FFmpeg
ass.c
Go to the documentation of this file.
1 /*
2  * SSA/ASS common functions
3  * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.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 "avcodec.h"
23 #include "ass.h"
24 #include "libavutil/avassert.h"
25 #include "libavutil/avstring.h"
26 #include "libavutil/bprint.h"
27 #include "libavutil/common.h"
28 
30  int play_res_x, int play_res_y,
31  const char *font, int font_size,
32  int primary_color, int secondary_color,
33  int outline_color, int back_color,
34  int bold, int italic, int underline,
35  int border_style, int alignment)
36 {
38  "[Script Info]\r\n"
39  "; Script generated by FFmpeg/Lavc%s\r\n"
40  "ScriptType: v4.00+\r\n"
41  "PlayResX: %d\r\n"
42  "PlayResY: %d\r\n"
43  "ScaledBorderAndShadow: yes\r\n"
44  "\r\n"
45  "[V4+ Styles]\r\n"
46 
47  /* ASSv4 header */
48  "Format: Name, "
49  "Fontname, Fontsize, "
50  "PrimaryColour, SecondaryColour, OutlineColour, BackColour, "
51  "Bold, Italic, Underline, StrikeOut, "
52  "ScaleX, ScaleY, "
53  "Spacing, Angle, "
54  "BorderStyle, Outline, Shadow, "
55  "Alignment, MarginL, MarginR, MarginV, "
56  "Encoding\r\n"
57 
58  "Style: "
59  "Default," /* Name */
60  "%s,%d," /* Font{name,size} */
61  "&H%x,&H%x,&H%x,&H%x," /* {Primary,Secondary,Outline,Back}Colour */
62  "%d,%d,%d,0," /* Bold, Italic, Underline, StrikeOut */
63  "100,100," /* Scale{X,Y} */
64  "0,0," /* Spacing, Angle */
65  "%d,1,0," /* BorderStyle, Outline, Shadow */
66  "%d,10,10,10," /* Alignment, Margin[LRV] */
67  "0\r\n" /* Encoding */
68 
69  "\r\n"
70  "[Events]\r\n"
71  "Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\r\n",
73  play_res_x, play_res_y, font, font_size,
74  primary_color, secondary_color, outline_color, back_color,
75  -bold, -italic, -underline, border_style, alignment);
76 
77  if (!avctx->subtitle_header)
78  return AVERROR(ENOMEM);
79  avctx->subtitle_header_size = strlen(avctx->subtitle_header);
80  return 0;
81 }
82 
84  const char *font, int font_size,
85  int color, int back_color,
86  int bold, int italic, int underline,
87  int border_style, int alignment)
88 {
89  return ff_ass_subtitle_header_full(avctx,
91  font, font_size, color, color,
92  back_color, back_color,
93  bold, italic, underline,
94  border_style, alignment);
95 }
96 
98 {
108 }
109 
110 char *ff_ass_get_dialog(int readorder, int layer, const char *style,
111  const char *speaker, const char *text)
112 {
113  return av_asprintf("%d,%d,%s,%s,0,0,0,,%s",
114  readorder, layer, style ? style : "Default",
115  speaker ? speaker : "", text);
116 }
117 
118 int ff_ass_add_rect(AVSubtitle *sub, const char *dialog,
119  int readorder, int layer, const char *style,
120  const char *speaker)
121 {
122  char *ass_str;
123  AVSubtitleRect **rects;
124 
125  rects = av_realloc_array(sub->rects, sub->num_rects+1, sizeof(*sub->rects));
126  if (!rects)
127  return AVERROR(ENOMEM);
128  sub->rects = rects;
129  rects[sub->num_rects] = av_mallocz(sizeof(*rects[0]));
130  if (!rects[sub->num_rects])
131  return AVERROR(ENOMEM);
132  rects[sub->num_rects]->type = SUBTITLE_ASS;
133  ass_str = ff_ass_get_dialog(readorder, layer, style, speaker, dialog);
134  if (!ass_str)
135  return AVERROR(ENOMEM);
136  rects[sub->num_rects]->ass = ass_str;
137  sub->num_rects++;
138  return 0;
139 }
140 
142 {
143  FFASSDecoderContext *s = avctx->priv_data;
144  if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
145  s->readorder = 0;
146 }
147 
148 void ff_ass_bprint_text_event(AVBPrint *buf, const char *p, int size,
149  const char *linebreaks, int keep_ass_markup)
150 {
151  const char *p_end = p + size;
152 
153  for (; p < p_end && *p; p++) {
154 
155  /* forced custom line breaks, not accounted as "normal" EOL */
156  if (linebreaks && strchr(linebreaks, *p)) {
157  av_bprintf(buf, "\\N");
158 
159  /* standard ASS escaping so random characters don't get mis-interpreted
160  * as ASS */
161  } else if (!keep_ass_markup && strchr("{}\\", *p)) {
162  av_bprintf(buf, "\\%c", *p);
163 
164  /* some packets might end abruptly (no \0 at the end, like for example
165  * in some cases of demuxing from a classic video container), some
166  * might be terminated with \n or \r\n which we have to remove (for
167  * consistency with those who haven't), and we also have to deal with
168  * evil cases such as \r at the end of the buffer (and no \0 terminated
169  * character) */
170  } else if (p[0] == '\n') {
171  /* some stuff left so we can insert a line break */
172  if (p < p_end - 1)
173  av_bprintf(buf, "\\N");
174  } else if (p[0] == '\r' && p < p_end - 1 && p[1] == '\n') {
175  /* \r followed by a \n, we can skip it. We don't insert the \N yet
176  * because we don't know if it is followed by more text */
177  continue;
178 
179  /* finally, a sane character */
180  } else {
181  av_bprint_chars(buf, *p, 1);
182  }
183  }
184 }
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:94
#define ASS_DEFAULT_BORDERSTYLE
Definition: ass.h:43
int ff_ass_subtitle_header(AVCodecContext *avctx, const char *font, int font_size, int color, int back_color, int bold, int italic, int underline, int border_style, int alignment)
Generate a suitable AVCodecContext.subtitle_header for SUBTITLE_ASS.
