FFmpeg: libavcodec/ansi.c Source File

00001 /*
00002  * ASCII/ANSI art decoder
00003  * Copyright (c) 2010 Peter Ross <pross@xvid.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 
00027 #include "libavutil/common.h"
00028 #include "libavutil/lfg.h"
00029 #include "avcodec.h"
00030 #include "cga_data.h"
00031 
00032 #define ATTR_BOLD         0x01  
00033 #define ATTR_FAINT        0x02  
00034 #define ATTR_UNDERLINE    0x08  
00035 #define ATTR_BLINK        0x10  
00036 #define ATTR_REVERSE      0x40  
00037 #define ATTR_CONCEALED    0x80  
00039 #define DEFAULT_FG_COLOR     7  
00040 #define DEFAULT_BG_COLOR     0
00041 #define DEFAULT_SCREEN_MODE  3  
00043 #define FONT_WIDTH           8  
00046 static const uint8_t ansi_to_cga[16] = {
00047     0,  4,  2,  6,  1,  5,  3, 7, 8, 12, 10, 14,  9, 13, 11, 15
00048 };
00049 
00050 typedef struct {
00051     AVFrame frame;
00052     int x;                
00053     int y;                
00054     int sx;               
00055     int sy;               
00056     const uint8_t* font;  
00057     int font_height;      
00058     int attributes;       
00059     int fg;               
00060     int bg;               
00061     int first_frame;
00062 
00063     /* ansi parser state machine */
00064     enum {
00065         STATE_NORMAL = 0,
00066         STATE_ESCAPE,
00067         STATE_CODE,
00068         STATE_MUSIC_PREAMBLE
00069     } state;
00070 #define MAX_NB_ARGS 4
00071     int args[MAX_NB_ARGS];
00072     int nb_args;          
00073 } AnsiContext;
00074 
00075 static av_cold int decode_init(AVCodecContext *avctx)
00076 {
00077     AnsiContext *s = avctx->priv_data;
00078     avctx->pix_fmt = PIX_FMT_PAL8;
00079 
00080     /* defaults */
00081     s->font        = ff_vga16_font;
00082     s->font_height = 16;
00083     s->fg          = DEFAULT_FG_COLOR;
00084     s->bg          = DEFAULT_BG_COLOR;
00085 
00086     avcodec_get_frame_defaults(&s->frame);
00087     if (!avctx->width || !avctx->height)
00088         avcodec_set_dimensions(avctx, 80<<3, 25<<4);
00089 
00090     return 0;
00091 }
00092 
00093 static void set_palette(uint32_t *pal)
00094 {
00095     int r, g, b;
00096     memcpy(pal, ff_cga_palette, 16 * 4);
00097     pal += 16;
00098 #define COLOR(x) ((x) * 40 + 55)
00099     for (r = 0; r < 6; r++)
00100         for (g = 0; g < 6; g++)
00101             for (b = 0; b < 6; b++)
00102                 *pal++ = 0xFF000000 | (COLOR(r) << 16) | (COLOR(g) << 8) | COLOR(b);
00103 #define GRAY(x) ((x) * 10 + 8)
00104     for (g = 0; g < 24; g++)
00105         *pal++ = 0xFF000000 | (GRAY(g) << 16) | (GRAY(g) << 8) | GRAY(g);
00106 }
00107 
00108 static void hscroll(AVCodecContext *avctx)
00109 {
00110     AnsiContext *s = avctx->priv_data;
00111     int i;
00112 
00113     if (s->y < avctx->height - s->font_height) {
00114         s->y += s->font_height;
00115         return;
00116     }
00117 
00118     i = 0;
00119     for (; i < avctx->height - s->font_height; i++)
00120         memcpy(s->frame.data[0] + i * s->frame.linesize[0],
00121                s->frame.data[0] + (i + s->font_height) * s->frame.linesize[0],
00122                avctx->width);
00123     for (; i < avctx->height; i++)
00124         memset(s->frame.data[0] + i * s->frame.linesize[0],
00125             DEFAULT_BG_COLOR, avctx->width);
00126 }
00127 
00128 static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
00129 {
00130     AnsiContext *s = avctx->priv_data;
00131     int i;
00132     for (i = 0; i < s->font_height; i++)
00133         memset(s->frame.data[0] + (s->y + i)*s->frame.linesize[0] + xoffset,
00134             DEFAULT_BG_COLOR, xlength);
00135 }
00136 
00137 static void erase_screen(AVCodecContext *avctx)
00138 {
00139     AnsiContext *s = avctx->priv_data;
00140     int i;
00141     for (i = 0; i < avctx->height; i++)
00142         memset(s->frame.data[0] + i * s->frame.linesize[0], DEFAULT_BG_COLOR, avctx->width);
00143     s->x = s->y = 0;
00144 }
00145 
00149 static void draw_char(AVCodecContext *avctx, int c)
00150 {
00151     AnsiContext *s = avctx->priv_data;
