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5c219e289e
The positioning was completely wrong. First, the coordinates are expressed in ASS playback resolution (which is by default 384x288). Secondly, the coordinates define a drawing rectangle, not a moving area. The previous code was making subtitles move from a random position to another random position. Here we rescale assuming the video resolution is a DVD one (720x480). We can't really do anything better so far, but since this positioning information is often from a DVD rip we can consider them relatively safe.
262 lines
10 KiB
C
262 lines
10 KiB
C
/*
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* SubRip subtitle decoder
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* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/avstring.h"
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#include "libavutil/common.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/parseutils.h"
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#include "avcodec.h"
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#include "ass.h"
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static int html_color_parse(AVCodecContext *avctx, const char *str)
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{
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uint8_t rgba[4];
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if (av_parse_color(rgba, str, strcspn(str, "\" >"), avctx) < 0)
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return -1;
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return rgba[0] | rgba[1] << 8 | rgba[2] << 16;
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}
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enum {
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PARAM_UNKNOWN = -1,
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PARAM_SIZE,
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PARAM_COLOR,
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PARAM_FACE,
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PARAM_NUMBER
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};
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typedef struct SrtStack {
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char tag[128];
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char param[PARAM_NUMBER][128];
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} SrtStack;
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static void rstrip_spaces_buf(AVBPrint *buf)
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{
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while (buf->len > 0 && buf->str[buf->len - 1] == ' ')
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buf->str[--buf->len] = 0;
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}
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static void srt_to_ass(AVCodecContext *avctx, AVBPrint *dst,
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const char *in, int x1, int y1, int x2, int y2)
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{
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char *param, buffer[128], tmp[128];
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int len, tag_close, sptr = 1, line_start = 1, an = 0, end = 0;
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SrtStack stack[16];
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stack[0].tag[0] = 0;
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strcpy(stack[0].param[PARAM_SIZE], "{\\fs}");
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strcpy(stack[0].param[PARAM_COLOR], "{\\c}");
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strcpy(stack[0].param[PARAM_FACE], "{\\fn}");
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if (x1 >= 0 && y1 >= 0) {
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/* XXX: here we rescale coordinate assuming they are in DVD resolution
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* (720x480) since we don't have anything better */
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if (x2 >= 0 && y2 >= 0 && (x2 != x1 || y2 != y1) && x2 >= x1 && y2 >= y1) {
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/* text rectangle defined, write the text at the center of the rectangle */
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const int cx = x1 + (x2 - x1)/2;
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const int cy = y1 + (y2 - y1)/2;
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const int scaled_x = cx * ASS_DEFAULT_PLAYRESX / 720;
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const int scaled_y = cy * ASS_DEFAULT_PLAYRESY / 480;
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av_bprintf(dst, "{\\an5}{\\pos(%d,%d)}", scaled_x, scaled_y);
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} else {
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/* only the top left corner, assume the text starts in that corner */
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const int scaled_x = x1 * ASS_DEFAULT_PLAYRESX / 720;
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const int scaled_y = y1 * ASS_DEFAULT_PLAYRESY / 480;
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av_bprintf(dst, "{\\an1}{\\pos(%d,%d)}", scaled_x, scaled_y);
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}
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}
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for (; !end && *in; in++) {
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switch (*in) {
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case '\r':
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break;
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case '\n':
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if (line_start) {
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end = 1;
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break;
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}
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rstrip_spaces_buf(dst);
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av_bprintf(dst, "\\N");
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line_start = 1;
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break;
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case ' ':
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if (!line_start)
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av_bprint_chars(dst, *in, 1);
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break;
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case '{': /* skip all {\xxx} substrings except for {\an%d}
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and all microdvd like styles such as {Y:xxx} */
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len = 0;
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an += sscanf(in, "{\\an%*1u}%n", &len) >= 0 && len > 0;
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if ((an != 1 && (len = 0, sscanf(in, "{\\%*[^}]}%n", &len) >= 0 && len > 0)) ||
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(len = 0, sscanf(in, "{%*1[CcFfoPSsYy]:%*[^}]}%n", &len) >= 0 && len > 0)) {
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in += len - 1;
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} else
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av_bprint_chars(dst, *in, 1);
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break;
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case '<':
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tag_close = in[1] == '/';
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len = 0;
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if (sscanf(in+tag_close+1, "%127[^>]>%n", buffer, &len) >= 1 && len > 0) {
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if ((param = strchr(buffer, ' ')))
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*param++ = 0;
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if ((!tag_close && sptr < FF_ARRAY_ELEMS(stack)) ||
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( tag_close && sptr > 0 && !strcmp(stack[sptr-1].tag, buffer))) {
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int i, j, unknown = 0;
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in += len + tag_close;
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if (!tag_close)
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memset(stack+sptr, 0, sizeof(*stack));
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if (!strcmp(buffer, "font")) {
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if (tag_close) {
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for (i=PARAM_NUMBER-1; i>=0; i--)
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if (stack[sptr-1].param[i][0])
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for (j=sptr-2; j>=0; j--)
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if (stack[j].param[i][0]) {
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av_bprintf(dst, "%s", stack[j].param[i]);
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break;
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}
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} else {
