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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. #include "libavutil/imgutils.h"
  39.  
  40. typedef struct MsrleContext {
  41.     AVCodecContext *avctx;
  42.     AVFrame *frame;
  43.  
  44.     GetByteContext gb;
  45.     const unsigned char *buf;
  46.     int size;
  47.  
  48.     uint32_t pal[256];
  49. } MsrleContext;
  50.  
  51. static av_cold int msrle_decode_init(AVCodecContext *avctx)
  52. {
  53.     MsrleContext *s = avctx->priv_data;
  54.     int i;
  55.  
  56.     s->avctx = avctx;
  57.  
  58.     switch (avctx->bits_per_coded_sample) {
  59.     case 1:
  60.         avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
  61.         break;
  62.     case 4:
  63.     case 8:
  64.         avctx->pix_fmt = AV_PIX_FMT_PAL8;
  65.         break;
  66.     case 24:
  67.         avctx->pix_fmt = AV_PIX_FMT_BGR24;
  68.         break;
  69.     default:
  70.         av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
  71.         return AVERROR_INVALIDDATA;
  72.     }
  73.  
  74.     s->frame = av_frame_alloc();
  75.     if (!s->frame)
  76.         return AVERROR(ENOMEM);
  77.  
  78.     if (avctx->extradata_size >= 4)
  79.         for (i = 0; i < FFMIN(avctx->extradata_size, AVPALETTE_SIZE)/4; i++)
  80.             s->pal[i] = 0xFFU<<24 | AV_RL32(avctx->extradata+4*i);
  81.  
  82.     return 0;
  83. }
  84.  
  85. static int msrle_decode_frame(AVCodecContext *avctx,
  86.                               void *data, int *got_frame,
  87.                               AVPacket *avpkt)
  88. {
  89.     const uint8_t *buf = avpkt->data;
  90.     int buf_size = avpkt->size;
  91.     MsrleContext *s = avctx->priv_data;
  92.     int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
  93.     int ret;
  94.  
  95.     s->buf = buf;
  96.     s->size = buf_size;
  97.  
  98.     if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
  99.         return ret;
  100.  
  101.     if (avctx->bits_per_coded_sample > 1 && avctx->bits_per_coded_sample <= 8) {
  102.         const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
  103.  
  104.         if (pal) {
  105.             s->frame->palette_has_changed = 1;
  106.             memcpy(s->pal, pal, AVPALETTE_SIZE);
  107.         }
  108.         /* make the palette available */
  109.         memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
  110.     }
  111.  
  112.     /* FIXME how to correctly detect RLE ??? */
  113.     if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
  114.         int linesize = av_image_get_linesize(avctx->pix_fmt, avctx->width, 0);
  115.         uint8_t *ptr = s->frame->data[0];
  116.         uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
  117.         int i, j;
  118.  
  119.         if (linesize < 0)
  120.             return linesize;
  121.  
  122.         for (i = 0; i < avctx->height; i++) {
  123.             if (avctx->bits_per_coded_sample == 4) {
  124.                 for (j = 0; j < avctx->width - 1; j += 2) {
  125.                     ptr[j+0] = buf[j>>1] >> 4;
  126.                     ptr[j+1] = buf[j>>1] & 0xF;
  127.                 }
  128.                 if (avctx->width & 1)
  129.                     ptr[j+0] = buf[j>>1] >> 4;
  130.             } else {
  131.                 memcpy(ptr, buf, linesize);
  132.             }
  133.             buf -= istride;
  134.             ptr += s->frame->linesize[0];
  135.         }
  136.     } else {
  137.         bytestream2_init(&s->gb, buf, buf_size);
  138.         ff_msrle_decode(avctx, (AVPicture*)s->frame, avctx->bits_per_coded_sample, &s->gb);
  139.     }
  140.  
  141.     if ((ret = av_frame_ref(data, s->frame)) < 0)
  142.         return ret;
  143.  
  144.     *got_frame      = 1;
  145.  
  146.     /* report that the buffer was completely consumed */
  147.     return buf_size;
  148. }
  149.  
  150. static av_cold int msrle_decode_end(AVCodecContext *avctx)
  151. {
  152.     MsrleContext *s = avctx->priv_data;
  153.  
  154.     /* release the last frame */
  155.     av_frame_free(&s->frame);
  156.  
  157.     return 0;
  158. }
  159.  
  160. AVCodec ff_msrle_decoder = {
  161.     .name           = "msrle",
  162.     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft RLE"),
  163.     .type           = AVMEDIA_TYPE_VIDEO,
  164.     .id             = AV_CODEC_ID_MSRLE,
  165.     .priv_data_size = sizeof(MsrleContext),
  166.     .init           = msrle_decode_init,
  167.     .close          = msrle_decode_end,
  168.     .decode         = msrle_decode_frame,
  169.     .capabilities   = AV_CODEC_CAP_DR1,
  170. };
  171.