FFmpeg
ansi.c
Go to the documentation of this file.
1 /*
2  * ASCII/ANSI art decoder
3  * Copyright (c) 2010 Peter Ross <pross@xvid.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 /**
23  * @file
24  * ASCII/ANSI art decoder
25  */
26 
27 #include "libavutil/common.h"
28 #include "libavutil/frame.h"
29 #include "libavutil/lfg.h"
30 #include "libavutil/xga_font_data.h"
31 #include "avcodec.h"
32 #include "cga_data.h"
33 #include "internal.h"
34 
35 #define ATTR_BOLD 0x01 /**< Bold/Bright-foreground (mode 1) */
36 #define ATTR_FAINT 0x02 /**< Faint (mode 2) */
37 #define ATTR_ITALICS 0x04 /**< Italics (mode 3) */
38 #define ATTR_UNDERLINE 0x08 /**< Underline (mode 4) */
39 #define ATTR_BLINK 0x10 /**< Blink/Bright-background (mode 5) */
40 #define ATTR_REVERSE 0x40 /**< Reverse (mode 7) */
41 #define ATTR_CONCEALED 0x80 /**< Concealed (mode 8) */
42 
43 #define DEFAULT_FG_COLOR 7 /**< CGA color index */
44 #define DEFAULT_BG_COLOR 0
45 #define DEFAULT_SCREEN_MODE 3 /**< 80x25 */
46 
47 #define FONT_WIDTH 8 /**< Font width */
48 
49 /** map ansi color index to cga palette index */
50 static const uint8_t ansi_to_cga[16] = {
51  0, 4, 2, 6, 1, 5, 3, 7, 8, 12, 10, 14, 9, 13, 11, 15
52 };
53 
54 typedef struct AnsiContext {
55  AVFrame *frame;
56  int x; /**< x cursor position (pixels) */
57  int y; /**< y cursor position (pixels) */
58  int sx; /**< saved x cursor position (pixels) */
59  int sy; /**< saved y cursor position (pixels) */
60  const uint8_t* font; /**< font */
61  int font_height; /**< font height */
62  int attributes; /**< attribute flags */
63  int fg; /**< foreground color */
64  int bg; /**< background color */
65  int first_frame;
66 
67  /* ansi parser state machine */
68  enum {
69  STATE_NORMAL = 0,
70  STATE_ESCAPE,
71  STATE_CODE,
72  STATE_MUSIC_PREAMBLE
73  } state;
74 #define MAX_NB_ARGS 4
75  int args[MAX_NB_ARGS];
76  int nb_args; /**< number of arguments (may exceed MAX_NB_ARGS) */
77 } AnsiContext;
78 
79 static av_cold int decode_init(AVCodecContext *avctx)
80 {
81  AnsiContext *s = avctx->priv_data;
82  avctx->pix_fmt = AV_PIX_FMT_PAL8;
83 
84  /* defaults */
85  s->font = avpriv_vga16_font;
86  s->font_height = 16;
87  s->fg = DEFAULT_FG_COLOR;
88  s->bg = DEFAULT_BG_COLOR;
89 
90  if (!avctx->width || !avctx->height) {
91  int ret = ff_set_dimensions(avctx, 80 << 3, 25 << 4);
92  if (ret < 0)
93  return ret;
94  } else if (avctx->width % FONT_WIDTH || avctx->height % s->font_height) {
95  av_log(avctx, AV_LOG_ERROR, "Invalid dimensions %d %d\n", avctx->width, avctx->height);
96  return AVERROR(EINVAL);
97  }
98 
99  s->frame = av_frame_alloc();
100  if (!s->frame)
101  return AVERROR(ENOMEM);
102 
103  return 0;
104 }
105 
106 static void set_palette(uint32_t *pal)
107 {
108  int r, g, b;
109  memcpy(pal, ff_cga_palette, 16 * 4);
110  pal += 16;
111 #define COLOR(x) ((x) * 40 + 55)
112  for (r = 0; r < 6; r++)
113  for (g = 0; g < 6; g++)
114  for (b = 0; b < 6; b++)
115  *pal++ = 0xFF000000 | (COLOR(r) << 16) | (COLOR(g) << 8) | COLOR(b);
116 #define GRAY(x) ((x) * 10 + 8)
117  for (g = 0; g < 24; g++)
118  *pal++ = 0xFF000000 | (GRAY(g) << 16) | (GRAY(g) << 8) | GRAY(g);
119 }
120 
121 static void hscroll(AVCodecContext *avctx)
122 {
123  AnsiContext *s = avctx->priv_data;
124  int i;
125 
126  if (s->y <= avctx->height - 2*s->font_height) {
127  s->y += s->font_height;
128  return;
129  }
130 
131  i = 0;
132  for (; i < avctx->height - s->font_height; i++)
133  memcpy(s->frame->data[0] + i * s->frame->linesize[0],
