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/
34 #include "libavutil/internal.h"
35 #include "libavutil/intreadwrite.h"
38 #define PALETTE_COUNT 256
39 #define CHECK_STREAM_PTR(n) \
40 if ((stream_ptr + n) > s->size ) { \
41 av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
42 stream_ptr + n, s->size); \
46 typedef struct Msvideo1Context {
48 AVCodecContext *avctx;
51 const unsigned char *buf;
54 int mode_8bit; /* if it's not 8-bit, it's 16-bit */
59 static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
61 Msvideo1Context *s = avctx->priv_data;
65 /* figure out the colorspace based on the presence of a palette */
66 if (s->avctx->bits_per_coded_sample == 8) {
68 avctx->pix_fmt = AV_PIX_FMT_PAL8;
71 avctx->pix_fmt = AV_PIX_FMT_RGB555;
74 avcodec_get_frame_defaults(&s->frame);
75 s->frame.data[0] = NULL;
80 static void msvideo1_decode_8bit(Msvideo1Context *s)
82 int block_ptr, pixel_ptr;
84 int pixel_x, pixel_y; /* pixel width and height iterators */
85 int block_x, block_y; /* block width and height iterators */
86 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
90 /* decoding parameters */
92 unsigned char byte_a, byte_b;
95 unsigned char colors[8];
96 unsigned char *pixels = s->frame.data[0];
97 int stride = s->frame.linesize[0];
101 blocks_wide = s->avctx->width / 4;
102 blocks_high = s->avctx->height / 4;
103 total_blocks = blocks_wide * blocks_high;
105 row_dec = stride + 4;
107 for (block_y = blocks_high; block_y > 0; block_y--) {
108 block_ptr = ((block_y * 4) - 1) * stride;
109 for (block_x = blocks_wide; block_x > 0; block_x--) {
110 /* check if this block should be skipped */
112 block_ptr += block_inc;
118 pixel_ptr = block_ptr;
120 /* get the next two bytes in the encoded data stream */
122 byte_a = s->buf[stream_ptr++];
123 byte_b = s->buf[stream_ptr++];
125 /* check if the decode is finished */
126 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
128 else if ((byte_b & 0xFC) == 0x84) {
129 /* skip code, but don't count the current block */
130 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
131 } else if (byte_b < 0x80) {
132 /* 2-color encoding */
133 flags = (byte_b << 8) | byte_a;
136 colors[0] = s->buf[stream_ptr++];
137 colors[1] = s->buf[stream_ptr++];
139 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
140 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
141 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
142 pixel_ptr -= row_dec;
144 } else if (byte_b >= 0x90) {
145 /* 8-color encoding */
146 flags = (byte_b << 8) | byte_a;
149 memcpy(colors, &s->buf[stream_ptr], 8);
152 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
153 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
154 pixels[pixel_ptr++] =
155 colors[((pixel_y & 0x2) << 1) +
156 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
157 pixel_ptr -= row_dec;
160 /* 1-color encoding */
163 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
164 for (pixel_x = 0; pixel_x < 4; pixel_x++)
165 pixels[pixel_ptr++] = colors[0];
166 pixel_ptr -= row_dec;
170 block_ptr += block_inc;
175 /* make the palette available on the way out */
176 if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8)
177 memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);
180 static void msvideo1_decode_16bit(Msvideo1Context *s)
182 int block_ptr, pixel_ptr;
184 int pixel_x, pixel_y; /* pixel width and height iterators */
185 int block_x, block_y; /* block width and height iterators */
186 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
190 /* decoding parameters */
192 unsigned char byte_a, byte_b;
193 unsigned short flags;
195 unsigned short colors[8];
196 unsigned short *pixels = (unsigned short *)s->frame.data[0];
197 int stride = s->frame.linesize[0] / 2;
201 blocks_wide = s->avctx->width / 4;
202 blocks_high = s->avctx->height / 4;
203 total_blocks = blocks_wide * blocks_high;
205 row_dec = stride + 4;
207 for (block_y = blocks_high; block_y > 0; block_y--) {
208 block_ptr = ((block_y * 4) - 1) * stride;
209 for (block_x = blocks_wide; block_x > 0; block_x--) {
210 /* check if this block should be skipped */
212 block_ptr += block_inc;
218 pixel_ptr = block_ptr;
220 /* get the next two bytes in the encoded data stream */
222 byte_a = s->buf[stream_ptr++];
223 byte_b = s->buf[stream_ptr++];
225 /* check if the decode is finished */
226 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
228 } else if ((byte_b & 0xFC) == 0x84) {
229 /* skip code, but don't count the current block */
230 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
231 } else if (byte_b < 0x80) {
232 /* 2- or 8-color encoding modes */
233 flags = (byte_b << 8) | byte_a;
236 colors[0] = AV_RL16(&s->buf[stream_ptr]);
238 colors[1] = AV_RL16(&s->buf[stream_ptr]);
241 if (colors[0] & 0x8000) {
242 /* 8-color encoding */
243 CHECK_STREAM_PTR(12);
244 colors[2] = AV_RL16(&s->buf[stream_ptr]);
246 colors[3] = AV_RL16(&s->buf[stream_ptr]);
248 colors[4] = AV_RL16(&s->buf[stream_ptr]);
250 colors[5] = AV_RL16(&s->buf[stream_ptr]);
252 colors[6] = AV_RL16(&s->buf[stream_ptr]);
254 colors[7] = AV_RL16(&s->buf[stream_ptr]);
257 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
258 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
259 pixels[pixel_ptr++] =
260 colors[((pixel_y & 0x2) << 1) +
261 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
262 pixel_ptr -= row_dec;
265 /* 2-color encoding */
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++] = colors[(flags & 0x1) ^ 1];
269 pixel_ptr -= row_dec;
273 /* otherwise, it's a 1-color block */
274 colors[0] = (byte_b << 8) | byte_a;
276 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
277 for (pixel_x = 0; pixel_x < 4; pixel_x++)
278 pixels[pixel_ptr++] = colors[0];
279 pixel_ptr -= row_dec;
283 block_ptr += block_inc;
289 static int msvideo1_decode_frame(AVCodecContext *avctx,
290 void *data, int *got_frame,
293 const uint8_t *buf = avpkt->data;
294 int buf_size = avpkt->size;
295 Msvideo1Context *s = avctx->priv_data;
300 s->frame.reference = 3;
301 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
302 if (avctx->reget_buffer(avctx, &s->frame)) {
303 av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
308 const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
311 memcpy(s->pal, pal, AVPALETTE_SIZE);
312 s->frame.palette_has_changed = 1;
317 msvideo1_decode_8bit(s);
319 msvideo1_decode_16bit(s);
322 *(AVFrame*)data = s->frame;
324 /* report that the buffer was completely consumed */
328 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
330 Msvideo1Context *s = avctx->priv_data;
332 if (s->frame.data[0])
333 avctx->release_buffer(avctx, &s->frame);
338 AVCodec ff_msvideo1_decoder = {
340 .type = AVMEDIA_TYPE_VIDEO,
341 .id = AV_CODEC_ID_MSVIDEO1,
342 .priv_data_size = sizeof(Msvideo1Context),
343 .init = msvideo1_decode_init,
344 .close = msvideo1_decode_end,
345 .decode = msvideo1_decode_frame,
346 .capabilities = CODEC_CAP_DR1,
347 .long_name = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),