Definition: ass.c:83
unsigned num_rects
Definition: avcodec.h:2698
int ff_ass_add_rect(AVSubtitle *sub, const char *dialog, int readorder, int layer, const char *style, const char *speaker)
Add an ASS dialog to a subtitle.
Definition: ass.c:118
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:237
AVSubtitleRect ** rects
Definition: avcodec.h:2699
#define ASS_DEFAULT_ALIGNMENT
Definition: ass.h:42
int subtitle_header_size
Definition: avcodec.h:2015
int ff_ass_subtitle_header_full(AVCodecContext *avctx, int play_res_x, int play_res_y, const char *font, int font_size, int primary_color, int secondary_color, int outline_color, int back_color, int bold, int italic, int underline, int border_style, int alignment)
Generate a suitable AVCodecContext.subtitle_header for SUBTITLE_ASS.
Definition: ass.c:29
int ff_ass_subtitle_header_default(AVCodecContext *avctx)
Generate a suitable AVCodecContext.subtitle_header for SUBTITLE_ASS with default style.
Definition: ass.c:97
ptrdiff_t size
Definition: opengl_enc.c:100
#define AV_CODEC_FLAG2_RO_FLUSH_NOOP
Do not reset ASS ReadOrder field on flush (subtitles decoding)
Definition: avcodec.h:388
void * av_realloc_array(void *ptr, size_t nmemb, size_t size)
Definition: mem.c:198
#define ASS_DEFAULT_PLAYRESY
Definition: ass.h:29
#define ASS_DEFAULT_BACK_COLOR
Definition: ass.h:38
#define ASS_DEFAULT_UNDERLINE
Definition: ass.h:41
char * ff_ass_get_dialog(int readorder, int layer, const char *style, const char *speaker, const char *text)
Craft an ASS dialog string.
Definition: ass.c:110
#define ASS_DEFAULT_FONT
Definition: ass.h:35
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:606
simple assert() macros that are a bit more flexible than ISO C assert().
#define ASS_DEFAULT_FONT_SIZE
Definition: ass.h:36
char * av_asprintf(const char *fmt,...)
Definition: avstring.c:113
#define AV_CODEC_FLAG_BITEXACT
Use only bitexact stuff (except (I)DCT).
Definition: avcodec.h:333
#define s(width, name)
Definition: cbs_vp9.c:257
Libavcodec external API header.
main external API structure.
Definition: avcodec.h:526
#define AV_STRINGIFY(s)
Definition: macros.h:36
void ff_ass_decoder_flush(AVCodecContext *avctx)
Helper to flush a text subtitles decoder making use of the FFASSDecoderContext.
Definition: ass.c:141
#define LIBAVCODEC_VERSION
Definition: version.h:37
common internal and external API header
#define ASS_DEFAULT_COLOR
Definition: ass.h:37
void * priv_data
Definition: avcodec.h:553
Formatted text, the ass field must be set by the decoder and is authoritative.
Definition: avcodec.h:2654
#define ASS_DEFAULT_ITALIC
Definition: ass.h:40
void ff_ass_bprint_text_event(AVBPrint *buf, const char *p, int size, const char *linebreaks, int keep_ass_markup)
Escape a text subtitle using ASS syntax into an AVBPrint buffer.
Definition: ass.c:148
#define ASS_DEFAULT_BOLD
Definition: ass.h:39
char * ass
0 terminated ASS/SSA compatible event line.
Definition: avcodec.h:2689
int flags2
AV_CODEC_FLAG2_*.
Definition: avcodec.h:613
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
enum AVSubtitleType type
Definition: avcodec.h:2680
#define ASS_DEFAULT_PLAYRESX
Definition: ass.h:28
uint8_t * subtitle_header
Header containing style information for text subtitles.
Definition: avcodec.h:2014
void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
Append char c n times to a print buffer.
Definition: bprint.c:140