134  s->frame->data[0] + (i + s->font_height) * s->frame->linesize[0],
135  avctx->width);
136  for (; i < avctx->height; i++)
137  memset(s->frame->data[0] + i * s->frame->linesize[0],
138  DEFAULT_BG_COLOR, avctx->width);
139 }
140 
141 static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
142 {
143  AnsiContext *s = avctx->priv_data;
144  int i;
145  for (i = 0; i < s->font_height; i++)
146  memset(s->frame->data[0] + (s->y + i)*s->frame->linesize[0] + xoffset,
147  DEFAULT_BG_COLOR, xlength);
148 }
149 
150 static void erase_screen(AVCodecContext *avctx)
151 {
152  AnsiContext *s = avctx->priv_data;
153  int i;
154  for (i = 0; i < avctx->height; i++)
155  memset(s->frame->data[0] + i * s->frame->linesize[0], DEFAULT_BG_COLOR, avctx->width);
156  s->x = s->y = 0;
157 }
158 
159 /**
160  * Draw character to screen
161  */
162 static void draw_char(AVCodecContext *avctx, int c)
163 {
164  AnsiContext *s = avctx->priv_data;
165  int fg = s->fg;
166  int bg = s->bg;
167 
168  if ((s->attributes & ATTR_BOLD))
169  fg += 8;
170  if ((s->attributes & ATTR_BLINK))
171  bg += 8;
172  if ((s->attributes & ATTR_REVERSE))
173  FFSWAP(int, fg, bg);
174  if ((s->attributes & ATTR_CONCEALED))
175  fg = bg;
176  ff_draw_pc_font(s->frame->data[0] + s->y * s->frame->linesize[0] + s->x,
177  s->frame->linesize[0], s->font, s->font_height, c, fg, bg);
178  s->x += FONT_WIDTH;
179  if (s->x > avctx->width - FONT_WIDTH) {
180  s->x = 0;
181  hscroll(avctx);
182  }
183 }
184 
185 /**
186  * Execute ANSI escape code
187  * @return 0 on success, negative on error
188  */
189 static int execute_code(AVCodecContext * avctx, int c)
190 {
191  AnsiContext *s = avctx->priv_data;
192  int ret, i;
193  int width = avctx->width;
194  int height = avctx->height;
195 
196  switch(c) {
197  case 'A': //Cursor Up
198  s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
199  break;
200  case 'B': //Cursor Down
201  s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
202  break;
203  case 'C': //Cursor Right
204  s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width - FONT_WIDTH);
205  break;
206  case 'D': //Cursor Left
207  s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
208  break;
209  case 'H': //Cursor Position
210  case 'f': //Horizontal and Vertical Position
211  s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
212  s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH, 0, avctx->width - FONT_WIDTH) : 0;
213  break;
214  case 'h': //set screen mode
215  case 'l': //reset screen mode
216  if (s->nb_args < 2)
217  s->args[0] = DEFAULT_SCREEN_MODE;
218  switch(s->args[0]) {
219  case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)
220  s->font = avpriv_cga_font;
221  s->font_height = 8;
222  width = 40<<3;
223  height = 25<<3;
224  break;
225  case 2: case 3: //640x400 (25 rows)
226  s->font = avpriv_vga16_font;
227  s->font_height = 16;
228  width = 80<<3;
229  height = 25<<4;
230  break;
231  case 6: case 14: //640x200 (25 rows)
232  s->font = avpriv_cga_font;
233  s->font_height = 8;
234  width = 80<<3;
235  height = 25<<3;
236  break;
237  case 7: //set line wrapping
238  break;
239  case 15: case 16: //640x350 (43 rows)
240  s->font = avpriv_cga_font;
241  s->font_height = 8;
242  width = 80<<3;
243  height = 43<<3;
244  break;
245  case 17: case 18: //640x480 (60 rows)
246  s->font = avpriv_cga_font;
247  s->font_height = 8;
248  width = 80<<3;
249  height = 60<<4;
250  break;
251  default:
