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 extradata.
41 typedef struct MsrleContext {
42 AVCodecContext *avctx;
49 unsigned int palette[256];
52 #define FETCH_NEXT_STREAM_BYTE() \
53 if (stream_ptr >= s->size) \
55 printf(" MS RLE: stream ptr just went out of bounds (1)\n"); \
58 stream_byte = s->buf[stream_ptr++];
60 static void msrle_decode_pal8(MsrleContext *s)
63 unsigned char rle_code;
64 unsigned char extra_byte;
65 unsigned char stream_byte;
67 int row_dec = s->frame.linesize[0];
68 int row_ptr = (s->avctx->height - 1) * row_dec;
69 int frame_size = row_dec * s->avctx->height;
71 while (row_ptr >= 0) {
72 FETCH_NEXT_STREAM_BYTE();
73 rle_code = stream_byte;
75 /* fetch the next byte to see how to handle escape code */
76 FETCH_NEXT_STREAM_BYTE();
77 if (stream_byte == 0) {
78 /* line is done, goto the next one */
81 } else if (stream_byte == 1) {
84 } else if (stream_byte == 2) {
85 /* reposition frame decode coordinates */
86 FETCH_NEXT_STREAM_BYTE();
87 pixel_ptr += stream_byte;
88 FETCH_NEXT_STREAM_BYTE();
89 row_ptr -= stream_byte * row_dec;
91 /* copy pixels from encoded stream */
92 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
94 printf(" MS RLE: frame ptr just went out of bounds (1)\n");
98 rle_code = stream_byte;
99 extra_byte = stream_byte & 0x01;
100 if (stream_ptr + rle_code + extra_byte > s->size) {
101 printf(" MS RLE: stream ptr just went out of bounds (2)\n");
106 FETCH_NEXT_STREAM_BYTE();
107 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
111 /* if the RLE code is odd, skip a byte in the stream */
116 /* decode a run of data */
117 if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
119 printf(" MS RLE: frame ptr just went out of bounds (2)\n");
123 FETCH_NEXT_STREAM_BYTE();
126 s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
132 /* make the palette available */
133 memcpy(s->frame.data[1], s->palette, 256 * 4);
135 /* one last sanity check on the way out */
136 if (stream_ptr < s->size)
137 printf(" MS RLE: ended frame decode with bytes left over (%d < %d)\n",
138 stream_ptr, s->size);
141 static int msrle_decode_init(AVCodecContext *avctx)
143 MsrleContext *s = (MsrleContext *)avctx->priv_data;
145 unsigned char *palette;
149 avctx->pix_fmt = PIX_FMT_PAL8;
150 avctx->has_b_frames = 0;
151 s->frame.data[0] = s->prev_frame.data[0] = NULL;
153 /* convert palette */
154 palette = (unsigned char *)s->avctx->extradata;
155 memset (s->palette, 0, 256 * 4);
156 for (i = 0, j = 0; i < s->avctx->extradata_size / 4; i++, j += 4)
158 (palette[j + 2] << 16) |
159 (palette[j + 1] << 8) |
160 (palette[j + 0] << 0);
165 static int msrle_decode_frame(AVCodecContext *avctx,
166 void *data, int *data_size,
167 uint8_t *buf, int buf_size)
169 MsrleContext *s = (MsrleContext *)avctx->priv_data;
174 s->frame.reference = 1;
175 if (avctx->get_buffer(avctx, &s->frame)) {
176 printf (" MS RLE: get_buffer() failed\n");
180 /* grossly inefficient, but...oh well */
181 if (s->prev_frame.data[0] != NULL)
182 memcpy(s->frame.data[0], s->prev_frame.data[0],
183 s->frame.linesize[0] * s->avctx->height);
185 msrle_decode_pal8(s);
187 if (s->prev_frame.data[0])
188 avctx->release_buffer(avctx, &s->prev_frame);
191 s->prev_frame = s->frame;
193 *data_size = sizeof(AVFrame);
194 *(AVFrame*)data = s->frame;
196 /* report that the buffer was completely consumed */
200 static int msrle_decode_end(AVCodecContext *avctx)
202 MsrleContext *s = (MsrleContext *)avctx->priv_data;
204 /* release the last frame */
205 if (s->prev_frame.data[0])
206 avctx->release_buffer(avctx, &s->prev_frame);
211 AVCodec msrle_decoder = {
215 sizeof(MsrleContext),