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/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     avcodec_get_frame_defaults(&s->frame);
00085     if (!avctx->width || !avctx->height)
00086         avcodec_set_dimensions(avctx, 80<<3, 25<<4);
00087 
00088     return 0;
00089 }
00090 
00091 static void hscroll(AVCodecContext *avctx)
00092 {
00093     AnsiContext *s = avctx->priv_data;
00094     int i;
00095 
00096     if (s->y < avctx->height - s->font_height) {
00097         s->y += s->font_height;
00098         return;
00099     }
00100 
00101     i = 0;
00102     for (; i < avctx->height - s->font_height; i++)
00103         memcpy(s->frame.data[0] + i * s->frame.linesize[0],
00104                s->frame.data[0] + (i + s->font_height) * s->frame.linesize[0],
00105                avctx->width);
00106     for (; i < avctx->height; i++)
00107         memset(s->frame.data[0] + i * s->frame.linesize[0],
00108             DEFAULT_BG_COLOR, avctx->width);
00109 }
00110 
00111 static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
00112 {
00113     AnsiContext *s = avctx->priv_data;
00114     int i;
00115     for (i = 0; i < s->font_height; i++)
00116         memset(s->frame.data[0] + (s->y + i)*s->frame.linesize[0] + xoffset,
00117             DEFAULT_BG_COLOR, xlength);
00118 }
00119 
00120 static void erase_screen(AVCodecContext *avctx)
00121 {
00122     AnsiContext *s = avctx->priv_data;
00123     int i;
00124     for (i = 0; i < avctx->height; i++)
00125         memset(s->frame.data[0] + i * s->frame.linesize[0], DEFAULT_BG_COLOR, avctx->width);
00126     s->x = s->y = 0;
00127 }
00128 
00132 static void draw_char(AVCodecContext *avctx, int c)
00133 {
00134     AnsiContext *s = avctx->priv_data;
00135     int fg = s->fg;
00136     int bg = s->bg;
00137 
00138     if ((s->attributes & ATTR_BOLD))
00139         fg += 8;
00140     if ((s->attributes & ATTR_BLINK))
00141         bg += 8;
00142     if ((s->attributes & ATTR_REVERSE))
00143         FFSWAP(int, fg, bg);
00144     if ((s->attributes & ATTR_CONCEALED))
00145         fg = bg;
00146     ff_draw_pc_font(s->frame.data[0] + s->y * s->frame.linesize[0] + s->x,
00147                     s->frame.linesize[0], s->font, s->font_height, c, fg, bg);
00148     s->x += FONT_WIDTH;
00149     if (s->x >= avctx->width) {
00150         s->x = 0;
00151         hscroll(avctx);
00152     }
00153 }
00154 
00159 static int execute_code(AVCodecContext * avctx, int c)
00160 {
00161     AnsiContext *s = avctx->priv_data;
00162     int ret, i, width, height;
00163     switch(c) {
00164     case 'A': //Cursor Up
00165         s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
00166         break;
00167     case 'B': //Cursor Down
00168         s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
00169         break;
00170     case 'C': //Cursor Right
00171         s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width  - FONT_WIDTH);
00172         break;
00173     case 'D': //Cursor Left
00174         s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
00175         break;
00176     case 'H': //Cursor Position
00177     case 'f': //Horizontal and Vertical Position
00178         s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
00179         s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH,     0, avctx->width  - FONT_WIDTH) : 0;
00180         break;
00181     case 'h': //set creen mode
00182     case 'l': //reset screen mode
00183         if (s->nb_args < 2)
00184             s->args[0] = DEFAULT_SCREEN_MODE;
00185         width = avctx->width;
00186         height = avctx->height;
00187         switch(s->args[0]) {
00188         case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)
00189             s->font = ff_cga_font;
00190             s->font_height = 8;
00191             width  = 40<<3;
00192             height = 25<<3;
00193             break;
00194         case 2: case 3: //640x400 (25 rows)
00195             s->font = ff_vga16_font;
00196             s->font_height = 16;
00197             width  = 80<<3;
00198             height = 25<<4;
00199             break;
00200         case 6: case 14: //640x200 (25 rows)
00201             s->font = ff_cga_font;
00202             s->font_height = 8;
00203             width  = 80<<3;
00204             height = 25<<3;
00205             break;
00206         case 7: //set line wrapping
00207             break;
00208         case 15: case 16: //640x350 (43 rows)