252  avpriv_request_sample(avctx, "Unsupported screen mode");
253  }
254  s->x = av_clip(s->x, 0, width - FONT_WIDTH);
255  s->y = av_clip(s->y, 0, height - s->font_height);
256  if (width != avctx->width || height != avctx->height) {
257  av_frame_unref(s->frame);
258  ret = ff_set_dimensions(avctx, width, height);
259  if (ret < 0)
260  return ret;
261  if ((ret = ff_get_buffer(avctx, s->frame,
262  AV_GET_BUFFER_FLAG_REF)) < 0)
263  return ret;
264  s->frame->pict_type = AV_PICTURE_TYPE_I;
265  s->frame->palette_has_changed = 1;
266  set_palette((uint32_t *)s->frame->data[1]);
267  erase_screen(avctx);
268  } else if (c == 'l') {
269  erase_screen(avctx);
270  }
271  break;
272  case 'J': //Erase in Page
273  switch (s->args[0]) {
274  case 0:
275  erase_line(avctx, s->x, avctx->width - s->x);
276  if (s->y < avctx->height - s->font_height)
277  memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0],
278  DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]);
279  break;
280  case 1:
281  erase_line(avctx, 0, s->x);
282  if (s->y > 0)
283  memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]);
284  break;
285  case 2:
286  erase_screen(avctx);
287  }
288  break;
289  case 'K': //Erase in Line
290  switch(s->args[0]) {
291  case 0:
292  erase_line(avctx, s->x, avctx->width - s->x);
293  break;
294  case 1:
295  erase_line(avctx, 0, s->x);
296  break;
297  case 2:
298  erase_line(avctx, 0, avctx->width);
299  }
300  break;
301  case 'm': //Select Graphics Rendition
302  if (s->nb_args == 0) {
303  s->nb_args = 1;
304  s->args[0] = 0;
305  }
306  for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
307  int m = s->args[i];
308  if (m == 0) {
309  s->attributes = 0;
310  s->fg = DEFAULT_FG_COLOR;
311  s->bg = DEFAULT_BG_COLOR;
312  } else if (m == 1 || m == 2 || m == 3 || m == 4 || m == 5 || m == 7 || m == 8) {
313  s->attributes |= 1 << (m - 1);
314  } else if (m >= 30 && m <= 37) {
315  s->fg = ansi_to_cga[m - 30];
316  } else if (m == 38 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
317  int index = s->args[i + 2];
318  s->fg = index < 16 ? ansi_to_cga[index] : index;
319  i += 2;
320  } else if (m == 39) {
321  s->fg = ansi_to_cga[DEFAULT_FG_COLOR];
322  } else if (m >= 40 && m <= 47) {
323  s->bg = ansi_to_cga[m - 40];
324  } else if (m == 48 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
325  int index = s->args[i + 2];
326  s->bg = index < 16 ? ansi_to_cga[index] : index;
327  i += 2;
328  } else if (m == 49) {
329  s->fg = ansi_to_cga[DEFAULT_BG_COLOR];
330  } else {
331  avpriv_request_sample(avctx, "Unsupported rendition parameter");
332  }
333  }
334  break;
335  case 'n': //Device Status Report
336  case 'R': //report current line and column
337  /* ignore */
338  break;
339  case 's': //Save Cursor Position
340  s->sx = s->x;
341  s->sy = s->y;
342  break;
343  case 'u': //Restore Cursor Position
344  s->x = av_clip(s->sx, 0, avctx->width - FONT_WIDTH);
345  s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
346  break;
347  default:
348  avpriv_request_sample(avctx, "Unknown escape code");
349  break;
350  }
351  s->x = av_clip(s->x, 0, avctx->width - FONT_WIDTH);
352  s->y = av_clip(s->y, 0, avctx->height - s->font_height);
353  return 0;
354 }
355 
356 static int decode_frame(AVCodecContext *avctx,
357  void *data, int *got_frame,
358  AVPacket *avpkt)
359 {
360  AnsiContext *s = avctx->priv_data;
361  uint8_t *buf = avpkt->data;
362  int buf_size = avpkt->size;
