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  1. /*
  2.  * Microsoft 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
  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.     int i;
  54.  
  55.     s->avctx = avctx;
  56.  
  57.     switch (avctx->bits_per_coded_sample) {
  58.     case 1:
  59.         avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
  60.         break;
  61.     case 4:
  62.     case 8:
  63.         avctx->pix_fmt = AV_PIX_FMT_PAL8;
  64.         break;
  65.     case 24:
  66.         avctx->pix_fmt = AV_PIX_FMT_BGR24;
  67.         break;
  68.     default:
  69.         av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
  70.         return AVERROR_INVALIDDATA;
  71.     }
  72.  
  73.     avcodec_get_frame_defaults(&s->frame);
  74.  
  75.     if (avctx->extradata_size >= 4)
  76.         for (i = 0; i < FFMIN(avctx->extradata_size, AVPALETTE_SIZE)/4; i++)
  77.             s->pal[i] = 0xFFU<<24 | AV_RL32(avctx->extradata+4*i);
  78.  
  79.     return 0;
  80. }
  81.  
  82. static int msrle_decode_frame(AVCodecContext *avctx,
  83.                               void *data, int *got_frame,
  84.                               AVPacket *avpkt)
  85. {
  86.     const uint8_t *buf = avpkt->data;
  87.     int buf_size = avpkt->size;
  88.     MsrleContext *s = avctx->priv_data;
  89.     int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
  90.     int ret;
  91.  
  92.     s->buf = buf;
  93.     s->size = buf_size;
  94.  
  95.     if ((ret = ff_reget_buffer(avctx, &s->frame)) < 0)
  96.         return ret;
  97.  
  98.     if (avctx->bits_per_coded_sample > 1 && avctx->bits_per_coded_sample <= 8) {
  99.         const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
  100.  
  101.         if (pal) {
  102.             s->frame.palette_has_changed = 1;
  103.             memcpy(s->pal, pal, AVPALETTE_SIZE);
  104.         }
  105.         /* make the palette available */
  106.         memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);
  107.     }
  108.  
  109.     /* FIXME how to correctly detect RLE ??? */
  110.     if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
  111.         int linesize = (avctx->width * avctx->bits_per_coded_sample + 7) / 8;
  112.         uint8_t *ptr = s->frame.data[0];
  113.         uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
  114.         int i, j;
  115.  
  116.         for (i = 0; i < avctx->height; i++) {
  117.             if (avctx->bits_per_coded_sample == 4) {
  118.                 for (j = 0; j < avctx->width - 1; j += 2) {
  119.                     ptr[j+0] = buf[j>>1] >> 4;
  120.                     ptr[j+1] = buf[j>>1] & 0xF;
  121.                 }
  122.                 if (avctx->width & 1)
  123.                     ptr[j+0] = buf[j>>1] >> 4;
  124.             } else {
  125.                 memcpy(ptr, buf, linesize);
  126.             }
  127.             buf -= istride;
  128.             ptr += s->frame.linesize[0];
  129.         }
  130.     } else {
  131.         bytestream2_init(&s->gb, buf, buf_size);
  132.         ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, &s->gb);
  133.     }
  134.  
  135.     if ((ret = av_frame_ref(data, &s->frame)) < 0)
  136.         return ret;
  137.  
  138.     *got_frame      = 1;
  139.  
  140.     /* report that the buffer was completely consumed */
  141.     return buf_size;
  142. }
  143.  
  144. static av_cold int msrle_decode_end(AVCodecContext *avctx)
  145. {
  146.     MsrleContext *s = avctx->priv_data;
  147.  
  148.     /* release the last frame */
  149.     av_frame_unref(&s->frame);
  150.  
  151.     return 0;
  152. }
  153.  
  154. AVCodec ff_msrle_decoder = {
  155.     .name           = "msrle",
  156.     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft RLE"),
  157.     .type           = AVMEDIA_TYPE_VIDEO,
  158.     .id             = AV_CODEC_ID_MSRLE,
  159.     .priv_data_size = sizeof(MsrleContext),
  160.     .init           = msrle_decode_init,
  161.     .close          = msrle_decode_end,
  162.     .decode         = msrle_decode_frame,
  163.     .capabilities   = CODEC_CAP_DR1,
  164. };
  165.