libavcodec/msrle.c

   1 /*
   2  * Micrsoft RLE Video Decoder
   3  * Copyright (C) 2003 the ffmpeg project
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file libavcodec/msrle.c
  24  * MS RLE Video Decoder by Mike Melanson (melanson@pcisys.net)
  25  * For more information about the MS RLE format, visit:
  26  *   http://www.pcisys.net/~melanson/codecs/
  27  *
  28  * The MS RLE decoder outputs PAL8 colorspace data.
  29  *
  30  * Note that this decoder expects the palette colors from the end of the
  31  * BITMAPINFO header passed through palctrl.
  32  */
  33
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <unistd.h>
  38
  39 #include "avcodec.h"
  40 #include "dsputil.h"
  41 #include "msrledec.h"
  42
  43 typedef struct MsrleContext {
  44     AVCodecContext *avctx;
  45     AVFrame frame;
  46
  47     const unsigned char *buf;
  48     int size;
  49
  50 } MsrleContext;
  51
  52 static av_cold int msrle_decode_init(AVCodecContext *avctx)
  53 {
  54     MsrleContext *s = avctx->priv_data;
  55
  56     s->avctx = avctx;
  57
  58     switch (avctx->bits_per_coded_sample) {
  59     case 4:
  60     case 8:
  61         avctx->pix_fmt = PIX_FMT_PAL8;
  62         break;
  63     case 24:
  64         avctx->pix_fmt = PIX_FMT_BGR24;
  65         break;
  66     default:
  67         av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
  68         return -1;
  69     }
  70
  71     s->frame.data[0] = NULL;
  72
  73     return 0;
  74 }
  75
  76 static int msrle_decode_frame(AVCodecContext *avctx,
  77                               void *data, int *data_size,
  78                               AVPacket *avpkt)
  79 {
  80     const uint8_t *buf = avpkt->data;
  81     int buf_size = avpkt->size;
  82     MsrleContext *s = avctx->priv_data;
  83     int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
  84
  85     s->buf = buf;
  86     s->size = buf_size;
  87
  88     s->frame.reference = 1;
  89     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
  90     if (avctx->reget_buffer(avctx, &s->frame)) {
  91         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
  92         return -1;
  93     }
  94
  95     if (s->avctx->palctrl) {
  96         /* make the palette available */
  97         memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
  98         if (s->avctx->palctrl->palette_changed) {
  99             s->frame.palette_has_changed = 1;
 100             s->avctx->palctrl->palette_changed = 0;
 101         }
 102     }
 103
 104     /* FIXME how to correctly detect RLE ??? */
 105     if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
 106         int linesize = avctx->width * avctx->bits_per_coded_sample / 8;
 107         uint8_t *ptr = s->frame.data[0];
 108         uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
 109         int i, j;
 110
 111         for (i = 0; i < avctx->height; i++) {
 112             if (avctx->bits_per_coded_sample == 4) {
 113                 for (j = 0; j < avctx->width - 1; j += 2) {
 114                     ptr[j+0] = buf[j>>1] >> 4;
 115                     ptr[j+1] = buf[j>>1] & 0xF;
 116                 }
 117                 if (avctx->width & 1)
 118                     ptr[j+0] = buf[j>>1] >> 4;
 119             } else {
 120                 memcpy(ptr, buf, linesize);
 121             }
 122             buf -= istride;
 123             ptr += s->frame.linesize[0];
 124         }
 125     } else {
 126         ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, buf, buf_size);
 127     }
 128
 129     *data_size = sizeof(AVFrame);
 130     *(AVFrame*)data = s->frame;
 131
 132     /* report that the buffer was completely consumed */
 133     return buf_size;
 134 }
 135
 136 static av_cold int msrle_decode_end(AVCodecContext *avctx)
 137 {
 138     MsrleContext *s = avctx->priv_data;
 139
 140     /* release the last frame */
 141     if (s->frame.data[0])
 142         avctx->release_buffer(avctx, &s->frame);
 143
 144     return 0;
 145 }
 146
 147 AVCodec msrle_decoder = {
 148     "msrle",
 149     CODEC_TYPE_VIDEO,
 150     CODEC_ID_MSRLE,
 151     sizeof(MsrleContext),
 152     msrle_decode_init,
 153     NULL,
 154     msrle_decode_end,
 155     msrle_decode_frame,
 156     CODEC_CAP_DR1,
 157     .long_name= NULL_IF_CONFIG_SMALL("Microsoft RLE"),
 158 };