363  const uint8_t *buf_end = buf+buf_size;
364  int ret, i, count;
365 
366  if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
367  return ret;
368  if (!avctx->frame_number) {
369  for (i=0; i<avctx->height; i++)
370  memset(s->frame->data[0]+ i*s->frame->linesize[0], 0, avctx->width);
371  memset(s->frame->data[1], 0, AVPALETTE_SIZE);
372  }
373 
374  s->frame->pict_type = AV_PICTURE_TYPE_I;
375  s->frame->palette_has_changed = 1;
376  set_palette((uint32_t *)s->frame->data[1]);
377  if (!s->first_frame) {
378  erase_screen(avctx);
379  s->first_frame = 1;
380  }
381 
382  while(buf < buf_end) {
383  switch(s->state) {
384  case STATE_NORMAL:
385  switch (buf[0]) {
386  case 0x00: //NUL
387  case 0x07: //BEL
388  case 0x1A: //SUB
389  /* ignore */
390  break;
391  case 0x08: //BS
392  s->x = FFMAX(s->x - 1, 0);
393  break;
394  case 0x09: //HT
395  i = s->x / FONT_WIDTH;
396  count = ((i + 8) & ~7) - i;
397  for (i = 0; i < count; i++)
398  draw_char(avctx, ' ');
399  break;
400  case 0x0A: //LF
401  hscroll(avctx);
402  case 0x0D: //CR
403  s->x = 0;
404  break;
405  case 0x0C: //FF
406  erase_screen(avctx);
407  break;
408  case 0x1B: //ESC
409  s->state = STATE_ESCAPE;
410  break;
411  default:
412  draw_char(avctx, buf[0]);
413  }
414  break;
415  case STATE_ESCAPE:
416  if (buf[0] == '[') {
417  s->state = STATE_CODE;
418  s->nb_args = 0;
419  s->args[0] = -1;
420  } else {
421  s->state = STATE_NORMAL;
422  draw_char(avctx, 0x1B);
423  continue;
424  }
425  break;
426  case STATE_CODE:
427  switch(buf[0]) {
428  case '0': case '1': case '2': case '3': case '4':
429  case '5': case '6': case '7': case '8': case '9':
430  if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] < 6553)
431  s->args[s->nb_args] = FFMAX(s->args[s->nb_args], 0) * 10 + buf[0] - '0';
432  break;
433  case ';':
434  if (s->nb_args < MAX_NB_ARGS)
435  s->nb_args++;
436  if (s->nb_args < MAX_NB_ARGS)
437  s->args[s->nb_args] = 0;
438  break;
439  case 'M':
440  s->state = STATE_MUSIC_PREAMBLE;
441  break;
442  case '=': case '?':
443  /* ignore */
444  break;
445  default:
446  if (s->nb_args > MAX_NB_ARGS)
447  av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);
448  if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] >= 0)
449  s->nb_args++;
450  if ((ret = execute_code(avctx, buf[0])) < 0)
451  return ret;
452  s->state = STATE_NORMAL;
453  }
454  break;
455  case STATE_MUSIC_PREAMBLE:
456  if (buf[0] == 0x0E || buf[0] == 0x1B)
457  s->state = STATE_NORMAL;
458  /* ignore music data */
459  break;
460  }
461  buf++;
462  }
463 
464  *got_frame = 1;
465  if ((ret = av_frame_ref(data, s->frame)) < 0)
466  return ret;
467  return buf_size;
468 }
469 
470 static av_cold int decode_close(AVCodecContext *avctx)
471 {
472  AnsiContext *s = avctx->priv_data;
473 
474  av_frame_free(&s->frame);
475  return 0;
476 }
477 
478 static const AVCodecDefault ansi_defaults[] = {
479  { "max_pixels", "640*480" },
480  { NULL },
481 };
482 
483 const AVCodec ff_ansi_decoder = {
484  .name = "ansi",
485  .long_name = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
486  .type = AVMEDIA_TYPE_VIDEO,
487  .id = AV_CODEC_ID_ANSI,
488  .priv_data_size = sizeof(AnsiContext),
489  .init = decode_init,
490  .close = decode_close,
491  .decode = decode_frame,
492  .capabilities = AV_CODEC_CAP_DR1,
493  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
494  .defaults = ansi_defaults,
495 };
AV_CODEC_ID_ANSI
@ AV_CODEC_ID_ANSI
Definition: codec_id.h:192
AVCodec
AVCodec.
