Libav 0.7.1
libavcodec/ansi.c
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00001 /*
00002  * ASCII/ANSI art decoder
00003  * Copyright (c) 2010 Peter Ross <pross@xvid.org>
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav 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  * Libav 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 Libav; 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/lfg.h"
00028 #include "avcodec.h"
00029 #include "cga_data.h"
00030 
00031 #define ATTR_BOLD         0x01  
00032 #define ATTR_FAINT        0x02  
00033 #define ATTR_UNDERLINE    0x08  
00034 #define ATTR_BLINK        0x10  
00035 #define ATTR_REVERSE      0x40  
00036 #define ATTR_CONCEALED    0x80  
00038 #define DEFAULT_FG_COLOR     7  
00039 #define DEFAULT_BG_COLOR     0
00040 #define DEFAULT_SCREEN_MODE  3  
00042 #define FONT_WIDTH           8  
00045 static const uint8_t ansi_to_cga[16] = {
00046     0,  4,  2,  6,  1,  5,  3, 7, 8, 12, 10, 14,  9, 13, 11, 15
00047 };
00048 
00049 typedef struct {
00050     AVFrame frame;
00051     int x;                
00052     int y;                
00053     int sx;               
00054     int sy;               
00055     const uint8_t* font;  
00056     int font_height;      
00057     int attributes;       
00058     int fg;               
00059     int bg;               
00061     /* ansi parser state machine */
00062     enum {
00063         STATE_NORMAL = 0,
00064         STATE_ESCAPE,
00065         STATE_CODE,
00066         STATE_MUSIC_PREAMBLE
00067     } state;
00068 #define MAX_NB_ARGS 4
00069     int args[MAX_NB_ARGS];
00070     int nb_args;          
00071 } AnsiContext;
00072 
00073 static av_cold int decode_init(AVCodecContext *avctx)
00074 {
00075     AnsiContext *s = avctx->priv_data;
00076     avctx->pix_fmt = PIX_FMT_PAL8;
00077 
00078     /* defaults */
00079     s->font        = ff_vga16_font;
00080     s->font_height = 16;
00081     s->fg          = DEFAULT_FG_COLOR;
00082     s->bg          = DEFAULT_BG_COLOR;
00083 
00084     if (!avctx->width || !avctx->height)
00085         avcodec_set_dimensions(avctx, 80<<3, 25<<4);
00086 
00087     return 0;
00088 }
00089 
00090 static void hscroll(AVCodecContext *avctx)
00091 {
00092     AnsiContext *s = avctx->priv_data;
00093     int i;
00094 
00095     if (s->y < avctx->height - s->font_height) {
00096         s->y += s->font_height;
00097         return;
00098     }
00099 
00100     i = 0;
00101     for (; i < avctx->height - s->font_height; i++)
00102         memcpy(s->frame.data[0] + i * s->frame.linesize[0],
00103                s->frame.data[0] + (i + s->font_height) * s->frame.linesize[0],
00104                avctx->width);
00105     for (; i < avctx->height; i++)
00106         memset(s->frame.data[0] + i * s->frame.linesize[0],
00107             DEFAULT_BG_COLOR, avctx->width);
00108 }
00109 
00110 static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
00111 {
00112     AnsiContext *s = avctx->priv_data;
00113     int i;
00114     for (i = 0; i < s->font_height; i++)
00115         memset(s->frame.data[0] + (s->y + i)*s->frame.linesize[0] + xoffset,
00116             DEFAULT_BG_COLOR, xlength);
00117 }
00118 
00119 static void erase_screen(AVCodecContext *avctx)
00120 {
00121     AnsiContext *s = avctx->priv_data;
00122     int i;
00123     for (i = 0; i < avctx->height; i++)
00124         memset(s->frame.data[0] + i * s->frame.linesize[0], DEFAULT_BG_COLOR, avctx->width);
00125     s->x = s->y = 0;
00126 }
00127 
00131 static void draw_char(AVCodecContext *avctx, int c)
00132 {
00133     AnsiContext *s = avctx->priv_data;
00134     int fg = s->fg;
00135     int bg = s->bg;
00136 
00137     if ((s->attributes & ATTR_BOLD))
00138         fg += 8;
00139     if ((s->attributes & ATTR_BLINK))
00140         bg += 8;
00141     if ((s->attributes & ATTR_REVERSE))
00142         FFSWAP(int, fg, bg);
00143     if ((s->attributes & ATTR_CONCEALED))
00144         fg = bg;
00145     ff_draw_pc_font(s->frame.data[0] + s->y * s->frame.linesize[0] + s->x,
00146                     s->frame.linesize[0], s->font, s->font_height, c, fg, bg);
00147     s->x += FONT_WIDTH;
00148     if (s->x >= avctx->width) {
00149         s->x = 0;
00150         hscroll(avctx);
00151     }
00152 }
00153 
00158 static int execute_code(AVCodecContext * avctx, int c)
00159 {
00160     AnsiContext *s = avctx->priv_data;
00161     int ret, i, width, height;
00162     switch(c) {
00163     case 'A': //Cursor Up
00164         s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
00165         break;
00166     case 'B': //Cursor Down
00167         s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
00168         break;
00169     case 'C': //Cursor Right
00170         s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width  - FONT_WIDTH);
00171         break;
00172     case 'D': //Cursor Left
00173         s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
00174         break;
00175     case 'H': //Cursor Position
00176     case 'f': //Horizontal and Vertical Position
