2 * Micrsoft RLE Video Decoder
3 * Copyright (C) 2003 the ffmpeg project
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 * MS RLE Video Decoder by Mike Melanson (melanson@pcisys.net)
23 * For more information about the MS RLE format, visit:
24 * http://www.pcisys.net/~melanson/codecs/
26 * The MS RLE decoder outputs PAL8 colorspace data.
28 * Note that this decoder expects the palette colors from the end of the
29 * BITMAPINFO header passed through palctrl.
41 typedef struct MsrleContext {
42 AVCodecContext *avctx;
51 #define FETCH_NEXT_STREAM_BYTE() \
52 if (stream_ptr >= s->size) \
54 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (1)\n"); \
57 stream_byte = s->buf[stream_ptr++];
59 static void msrle_decode_pal8(MsrleContext *s)
62 unsigned char rle_code;
63 unsigned char extra_byte;
64 unsigned char stream_byte;
66 int row_dec = s->frame.linesize[0];
67 int row_ptr = (s->avctx->height - 1) * row_dec;
68 int frame_size = row_dec * s->avctx->height;
70 /* make the palette available */
71 memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
72 if (s->avctx->palctrl->palette_changed) {
73 s->frame.palette_has_changed = 1;
74 s->avctx->palctrl->palette_changed = 0;
77 while (row_ptr >= 0) {
78 FETCH_NEXT_STREAM_BYTE();
79 rle_code = stream_byte;
81 /* fetch the next byte to see how to handle escape code */
82 FETCH_NEXT_STREAM_BYTE();
83 if (stream_byte == 0) {
84 /* line is done, goto the next one */
87 } else if (stream_byte == 1) {
90 } else if (stream_byte == 2) {
91 /* reposition frame decode coordinates */
92 FETCH_NEXT_STREAM_BYTE();
93 pixel_ptr += stream_byte;
94 FETCH_NEXT_STREAM_BYTE();
95 row_ptr -= stream_byte * row_dec;
97 /* copy pixels from encoded stream */
98 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
100 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
104 rle_code = stream_byte;
105 extra_byte = stream_byte & 0x01;
106 if (stream_ptr + rle_code + extra_byte > s->size) {
107 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (2)\n");
112 FETCH_NEXT_STREAM_BYTE();
113 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
117 /* if the RLE code is odd, skip a byte in the stream */
122 /* decode a run of data */
123 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
125 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (2)\n");
129 FETCH_NEXT_STREAM_BYTE();
132 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
138 /* one last sanity check on the way out */
139 if (stream_ptr < s->size)
140 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
141 stream_ptr, s->size);
144 static int msrle_decode_init(AVCodecContext *avctx)
146 MsrleContext *s = (MsrleContext *)avctx->priv_data;
150 avctx->pix_fmt = PIX_FMT_PAL8;
151 avctx->has_b_frames = 0;
152 s->frame.data[0] = s->prev_frame.data[0] = NULL;
157 static int msrle_decode_frame(AVCodecContext *avctx,
158 void *data, int *data_size,
159 uint8_t *buf, int buf_size)
161 MsrleContext *s = (MsrleContext *)avctx->priv_data;
166 s->frame.reference = 1;
167 if (avctx->get_buffer(avctx, &s->frame)) {
168 av_log(avctx, AV_LOG_ERROR, " MS RLE: get_buffer() failed\n");
172 if (s->prev_frame.data[0] && (s->frame.linesize[0] != s->prev_frame.linesize[0]))
173 av_log(avctx, AV_LOG_ERROR, " MS RLE: Buffer linesize changed: current %u, previous %u.\n"
174 " Expect wrong image and/or crash!\n",
175 s->frame.linesize[0], s->prev_frame.linesize[0]);
177 /* grossly inefficient, but...oh well */
178 if (s->prev_frame.data[0] != NULL)
179 memcpy(s->frame.data[0], s->prev_frame.data[0],
180 s->frame.linesize[0] * s->avctx->height);
182 msrle_decode_pal8(s);
184 if (s->prev_frame.data[0])
185 avctx->release_buffer(avctx, &s->prev_frame);
188 s->prev_frame = s->frame;
190 *data_size = sizeof(AVFrame);
191 *(AVFrame*)data = s->frame;
193 /* report that the buffer was completely consumed */
197 static int msrle_decode_end(AVCodecContext *avctx)
199 MsrleContext *s = (MsrleContext *)avctx->priv_data;
201 /* release the last frame */
202 if (s->prev_frame.data[0])
203 avctx->release_buffer(avctx, &s->prev_frame);
208 AVCodec msrle_decoder = {
212 sizeof(MsrleContext),