00152     int fg = s->fg;
00153     int bg = s->bg;
00154 
00155     if ((s->attributes & ATTR_BOLD))
00156         fg += 8;
00157     if ((s->attributes & ATTR_BLINK))
00158         bg += 8;
00159     if ((s->attributes & ATTR_REVERSE))
00160         FFSWAP(int, fg, bg);
00161     if ((s->attributes & ATTR_CONCEALED))
00162         fg = bg;
00163     ff_draw_pc_font(s->frame.data[0] + s->y * s->frame.linesize[0] + s->x,
00164                     s->frame.linesize[0], s->font, s->font_height, c, fg, bg);
00165     s->x += FONT_WIDTH;
00166     if (s->x >= avctx->width) {
00167         s->x = 0;
00168         hscroll(avctx);
00169     }
00170 }
00171 
00176 static int execute_code(AVCodecContext * avctx, int c)
00177 {
00178     AnsiContext *s = avctx->priv_data;
00179     int ret, i, width, height;
00180     switch(c) {
00181     case 'A': //Cursor Up
00182         s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
00183         break;
00184     case 'B': //Cursor Down
00185         s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
00186         break;
00187     case 'C': //Cursor Right
00188         s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width  - FONT_WIDTH);
00189         break;
00190     case 'D': //Cursor Left
00191         s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
00192         break;
00193     case 'H': //Cursor Position
00194     case 'f': //Horizontal and Vertical Position
00195         s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
00196         s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH,     0, avctx->width  - FONT_WIDTH) : 0;
00197         break;
00198     case 'h': //set creen mode
00199     case 'l': //reset screen mode
00200         if (s->nb_args < 2)
00201             s->args[0] = DEFAULT_SCREEN_MODE;
00202         width = avctx->width;
00203         height = avctx->height;
00204         switch(s->args[0]) {
00205         case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)
00206             s->font = ff_cga_font;
00207             s->font_height = 8;
00208             width  = 40<<3;
00209             height = 25<<3;
00210             break;
00211         case 2: case 3: //640x400 (25 rows)
00212             s->font = ff_vga16_font;
00213             s->font_height = 16;
00214             width  = 80<<3;
00215             height = 25<<4;
00216             break;
00217         case 6: case 14: //640x200 (25 rows)
00218             s->font = ff_cga_font;
00219             s->font_height = 8;
00220             width  = 80<<3;
00221             height = 25<<3;
00222             break;
00223         case 7: //set line wrapping
00224             break;
00225         case 15: case 16: //640x350 (43 rows)
00226             s->font = ff_cga_font;
00227             s->font_height = 8;
00228             width  = 80<<3;
00229             height = 43<<3;
00230             break;
00231         case 17: case 18: //640x480 (60 rows)
00232             s->font = ff_cga_font;
00233             s->font_height = 8;
00234             width  = 80<<3;
00235             height = 60<<4;
00236             break;
00237         default:
00238             av_log_ask_for_sample(avctx, "unsupported screen mode\n");
00239         }
00240         if (width != avctx->width || height != avctx->height) {
00241             if (s->frame.data[0])
00242                 avctx->release_buffer(avctx, &s->frame);
00243             avcodec_set_dimensions(avctx, width, height);
00244             ret = avctx->get_buffer(avctx, &s->frame);
00245             if (ret < 0) {
00246                 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00247                 return ret;
00248             }
00249             s->frame.pict_type           = AV_PICTURE_TYPE_I;
00250             s->frame.palette_has_changed = 1;
00251             set_palette((uint32_t *)s->frame.data[1]);
00252             erase_screen(avctx);
00253         } else if (c == 'l') {
00254             erase_screen(avctx);
00255         }
00256         break;
00257     case 'J': //Erase in Page