00177         s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
00178         s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH,     0, avctx->width  - FONT_WIDTH) : 0;
00179         break;
00180     case 'h': //set creen mode
00181     case 'l': //reset screen mode
00182         if (s->nb_args < 2)
00183             s->args[0] = DEFAULT_SCREEN_MODE;
00184         switch(s->args[0]) {
00185         case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)
00186             s->font = ff_cga_font;
00187             s->font_height = 8;
00188             width  = 40<<3;
00189             height = 25<<3;
00190             break;
00191         case 2: case 3: //640x400 (25 rows)
00192             s->font = ff_vga16_font;
00193             s->font_height = 16;
00194             width  = 80<<3;
00195             height = 25<<4;
00196             break;
00197         case 6: case 14: //640x200 (25 rows)
00198             s->font = ff_cga_font;
00199             s->font_height = 8;
00200             width  = 80<<3;
00201             height = 25<<3;
00202             break;
00203         case 7: //set line wrapping
00204             break;
00205         case 15: case 16: //640x350 (43 rows)
00206             s->font = ff_cga_font;
00207             s->font_height = 8;
00208             width  = 80<<3;
00209             height = 43<<3;
00210             break;
00211         case 17: case 18: //640x480 (60 rows)
00212             s->font = ff_cga_font;
00213             s->font_height = 8;
00214             width  = 80<<3;
00215             height = 60<<4;
00216             break;
00217         default:
00218             av_log_ask_for_sample(avctx, "unsupported screen mode\n");
00219         }
00220         if (width != avctx->width || height != avctx->height) {
00221             if (s->frame.data[0])
00222                 avctx->release_buffer(avctx, &s->frame);
00223             avcodec_set_dimensions(avctx, width, height);
00224             ret = avctx->get_buffer(avctx, &s->frame);
00225             if (ret < 0) {
00226                 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00227                 return ret;
00228             }
00229             s->frame.pict_type           = AV_PICTURE_TYPE_I;
00230             s->frame.palette_has_changed = 1;
00231             memcpy(s->frame.data[1], ff_cga_palette, 16 * 4);
00232             erase_screen(avctx);
00233         } else if (c == 'l') {
00234             erase_screen(avctx);
00235         }
00236         break;
00237     case 'J': //Erase in Page
00238         switch (s->args[0]) {
00239         case 0:
00240             erase_line(avctx, s->x, avctx->width - s->x);
00241             if (s->y < avctx->height - s->font_height)
00242                 memset(s->frame.data[0] + (s->y + s->font_height)*s->frame.linesize[0],
00243                     DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame.linesize[0]);
00244             break;
00245         case 1:
00246             erase_line(avctx, 0, s->x);
00247             if (s->y > 0)
00248                 memset(s->frame.data[0], DEFAULT_BG_COLOR, s->y * s->frame.linesize[0]);
00249             break;
00250         case 2:
00251             erase_screen(avctx);
00252         }
00253         break;
00254     case 'K': //Erase in Line
00255         switch(s->args[0]) {
00256         case 0:
00257             erase_line(avctx, s->x, avctx->width - s->x);
00258             break;
00259         case 1:
00260             erase_line(avctx, 0, s->x);
00261             break;
00262         case 2:
00263             erase_line(avctx, 0, avctx->width);
00264         }
00265         break;
00266     case 'm': //Select Graphics Rendition
00267         if (s->nb_args == 0) {
00268             s->nb_args = 1;
00269             s->args[0] = 0;
00270         }
00271         for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
00272             int m = s->args[i];
00273             if (m == 0) {
00274                 s->attributes = 0;
00275                 s->fg = DEFAULT_FG_COLOR;
00276                 s->bg = DEFAULT_BG_COLOR;
00277             } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {
00278                 s->attributes |= 1 << (m - 1);
00279             } else if (m >= 30 && m <= 38) {
00280                 s->fg = ansi_to_cga[m - 30];
00281             } else if (m == 39) {
00282                 s->fg = ansi_to_cga[DEFAULT_FG_COLOR];
00283             } else if (m >= 40 && m <= 47) {
00284                 s->bg = ansi_to_cga[m - 40];
00285             } else if (m == 49) {
00286                 s->fg = ansi_to_cga[DEFAULT_BG_COLOR];
00287             } else {
00288                 av_log_ask_for_sample(avctx, "unsupported rendition parameter\n");
00289             }
00290         }
00291         break;
00292     case 'n': //Device Status Report
00293     case 'R': //report current line and column
00294         /* ignore */
00295         break;
00296     case 's': //Save Cursor Position
00297         s->sx = s->x;
00298         s->sy = s->y;
