2 * Micrsoft RLE Video Decoder
3 * Copyright (C) 2003 the ffmpeg project
5 * This file is part of FFmpeg.
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.
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.
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
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/
28 * The MS RLE decoder outputs PAL8 colorspace data.
30 * Note that this decoder expects the palette colors from the end of the
31 * BITMAPINFO header passed through palctrl.
42 typedef struct MsrleContext {
43 AVCodecContext *avctx;
46 const unsigned char *buf;
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_pal4(MsrleContext *s)
62 unsigned char rle_code;
63 unsigned char extra_byte, odd_pixel;
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;
71 /* make the palette available */
72 memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
73 if (s->avctx->palctrl->palette_changed) {
74 s->frame.palette_has_changed = 1;
75 s->avctx->palctrl->palette_changed = 0;
78 while (row_ptr >= 0) {
79 FETCH_NEXT_STREAM_BYTE();
80 rle_code = stream_byte;
82 /* fetch the next byte to see how to handle escape code */
83 FETCH_NEXT_STREAM_BYTE();
84 if (stream_byte == 0) {
85 /* line is done, goto the next one */
88 } else if (stream_byte == 1) {
91 } else if (stream_byte == 2) {
92 /* reposition frame decode coordinates */
93 FETCH_NEXT_STREAM_BYTE();
94 pixel_ptr += stream_byte;
95 FETCH_NEXT_STREAM_BYTE();
96 row_ptr -= stream_byte * row_dec;
98 // copy pixels from encoded stream
99 odd_pixel = stream_byte & 1;
100 rle_code = (stream_byte + 1) / 2;
101 extra_byte = rle_code & 0x01;
102 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
104 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
108 for (i = 0; i < rle_code; i++) {
109 if (pixel_ptr >= s->avctx->width)
111 FETCH_NEXT_STREAM_BYTE();
112 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
114 if (i + 1 == rle_code && odd_pixel)
116 if (pixel_ptr >= s->avctx->width)
118 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
122 // if the RLE code is odd, skip a byte in the stream
127 // decode a run of data
128 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
130 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
133 FETCH_NEXT_STREAM_BYTE();
134 for (i = 0; i < rle_code; i++) {
135 if (pixel_ptr >= s->avctx->width)
138 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
140 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
146 /* one last sanity check on the way out */
147 if (stream_ptr < s->size)
148 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
149 stream_ptr, s->size);
154 static void msrle_decode_pal8(MsrleContext *s)
157 unsigned char rle_code;
158 unsigned char extra_byte;
159 unsigned char stream_byte;
161 int row_dec = s->frame.linesize[0];
162 int row_ptr = (s->avctx->height - 1) * row_dec;
163 int frame_size = row_dec * s->avctx->height;
165 /* make the palette available */
166 memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
167 if (s->avctx->palctrl->palette_changed) {
168 s->frame.palette_has_changed = 1;
169 s->avctx->palctrl->palette_changed = 0;
172 while (row_ptr >= 0) {
173 FETCH_NEXT_STREAM_BYTE();
174 rle_code = stream_byte;
176 /* fetch the next byte to see how to handle escape code */
177 FETCH_NEXT_STREAM_BYTE();
178 if (stream_byte == 0) {
179 /* line is done, goto the next one */
182 } else if (stream_byte == 1) {
185 } else if (stream_byte == 2) {
186 /* reposition frame decode coordinates */
187 FETCH_NEXT_STREAM_BYTE();
188 pixel_ptr += stream_byte;
189 FETCH_NEXT_STREAM_BYTE();
190 row_ptr -= stream_byte * row_dec;
192 /* copy pixels from encoded stream */
193 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
195 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
199 rle_code = stream_byte;
200 extra_byte = stream_byte & 0x01;
201 if (stream_ptr + rle_code + extra_byte > s->size) {
202 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (2)\n");
207 FETCH_NEXT_STREAM_BYTE();
208 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
212 /* if the RLE code is odd, skip a byte in the stream */
217 /* decode a run of data */
218 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
220 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (2)\n");
224 FETCH_NEXT_STREAM_BYTE();
227 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
233 /* one last sanity check on the way out */
234 if (stream_ptr < s->size)
235 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
236 stream_ptr, s->size);
239 static int msrle_decode_init(AVCodecContext *avctx)
241 MsrleContext *s = avctx->priv_data;
245 avctx->pix_fmt = PIX_FMT_PAL8;
246 s->frame.data[0] = NULL;
251 static int msrle_decode_frame(AVCodecContext *avctx,
252 void *data, int *data_size,
253 const uint8_t *buf, int buf_size)
255 MsrleContext *s = avctx->priv_data;
260 s->frame.reference = 1;
261 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
262 if (avctx->reget_buffer(avctx, &s->frame)) {
263 av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
267 switch (avctx->bits_per_sample) {
269 msrle_decode_pal8(s);
272 msrle_decode_pal4(s);
275 av_log(avctx, AV_LOG_ERROR, "Don't know how to decode depth %u.\n",
276 avctx->bits_per_sample);
279 *data_size = sizeof(AVFrame);
280 *(AVFrame*)data = s->frame;
282 /* report that the buffer was completely consumed */
286 static int msrle_decode_end(AVCodecContext *avctx)
288 MsrleContext *s = avctx->priv_data;
290 /* release the last frame */
291 if (s->frame.data[0])
292 avctx->release_buffer(avctx, &s->frame);
297 AVCodec msrle_decoder = {
301 sizeof(MsrleContext),