Definition: codec.h:202
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
FF_CODEC_CAP_INIT_THREADSAFE
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:42
decode_close
static av_cold int decode_close(AVCodecContext *avctx)
Definition: ansi.c:470
av_clip
#define av_clip
Definition: common.h:96
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
r
const char * r
Definition: vf_curves.c:116
AVERROR
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
ff_cga_palette
const uint32_t ff_cga_palette[16]
Definition: cga_data.c:30
COLOR
#define COLOR(x)
AnsiContext::STATE_NORMAL
@ STATE_NORMAL
Definition: ansi.c:69
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:112
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
index
fg index
Definition: ffmpeg_filter.c:168
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:373
execute_code
static int execute_code(AVCodecContext *avctx, int c)
Execute ANSI escape code.
Definition: ansi.c:189
b
#define b
Definition: input.c:40
data
const char data[16]
Definition: mxf.c:143
AnsiContext::STATE_CODE
@ STATE_CODE
Definition: ansi.c:71
FFMAX
#define FFMAX(a, b)
Definition: macros.h:47
AnsiContext
Definition: ansi.c:54
AnsiContext::font
const uint8_t * font
font
Definition: ansi.c:60
AnsiContext::sy
int sy
saved y cursor position (pixels)
Definition: ansi.c:59
AnsiContext::first_frame
int first_frame
Definition: ansi.c:65
AnsiContext::nb_args
int nb_args
number of arguments (may exceed MAX_NB_ARGS)
Definition: ansi.c:76
AnsiContext::STATE_ESCAPE
@ STATE_ESCAPE
Definition: ansi.c:70
defaults
static const AVCodecDefault defaults[]
Definition: amfenc_h264.c:361
av_frame_alloc
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:99
ff_draw_pc_font
void ff_draw_pc_font(uint8_t *dst, int linesize, const uint8_t *font, int font_height, int ch, int fg, int bg)
Draw CGA/EGA/VGA font to 8-bit pixel buffer.
Definition: cga_data.c:46
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
av_cold
#define av_cold
Definition: attributes.h:90
decode
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
width
#define width
AnsiContext::y
int y
y cursor position (pixels)
Definition: ansi.c:57
s
#define s(width, name)
Definition: cbs_vp9.c:257
g
const char * g
Definition: vf_curves.c:117
AV_GET_BUFFER_FLAG_REF
#define AV_GET_BUFFER_FLAG_REF
The decoder will keep a reference to the frame and may reuse it later.
Definition: avcodec.h:361
lfg.h
draw_char
static void draw_char(AVCodecContext *avctx, int c)
Draw character to screen.
Definition: ansi.c:162
ATTR_BLINK
#define ATTR_BLINK
Blink/Bright-background (mode 5)
Definition: ansi.c:39
ATTR_CONCEALED
#define ATTR_CONCEALED
Concealed (mode 8)
Definition: ansi.c:41
ATTR_BOLD
#define ATTR_BOLD
Bold/Bright-foreground (mode 1)
Definition: ansi.c:35
AVCodecDefault
Definition: internal.h:206
GRAY
#define GRAY(x)
NULL
#define NULL
Definition: coverity.c:32
DEFAULT_SCREEN_MODE
#define DEFAULT_SCREEN_MODE
80x25
Definition: ansi.c:45
AVPALETTE_SIZE
#define AVPALETTE_SIZE
Definition: pixfmt.h:32
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
AnsiContext::sx
int sx
saved x cursor position (pixels)
Definition: ansi.c:58
AnsiContext::attributes
int attributes
attribute flags
Definition: ansi.c:62
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1652
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:374
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
av_frame_ref
int av_frame_ref(AVFrame *dst, const AVFrame *src)
Set up a new reference to the data described by the source frame.
