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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 
46     uint32_t pal[256];
47 } MsrleContext;
48 
msrle_decode_init(AVCodecContext * avctx)49 static av_cold int msrle_decode_init(AVCodecContext *avctx)
50 {
51     MsrleContext *s = avctx->priv_data;
52     int i;
53 
54     s->avctx = avctx;
55 
56     switch (avctx->bits_per_coded_sample) {
57     case 1:
58         avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
59         break;
60     case 4:
61     case 8:
62         avctx->pix_fmt = AV_PIX_FMT_PAL8;
63         break;
64     case 24:
65         avctx->pix_fmt = AV_PIX_FMT_BGR24;
66         break;
67     default:
68         av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
69         return AVERROR_INVALIDDATA;
70     }
71 
72     s->frame = av_frame_alloc();
73     if (!s->frame)
74         return AVERROR(ENOMEM);
75 
76     if (avctx->extradata_size >= 4)
77         for (i = 0; i < FFMIN(avctx->extradata_size, AVPALETTE_SIZE)/4; i++)
78             s->pal[i] = 0xFFU<<24 | AV_RL32(avctx->extradata+4*i);
79 
80     return 0;
81 }
82 
msrle_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)83 static int msrle_decode_frame(AVCodecContext *avctx,
84                               void *data, int *got_frame,
85                               AVPacket *avpkt)
86 {
87     const uint8_t *buf = avpkt->data;
88     int buf_size = avpkt->size;
89     MsrleContext *s = avctx->priv_data;
90     int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
91     int ret;
92 
93     if (buf_size < 2) //Minimally a end of picture code should be there
94         return AVERROR_INVALIDDATA;
95 
96     if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
97         return ret;
98 
99     if (avctx->bits_per_coded_sample > 1 && avctx->bits_per_coded_sample <= 8) {
100         buffer_size_t size;
101         const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, &size);
102 
103         if (pal && size == AVPALETTE_SIZE) {
104             s->frame->palette_has_changed = 1;
105             memcpy(s->pal, pal, AVPALETTE_SIZE);
106         } else if (pal) {
107             av_log(avctx, AV_LOG_ERROR, "Palette size %d is wrong\n", size);
108         }
109         /* make the palette available */
110         memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
111     }
112 
113     /* FIXME how to correctly detect RLE ??? */
114     if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
115         int linesize = av_image_get_linesize(avctx->pix_fmt, avctx->width, 0);
116         uint8_t *ptr = s->frame->data[0];
117         uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
118         int i, j;
119 
120         if (linesize < 0)
121             return linesize;
122 
123         for (i = 0; i < avctx->height; i++) {
124             if (avctx->bits_per_coded_sample == 4) {
125                 for (j = 0; j < avctx->width - 1; j += 2) {
126                     ptr[j+0] = buf[j>>1] >> 4;
127                     ptr[j+1] = buf[j>>1] & 0xF;
128                 }
129                 if (avctx->width & 1)
130                     ptr[j+0] = buf[j>>1] >> 4;
131             } else {
132                 memcpy(ptr, buf, linesize);
133             }
134             buf -= istride;
135             ptr += s->frame->linesize[0];
136         }
137     } else {
138         bytestream2_init(&s->gb, buf, buf_size);
139         ff_msrle_decode(avctx, s->frame, avctx->bits_per_coded_sample, &s->gb);
140     }
141 
142     if ((ret = av_frame_ref(data, s->frame)) < 0)
143         return ret;
144 
145     *got_frame      = 1;
146 
147     /* report that the buffer was completely consumed */
148     return buf_size;
149 }
150 
msrle_decode_flush(AVCodecContext * avctx)151 static void msrle_decode_flush(AVCodecContext *avctx)
152 {
153     MsrleContext *s = avctx->priv_data;
154 
155     av_frame_unref(s->frame);
156 }
157 
msrle_decode_end(AVCodecContext * avctx)158 static av_cold int msrle_decode_end(AVCodecContext *avctx)
159 {
160     MsrleContext *s = avctx->priv_data;
161 
162     /* release the last frame */
163     av_frame_free(&s->frame);
164 
165     return 0;
166 }
167 
168 AVCodec ff_msrle_decoder = {
169     .name           = "msrle",
170     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft RLE"),
171     .type           = AVMEDIA_TYPE_VIDEO,
172     .id             = AV_CODEC_ID_MSRLE,
173     .priv_data_size = sizeof(MsrleContext),
174     .init           = msrle_decode_init,
175     .close          = msrle_decode_end,
176     .decode         = msrle_decode_frame,
177     .flush          = msrle_decode_flush,
178     .capabilities   = AV_CODEC_CAP_DR1,
179 };
180