00258         switch (s->args[0]) {
00259         case 0:
00260             erase_line(avctx, s->x, avctx->width - s->x);
00261             if (s->y < avctx->height - s->font_height)
00262                 memset(s->frame.data[0] + (s->y + s->font_height)*s->frame.linesize[0],
00263                     DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame.linesize[0]);
00264             break;
00265         case 1:
00266             erase_line(avctx, 0, s->x);
00267             if (s->y > 0)
00268                 memset(s->frame.data[0], DEFAULT_BG_COLOR, s->y * s->frame.linesize[0]);
00269             break;
00270         case 2:
00271             erase_screen(avctx);
00272         }
00273         break;
00274     case 'K': //Erase in Line
00275         switch(s->args[0]) {
00276         case 0:
00277             erase_line(avctx, s->x, avctx->width - s->x);
00278             break;
00279         case 1:
00280             erase_line(avctx, 0, s->x);
00281             break;
00282         case 2:
00283             erase_line(avctx, 0, avctx->width);
00284         }
00285         break;
00286     case 'm': //Select Graphics Rendition
00287         if (s->nb_args == 0) {
00288             s->nb_args = 1;
00289             s->args[0] = 0;
00290         }
00291         for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
00292             int m = s->args[i];
00293             if (m == 0) {
00294                 s->attributes = 0;
00295                 s->fg = DEFAULT_FG_COLOR;
00296                 s->bg = DEFAULT_BG_COLOR;
00297             } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {
00298                 s->attributes |= 1 << (m - 1);
00299             } else if (m >= 30 && m <= 37) {
00300                 s->fg = ansi_to_cga[m - 30];
00301             } else if (m == 38 && i + 2 < s->nb_args && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
00302                 int index = s->args[i + 2];
00303                 s->fg = index < 16 ? ansi_to_cga[index] : index;
00304                 i += 2;
00305             } else if (m == 39) {
00306                 s->fg = ansi_to_cga[DEFAULT_FG_COLOR];
00307             } else if (m >= 40 && m <= 47) {
00308                 s->bg = ansi_to_cga[m - 40];
00309             } else if (m == 48 && i + 2 < s->nb_args && s->args[i + 1] == 5 && s->args[i + 2] < 256) {
00310                 int index = s->args[i + 2];
00311                 s->bg = index < 16 ? ansi_to_cga[index] : index;
00312                 i += 2;
00313             } else if (m == 49) {
00314                 s->fg = ansi_to_cga[DEFAULT_BG_COLOR];
00315             } else {
00316                 av_log_ask_for_sample(avctx, "unsupported rendition parameter\n");
00317             }
00318         }
00319         break;
00320     case 'n': //Device Status Report
00321     case 'R': //report current line and column
00322         /* ignore */
00323         break;
00324     case 's': //Save Cursor Position
00325         s->sx = s->x;
00326         s->sy = s->y;
00327         break;
00328     case 'u': //Restore Cursor Position
00329         s->x = av_clip(s->sx, 0, avctx->width  - FONT_WIDTH);
00330         s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
00331         break;
00332     default:
00333         av_log_ask_for_sample(avctx, "unsupported escape code\n");
00334         break;
00335     }
00336     return 0;
00337 }
00338 
00339 static int decode_frame(AVCodecContext *avctx,
00340                             void *data, int *data_size,
00341                             AVPacket *avpkt)
00342 {
00343     AnsiContext *s = avctx->priv_data;
00344     uint8_t *buf = avpkt->data;
00345     int buf_size = avpkt->size;
00346     const uint8_t *buf_end   = buf+buf_size;
00347     int ret, i, count;
00348 
00349     ret = avctx->reget_buffer(avctx, &s->frame);
00350     if (ret < 0){
00351         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00352         return ret;
00353     }
00354     s->frame.pict_type           = AV_PICTURE_TYPE_I;
00355     s->frame.palette_has_changed = 1;