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while (param) {
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if (!strncmp(param, "size=", 5)) {
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unsigned font_size;
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param += 5 + (param[5] == '"');
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if (sscanf(param, "%u", &font_size) == 1) {
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snprintf(stack[sptr].param[PARAM_SIZE],
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sizeof(stack[0].param[PARAM_SIZE]),
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"{\\fs%u}", font_size);
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}
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} else if (!strncmp(param, "color=", 6)) {
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param += 6 + (param[6] == '"');
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snprintf(stack[sptr].param[PARAM_COLOR],
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sizeof(stack[0].param[PARAM_COLOR]),
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"{\\c&H%X&}",
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html_color_parse(avctx, param));
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} else if (!strncmp(param, "face=", 5)) {
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param += 5 + (param[5] == '"');
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len = strcspn(param,
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param[-1] == '"' ? "\"" :" ");
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av_strlcpy(tmp, param,
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FFMIN(sizeof(tmp), len+1));
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param += len;
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snprintf(stack[sptr].param[PARAM_FACE],
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sizeof(stack[0].param[PARAM_FACE]),
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"{\\fn%s}", tmp);
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}
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if ((param = strchr(param, ' ')))
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param++;
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}
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for (i=0; i<PARAM_NUMBER; i++)
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if (stack[sptr].param[i][0])
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av_bprintf(dst, "%s", stack[sptr].param[i]);
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}
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} else if (!buffer[1] && strspn(buffer, "bisu") == 1) {
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av_bprintf(dst, "{\\%c%d}", buffer[0], !tag_close);
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} else {
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unknown = 1;
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snprintf(tmp, sizeof(tmp), "</%s>", buffer);
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}
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if (tag_close) {
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sptr--;
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} else if (unknown && !strstr(in, tmp)) {
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in -= len + tag_close;
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av_bprint_chars(dst, *in, 1);
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} else
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av_strlcpy(stack[sptr++].tag, buffer,
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sizeof(stack[0].tag));
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break;
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}
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}
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default:
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av_bprint_chars(dst, *in, 1);
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break;
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}
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if (*in != ' ' && *in != '\r' && *in != '\n')
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line_start = 0;
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}
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while (dst->len >= 2 && !strncmp(&dst->str[dst->len - 2], "\\N", 2))
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dst->len -= 2;
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dst->str[dst->len] = 0;
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rstrip_spaces_buf(dst);
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}
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static int srt_decode_frame(AVCodecContext *avctx,
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void *data, int *got_sub_ptr, AVPacket *avpkt)
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{
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AVSubtitle *sub = data;
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AVBPrint buffer;
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int ts_start, ts_end, x1 = -1, y1 = -1, x2 = -1, y2 = -1;
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int size, ret;
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const uint8_t *p = av_packet_get_side_data(avpkt, AV_PKT_DATA_SUBTITLE_POSITION, &size);
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if (p && size == 16) {
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x1 = AV_RL32(p );
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y1 = AV_RL32(p + 4);
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x2 = AV_RL32(p + 8);
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y2 = AV_RL32(p + 12);
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}
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if (avpkt->size <= 0)
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return avpkt->size;
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av_bprint_init(&buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
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// TODO: reindent
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// Do final divide-by-10 outside rescale to force rounding down.
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ts_start = av_rescale_q(avpkt->pts,
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avctx->time_base,
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(AVRational){1,100});
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ts_end = av_rescale_q(avpkt->pts + avpkt->duration,
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avctx->time_base,
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(AVRational){1,100});
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srt_to_ass(avctx, &buffer, avpkt->data, x1, y1, x2, y2);
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ret = ff_ass_add_rect_bprint(sub, &buffer, ts_start, ts_end-ts_start);
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av_bprint_finalize(&buffer, NULL);
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if (ret < 0)
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return ret;
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*got_sub_ptr = sub->num_rects > 0;
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return avpkt->size;
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}
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#if CONFIG_SRT_DECODER
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/* deprecated decoder */
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AVCodec ff_srt_decoder = {
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.name = "srt",
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.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
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.type = AVMEDIA_TYPE_SUBTITLE,
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.id = AV_CODEC_ID_SUBRIP,
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.init = ff_ass_subtitle_header_default,
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.decode = srt_decode_frame,
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};
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#endif
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#if CONFIG_SUBRIP_DECODER
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AVCodec ff_subrip_decoder = {
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.name = "subrip",
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.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
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.type = AVMEDIA_TYPE_SUBTITLE,
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.id = AV_CODEC_ID_SUBRIP,
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.init = ff_ass_subtitle_header_default,
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.decode = srt_decode_frame,
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};
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#endif
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