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/
33 #include "libavutil/internal.h"
34 #include "libavutil/intreadwrite.h"
39 #define PALETTE_COUNT 256
40 #define CHECK_STREAM_PTR(n) \
41 if ((stream_ptr + n) > s->size ) { \
42 av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
43 stream_ptr + n, s->size); \
47 typedef struct Msvideo1Context {
49 AVCodecContext *avctx;
52 const unsigned char *buf;
55 int mode_8bit; /* if it's not 8-bit, it's 16-bit */
60 static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
62 Msvideo1Context *s = avctx->priv_data;
66 if (avctx->width < 4 || avctx->height < 4)
67 return AVERROR_INVALIDDATA;
69 /* figure out the colorspace based on the presence of a palette */
70 if (s->avctx->bits_per_coded_sample == 8) {
72 avctx->pix_fmt = AV_PIX_FMT_PAL8;
73 if (avctx->extradata_size >= AVPALETTE_SIZE)
74 memcpy(s->pal, avctx->extradata, AVPALETTE_SIZE);
77 avctx->pix_fmt = AV_PIX_FMT_RGB555;
80 s->frame = av_frame_alloc();
82 return AVERROR(ENOMEM);
87 static void msvideo1_decode_8bit(Msvideo1Context *s)
89 int block_ptr, pixel_ptr;
91 int pixel_x, pixel_y; /* pixel width and height iterators */
92 int block_x, block_y; /* block width and height iterators */
93 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
97 /* decoding parameters */
99 unsigned char byte_a, byte_b;
100 unsigned short flags;
102 unsigned char colors[8];
103 unsigned char *pixels = s->frame->data[0];
104 int stride = s->frame->linesize[0];
108 blocks_wide = s->avctx->width / 4;
109 blocks_high = s->avctx->height / 4;
110 total_blocks = blocks_wide * blocks_high;
112 row_dec = stride + 4;
114 for (block_y = blocks_high; block_y > 0; block_y--) {
115 block_ptr = ((block_y * 4) - 1) * stride;
116 for (block_x = blocks_wide; block_x > 0; block_x--) {
117 /* check if this block should be skipped */
119 block_ptr += block_inc;
125 pixel_ptr = block_ptr;
127 /* get the next two bytes in the encoded data stream */
129 byte_a = s->buf[stream_ptr++];
130 byte_b = s->buf[stream_ptr++];
132 /* check if the decode is finished */
133 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
135 else if ((byte_b & 0xFC) == 0x84) {
136 /* skip code, but don't count the current block */
137 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
138 } else if (byte_b < 0x80) {
139 /* 2-color encoding */
140 flags = (byte_b << 8) | byte_a;
143 colors[0] = s->buf[stream_ptr++];
144 colors[1] = s->buf[stream_ptr++];
146 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
147 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
148 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
149 pixel_ptr -= row_dec;
151 } else if (byte_b >= 0x90) {
152 /* 8-color encoding */
153 flags = (byte_b << 8) | byte_a;
156 memcpy(colors, &s->buf[stream_ptr], 8);
159 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
160 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
161 pixels[pixel_ptr++] =
162 colors[((pixel_y & 0x2) << 1) +
163 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
164 pixel_ptr -= row_dec;
167 /* 1-color encoding */
170 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
171 for (pixel_x = 0; pixel_x < 4; pixel_x++)
172 pixels[pixel_ptr++] = colors[0];
173 pixel_ptr -= row_dec;
177 block_ptr += block_inc;
182 /* make the palette available on the way out */
183 if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8)
184 memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
187 static void msvideo1_decode_16bit(Msvideo1Context *s)
189 int block_ptr, pixel_ptr;
191 int pixel_x, pixel_y; /* pixel width and height iterators */
192 int block_x, block_y; /* block width and height iterators */
193 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
197 /* decoding parameters */
199 unsigned char byte_a, byte_b;
200 unsigned short flags;
202 unsigned short colors[8];
203 unsigned short *pixels = (unsigned short *)s->frame->data[0];
204 int stride = s->frame->linesize[0] / 2;
208 blocks_wide = s->avctx->width / 4;
209 blocks_high = s->avctx->height / 4;
210 total_blocks = blocks_wide * blocks_high;
212 row_dec = stride + 4;
214 for (block_y = blocks_high; block_y > 0; block_y--) {
215 block_ptr = ((block_y * 4) - 1) * stride;
216 for (block_x = blocks_wide; block_x > 0; block_x--) {
217 /* check if this block should be skipped */
219 block_ptr += block_inc;
225 pixel_ptr = block_ptr;
227 /* get the next two bytes in the encoded data stream */
229 byte_a = s->buf[stream_ptr++];
230 byte_b = s->buf[stream_ptr++];
232 /* check if the decode is finished */
233 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
235 } else if ((byte_b & 0xFC) == 0x84) {
236 /* skip code, but don't count the current block */
237 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
238 } else if (byte_b < 0x80) {
239 /* 2- or 8-color encoding modes */
240 flags = (byte_b << 8) | byte_a;
243 colors[0] = AV_RL16(&s->buf[stream_ptr]);
245 colors[1] = AV_RL16(&s->buf[stream_ptr]);
248 if (colors[0] & 0x8000) {
249 /* 8-color encoding */
250 CHECK_STREAM_PTR(12);
251 colors[2] = AV_RL16(&s->buf[stream_ptr]);
253 colors[3] = AV_RL16(&s->buf[stream_ptr]);
255 colors[4] = AV_RL16(&s->buf[stream_ptr]);
257 colors[5] = AV_RL16(&s->buf[stream_ptr]);
259 colors[6] = AV_RL16(&s->buf[stream_ptr]);
261 colors[7] = AV_RL16(&s->buf[stream_ptr]);
264 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
265 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
266 pixels[pixel_ptr++] =
267 colors[((pixel_y & 0x2) << 1) +
268 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
269 pixel_ptr -= row_dec;
272 /* 2-color encoding */
273 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
274 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
275 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
276 pixel_ptr -= row_dec;
280 /* otherwise, it's a 1-color block */
281 colors[0] = (byte_b << 8) | byte_a;
283 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
284 for (pixel_x = 0; pixel_x < 4; pixel_x++)
285 pixels[pixel_ptr++] = colors[0];
286 pixel_ptr -= row_dec;
290 block_ptr += block_inc;
296 static int msvideo1_decode_frame(AVCodecContext *avctx,
297 void *data, int *got_frame,
300 const uint8_t *buf = avpkt->data;
301 int buf_size = avpkt->size;
302 Msvideo1Context *s = avctx->priv_data;
308 // Discard frame if its smaller than the minimum frame size
309 if (buf_size < (avctx->width/4) * (avctx->height/4) / 512) {
310 av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
311 return AVERROR_INVALIDDATA;
314 if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
318 s->frame->palette_has_changed = ff_copy_palette(s->pal, avpkt, avctx);
322 msvideo1_decode_8bit(s);
324 msvideo1_decode_16bit(s);
326 if ((ret = av_frame_ref(data, s->frame)) < 0)
331 /* report that the buffer was completely consumed */
335 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
337 Msvideo1Context *s = avctx->priv_data;
339 av_frame_free(&s->frame);
344 AVCodec ff_msvideo1_decoder = {
346 .long_name = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
347 .type = AVMEDIA_TYPE_VIDEO,
348 .id = AV_CODEC_ID_MSVIDEO1,
349 .priv_data_size = sizeof(Msvideo1Context),
350 .init = msvideo1_decode_init,
351 .close = msvideo1_decode_end,
352 .decode = msvideo1_decode_frame,
353 .capabilities = AV_CODEC_CAP_DR1,