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"
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 /* figure out the colorspace based on the presence of a palette */
67 if (s->avctx->bits_per_coded_sample == 8) {
69 avctx->pix_fmt = AV_PIX_FMT_PAL8;
72 avctx->pix_fmt = AV_PIX_FMT_RGB555;
75 s->frame = av_frame_alloc();
77 return AVERROR(ENOMEM);
82 static void msvideo1_decode_8bit(Msvideo1Context *s)
84 int block_ptr, pixel_ptr;
86 int pixel_x, pixel_y; /* pixel width and height iterators */
87 int block_x, block_y; /* block width and height iterators */
88 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
92 /* decoding parameters */
94 unsigned char byte_a, byte_b;
97 unsigned char colors[8];
98 unsigned char *pixels = s->frame->data[0];
99 int stride = s->frame->linesize[0];
103 blocks_wide = s->avctx->width / 4;
104 blocks_high = s->avctx->height / 4;
105 total_blocks = blocks_wide * blocks_high;
107 row_dec = stride + 4;
109 for (block_y = blocks_high; block_y > 0; block_y--) {
110 block_ptr = ((block_y * 4) - 1) * stride;
111 for (block_x = blocks_wide; block_x > 0; block_x--) {
112 /* check if this block should be skipped */
114 block_ptr += block_inc;
120 pixel_ptr = block_ptr;
122 /* get the next two bytes in the encoded data stream */
124 byte_a = s->buf[stream_ptr++];
125 byte_b = s->buf[stream_ptr++];
127 /* check if the decode is finished */
128 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
130 else if ((byte_b & 0xFC) == 0x84) {
131 /* skip code, but don't count the current block */
132 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
133 } else if (byte_b < 0x80) {
134 /* 2-color encoding */
135 flags = (byte_b << 8) | byte_a;
138 colors[0] = s->buf[stream_ptr++];
139 colors[1] = s->buf[stream_ptr++];
141 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
142 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
143 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
144 pixel_ptr -= row_dec;
146 } else if (byte_b >= 0x90) {
147 /* 8-color encoding */
148 flags = (byte_b << 8) | byte_a;
151 memcpy(colors, &s->buf[stream_ptr], 8);
154 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
155 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
156 pixels[pixel_ptr++] =
157 colors[((pixel_y & 0x2) << 1) +
158 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
159 pixel_ptr -= row_dec;
162 /* 1-color encoding */
165 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
166 for (pixel_x = 0; pixel_x < 4; pixel_x++)
167 pixels[pixel_ptr++] = colors[0];
168 pixel_ptr -= row_dec;
172 block_ptr += block_inc;
177 /* make the palette available on the way out */
178 if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8)
179 memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
182 static void msvideo1_decode_16bit(Msvideo1Context *s)
184 int block_ptr, pixel_ptr;
186 int pixel_x, pixel_y; /* pixel width and height iterators */
187 int block_x, block_y; /* block width and height iterators */
188 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
192 /* decoding parameters */
194 unsigned char byte_a, byte_b;
195 unsigned short flags;
197 unsigned short colors[8];
198 unsigned short *pixels = (unsigned short *)s->frame->data[0];
199 int stride = s->frame->linesize[0] / 2;
203 blocks_wide = s->avctx->width / 4;
204 blocks_high = s->avctx->height / 4;
205 total_blocks = blocks_wide * blocks_high;
207 row_dec = stride + 4;
209 for (block_y = blocks_high; block_y > 0; block_y--) {
210 block_ptr = ((block_y * 4) - 1) * stride;
211 for (block_x = blocks_wide; block_x > 0; block_x--) {
212 /* check if this block should be skipped */
214 block_ptr += block_inc;
220 pixel_ptr = block_ptr;
222 /* get the next two bytes in the encoded data stream */
224 byte_a = s->buf[stream_ptr++];
225 byte_b = s->buf[stream_ptr++];
227 /* check if the decode is finished */
228 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
230 } else if ((byte_b & 0xFC) == 0x84) {
231 /* skip code, but don't count the current block */
232 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
233 } else if (byte_b < 0x80) {
234 /* 2- or 8-color encoding modes */
235 flags = (byte_b << 8) | byte_a;
238 colors[0] = AV_RL16(&s->buf[stream_ptr]);
240 colors[1] = AV_RL16(&s->buf[stream_ptr]);
243 if (colors[0] & 0x8000) {
244 /* 8-color encoding */
245 CHECK_STREAM_PTR(12);
246 colors[2] = AV_RL16(&s->buf[stream_ptr]);
248 colors[3] = AV_RL16(&s->buf[stream_ptr]);
250 colors[4] = AV_RL16(&s->buf[stream_ptr]);
252 colors[5] = AV_RL16(&s->buf[stream_ptr]);
254 colors[6] = AV_RL16(&s->buf[stream_ptr]);
256 colors[7] = AV_RL16(&s->buf[stream_ptr]);
259 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
260 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
261 pixels[pixel_ptr++] =
262 colors[((pixel_y & 0x2) << 1) +
263 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
264 pixel_ptr -= row_dec;
267 /* 2-color encoding */
268 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
269 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
270 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
271 pixel_ptr -= row_dec;
275 /* otherwise, it's a 1-color block */
276 colors[0] = (byte_b << 8) | byte_a;
278 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
279 for (pixel_x = 0; pixel_x < 4; pixel_x++)
280 pixels[pixel_ptr++] = colors[0];
281 pixel_ptr -= row_dec;
285 block_ptr += block_inc;
291 static int msvideo1_decode_frame(AVCodecContext *avctx,
292 void *data, int *got_frame,
295 const uint8_t *buf = avpkt->data;
296 int buf_size = avpkt->size;
297 Msvideo1Context *s = avctx->priv_data;
303 if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
307 const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
310 memcpy(s->pal, pal, AVPALETTE_SIZE);
311 s->frame->palette_has_changed = 1;
316 msvideo1_decode_8bit(s);
318 msvideo1_decode_16bit(s);
320 if ((ret = av_frame_ref(data, s->frame)) < 0)
325 /* report that the buffer was completely consumed */
329 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
331 Msvideo1Context *s = avctx->priv_data;
333 av_frame_free(&s->frame);
338 AVCodec ff_msvideo1_decoder = {
340 .long_name = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
341 .type = AVMEDIA_TYPE_VIDEO,
342 .id = AV_CODEC_ID_MSVIDEO1,
343 .priv_data_size = sizeof(Msvideo1Context),
344 .init = msvideo1_decode_init,
345 .close = msvideo1_decode_end,
346 .decode = msvideo1_decode_frame,
347 .capabilities = CODEC_CAP_DR1,