Definition: frame.c:327
MAX_NB_ARGS
#define MAX_NB_ARGS
Definition: ansi.c:74
hscroll
static void hscroll(AVCodecContext *avctx)
Definition: ansi.c:121
frame.h
cga_data.h
erase_line
static void erase_line(AVCodecContext *avctx, int xoffset, int xlength)
Definition: ansi.c:141
height
#define height
DEFAULT_FG_COLOR
#define DEFAULT_FG_COLOR
CGA color index.
Definition: ansi.c:43
xga_font_data.h
AnsiContext::frame
AVFrame * frame
Definition: ansi.c:55
AnsiContext::state
enum AnsiContext::@13 state
i
int i
Definition: input.c:406
avpriv_vga16_font
const uint8_t avpriv_vga16_font[4096]
Definition: xga_font_data.c:160
set_palette
static void set_palette(uint32_t *pal)
Definition: ansi.c:106
ATTR_REVERSE
#define ATTR_REVERSE
Reverse (mode 7)
Definition: ansi.c:40
DEFAULT_BG_COLOR
#define DEFAULT_BG_COLOR
Definition: ansi.c:44
common.h
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
av_frame_unref
void av_frame_unref(AVFrame *frame)
Unreference all the buffers referenced by frame and reset the frame fields.
Definition: frame.c:437
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:209
AVCodecContext::height
int height
Definition: avcodec.h:556
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:593
AnsiContext::bg
int bg
background color
Definition: ansi.c:64
avcodec.h
AV_PIX_FMT_PAL8
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:77
ff_reget_buffer
int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Identical in function to ff_get_buffer(), except it reuses the existing buffer if available.
Definition: decode.c:1759
ret
ret
Definition: filter_design.txt:187
FFSWAP
#define FFSWAP(type, a, b)
Definition: macros.h:52
FONT_WIDTH
#define FONT_WIDTH
Font width.
Definition: ansi.c:47
ansi_defaults
static const AVCodecDefault ansi_defaults[]
Definition: ansi.c:478
AnsiContext::fg
int fg
foreground color
Definition: ansi.c:63
ff_ansi_decoder
const AVCodec ff_ansi_decoder
Definition: ansi.c:483
AVCodecContext
main external API structure.
Definition: avcodec.h:383
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
ff_set_dimensions
int ff_set_dimensions(AVCodecContext *s, int width, int height)
Check that the provided frame dimensions are valid and set them on the codec context.
Definition: utils.c:86
AVCodecContext::frame_number
int frame_number
Frame counter, set by libavcodec.
Definition: avcodec.h:1023
avpriv_request_sample
#define avpriv_request_sample(...)
Definition: tableprint_vlc.h:37
avpriv_cga_font
const uint8_t avpriv_cga_font[2048]
Definition: xga_font_data.c:29
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:410
decode_frame
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: ansi.c:356
AnsiContext::args
int args[MAX_NB_ARGS]
Definition: ansi.c:75
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:556
AnsiContext::x
int x
x cursor position (pixels)
Definition: ansi.c:56
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AnsiContext::font_height
int font_height
font height
Definition: ansi.c:61
decode_init
static av_cold int decode_init(AVCodecContext *avctx)
Definition: ansi.c:79
AnsiContext::STATE_MUSIC_PREAMBLE
@ STATE_MUSIC_PREAMBLE
Definition: ansi.c:72
erase_screen
static void erase_screen(AVCodecContext *avctx)
Definition: ansi.c:150
ansi_to_cga
static const uint8_t ansi_to_cga[16]
map ansi color index to cga palette index
Definition: ansi.c:50
Generated on Wed Sep 22 2021 19:21:05 for FFmpeg by   doxygen 1.8.17