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
  38 #include "avcodec.h"
  39 #include "dsputil.h"
  40 #include "msrledec.h"
  41
  42 typedef struct MsrleContext {
  43     AVCodecContext *avctx;
  44     AVFrame frame;
  45
  46     const unsigned char *buf;
  47     int size;
  48
  49 } MsrleContext;
  50
  51 static av_cold int msrle_decode_init(AVCodecContext *avctx)
  52 {
  53     MsrleContext *s = avctx->priv_data;
  54
  55     s->avctx = avctx;
  56
  57     switch (avctx->bits_per_coded_sample) {
  58     case 4:
  59     case 8:
  60         avctx->pix_fmt = PIX_FMT_PAL8;
  61         break;
  62     case 24:
  63         avctx->pix_fmt = PIX_FMT_BGR24;
  64         break;
  65     default:
  66         av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
  67         return -1;
  68     }
  69
  70     s->frame.data[0] = NULL;
  71
  72     return 0;
  73 }
  74
  75 static int msrle_decode_frame(AVCodecContext *avctx,
  76                               void *data, int *data_size,
  77                               AVPacket *avpkt)
  78 {
  79     const uint8_t *buf = avpkt->data;
  80     int buf_size = avpkt->size;
  81     MsrleContext *s = avctx->priv_data;
  82     int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
  83
  84     s->buf = buf;
  85     s->size = buf_size;
  86
  87     s->frame.reference = 1;
  88     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
  89     if (avctx->reget_buffer(avctx, &s->frame)) {
  90         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
  91         return -1;
  92     }
  93
  94     if (s->avctx->palctrl) {
  95         /* make the palette available */
  96         memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
  97         if (s->avctx->palctrl->palette_changed) {
  98             s->frame.palette_has_changed = 1;
  99             s->avctx->palctrl->palette_changed = 0;
 100         }
 101     }
 102
 103     /* FIXME how to correctly detect RLE ??? */
 104     if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
 105         int linesize = avctx->width * avctx->bits_per_coded_sample / 8;
 106         uint8_t *ptr = s->frame.data[0];
 107         uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
 108         int i, j;
 109
 110         for (i = 0; i < avctx->height; i++) {
 111             if (avctx->bits_per_coded_sample == 4) {
 112                 for (j = 0; j < avctx->width - 1; j += 2) {
 113                     ptr[j+0] = buf[j>>1] >> 4;
 114                     ptr[j+1] = buf[j>>1] & 0xF;
 115                 }
 116                 if (avctx->width & 1)
 117                     ptr[j+0] = buf[j>>1] >> 4;
 118             } else {
 119                 memcpy(ptr, buf, linesize);
 120             }
 121             buf -= istride;
 122             ptr += s->frame.linesize[0];
 123         }
 124     } else {
 125         ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, buf, buf_size);
 126     }
 127
 128     *data_size = sizeof(AVFrame);
 129     *(AVFrame*)data = s->frame;
 130
 131     /* report that the buffer was completely consumed */
 132     return buf_size;
 133 }
 134
 135 static av_cold int msrle_decode_end(AVCodecContext *avctx)
 136 {
 137     MsrleContext *s = avctx->priv_data;
 138
 139     /* release the last frame */
 140     if (s->frame.data[0])
 141         avctx->release_buffer(avctx, &s->frame);
 142
 143     return 0;
 144 }
 145
 146 AVCodec msrle_decoder = {
 147     "msrle",
 148     CODEC_TYPE_VIDEO,
 149     CODEC_ID_MSRLE,
 150     sizeof(MsrleContext),
 151     msrle_decode_init,
 152     NULL,
 153     msrle_decode_end,
 154     msrle_decode_frame,
 155     CODEC_CAP_DR1,
 156     .long_name= NULL_IF_CONFIG_SMALL("Microsoft RLE"),
 157 };