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4349 | Serge | 1 | /* |
2 | * DivX (XSUB) subtitle encoder |
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3 | * Copyright (c) 2005 DivX, Inc. |
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4 | * Copyright (c) 2009 Bjorn Axelsson |
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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 "avcodec.h" |
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24 | #include "bytestream.h" |
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25 | #include "put_bits.h" |
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26 | |||
27 | /** |
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28 | * Number of pixels to pad left and right. |
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29 | * |
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30 | * The official encoder pads the subtitles with two pixels on either side, |
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31 | * but until we find out why, we won't do it (we will pad to have width |
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32 | * divisible by 2 though). |
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33 | */ |
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34 | #define PADDING 0 |
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35 | #define PADDING_COLOR 0 |
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36 | |||
37 | /** |
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38 | * Encode a single color run. At most 16 bits will be used. |
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39 | * @param len length of the run, values > 255 mean "until end of line", may not be < 0. |
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40 | * @param color color to encode, only the lowest two bits are used and all others must be 0. |
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41 | */ |
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42 | static void put_xsub_rle(PutBitContext *pb, int len, int color) |
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43 | { |
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44 | if (len <= 255) |
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45 | put_bits(pb, 2 + ((ff_log2_tab[len] >> 1) << 2), len); |
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46 | else |
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47 | put_bits(pb, 14, 0); |
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48 | put_bits(pb, 2, color); |
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49 | } |
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50 | |||
51 | /** |
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52 | * Encode a 4-color bitmap with XSUB rle. |
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53 | * |
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54 | * The encoded bitmap may be wider than the source bitmap due to padding. |
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55 | */ |
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56 | static int xsub_encode_rle(PutBitContext *pb, const uint8_t *bitmap, |
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57 | int linesize, int w, int h) |
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58 | { |
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59 | int x0, x1, y, len, color = PADDING_COLOR; |
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60 | |||
61 | for (y = 0; y < h; y++) { |
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62 | x0 = 0; |
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63 | while (x0 < w) { |
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64 | // Make sure we have enough room for at least one run and padding |
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65 | if (pb->size_in_bits - put_bits_count(pb) < 7*8) |
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66 | return -1; |
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67 | |||
68 | x1 = x0; |
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69 | color = bitmap[x1++] & 3; |
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70 | while (x1 < w && (bitmap[x1] & 3) == color) |
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71 | x1++; |
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72 | len = x1 - x0; |
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73 | if (PADDING && x0 == 0) { |
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74 | if (color == PADDING_COLOR) { |
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75 | len += PADDING; |
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76 | x0 -= PADDING; |
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77 | } else |
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78 | put_xsub_rle(pb, PADDING, PADDING_COLOR); |
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79 | } |
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80 | |||
81 | // Run can't be longer than 255, unless it is the rest of a row |
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82 | if (x1 == w && color == PADDING_COLOR) { |
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83 | len += PADDING + (w&1); |
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84 | } else |
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85 | len = FFMIN(len, 255); |
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86 | put_xsub_rle(pb, len, color); |
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87 | |||
88 | x0 += len; |
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89 | } |
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90 | if (color != PADDING_COLOR && (PADDING + (w&1))) |
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91 | put_xsub_rle(pb, PADDING + (w&1), PADDING_COLOR); |
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92 | |||
93 | avpriv_align_put_bits(pb); |
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94 | |||
95 | bitmap += linesize; |
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96 | } |
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97 | |||
98 | return 0; |
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99 | } |
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100 | |||
101 | static int make_tc(uint64_t ms, int *tc) |
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102 | { |
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103 | static const int tc_divs[3] = { 1000, 60, 60 }; |
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104 | int i; |
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105 | for (i=0; i<3; i++) { |
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106 | tc[i] = ms % tc_divs[i]; |
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107 | ms /= tc_divs[i]; |
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108 | } |
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109 | tc[3] = ms; |
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110 | return ms > 99; |
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111 | } |
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112 | |||
113 | static int xsub_encode(AVCodecContext *avctx, unsigned char *buf, |
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114 | int bufsize, const AVSubtitle *h) |
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115 | { |
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116 | uint64_t startTime = h->pts / 1000; // FIXME: need better solution... |
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117 | uint64_t endTime = startTime + h->end_display_time - h->start_display_time; |
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118 | int start_tc[4], end_tc[4]; |
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119 | uint8_t *hdr = buf + 27; // Point behind the timestamp |
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120 | uint8_t *rlelenptr; |
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121 | uint16_t width, height; |