00356     set_palette((uint32_t *)s->frame.data[1]);
00357     if (!s->first_frame) {
00358         erase_screen(avctx);
00359         s->first_frame = 1;
00360     }
00361 
00362     while(buf < buf_end) {
00363         switch(s->state) {
00364         case STATE_NORMAL:
00365             switch (buf[0]) {
00366             case 0x00: //NUL
00367             case 0x07: //BEL
00368             case 0x1A: //SUB
00369                 /* ignore */
00370                 break;
00371             case 0x08: //BS
00372                 s->x = FFMAX(s->x - 1, 0);
00373                 break;
00374             case 0x09: //HT
00375                 i = s->x / FONT_WIDTH;
00376                 count = ((i + 8) & ~7) - i;
00377                 for (i = 0; i < count; i++)
00378                     draw_char(avctx, ' ');
00379                 break;
00380             case 0x0A: //LF
00381                 hscroll(avctx);
00382             case 0x0D: //CR
00383                 s->x = 0;
00384                 break;
00385             case 0x0C: //FF
00386                 erase_screen(avctx);
00387                 break;
00388             case 0x1B: //ESC
00389                 s->state = STATE_ESCAPE;
00390                 break;
00391             default:
00392                 draw_char(avctx, buf[0]);
00393             }
00394             break;
00395         case STATE_ESCAPE:
00396             if (buf[0] == '[') {
00397                 s->state   = STATE_CODE;
00398                 s->nb_args = 0;
00399                 s->args[0] = -1;
00400             } else {
00401                 s->state = STATE_NORMAL;
00402                 draw_char(avctx, 0x1B);
00403                 continue;
00404             }
00405             break;
00406         case STATE_CODE:
00407             switch(buf[0]) {
00408             case '0': case '1': case '2': case '3': case '4':
00409             case '5': case '6': case '7': case '8': case '9':
00410                 if (s->nb_args < MAX_NB_ARGS)
00411                     s->args[s->nb_args] = FFMAX(s->args[s->nb_args], 0) * 10 + buf[0] - '0';
00412                 break;
00413             case ';':
00414                 s->nb_args++;
00415                 if (s->nb_args < MAX_NB_ARGS)
00416                     s->args[s->nb_args] = 0;
00417                 break;
00418             case 'M':
00419                 s->state = STATE_MUSIC_PREAMBLE;
00420                 break;
00421             case '=': case '?':
00422                 /* ignore */
00423                 break;
00424             default:
00425                 if (s->nb_args > MAX_NB_ARGS)
00426                     av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);
00427                 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] >= 0)
00428                     s->nb_args++;
00429                 if (execute_code(avctx, buf[0]) < 0)
00430                     return -1;
00431                 s->state = STATE_NORMAL;
00432             }
00433             break;
00434         case STATE_MUSIC_PREAMBLE:
00435             if (buf[0] == 0x0E || buf[0] == 0x1B)
00436                 s->state = STATE_NORMAL;
00437             /* ignore music data */
00438             break;
00439         }
00440         buf++;
00441     }
00442 
00443     *data_size = sizeof(AVFrame);
00444     *(AVFrame*)data = s->frame;
00445     return buf_size;
00446 }
00447 
00448 static av_cold int decode_close(AVCodecContext *avctx)
00449 {
00450     AnsiContext *s = avctx->priv_data;
00451     if (s->frame.data[0])
00452         avctx->release_buffer(avctx, &s->frame);
00453     return 0;
00454 }
00455 
00456 AVCodec ff_ansi_decoder = {
00457     .name           = "ansi",
00458     .type           = AVMEDIA_TYPE_VIDEO,
00459     .id             = AV_CODEC_ID_ANSI,
00460     .priv_data_size = sizeof(AnsiContext),
00461     .init           = decode_init,
00462     .close          = decode_close,
00463     .decode         = decode_frame,
00464     .capabilities   = CODEC_CAP_DR1,
00465     .long_name      = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
00466 };