libavcodec/msrle.c

   1 /*
   2  * Microsoft RLE video decoder
   3  * Copyright (C) 2003 the ffmpeg project
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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
  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
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include "avcodec.h"
  36 #include "msrledec.h"
  37
  38 typedef struct MsrleContext {
  39     AVCodecContext *avctx;
  40     AVFrame frame;
  41
  42     GetByteContext gb;
  43     const unsigned char *buf;
  44     int size;
  45
  46     uint32_t pal[256];
  47 } MsrleContext;
  48
  49 static av_cold int msrle_decode_init(AVCodecContext *avctx)
  50 {
  51     MsrleContext *s = avctx->priv_data;
  52
  53     s->avctx = avctx;
  54
  55     switch (avctx->bits_per_coded_sample) {
  56     case 4:
  57     case 8:
  58         avctx->pix_fmt = AV_PIX_FMT_PAL8;
  59         break;
  60     case 24:
  61         avctx->pix_fmt = AV_PIX_FMT_BGR24;
  62         break;
  63     default:
  64         av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
  65         return AVERROR_INVALIDDATA;
  66     }
  67
  68     s->frame.data[0] = NULL;
  69
  70     return 0;
  71 }
  72
  73 static int msrle_decode_frame(AVCodecContext *avctx,
  74                               void *data, int *got_frame,
  75                               AVPacket *avpkt)
  76 {
  77     const uint8_t *buf = avpkt->data;
  78     int buf_size = avpkt->size;
  79     MsrleContext *s = avctx->priv_data;
  80     int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
  81     int ret;
  82
  83     s->buf = buf;
  84     s->size = buf_size;
  85
  86     s->frame.reference = 1;
  87     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
  88     if ((ret = avctx->reget_buffer(avctx, &s->frame)) < 0) {
  89         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
  90         return ret;
  91     }
  92
  93     if (avctx->bits_per_coded_sample <= 8) {
  94         const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
  95
  96         if (pal) {
  97             s->frame.palette_has_changed = 1;
  98             memcpy(s->pal, pal, AVPALETTE_SIZE);
  99         }
 100
 101         /* make the palette available */
 102         memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);
 103     }
 104
 105     /* FIXME how to correctly detect RLE ??? */
 106     if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
 107         int linesize = avctx->width * avctx->bits_per_coded_sample / 8;
 108         uint8_t *ptr = s->frame.data[0];
 109         uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
 110         int i, j;
 111
 112         for (i = 0; i < avctx->height; i++) {
 113             if (avctx->bits_per_coded_sample == 4) {
 114                 for (j = 0; j < avctx->width - 1; j += 2) {
 115                     ptr[j+0] = buf[j>>1] >> 4;
 116                     ptr[j+1] = buf[j>>1] & 0xF;
 117                 }
 118                 if (avctx->width & 1)
 119                     ptr[j+0] = buf[j>>1] >> 4;
 120             } else {
 121                 memcpy(ptr, buf, linesize);
 122             }
 123             buf -= istride;
 124             ptr += s->frame.linesize[0];
 125         }
 126     } else {
 127         bytestream2_init(&s->gb, buf, buf_size);
 128         ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, &s->gb);
 129     }
 130
 131     *got_frame      = 1;
 132     *(AVFrame*)data = s->frame;
 133
 134     /* report that the buffer was completely consumed */
 135     return buf_size;
 136 }
 137
 138 static av_cold int msrle_decode_end(AVCodecContext *avctx)
 139 {
 140     MsrleContext *s = avctx->priv_data;
 141
 142     /* release the last frame */
 143     if (s->frame.data[0])
 144         avctx->release_buffer(avctx, &s->frame);
 145
 146     return 0;
 147 }
 148
 149 AVCodec ff_msrle_decoder = {
 150     .name           = "msrle",
 151     .type           = AVMEDIA_TYPE_VIDEO,
 152     .id             = AV_CODEC_ID_MSRLE,
 153     .priv_data_size = sizeof(MsrleContext),
 154     .init           = msrle_decode_init,
 155     .close          = msrle_decode_end,
 156     .decode         = msrle_decode_frame,
 157     .capabilities   = CODEC_CAP_DR1,
 158     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft RLE"),
 159 };