2 * Microsoft Video-1 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 * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net)
25 * For more information about the MS Video-1 format, visit:
26 * http://www.pcisys.net/~melanson/codecs/
28 * This decoder outputs either PAL8 or RGB555 data, depending on the
29 * whether a RGB palette was passed through palctrl;
30 * if it's present, then the data is PAL8; RGB555 otherwise.
41 #define PALETTE_COUNT 256
42 #define CHECK_STREAM_PTR(n) \
43 if ((stream_ptr + n) > s->size ) { \
44 av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
45 stream_ptr + n, s->size); \
49 typedef struct Msvideo1Context {
51 AVCodecContext *avctx;
58 int mode_8bit; /* if it's not 8-bit, it's 16-bit */
62 static int msvideo1_decode_init(AVCodecContext *avctx)
64 Msvideo1Context *s = avctx->priv_data;
68 /* figure out the colorspace based on the presence of a palette */
69 if (s->avctx->palctrl) {
71 avctx->pix_fmt = PIX_FMT_PAL8;
74 avctx->pix_fmt = PIX_FMT_RGB555;
77 dsputil_init(&s->dsp, avctx);
79 s->frame.data[0] = NULL;
84 static void msvideo1_decode_8bit(Msvideo1Context *s)
86 int block_ptr, pixel_ptr;
88 int pixel_x, pixel_y; /* pixel width and height iterators */
89 int block_x, block_y; /* block width and height iterators */
90 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
94 /* decoding parameters */
96 unsigned char byte_a, byte_b;
99 unsigned char colors[8];
100 unsigned char *pixels = s->frame.data[0];
101 int stride = s->frame.linesize[0];
105 blocks_wide = s->avctx->width / 4;
106 blocks_high = s->avctx->height / 4;
107 total_blocks = blocks_wide * blocks_high;
109 row_dec = stride + 4;
111 for (block_y = blocks_high; block_y > 0; block_y--) {
112 block_ptr = ((block_y * 4) - 1) * stride;
113 for (block_x = blocks_wide; block_x > 0; block_x--) {
114 /* check if this block should be skipped */
116 block_ptr += block_inc;
122 pixel_ptr = block_ptr;
124 /* get the next two bytes in the encoded data stream */
126 byte_a = s->buf[stream_ptr++];
127 byte_b = s->buf[stream_ptr++];
129 /* check if the decode is finished */
130 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
132 else if ((byte_b & 0xFC) == 0x84) {
133 /* skip code, but don't count the current block */
134 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
135 } else if (byte_b < 0x80) {
136 /* 2-color encoding */
137 flags = (byte_b << 8) | byte_a;
140 colors[0] = s->buf[stream_ptr++];
141 colors[1] = s->buf[stream_ptr++];
143 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
144 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
145 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
146 pixel_ptr -= row_dec;
148 } else if (byte_b >= 0x90) {
149 /* 8-color encoding */
150 flags = (byte_b << 8) | byte_a;
153 memcpy(colors, &s->buf[stream_ptr], 8);
156 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
157 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
158 pixels[pixel_ptr++] =
159 colors[((pixel_y & 0x2) << 1) +
160 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
161 pixel_ptr -= row_dec;
164 /* 1-color encoding */
167 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
168 for (pixel_x = 0; pixel_x < 4; pixel_x++)
169 pixels[pixel_ptr++] = colors[0];
170 pixel_ptr -= row_dec;
174 block_ptr += block_inc;
179 /* make the palette available on the way out */
180 if (s->avctx->pix_fmt == PIX_FMT_PAL8) {
181 memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
182 if (s->avctx->palctrl->palette_changed) {
183 s->frame.palette_has_changed = 1;
184 s->avctx->palctrl->palette_changed = 0;
189 static void msvideo1_decode_16bit(Msvideo1Context *s)
191 int block_ptr, pixel_ptr;
193 int pixel_x, pixel_y; /* pixel width and height iterators */
194 int block_x, block_y; /* block width and height iterators */
195 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
199 /* decoding parameters */
201 unsigned char byte_a, byte_b;
202 unsigned short flags;
204 unsigned short colors[8];
205 unsigned short *pixels = (unsigned short *)s->frame.data[0];
206 int stride = s->frame.linesize[0] / 2;
210 blocks_wide = s->avctx->width / 4;
211 blocks_high = s->avctx->height / 4;
212 total_blocks = blocks_wide * blocks_high;
214 row_dec = stride + 4;
216 for (block_y = blocks_high; block_y > 0; block_y--) {
217 block_ptr = ((block_y * 4) - 1) * stride;
218 for (block_x = blocks_wide; block_x > 0; block_x--) {
219 /* check if this block should be skipped */
221 block_ptr += block_inc;
227 pixel_ptr = block_ptr;
229 /* get the next two bytes in the encoded data stream */
231 byte_a = s->buf[stream_ptr++];
232 byte_b = s->buf[stream_ptr++];
234 /* check if the decode is finished */
235 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
237 } else if ((byte_b & 0xFC) == 0x84) {
238 /* skip code, but don't count the current block */
239 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
240 } else if (byte_b < 0x80) {
241 /* 2- or 8-color encoding modes */
242 flags = (byte_b << 8) | byte_a;
245 colors[0] = AV_RL16(&s->buf[stream_ptr]);
247 colors[1] = AV_RL16(&s->buf[stream_ptr]);
250 if (colors[0] & 0x8000) {
251 /* 8-color encoding */
252 CHECK_STREAM_PTR(12);
253 colors[2] = AV_RL16(&s->buf[stream_ptr]);
255 colors[3] = AV_RL16(&s->buf[stream_ptr]);
257 colors[4] = AV_RL16(&s->buf[stream_ptr]);
259 colors[5] = AV_RL16(&s->buf[stream_ptr]);
261 colors[6] = AV_RL16(&s->buf[stream_ptr]);
263 colors[7] = AV_RL16(&s->buf[stream_ptr]);
266 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
267 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
268 pixels[pixel_ptr++] =
269 colors[((pixel_y & 0x2) << 1) +
270 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
271 pixel_ptr -= row_dec;
274 /* 2-color encoding */
275 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
276 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
277 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
278 pixel_ptr -= row_dec;
282 /* otherwise, it's a 1-color block */
283 colors[0] = (byte_b << 8) | byte_a;
285 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
286 for (pixel_x = 0; pixel_x < 4; pixel_x++)
287 pixels[pixel_ptr++] = colors[0];
288 pixel_ptr -= row_dec;
292 block_ptr += block_inc;
298 static int msvideo1_decode_frame(AVCodecContext *avctx,
299 void *data, int *data_size,
300 uint8_t *buf, int buf_size)
302 Msvideo1Context *s = avctx->priv_data;
307 s->frame.reference = 1;
308 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
309 if (avctx->reget_buffer(avctx, &s->frame)) {
310 av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
315 msvideo1_decode_8bit(s);
317 msvideo1_decode_16bit(s);
319 *data_size = sizeof(AVFrame);
320 *(AVFrame*)data = s->frame;
322 /* report that the buffer was completely consumed */
326 static int msvideo1_decode_end(AVCodecContext *avctx)
328 Msvideo1Context *s = avctx->priv_data;
330 if (s->frame.data[0])
331 avctx->release_buffer(avctx, &s->frame);
336 AVCodec msvideo1_decoder = {
340 sizeof(Msvideo1Context),
341 msvideo1_decode_init,
344 msvideo1_decode_frame,