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 "internal.h"
  37 #include "msrledec.h"
  38
  39 typedef struct MsrleContext {
  40     AVCodecContext *avctx;
  41     AVFrame frame;
  42
  43     GetByteContext gb;
  44     const unsigned char *buf;
  45     int size;
  46
  47     uint32_t pal[256];
  48 } MsrleContext;
  49
  50 static av_cold int msrle_decode_init(AVCodecContext *avctx)
  51 {
  52     MsrleContext *s = avctx->priv_data;
  53
  54     s->avctx = avctx;
  55
  56     switch (avctx->bits_per_coded_sample) {
  57     case 4:
  58     case 8:
  59         avctx->pix_fmt = AV_PIX_FMT_PAL8;
  60         break;
  61     case 24:
  62         avctx->pix_fmt = AV_PIX_FMT_BGR24;
  63         break;
  64     default:
  65         av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
  66         return AVERROR_INVALIDDATA;
  67     }
  68
  69     s->frame.data[0] = NULL;
  70
  71     return 0;
  72 }
  73
  74 static int msrle_decode_frame(AVCodecContext *avctx,
  75                               void *data, int *got_frame,
  76                               AVPacket *avpkt)
  77 {
  78     const uint8_t *buf = avpkt->data;
  79     int buf_size = avpkt->size;
  80     MsrleContext *s = avctx->priv_data;
  81     int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
  82     int ret;
  83
  84     s->buf = buf;
  85     s->size = buf_size;
  86
  87     if ((ret = ff_reget_buffer(avctx, &s->frame)) < 0) {
  88         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
  89         return ret;
  90     }
  91
  92     if (avctx->bits_per_coded_sample <= 8) {
  93         const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
  94
  95         if (pal) {
  96             s->frame.palette_has_changed = 1;
  97             memcpy(s->pal, pal, AVPALETTE_SIZE);
  98         }
  99
 100         /* make the palette available */
 101         memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);
 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         bytestream2_init(&s->gb, buf, buf_size);
 127         ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, &s->gb);
 128     }
 129
 130     if ((ret = av_frame_ref(data, &s->frame)) < 0)
 131         return ret;
 132
 133     *got_frame      = 1;
 134
 135     /* report that the buffer was completely consumed */
 136     return buf_size;
 137 }
 138
 139 static av_cold int msrle_decode_end(AVCodecContext *avctx)
 140 {
 141     MsrleContext *s = avctx->priv_data;
 142
 143     /* release the last frame */
 144     av_frame_unref(&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 };