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Rev | Author | Line No. | Line |
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6147 | serge | 1 | /* |
2 | * WebVTT subtitle encoder |
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3 | * Copyright (c) 2010 Aurelien Jacobs |
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4 | * Copyright (c) 2014 Aman Gupta |
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5 | * |
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6 | * This file is part of FFmpeg. |
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7 | * |
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8 | * FFmpeg is free software; you can redistribute it and/or |
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9 | * modify it under the terms of the GNU Lesser General Public |
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10 | * License as published by the Free Software Foundation; either |
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11 | * version 2.1 of the License, or (at your option) any later version. |
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12 | * |
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13 | * FFmpeg is distributed in the hope that it will be useful, |
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14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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16 | * Lesser General Public License for more details. |
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17 | * |
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18 | * You should have received a copy of the GNU Lesser General Public |
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19 | * License along with FFmpeg; if not, write to the Free Software |
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20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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21 | */ |
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22 | |||
23 | #include |
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24 | #include "avcodec.h" |
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25 | #include "libavutil/avstring.h" |
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26 | #include "libavutil/bprint.h" |
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27 | #include "ass_split.h" |
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28 | #include "ass.h" |
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29 | |||
30 | #define WEBVTT_STACK_SIZE 64 |
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31 | typedef struct { |
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32 | AVCodecContext *avctx; |
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33 | ASSSplitContext *ass_ctx; |
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34 | AVBPrint buffer; |
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35 | unsigned timestamp_end; |
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36 | int count; |
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37 | char stack[WEBVTT_STACK_SIZE]; |
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38 | int stack_ptr; |
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39 | } WebVTTContext; |
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40 | |||
41 | #ifdef __GNUC__ |
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42 | __attribute__ ((__format__ (__printf__, 2, 3))) |
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43 | #endif |
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44 | static void webvtt_print(WebVTTContext *s, const char *str, ...) |
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45 | { |
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46 | va_list vargs; |
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47 | va_start(vargs, str); |
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48 | av_vbprintf(&s->buffer, str, vargs); |
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49 | va_end(vargs); |
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50 | } |
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51 | |||
52 | static int webvtt_stack_push(WebVTTContext *s, const char c) |
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53 | { |
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54 | if (s->stack_ptr >= WEBVTT_STACK_SIZE) |
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55 | return -1; |
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56 | s->stack[s->stack_ptr++] = c; |
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57 | return 0; |
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58 | } |
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59 | |||
60 | static char webvtt_stack_pop(WebVTTContext *s) |
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61 | { |
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62 | if (s->stack_ptr <= 0) |
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63 | return 0; |
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64 | return s->stack[--s->stack_ptr]; |
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65 | } |
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66 | |||
67 | static int webvtt_stack_find(WebVTTContext *s, const char c) |
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68 | { |
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69 | int i; |
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70 | for (i = s->stack_ptr-1; i >= 0; i--) |
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71 | if (s->stack[i] == c) |
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72 | break; |
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73 | return i; |
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74 | } |
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75 | |||
76 | static void webvtt_close_tag(WebVTTContext *s, char tag) |
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77 | { |
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78 | webvtt_print(s, "%c>", tag); |
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79 | } |
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80 | |||
81 | static void webvtt_stack_push_pop(WebVTTContext *s, const char c, int close) |
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82 | { |
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83 | if (close) { |
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84 | int i = c ? webvtt_stack_find(s, c) : 0; |
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85 | if (i < 0) |
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86 | return; |
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87 | while (s->stack_ptr != i) |
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88 | webvtt_close_tag(s, webvtt_stack_pop(s)); |
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89 | } else if (webvtt_stack_push(s, c) < 0) |
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90 | av_log(s->avctx, AV_LOG_ERROR, "tag stack overflow\n"); |
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91 | } |
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92 | |||
93 | static void webvtt_style_apply(WebVTTContext *s, const char *style) |
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94 | { |
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95 | ASSStyle *st = ff_ass_style_get(s->ass_ctx, style); |
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96 | if (st) { |
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97 | if (st->bold != ASS_DEFAULT_BOLD) { |
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98 | webvtt_print(s, ""); |
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99 | webvtt_stack_push(s, 'b'); |
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100 | } |
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101 | if (st->italic != ASS_DEFAULT_ITALIC) { |
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102 | webvtt_print(s, ""); |
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103 | webvtt_stack_push(s, 'i'); |
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104 | } |
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105 | if (st->underline != ASS_DEFAULT_UNDERLINE) { |
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106 | webvtt_print(s, ""); |
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107 | webvtt_stack_push(s, 'u'); |
