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libavcodec/pnm.c

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00001 /*
00002  * PNM image format
00003  * Copyright (c) 2002, 2003 Fabrice Bellard
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 
00022 #include "avcodec.h"
00023 #include "pnm.h"
00024 
00025 static inline int pnm_space(int c)
00026 {
00027     return c == ' ' || c == '\n' || c == '\r' || c == '\t';
00028 }
00029 
00030 static void pnm_get(PNMContext *sc, char *str, int buf_size)
00031 {
00032     char *s;
00033     int c;
00034 
00035     /* skip spaces and comments */
00036     for (;;) {
00037         c = *sc->bytestream++;
00038         if (c == '#')  {
00039             do {
00040                 c = *sc->bytestream++;
00041             } while (c != '\n' && sc->bytestream < sc->bytestream_end);
00042         } else if (!pnm_space(c)) {
00043             break;
00044         }
00045     }
00046 
00047     s = str;
00048     while (sc->bytestream < sc->bytestream_end && !pnm_space(c)) {
00049         if ((s - str)  < buf_size - 1)
00050             *s++ = c;
00051         c = *sc->bytestream++;
00052     }
00053     *s = '\0';
00054 }
00055 
00056 int ff_pnm_decode_header(AVCodecContext *avctx, PNMContext * const s)
00057 {
00058     char buf1[32], tuple_type[32];
00059     int h, w, depth, maxval;
00060 
00061     pnm_get(s, buf1, sizeof(buf1));
00062     s->type= buf1[1]-'0';
00063     if(buf1[0] != 'P')
00064         return -1;
00065 
00066     if (s->type==1 || s->type==4) {
00067         avctx->pix_fmt = PIX_FMT_MONOWHITE;
00068     } else if (s->type==2 || s->type==5) {
00069         if (avctx->codec_id == CODEC_ID_PGMYUV)
00070             avctx->pix_fmt = PIX_FMT_YUV420P;
00071         else
00072             avctx->pix_fmt = PIX_FMT_GRAY8;
00073     } else if (s->type==3 || s->type==6) {
00074         avctx->pix_fmt = PIX_FMT_RGB24;
00075     } else if (s->type==7) {
00076         w      = -1;
00077         h      = -1;
00078         maxval = -1;
00079         depth  = -1;
00080         tuple_type[0] = '\0';
00081         for (;;) {
00082             pnm_get(s, buf1, sizeof(buf1));
00083             if (!strcmp(buf1, "WIDTH")) {
00084                 pnm_get(s, buf1, sizeof(buf1));
00085                 w = strtol(buf1, NULL, 10);
00086             } else if (!strcmp(buf1, "HEIGHT")) {
00087                 pnm_get(s, buf1, sizeof(buf1));
00088                 h = strtol(buf1, NULL, 10);
00089             } else if (!strcmp(buf1, "DEPTH")) {
00090                 pnm_get(s, buf1, sizeof(buf1));
00091                 depth = strtol(buf1, NULL, 10);
00092             } else if (!strcmp(buf1, "MAXVAL")) {
00093                 pnm_get(s, buf1, sizeof(buf1));
00094                 maxval = strtol(buf1, NULL, 10);
00095             } else if (!strcmp(buf1, "TUPLETYPE")) {
00096                 pnm_get(s, tuple_type, sizeof(tuple_type));
00097             } else if (!strcmp(buf1, "ENDHDR")) {
00098                 break;
00099             } else {
00100                 return -1;
00101             }
00102         }
00103         /* check that all tags are present */
00104         if (w <= 0 || h <= 0 || maxval <= 0 || depth <= 0 || tuple_type[0] == '\0' || avcodec_check_dimensions(avctx, w, h))
00105             return -1;
00106 
00107         avctx->width  = w;
00108         avctx->height = h;
00109         if (depth == 1) {
00110             if (maxval == 1)
00111                 avctx->pix_fmt = PIX_FMT_MONOWHITE;
00112             else
00113                 avctx->pix_fmt = PIX_FMT_GRAY8;
00114         } else if (depth == 3) {
00115             if (maxval < 256) {
00116             avctx->pix_fmt = PIX_FMT_RGB24;
00117             } else {
00118                 av_log(avctx, AV_LOG_ERROR, "16-bit components are only supported for grayscale\n");
00119                 avctx->pix_fmt = PIX_FMT_NONE;
00120                 return -1;
00121             }
00122         } else if (depth == 4) {
00123             avctx->pix_fmt = PIX_FMT_RGB32;
00124         } else {
00125             return -1;
00126         }
00127         return 0;
00128     } else {
00129         return -1;
00130     }
00131     pnm_get(s, buf1, sizeof(buf1));
00132     avctx->width = atoi(buf1);
00133     if (avctx->width <= 0)
00134         return -1;
00135     pnm_get(s, buf1, sizeof(buf1));
00136     avctx->height = atoi(buf1);
00137     if(avcodec_check_dimensions(avctx, avctx->width, avctx->height))
00138         return -1;
00139     if (avctx->pix_fmt != PIX_FMT_MONOWHITE) {
00140         pnm_get(s, buf1, sizeof(buf1));
00141         s->maxval = atoi(buf1);
00142         if (s->maxval >= 256) {
00143             if (avctx->pix_fmt == PIX_FMT_GRAY8) {
00144                 avctx->pix_fmt = PIX_FMT_GRAY16BE;
00145                 if (s->maxval != 65535)
00146                     avctx->pix_fmt = PIX_FMT_GRAY16;
00147             } else if (avctx->pix_fmt == PIX_FMT_RGB24) {
00148                 if (s->maxval > 255)
00149                     avctx->pix_fmt = PIX_FMT_RGB48BE;
00150             } else {
00151                 av_log(avctx, AV_LOG_ERROR, "Unsupported pixel format\n");
00152                 avctx->pix_fmt = PIX_FMT_NONE;
00153                 return -1;
00154             }
00155         }
00156     }else
00157         s->maxval=1;
00158     /* more check if YUV420 */
00159     if (avctx->pix_fmt == PIX_FMT_YUV420P) {
00160         if ((avctx->width & 1) != 0)
00161             return -1;
00162         h = (avctx->height * 2);
00163         if ((h % 3) != 0)
00164             return -1;
00165         h /= 3;
00166         avctx->height = h;
00167     }
00168     return 0;
00169 }
00170 
00171 av_cold int ff_pnm_end(AVCodecContext *avctx)
00172 {
00173     PNMContext *s = avctx->priv_data;
00174 
00175     if (s->picture.data[0])
00176         avctx->release_buffer(avctx, &s->picture);
00177 
00178     return 0;
00179 }
00180 
00181 av_cold int ff_pnm_init(AVCodecContext *avctx)
00182 {
00183     PNMContext *s = avctx->priv_data;
00184 
00185     avcodec_get_frame_defaults((AVFrame*)&s->picture);
00186     avctx->coded_frame = (AVFrame*)&s->picture;
00187 
00188     return 0;
00189 }

Generated on Fri Sep 16 2011 17:17:41 for FFmpeg by  doxygen 1.7.1