• Main Page
  • Related Pages
  • Modules
  • Data Structures
  • Files
  • Examples
  • File List
  • Globals

libavcodec/8bps.c

Go to the documentation of this file.
00001 /*
00002  * Quicktime Planar RGB (8BPS) Video Decoder
00003  * Copyright (C) 2003 Roberto Togni
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 
00034 #include <stdio.h>
00035 #include <stdlib.h>
00036 
00037 #include "libavutil/intreadwrite.h"
00038 #include "avcodec.h"
00039 
00040 
00041 static const enum PixelFormat pixfmt_rgb24[] = {PIX_FMT_BGR24, PIX_FMT_RGB32, PIX_FMT_NONE};
00042 
00043 /*
00044  * Decoder context
00045  */
00046 typedef struct EightBpsContext {
00047 
00048         AVCodecContext *avctx;
00049         AVFrame pic;
00050 
00051         unsigned char planes;
00052         unsigned char planemap[4];
00053 
00054         uint32_t pal[256];
00055 } EightBpsContext;
00056 
00057 
00058 /*
00059  *
00060  * Decode a frame
00061  *
00062  */
00063 static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)
00064 {
00065         const uint8_t *buf = avpkt->data;
00066         int buf_size = avpkt->size;
00067         EightBpsContext * const c = avctx->priv_data;
00068         const unsigned char *encoded = buf;
00069         unsigned char *pixptr, *pixptr_end;
00070         unsigned int height = avctx->height; // Real image height
00071         unsigned int dlen, p, row;
00072         const unsigned char *lp, *dp;
00073         unsigned char count;
00074         unsigned int px_inc;
00075         unsigned int planes = c->planes;
00076         unsigned char *planemap = c->planemap;
00077 
00078         if(c->pic.data[0])
00079                 avctx->release_buffer(avctx, &c->pic);
00080 
00081         c->pic.reference = 0;
00082         c->pic.buffer_hints = FF_BUFFER_HINTS_VALID;
00083         if(avctx->get_buffer(avctx, &c->pic) < 0){
00084                 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00085                 return -1;
00086         }
00087 
00088         /* Set data pointer after line lengths */
00089         dp = encoded + planes * (height << 1);
00090 
00091         /* Ignore alpha plane, don't know what to do with it */
00092         if (planes == 4)
00093                 planes--;
00094 
00095         px_inc = planes + (avctx->pix_fmt == PIX_FMT_RGB32);
00096 
00097         for (p = 0; p < planes; p++) {
00098                 /* Lines length pointer for this plane */
00099                 lp = encoded + p * (height << 1);
00100 
00101                 /* Decode a plane */
00102                 for(row = 0; row < height; row++) {
00103                         pixptr = c->pic.data[0] + row * c->pic.linesize[0] + planemap[p];
00104                         pixptr_end = pixptr + c->pic.linesize[0];
00105                         dlen = av_be2ne16(*(const unsigned short *)(lp+row*2));
00106                         /* Decode a row of this plane */
00107                         while(dlen > 0) {
00108                                 if(dp + 1 >= buf+buf_size) return -1;
00109                                 if ((count = *dp++) <= 127) {
00110                                         count++;
00111                                         dlen -= count + 1;
00112                                         if (pixptr + count * px_inc > pixptr_end)
00113                                             break;
00114                                         if(dp + count > buf+buf_size) return -1;
00115                                         while(count--) {
00116                                                 *pixptr = *dp++;
00117                                                 pixptr += px_inc;
00118                                         }
00119                                 } else {
00120                                         count = 257 - count;
00121                                         if (pixptr + count * px_inc > pixptr_end)
00122                                             break;
00123                                         while(count--) {
00124                                                 *pixptr = *dp;