00209             s->font = ff_cga_font;
00210             s->font_height = 8;
00211             width  = 80<<3;
00212             height = 43<<3;
00213             break;
00214         case 17: case 18: //640x480 (60 rows)
00215             s->font = ff_cga_font;
00216             s->font_height = 8;
00217             width  = 80<<3;
00218             height = 60<<4;
00219             break;
00220         default:
00221             av_log_ask_for_sample(avctx, "unsupported screen mode\n");
00222         }
00223         if (width != avctx->width || height != avctx->height) {
00224             if (s->frame.data[0])
00225                 avctx->release_buffer(avctx, &s->frame);
00226             avcodec_set_dimensions(avctx, width, height);
00227             ret = avctx->get_buffer(avctx, &s->frame);
00228             if (ret < 0) {
00229                 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00230                 return ret;
00231             }
00232             s->frame.pict_type           = AV_PICTURE_TYPE_I;
00233             s->frame.palette_has_changed = 1;
00234             memcpy(s->frame.data[1], ff_cga_palette, 16 * 4);
00235             erase_screen(avctx);
00236         } else if (c == 'l') {
00237             erase_screen(avctx);
00238         }
00239         break;
00240     case 'J': //Erase in Page
00241         switch (s->args[0]) {
00242         case 0:
00243             erase_line(avctx, s->x, avctx->width - s->x);
00244             if (s->y < avctx->height - s->font_height)
00245                 memset(s->frame.data[0] + (s->y + s->font_height)*s->frame.linesize[0],
00246                     DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame.linesize[0]);
00247             break;
00248         case 1:
00249             erase_line(avctx, 0, s->x);
00250             if (s->y > 0)
00251                 memset(s->frame.data[0], DEFAULT_BG_COLOR, s->y * s->frame.linesize[0]);
00252             break;
00253         case 2:
00254             erase_screen(avctx);
00255         }
00256         break;
00257     case 'K': //Erase in Line
00258         switch(s->args[0]) {
00259         case 0:
00260             erase_line(avctx, s->x, avctx->width - s->x);
00261             break;
00262         case 1:
00263             erase_line(avctx, 0, s->x);
00264             break;
00265         case 2:
00266             erase_line(avctx, 0, avctx->width);
00267         }
00268         break;
00269     case 'm': //Select Graphics Rendition
00270         if (s->nb_args == 0) {
00271             s->nb_args = 1;
00272             s->args[0] = 0;
00273         }
00274         for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
00275             int m = s->args[i];
00276             if (m == 0) {
00277                 s->attributes = 0;
00278                 s->fg = DEFAULT_FG_COLOR;
00279                 s->bg = DEFAULT_BG_COLOR;
00280             } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {
00281                 s->attributes |= 1 << (m - 1);
00282             } else if (m >= 30 && m <= 38) {
00283                 s->fg = ansi_to_cga[m - 30];
00284             } else if (m == 39) {
00285                 s->fg = ansi_to_cga[DEFAULT_FG_COLOR];
00286             } else if (m >= 40 && m <= 47) {
00287                 s->bg = ansi_to_cga[m - 40];
00288             } else if (m == 49) {
00289                 s->fg = ansi_to_cga[DEFAULT_BG_COLOR];
00290             } else {
00291                 av_log_ask_for_sample(avctx, "unsupported rendition parameter\n");
00292             }
00293         }
00294         break;
00295     case 'n': //Device Status Report
00296     case 'R': //report current line and column
00297         /* ignore */
00298         break;
00299     case 's': //Save Cursor Position
00300         s->sx = s->x;
00301         s->sy = s->y;
00302         break;
00303     case 'u': //Restore Cursor Position
00304         s->x = av_clip(s->sx, 0, avctx->width  - FONT_WIDTH);
00305         s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
00306         break;
00307     default:
00308         av_log_ask_for_sample(avctx, "unsupported escape code\n");
00309         break;
00310     }
00311     return 0;
00312 }
00313 
00314 static int decode_frame(AVCodecContext *avctx,
00315                             void *data, int *data_size,
00316                             AVPacket *avpkt)
00317 {
00318     AnsiContext *s = avctx->priv_data;