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108 | } |
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109 | } |
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110 | } |
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111 | |||
112 | static void webvtt_text_cb(void *priv, const char *text, int len) |
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113 | { |
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114 | WebVTTContext *s = priv; |
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115 | av_bprint_append_data(&s->buffer, text, len); |
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116 | } |
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117 | |||
118 | static void webvtt_new_line_cb(void *priv, int forced) |
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119 | { |
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120 | webvtt_print(priv, "\n"); |
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121 | } |
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122 | |||
123 | static void webvtt_style_cb(void *priv, char style, int close) |
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124 | { |
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125 | if (style == 's') // strikethrough unsupported |
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126 | return; |
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127 | |||
128 | webvtt_stack_push_pop(priv, style, close); |
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129 | if (!close) |
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130 | webvtt_print(priv, "<%c>", style); |
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131 | } |
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132 | |||
133 | static void webvtt_cancel_overrides_cb(void *priv, const char *style) |
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134 | { |
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135 | webvtt_stack_push_pop(priv, 0, 1); |
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136 | webvtt_style_apply(priv, style); |
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137 | } |
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138 | |||
139 | static void webvtt_end_cb(void *priv) |
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140 | { |
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141 | webvtt_stack_push_pop(priv, 0, 1); |
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142 | } |
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143 | |||
144 | static const ASSCodesCallbacks webvtt_callbacks = { |
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145 | .text = webvtt_text_cb, |
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146 | .new_line = webvtt_new_line_cb, |
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147 | .style = webvtt_style_cb, |
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148 | .color = NULL, |
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149 | .font_name = NULL, |
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150 | .font_size = NULL, |
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151 | .alignment = NULL, |
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152 | .cancel_overrides = webvtt_cancel_overrides_cb, |
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153 | .move = NULL, |
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154 | .end = webvtt_end_cb, |
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155 | }; |
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156 | |||
157 | static int webvtt_encode_frame(AVCodecContext *avctx, |
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158 | unsigned char *buf, int bufsize, const AVSubtitle *sub) |
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159 | { |
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160 | WebVTTContext *s = avctx->priv_data; |
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161 | ASSDialog *dialog; |
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162 | int i, num; |
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163 | |||
164 | av_bprint_clear(&s->buffer); |
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165 | |||
166 | for (i=0; i |
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167 | if (sub->rects[i]->type != SUBTITLE_ASS) { |
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168 | av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n"); |
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169 | return AVERROR(ENOSYS); |
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170 | } |
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171 | |||
172 | dialog = ff_ass_split_dialog(s->ass_ctx, sub->rects[i]->ass, 0, &num); |
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173 | for (; dialog && num--; dialog++) { |
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174 | webvtt_style_apply(s, dialog->style); |
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175 | ff_ass_split_override_codes(&webvtt_callbacks, s, dialog->text); |
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176 | } |
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177 | } |
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178 | |||
179 | if (!av_bprint_is_complete(&s->buffer)) |
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180 | return AVERROR(ENOMEM); |
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181 | if (!s->buffer.len) |
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182 | return 0; |
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183 | |||
184 | if (s->buffer.len > bufsize) { |
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185 | av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n"); |
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186 | return -1; |
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187 | } |
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188 | memcpy(buf, s->buffer.str, s->buffer.len); |
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189 | |||
190 | return s->buffer.len; |
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191 | } |
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192 | |||
193 | static int webvtt_encode_close(AVCodecContext *avctx) |
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194 | { |
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195 | WebVTTContext *s = avctx->priv_data; |
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196 | ff_ass_split_free(s->ass_ctx); |
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197 | av_bprint_finalize(&s->buffer, NULL); |
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198 | return 0; |
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199 | } |
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200 | |||
201 | static av_cold int webvtt_encode_init(AVCodecContext *avctx) |
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202 | { |
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203 | WebVTTContext *s = avctx->priv_data; |
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204 | s->avctx = avctx; |
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205 | s->ass_ctx = ff_ass_split(avctx->subtitle_header); |
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206 | av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED); |
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207 | return s->ass_ctx ? 0 : AVERROR_INVALIDDATA; |
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208 | } |
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209 | |||
210 | AVCodec ff_webvtt_encoder = { |
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211 | .name = "webvtt", |
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212 | .long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"), |
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213 | .type = AVMEDIA_TYPE_SUBTITLE, |
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214 | .id = AV_CODEC_ID_WEBVTT, |
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215 | .priv_data_size = sizeof(WebVTTContext), |
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216 | .init = webvtt_encode_init, |
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217 | .encode_sub = webvtt_encode_frame, |
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218 | .close = webvtt_encode_close, |
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219 | };%c>>>=> |