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 "codec_internal.h"
37 #include "decode.h"
38 #include "internal.h"
39 #include "msrledec.h"
40 #include "libavutil/imgutils.h"
41 
42 typedef struct MsrleContext {
43     AVCodecContext *avctx;
44     AVFrame *frame;
45 
46     GetByteContext gb;
47 
48     uint32_t pal[256];
49 } MsrleContext;
50 
msrle_decode_init(AVCodecContext *avctx)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 
msrle_decode_frame(AVCodecContext *avctx, AVFrame *rframe, int *got_frame, AVPacket *avpkt)85 static int msrle_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
86                               int *got_frame, AVPacket *avpkt)
87 {
88     const uint8_t *buf = avpkt->data;
89     int buf_size = avpkt->size;
90     MsrleContext *s = avctx->priv_data;
91     int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
92     int ret;
93 
94     if (buf_size < 2) //Minimally a end of picture code should be there
95         return AVERROR_INVALIDDATA;
96 
97     if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
98         return ret;
99 
100     if (avctx->bits_per_coded_sample > 1 && avctx->bits_per_coded_sample <= 8) {
101         s->frame->palette_has_changed = ff_copy_palette(s->pal, avpkt, avctx);
102 
103         /* make the palette available */
104         memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
105     }
106 
107     /* FIXME how to correctly detect RLE ??? */
108     if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
109         int linesize = av_image_get_linesize(avctx->pix_fmt, avctx->width, 0);
110         uint8_t *ptr = s->frame->data[0];
111         const uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
112         int i, j;
113 
114         if (linesize < 0)
115             return linesize;
116 
117         for (i = 0; i < avctx->height; i++) {
118             if (avctx->bits_per_coded_sample == 4) {
119                 for (j = 0; j < avctx->width - 1; j += 2) {
120                     ptr[j+0] = buf[j>>1] >> 4;
121                     ptr[j+1] = buf[j>>1] & 0xF;
122                 }
123                 if (avctx->width & 1)
124                     ptr[j+0] = buf[j>>1] >> 4;
125             } else {
126                 memcpy(ptr, buf, linesize);
127             }
128             buf -= istride;
129             ptr += s->frame->linesize[0];
130         }
131     } else {
132         bytestream2_init(&s->gb, buf, buf_size);
133         ff_msrle_decode(avctx, s->frame, avctx->bits_per_coded_sample, &s->gb);
134     }
135 
136     if ((ret = av_frame_ref(rframe, s->frame)) < 0)
137         return ret;
138 
139     *got_frame      = 1;
140 
141     /* report that the buffer was completely consumed */
142     return buf_size;
143 }
144 
msrle_decode_flush(AVCodecContext *avctx)145 static void msrle_decode_flush(AVCodecContext *avctx)
146 {
147     MsrleContext *s = avctx->priv_data;
148 
149     av_frame_unref(s->frame);
150 }
151 
msrle_decode_end(AVCodecContext *avctx)152 static av_cold int msrle_decode_end(AVCodecContext *avctx)
153 {
154     MsrleContext *s = avctx->priv_data;
155 
156     /* release the last frame */
157     av_frame_free(&s->frame);
158 
159     return 0;
160 }
161 
162 const FFCodec ff_msrle_decoder = {
163     .p.name         = "msrle",
164     .p.long_name    = NULL_IF_CONFIG_SMALL("Microsoft RLE"),
165     .p.type         = AVMEDIA_TYPE_VIDEO,
166     .p.id           = AV_CODEC_ID_MSRLE,
167     .priv_data_size = sizeof(MsrleContext),
168     .init           = msrle_decode_init,
169     .close          = msrle_decode_end,
170     FF_CODEC_DECODE_CB(msrle_decode_frame),
171     .flush          = msrle_decode_flush,
172     .p.capabilities = AV_CODEC_CAP_DR1,
173     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
174 };
175