• Main Page
  • Related Pages
  • Modules
  • Data Structures
  • Files
  • Examples
  • File List
  • Globals

libavcodec/srtenc.c

Go to the documentation of this file.
00001 /*
00002  * SubRip subtitle encoder
00003  * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include <stdarg.h>
00023 #include "avcodec.h"
00024 #include "libavutil/avstring.h"
00025 #include "ass_split.h"
00026 #include "ass.h"
00027 
00028 
00029 #define SRT_STACK_SIZE 64
00030 
00031 typedef struct {
00032     AVCodecContext *avctx;
00033     ASSSplitContext *ass_ctx;
00034     char buffer[2048];
00035     char *ptr;
00036     char *end;
00037     char *dialog_start;
00038     int count;
00039     char stack[SRT_STACK_SIZE];
00040     int stack_ptr;
00041     int alignment_applied;
00042 } SRTContext;
00043 
00044 
00045 #ifdef __GNUC__
00046 __attribute__ ((__format__ (__printf__, 2, 3)))
00047 #endif
00048 static void srt_print(SRTContext *s, const char *str, ...)
00049 {
00050     va_list vargs;
00051     va_start(vargs, str);
00052     s->ptr += vsnprintf(s->ptr, s->end - s->ptr, str, vargs);
00053     va_end(vargs);
00054 }
00055 
00056 static int srt_stack_push(SRTContext *s, const char c)
00057 {
00058     if (s->stack_ptr >= SRT_STACK_SIZE)
00059         return -1;
00060     s->stack[s->stack_ptr++] = c;
00061     return 0;
00062 }
00063 
00064 static char srt_stack_pop(SRTContext *s)
00065 {
00066     if (s->stack_ptr <= 0)
00067         return 0;
00068     return s->stack[--s->stack_ptr];
00069 }
00070 
00071 static int srt_stack_find(SRTContext *s, const char c)
00072 {
00073     int i;
00074     for (i = s->stack_ptr-1; i >= 0; i--)
00075         if (s->stack[i] == c)
00076             break;
00077     return i;
00078 }
00079 
00080 static void srt_close_tag(SRTContext *s, char tag)
00081 {
00082     srt_print(s, "</%c%s>", tag, tag == 'f' ? "ont" : "");
00083 }
00084 
00085 static void srt_stack_push_pop(SRTContext *s, const char c, int close)
00086 {
00087     if (close) {
00088         int i = c ? srt_stack_find(s, c) : 0;
00089         if (i < 0)
00090             return;
00091         while (s->stack_ptr != i)
00092             srt_close_tag(s, srt_stack_pop(s));
00093     } else if (srt_stack_push(s, c) < 0)
00094         av_log(s->avctx, AV_LOG_ERROR, "tag stack overflow\n");
00095 }
00096 
00097 static void srt_style_apply(SRTContext *s, const char *style)
00098 {
00099     ASSStyle *st = ass_style_get(s->ass_ctx, style);
00100     if (st) {
00101         int c = st->primary_color & 0xFFFFFF;
00102         if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT) ||
00103             st->font_size != ASS_DEFAULT_FONT_SIZE ||
00104             c != ASS_DEFAULT_COLOR) {
00105             srt_print(s, "<font");
00106             if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT))
00107                 srt_print(s, " face=\"%s\"", st->font_name);
00108             if (st->font_size != ASS_DEFAULT_FONT_SIZE)
00109                 srt_print(s, " size=\"%d\"", st->font_size);
00110             if (c != ASS_DEFAULT_COLOR)
00111                 srt_print(s, " color=\"#%06x\"",
00112                           (c & 0xFF0000) >> 16 | c & 0xFF00 | (c & 0xFF) << 16);
00113             srt_print(s, ">");
00114             srt_stack_push(s, 'f');
00115         }
00116         if (st->bold != ASS_DEFAULT_BOLD) {
00117             srt_print(s, "<b>");
00118             srt_stack_push(s, 'b');
00119         }
00120         if (st->italic != ASS_DEFAULT_ITALIC) {
00121             srt_print(s, "<i>");
00122             srt_stack_push(s, 'i');
00123         }
00124         if (st->underline != ASS_DEFAULT_UNDERLINE) {
00125             srt_print(s, "<u>");
00126             srt_stack_push(s, 'u');
00127         }
00128         if (st->alignment != ASS_DEFAULT_ALIGNMENT) {
00129             srt_print(s, "{\\an%d}", st->alignment);
00130             s->alignment_applied = 1;
00131         }
00132     }
00133 }
00134 
00135 
00136 static av_cold int srt_encode_init(AVCodecContext *avctx)
00137 {
00138     SRTContext *s = avctx->priv_data;
00139     s->avctx = avctx;
00140     s->ass_ctx = ff_ass_split(avctx->subtitle_header);
00141     return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
00142 }
00143 
00144 static void srt_text_cb(void *priv, const char *text, int len)
00145 {
00146     SRTContext *s = priv;
00147     av_strlcpy(s->ptr, text, FFMIN(s->end-s->ptr, len+1));
00148     s->ptr += len;
00149 }
00150 
00151 static void srt_new_line_cb(void *priv, int forced)
00152 {
00153     srt_print(priv, "\r\n");
00154 }
00155 
00156 static void srt_style_cb(void *priv, char style, int close)
00157 {
00158     srt_stack_push_pop(priv, style, close);
00159     if (!close)
00160         srt_print(priv, "<%c>", style);
00161 }
00162 
00163 static void srt_color_cb(void *priv, unsigned int color, unsigned int color_id)
00164 {
00165     if (color_id > 1)
00166         return;