00125                                                 pixptr += px_inc;
00126                                         }
00127                                         dp++;
00128                                         dlen -= 2;
00129                                 }
00130                         }
00131                 }
00132         }
00133 
00134         if (avctx->bits_per_coded_sample <= 8) {
00135                 const uint8_t *pal = av_packet_get_side_data(avpkt,
00136                                                              AV_PKT_DATA_PALETTE,
00137                                                              NULL);
00138                 if (pal) {
00139                         c->pic.palette_has_changed = 1;
00140                         memcpy(c->pal, pal, AVPALETTE_SIZE);
00141                 }
00142 
00143                 memcpy (c->pic.data[1], c->pal, AVPALETTE_SIZE);
00144         }
00145 
00146         *data_size = sizeof(AVFrame);
00147         *(AVFrame*)data = c->pic;
00148 
00149         /* always report that the buffer was completely consumed */
00150         return buf_size;
00151 }
00152 
00153 
00154 /*
00155  *
00156  * Init 8BPS decoder
00157  *
00158  */
00159 static av_cold int decode_init(AVCodecContext *avctx)
00160 {
00161         EightBpsContext * const c = avctx->priv_data;
00162 
00163         c->avctx = avctx;
00164 
00165         c->pic.data[0] = NULL;
00166 
00167         switch (avctx->bits_per_coded_sample) {
00168                 case 8:
00169                         avctx->pix_fmt = PIX_FMT_PAL8;
00170                         c->planes = 1;
00171                         c->planemap[0] = 0; // 1st plane is palette indexes
00172                         break;
00173                 case 24:
00174                         avctx->pix_fmt = avctx->get_format(avctx, pixfmt_rgb24);
00175                         c->planes = 3;
00176                         c->planemap[0] = 2; // 1st plane is red
00177                         c->planemap[1] = 1; // 2nd plane is green
00178                         c->planemap[2] = 0; // 3rd plane is blue
00179                         break;
00180                 case 32:
00181                         avctx->pix_fmt = PIX_FMT_RGB32;
00182                         c->planes = 4;
00183 #if HAVE_BIGENDIAN
00184                         c->planemap[0] = 1; // 1st plane is red
00185                         c->planemap[1] = 2; // 2nd plane is green
00186                         c->planemap[2] = 3; // 3rd plane is blue
00187                         c->planemap[3] = 0; // 4th plane is alpha???
00188 #else
00189                         c->planemap[0] = 2; // 1st plane is red
00190                         c->planemap[1] = 1; // 2nd plane is green
00191                         c->planemap[2] = 0; // 3rd plane is blue
00192                         c->planemap[3] = 3; // 4th plane is alpha???
00193 #endif
00194                         break;
00195                 default:
00196                         av_log(avctx, AV_LOG_ERROR, "Error: Unsupported color depth: %u.\n", avctx->bits_per_coded_sample);
00197                         return -1;
00198         }
00199 
00200   return 0;
00201 }
00202 
00203 
00204 
00205 
00206 /*
00207  *
00208  * Uninit 8BPS decoder
00209  *
00210  */
00211 static av_cold int decode_end(AVCodecContext *avctx)
00212 {
00213         EightBpsContext * const c = avctx->priv_data;
00214 
00215         if (c->pic.data[0])
00216                 avctx->release_buffer(avctx, &c->pic);
00217 
00218         return 0;
00219 }
00220 
00221 
00222 
00223 AVCodec ff_eightbps_decoder = {
00224     .name           = "8bps",
00225     .type           = AVMEDIA_TYPE_VIDEO,
00226     .id             = CODEC_ID_8BPS,
00227     .priv_data_size = sizeof(EightBpsContext),
00228     .init           = decode_init,
00229     .close          = decode_end,
00230     .decode         = decode_frame,
00231     .capabilities   = CODEC_CAP_DR1,
00232     .long_name      = NULL_IF_CONFIG_SMALL("QuickTime 8BPS video"),
00233 };
Generated on Thu Jul 11 2013 15:38:18 for Libav by doxygen 1.7.1