(AVCodecContext *avctx) 150{ 151 MovTextContext *s = avctx->priv_data; 152 ff_ass_split_free(s->ass_ctx); 153 return 0; 154} 155 156AVCodec ff_movtext_encoder = { 157 .name = "mov_text", 158 .long_name = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"), 159 .type = AVMEDIA_TYPE_SUBTITLE, 160 .id = AV_CODEC_ID_MOV_TEXT, 161 .priv_data_size = sizeof(MovTextContext), 162 .init = mov_text_encode_init, 163 .encode_sub = mov_text_encode_frame, 164 .close = mov_text_encode_close, 165}; 166