00319     uint8_t *buf = avpkt->data;
00320     int buf_size = avpkt->size;
00321     const uint8_t *buf_end   = buf+buf_size;
00322     int ret, i, count;
00323 
00324     ret = avctx->reget_buffer(avctx, &s->frame);
00325     if (ret < 0){
00326         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00327         return ret;
00328     }
00329     s->frame.pict_type           = AV_PICTURE_TYPE_I;
00330     s->frame.palette_has_changed = 1;
00331     memcpy(s->frame.data[1], ff_cga_palette, 16 * 4);
00332 
00333     while(buf < buf_end) {
00334         switch(s->state) {
00335         case STATE_NORMAL:
00336             switch (buf[0]) {
00337             case 0x00: //NUL
00338             case 0x07: //BEL
00339             case 0x1A: //SUB
00340                 /* ignore */
00341                 break;
00342             case 0x08: //BS
00343                 s->x = FFMAX(s->x - 1, 0);
00344                 break;
00345             case 0x09: //HT
00346                 i = s->x / FONT_WIDTH;
00347                 count = ((i + 8) & ~7) - i;
00348                 for (i = 0; i < count; i++)
00349                     draw_char(avctx, ' ');
00350                 break;
00351             case 0x0A: //LF
00352                 hscroll(avctx);
00353             case 0x0D: //CR
00354                 s->x = 0;
00355                 break;
00356             case 0x0C: //FF
00357                 erase_screen(avctx);
00358                 break;
00359             case 0x1B: //ESC
00360                 s->state = STATE_ESCAPE;
00361                 break;
00362             default:
00363                 draw_char(avctx, buf[0]);
00364             }
00365             break;
00366         case STATE_ESCAPE:
00367             if (buf[0] == '[') {
00368                 s->state   = STATE_CODE;
00369                 s->nb_args = 0;
00370                 s->args[0] = 0;
00371             } else {
00372                 s->state = STATE_NORMAL;
00373                 draw_char(avctx, 0x1B);
00374                     return -1;
00375                 continue;
00376             }
00377             break;
00378         case STATE_CODE:
00379             switch(buf[0]) {
00380             case '0': case '1': case '2': case '3': case '4':
00381             case '5': case '6': case '7': case '8': case '9':
00382                 if (s->nb_args < MAX_NB_ARGS)
00383                     s->args[s->nb_args] = s->args[s->nb_args] * 10 + buf[0] - '0';
00384                 break;
00385             case ';':
00386                 s->nb_args++;
00387                 if (s->nb_args < MAX_NB_ARGS)
00388                     s->args[s->nb_args] = 0;
00389                 break;
00390             case 'M':
00391                 s->state = STATE_MUSIC_PREAMBLE;
00392                 break;
00393             case '=': case '?':
00394                 /* ignore */
00395                 break;
00396             default:
00397                 if (s->nb_args > MAX_NB_ARGS)
00398                     av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);
00399                 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args])
00400                     s->nb_args++;
00401                 if (execute_code(avctx, buf[0]) < 0)
00402                     return -1;
00403                 s->state = STATE_NORMAL;
00404             }
00405             break;
00406         case STATE_MUSIC_PREAMBLE:
00407             if (buf[0] == 0x0E || buf[0] == 0x1B)
00408                 s->state = STATE_NORMAL;
00409             /* ignore music data */
00410             break;
00411         }
00412         buf++;
00413     }
00414 
00415     *data_size = sizeof(AVFrame);
00416     *(AVFrame*)data = s->frame;
00417     return buf_size;
00418 }
00419 
00420 static av_cold int decode_close(AVCodecContext *avctx)
00421 {
00422     AnsiContext *s = avctx->priv_data;
00423     if (s->frame.data[0])
00424         avctx->release_buffer(avctx, &s->frame);
00425     return 0;
00426 }
00427 
00428 AVCodec ff_ansi_decoder = {
00429     .name           = "ansi",
00430     .type           = AVMEDIA_TYPE_VIDEO,
00431     .id             = CODEC_ID_ANSI,
00432     .priv_data_size = sizeof(AnsiContext),
00433     .init           = decode_init,
00434     .close          = decode_close,
00435     .decode         = decode_frame,
00436     .capabilities   = CODEC_CAP_DR1,
00437     .long_name      = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
00438 };