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;
50 #define FETCH_NEXT_STREAM_BYTE() \
51 if (stream_ptr >= s->size) \
53 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (1)\n"); \
56 stream_byte = s->buf[stream_ptr++];
58 static void msrle_decode_pal4(MsrleContext *s)
61 unsigned char rle_code;
62 unsigned char extra_byte, odd_pixel;
63 unsigned char stream_byte;
65 int row_dec = s->frame.linesize[0];
66 int row_ptr = (s->avctx->height - 1) * row_dec;
67 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 odd_pixel = stream_byte & 1;
99 rle_code = (stream_byte + 1) / 2;
100 extra_byte = rle_code & 0x01;
101 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
103 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
107 for (i = 0; i < rle_code; i++) {
108 if (pixel_ptr >= s->avctx->width)
110 FETCH_NEXT_STREAM_BYTE();
111 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
113 if (i + 1 == rle_code && odd_pixel)
115 if (pixel_ptr >= s->avctx->width)
117 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
121 // if the RLE code is odd, skip a byte in the stream
126 // decode a run of data
127 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
129 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
132 FETCH_NEXT_STREAM_BYTE();
133 for (i = 0; i < rle_code; i++) {
134 if (pixel_ptr >= s->avctx->width)
137 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
139 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
145 /* one last sanity check on the way out */
146 if (stream_ptr < s->size)
147 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
148 stream_ptr, s->size);
153 static void msrle_decode_pal8(MsrleContext *s)
156 unsigned char rle_code;
157 unsigned char extra_byte;
158 unsigned char stream_byte;
160 int row_dec = s->frame.linesize[0];
161 int row_ptr = (s->avctx->height - 1) * row_dec;
162 int frame_size = row_dec * s->avctx->height;
164 /* make the palette available */
165 memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
166 if (s->avctx->palctrl->palette_changed) {
167 s->frame.palette_has_changed = 1;
168 s->avctx->palctrl->palette_changed = 0;
171 while (row_ptr >= 0) {
172 FETCH_NEXT_STREAM_BYTE();
173 rle_code = stream_byte;
175 /* fetch the next byte to see how to handle escape code */
176 FETCH_NEXT_STREAM_BYTE();
177 if (stream_byte == 0) {
178 /* line is done, goto the next one */
181 } else if (stream_byte == 1) {
184 } else if (stream_byte == 2) {
185 /* reposition frame decode coordinates */
186 FETCH_NEXT_STREAM_BYTE();
187 pixel_ptr += stream_byte;
188 FETCH_NEXT_STREAM_BYTE();
189 row_ptr -= stream_byte * row_dec;
191 /* copy pixels from encoded stream */
192 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
194 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
198 rle_code = stream_byte;
199 extra_byte = stream_byte & 0x01;
200 if (stream_ptr + rle_code + extra_byte > s->size) {
201 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (2)\n");
206 FETCH_NEXT_STREAM_BYTE();
207 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
211 /* if the RLE code is odd, skip a byte in the stream */
216 /* decode a run of data */
217 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
219 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (2)\n");
223 FETCH_NEXT_STREAM_BYTE();
226 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
232 /* one last sanity check on the way out */
233 if (stream_ptr < s->size)
234 av_log(s->avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
235 stream_ptr, s->size);
238 static int msrle_decode_init(AVCodecContext *avctx)
240 MsrleContext *s = (MsrleContext *)avctx->priv_data;
244 avctx->pix_fmt = PIX_FMT_PAL8;
245 avctx->has_b_frames = 0;
246 s->frame.data[0] = NULL;
251 static int msrle_decode_frame(AVCodecContext *avctx,
252 void *data, int *data_size,
253 uint8_t *buf, int buf_size)
255 MsrleContext *s = (MsrleContext *)avctx->priv_data;
257 /* no supplementary picture */
264 s->frame.reference = 1;
265 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
266 if (avctx->reget_buffer(avctx, &s->frame)) {
267 av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
271 switch (avctx->bits_per_sample) {
273 msrle_decode_pal8(s);
276 msrle_decode_pal4(s);
279 av_log(avctx, AV_LOG_ERROR, "Don't know how to decode depth %u.\n",
280 avctx->bits_per_sample);
283 *data_size = sizeof(AVFrame);
284 *(AVFrame*)data = s->frame;
286 /* report that the buffer was completely consumed */
290 static int msrle_decode_end(AVCodecContext *avctx)
292 MsrleContext *s = (MsrleContext *)avctx->priv_data;
294 /* release the last frame */
295 if (s->frame.data[0])
296 avctx->release_buffer(avctx, &s->frame);
301 AVCodec msrle_decoder = {
305 sizeof(MsrleContext),