00167     srt_stack_push_pop(priv, 'f', color == 0xFFFFFFFF);
00168     if (color != 0xFFFFFFFF)
00169         srt_print(priv, "<font color=\"#%06x\">",
00170               (color & 0xFF0000) >> 16 | color & 0xFF00 | (color & 0xFF) << 16);
00171 }
00172 
00173 static void srt_font_name_cb(void *priv, const char *name)
00174 {
00175     srt_stack_push_pop(priv, 'f', !name);
00176     if (name)
00177         srt_print(priv, "<font face=\"%s\">", name);
00178 }
00179 
00180 static void srt_font_size_cb(void *priv, int size)
00181 {
00182     srt_stack_push_pop(priv, 'f', size < 0);
00183     if (size >= 0)
00184         srt_print(priv, "<font size=\"%d\">", size);
00185 }
00186 
00187 static void srt_alignment_cb(void *priv, int alignment)
00188 {
00189     SRTContext *s = priv;
00190     if (!s->alignment_applied && alignment >= 0) {
00191         srt_print(s, "{\\an%d}", alignment);
00192         s->alignment_applied = 1;
00193     }
00194 }
00195 
00196 static void srt_cancel_overrides_cb(void *priv, const char *style)
00197 {
00198     srt_stack_push_pop(priv, 0, 1);
00199     srt_style_apply(priv, style);
00200 }
00201 
00202 static void srt_move_cb(void *priv, int x1, int y1, int x2, int y2,
00203                         int t1, int t2)
00204 {
00205     SRTContext *s = priv;
00206     char buffer[32];
00207     int len = snprintf(buffer, sizeof(buffer),
00208                        "  X1:%03u X2:%03u Y1:%03u Y2:%03u", x1, x2, y1, y2);
00209     if (s->end - s->ptr > len) {
00210         memmove(s->dialog_start+len, s->dialog_start, s->ptr-s->dialog_start+1);
00211         memcpy(s->dialog_start, buffer, len);
00212         s->ptr += len;
00213     }
00214 }
00215 
00216 static void srt_end_cb(void *priv)
00217 {
00218     srt_stack_push_pop(priv, 0, 1);
00219     srt_print(priv, "\r\n\r\n");
00220 }
00221 
00222 static const ASSCodesCallbacks srt_callbacks = {
00223     .text             = srt_text_cb,
00224     .new_line         = srt_new_line_cb,
00225     .style            = srt_style_cb,
00226     .color            = srt_color_cb,
00227     .font_name        = srt_font_name_cb,
00228     .font_size        = srt_font_size_cb,
00229     .alignment        = srt_alignment_cb,
00230     .cancel_overrides = srt_cancel_overrides_cb,
00231     .move             = srt_move_cb,
00232     .end              = srt_end_cb,
00233 };
00234 
00235 static int srt_encode_frame(AVCodecContext *avctx,
00236                             unsigned char *buf, int bufsize, void *data)
00237 {
00238     SRTContext *s = avctx->priv_data;
00239     AVSubtitle *sub = data;
00240     ASSDialog *dialog;
00241     int i, len, num;
00242 
00243     s->ptr = s->buffer;
00244     s->end = s->ptr + sizeof(s->buffer);
00245 
00246     for (i=0; i<sub->num_rects; i++) {
00247 
00248         if (sub->rects[i]->type != SUBTITLE_ASS) {
00249             av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
00250             return AVERROR(ENOSYS);
00251         }
00252 
00253         dialog = ff_ass_split_dialog(s->ass_ctx, sub->rects[i]->ass, 0, &num);
00254         for (; dialog && num--; dialog++) {
00255             int sh, sm, ss, sc = 10 * dialog->start;
00256             int eh, em, es, ec = 10 * dialog->end;
00257             sh = sc/3600000;  sc -= 3600000*sh;
00258             sm = sc/  60000;  sc -=   60000*sm;
00259             ss = sc/   1000;  sc -=    1000*ss;
00260             eh = ec/3600000;  ec -= 3600000*eh;
00261             em = ec/  60000;  ec -=   60000*em;
00262             es = ec/   1000;  ec -=    1000*es;
00263             srt_print(s,"%d\r\n%02d:%02d:%02d,%03d --> %02d:%02d:%02d,%03d\r\n",
00264                       ++s->count, sh, sm, ss, sc, eh, em, es, ec);
00265             s->alignment_applied = 0;
00266             s->dialog_start = s->ptr - 2;
00267             srt_style_apply(s, dialog->style);
00268             ff_ass_split_override_codes(&srt_callbacks, s, dialog->text);
00269         }
00270     }
00271 
00272     if (s->ptr == s->buffer)
00273         return 0;
00274 
00275     len = av_strlcpy(buf, s->buffer, bufsize);
00276 
00277     if (len > bufsize-1) {
00278         av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
00279         return -1;
00280     }
00281 
00282     return len;
00283 }
00284 
00285 static int srt_encode_close(AVCodecContext *avctx)
00286 {
00287     SRTContext *s = avctx->priv_data;
00288     ff_ass_split_free(s->ass_ctx);
00289     return 0;
00290 }
00291 
00292 AVCodec ff_srt_encoder = {
00293     .name           = "srt",
00294     .long_name      = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
00295     .type           = AVMEDIA_TYPE_SUBTITLE,
00296     .id             = CODEC_ID_SRT,
00297     .priv_data_size = sizeof(SRTContext),
00298     .init           = srt_encode_init,
00299     .encode         = srt_encode_frame,
00300     .close          = srt_encode_close,
00301 };

Generated on Fri Feb 22 2013 07:24:28 for FFmpeg by  doxygen 1.7.1