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122 | int i; |
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123 | PutBitContext pb; |
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124 | |||
125 | if (bufsize < 27 + 7*2 + 4*3) { |
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126 | av_log(avctx, AV_LOG_ERROR, "Buffer too small for XSUB header.\n"); |
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127 | return -1; |
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128 | } |
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129 | |||
130 | // TODO: support multiple rects |
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131 | if (h->num_rects != 1) |
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132 | av_log(avctx, AV_LOG_WARNING, "Only single rects supported (%d in subtitle.)\n", h->num_rects); |
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133 | |||
134 | // TODO: render text-based subtitles into bitmaps |
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135 | if (!h->rects[0]->pict.data[0] || !h->rects[0]->pict.data[1]) { |
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136 | av_log(avctx, AV_LOG_WARNING, "No subtitle bitmap available.\n"); |
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137 | return -1; |
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138 | } |
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139 | |||
140 | // TODO: color reduction, similar to dvdsub encoder |
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141 | if (h->rects[0]->nb_colors > 4) |
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142 | av_log(avctx, AV_LOG_WARNING, "No more than 4 subtitle colors supported (%d found.)\n", h->rects[0]->nb_colors); |
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143 | |||
144 | // TODO: Palette swapping if color zero is not transparent |
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145 | if (((uint32_t *)h->rects[0]->pict.data[1])[0] & 0xff) |
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146 | av_log(avctx, AV_LOG_WARNING, "Color index 0 is not transparent. Transparency will be messed up.\n"); |
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147 | |||
148 | if (make_tc(startTime, start_tc) || make_tc(endTime, end_tc)) { |
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149 | av_log(avctx, AV_LOG_WARNING, "Time code >= 100 hours.\n"); |
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150 | return -1; |
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151 | } |
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152 | |||
153 | snprintf(buf, 28, |
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154 | "[%02d:%02d:%02d.%03d-%02d:%02d:%02d.%03d]", |
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155 | start_tc[3], start_tc[2], start_tc[1], start_tc[0], |
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156 | end_tc[3], end_tc[2], end_tc[1], end_tc[0]); |
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157 | |||
158 | // Width and height must probably be multiples of 2. |
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159 | // 2 pixels required on either side of subtitle. |
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160 | // Possibly due to limitations of hardware renderers. |
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161 | // TODO: check if the bitmap is already padded |
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162 | width = FFALIGN(h->rects[0]->w, 2) + PADDING * 2; |
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163 | height = FFALIGN(h->rects[0]->h, 2); |
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164 | |||
165 | bytestream_put_le16(&hdr, width); |
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166 | bytestream_put_le16(&hdr, height); |
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167 | bytestream_put_le16(&hdr, h->rects[0]->x); |
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168 | bytestream_put_le16(&hdr, h->rects[0]->y); |
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169 | bytestream_put_le16(&hdr, h->rects[0]->x + width); |
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170 | bytestream_put_le16(&hdr, h->rects[0]->y + height); |
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171 | |||
172 | rlelenptr = hdr; // Will store length of first field here later. |
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173 | hdr+=2; |
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174 | |||
175 | // Palette |
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176 | for (i=0; i<4; i++) |
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177 | bytestream_put_be24(&hdr, ((uint32_t *)h->rects[0]->pict.data[1])[i]); |
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178 | |||
179 | // Bitmap |
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180 | // RLE buffer. Reserve 2 bytes for possible padding after the last row. |
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181 | init_put_bits(&pb, hdr, bufsize - (hdr - buf) - 2); |
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182 | if (xsub_encode_rle(&pb, h->rects[0]->pict.data[0], |
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183 | h->rects[0]->pict.linesize[0]*2, |
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184 | h->rects[0]->w, (h->rects[0]->h + 1) >> 1)) |
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185 | return -1; |
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186 | bytestream_put_le16(&rlelenptr, put_bits_count(&pb) >> 3); // Length of first field |
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187 | |||
188 | if (xsub_encode_rle(&pb, h->rects[0]->pict.data[0] + h->rects[0]->pict.linesize[0], |
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189 | h->rects[0]->pict.linesize[0]*2, |
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190 | h->rects[0]->w, h->rects[0]->h >> 1)) |
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191 | return -1; |
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192 | |||
193 | // Enforce total height to be a multiple of 2 |
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194 | if (h->rects[0]->h & 1) { |
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195 | put_xsub_rle(&pb, h->rects[0]->w, PADDING_COLOR); |
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196 | avpriv_align_put_bits(&pb); |
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197 | } |
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198 | |||
199 | flush_put_bits(&pb); |
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200 | |||
201 | return hdr - buf + put_bits_count(&pb)/8; |
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202 | } |
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203 | |||
204 | static av_cold int xsub_encoder_init(AVCodecContext *avctx) |
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205 | { |
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206 | if (!avctx->codec_tag) |
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207 | avctx->codec_tag = MKTAG('D','X','S','B'); |
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208 | |||
209 | return 0; |
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210 | } |
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211 | |||
212 | AVCodec ff_xsub_encoder = { |
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213 | .name = "xsub", |
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214 | .long_name = NULL_IF_CONFIG_SMALL("DivX subtitles (XSUB)"), |
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215 | .type = AVMEDIA_TYPE_SUBTITLE, |
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216 | .id = AV_CODEC_ID_XSUB, |
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217 | .init = xsub_encoder_init, |
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218 | .encode_sub = xsub_encode, |
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219 | };4;>>3;>>>>>><>=>> |