00299         break;
00300     case 'u': //Restore Cursor Position
00301         s->x = av_clip(s->sx, 0, avctx->width  - FONT_WIDTH);
00302         s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
00303         break;
00304     default:
00305         av_log_ask_for_sample(avctx, "unsupported escape code\n");
00306         break;
00307     }
00308     return 0;
00309 }
00310 
00311 static int decode_frame(AVCodecContext *avctx,
00312                             void *data, int *data_size,
00313                             AVPacket *avpkt)
00314 {
00315     AnsiContext *s = avctx->priv_data;
00316     uint8_t *buf = avpkt->data;
00317     int buf_size = avpkt->size;
00318     const uint8_t *buf_end   = buf+buf_size;
00319     int ret, i, count;
00320 
00321     ret = avctx->reget_buffer(avctx, &s->frame);
00322     if (ret < 0){
00323         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00324         return ret;
00325     }
00326     s->frame.pict_type           = AV_PICTURE_TYPE_I;
00327     s->frame.palette_has_changed = 1;
00328     memcpy(s->frame.data[1], ff_cga_palette, 16 * 4);
00329 
00330     while(buf < buf_end) {
00331         switch(s->state) {
00332         case STATE_NORMAL:
00333             switch (buf[0]) {
00334             case 0x00: //NUL
00335             case 0x07: //BEL
00336             case 0x1A: //SUB
00337                 /* ignore */
00338                 break;
00339             case 0x08: //BS
00340                 s->x = FFMAX(s->x - 1, 0);
00341                 break;
00342             case 0x09: //HT
00343                 i = s->x / FONT_WIDTH;
00344                 count = ((i + 8) & ~7) - i;
00345                 for (i = 0; i < count; i++)
00346                     draw_char(avctx, ' ');
00347                 break;
00348             case 0x0A: //LF
00349                 hscroll(avctx);
00350             case 0x0D: //CR
00351                 s->x = 0;
00352                 break;
00353             case 0x0C: //FF
00354                 erase_screen(avctx);
00355                 break;
00356             case 0x1B: //ESC
00357                 s->state = STATE_ESCAPE;
00358                 break;
00359             default:
00360                 draw_char(avctx, buf[0]);
00361             }
00362             break;
00363         case STATE_ESCAPE:
00364             if (buf[0] == '[') {
00365                 s->state   = STATE_CODE;
00366                 s->nb_args = 0;
00367                 s->args[0] = 0;
00368             } else {
00369                 s->state = STATE_NORMAL;
00370                 draw_char(avctx, 0x1B);
00371                     return -1;
00372                 continue;
00373             }
00374             break;
00375         case STATE_CODE:
00376             switch(buf[0]) {
00377             case '0': case '1': case '2': case '3': case '4':
00378             case '5': case '6': case '7': case '8': case '9':
00379                 if (s->nb_args < MAX_NB_ARGS)
00380                     s->args[s->nb_args] = s->args[s->nb_args] * 10 + buf[0] - '0';
00381                 break;
00382             case ';':
00383                 s->nb_args++;
00384                 if (s->nb_args < MAX_NB_ARGS)
00385                     s->args[s->nb_args] = 0;
00386                 break;
00387             case 'M':
00388                 s->state = STATE_MUSIC_PREAMBLE;
00389                 break;
00390             case '=': case '?':
00391                 /* ignore */
00392                 break;
00393             default:
00394                 if (s->nb_args > MAX_NB_ARGS)
00395                     av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);
00396                 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args])
00397                     s->nb_args++;
00398                 if (execute_code(avctx, buf[0]) < 0)
00399                     return -1;
00400                 s->state = STATE_NORMAL;
00401             }
00402             break;
00403         case STATE_MUSIC_PREAMBLE:
00404             if (buf[0] == 0x0E || buf[0] == 0x1B)
00405                 s->state = STATE_NORMAL;
00406             /* ignore music data */
00407             break;
00408         }
00409         buf++;
00410     }
00411 
00412     *data_size = sizeof(AVFrame);
00413     *(AVFrame*)data = s->frame;
00414     return buf_size;
00415 }
00416 
00417 static av_cold int decode_close(AVCodecContext *avctx)
00418 {
00419     AnsiContext *s = avctx->priv_data;
00420     if (s->frame.data[0])
00421         avctx->release_buffer(avctx, &s->frame);
00422     return 0;
00423 }
00424 
00425 AVCodec ff_ansi_decoder = {
00426     .name           = "ansi",
00427     .type           = AVMEDIA_TYPE_VIDEO,
00428     .id             = CODEC_ID_ANSI,
00429     .priv_data_size = sizeof(AnsiContext),
00430     .init           = decode_init,
00431     .close          = decode_close,
00432     .decode         = decode_frame,
00433     .capabilities   = CODEC_CAP_DR1,
00434     .long_name      = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
00435 };