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
;
70 if (avctx
->extradata_size
>= AVPALETTE_SIZE
)
71 memcpy(s
->pal
, avctx
->extradata
, AVPALETTE_SIZE
);
74 avctx
->pix_fmt
= AV_PIX_FMT_RGB555
;
77 s
->frame
= av_frame_alloc();
79 return AVERROR(ENOMEM
);
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
== AV_PIX_FMT_PAL8
)
181 memcpy(s
->frame
->data
[1], s
->pal
, AVPALETTE_SIZE
);
184 static void msvideo1_decode_16bit(Msvideo1Context
*s
)
186 int block_ptr
, pixel_ptr
;
188 int pixel_x
, pixel_y
; /* pixel width and height iterators */
189 int block_x
, block_y
; /* block width and height iterators */
190 int blocks_wide
, blocks_high
; /* width and height in 4x4 blocks */
194 /* decoding parameters */
196 unsigned char byte_a
, byte_b
;
197 unsigned short flags
;
199 unsigned short colors
[8];
200 unsigned short *pixels
= (unsigned short *)s
->frame
->data
[0];
201 int stride
= s
->frame
->linesize
[0] / 2;
205 blocks_wide
= s
->avctx
->width
/ 4;
206 blocks_high
= s
->avctx
->height
/ 4;
207 total_blocks
= blocks_wide
* blocks_high
;
209 row_dec
= stride
+ 4;
211 for (block_y
= blocks_high
; block_y
> 0; block_y
--) {
212 block_ptr
= ((block_y
* 4) - 1) * stride
;
213 for (block_x
= blocks_wide
; block_x
> 0; block_x
--) {
214 /* check if this block should be skipped */
216 block_ptr
+= block_inc
;
222 pixel_ptr
= block_ptr
;
224 /* get the next two bytes in the encoded data stream */
226 byte_a
= s
->buf
[stream_ptr
++];
227 byte_b
= s
->buf
[stream_ptr
++];
229 /* check if the decode is finished */
230 if ((byte_a
== 0) && (byte_b
== 0) && (total_blocks
== 0)) {
232 } else if ((byte_b
& 0xFC) == 0x84) {
233 /* skip code, but don't count the current block */
234 skip_blocks
= ((byte_b
- 0x84) << 8) + byte_a
- 1;
235 } else if (byte_b
< 0x80) {
236 /* 2- or 8-color encoding modes */
237 flags
= (byte_b
<< 8) | byte_a
;
240 colors
[0] = AV_RL16(&s
->buf
[stream_ptr
]);
242 colors
[1] = AV_RL16(&s
->buf
[stream_ptr
]);
245 if (colors
[0] & 0x8000) {
246 /* 8-color encoding */
247 CHECK_STREAM_PTR(12);
248 colors
[2] = AV_RL16(&s
->buf
[stream_ptr
]);
250 colors
[3] = AV_RL16(&s
->buf
[stream_ptr
]);
252 colors
[4] = AV_RL16(&s
->buf
[stream_ptr
]);
254 colors
[5] = AV_RL16(&s
->buf
[stream_ptr
]);
256 colors
[6] = AV_RL16(&s
->buf
[stream_ptr
]);
258 colors
[7] = AV_RL16(&s
->buf
[stream_ptr
]);
261 for (pixel_y
= 0; pixel_y
< 4; pixel_y
++) {
262 for (pixel_x
= 0; pixel_x
< 4; pixel_x
++, flags
>>= 1)
263 pixels
[pixel_ptr
++] =
264 colors
[((pixel_y
& 0x2) << 1) +
265 (pixel_x
& 0x2) + ((flags
& 0x1) ^ 1)];
266 pixel_ptr
-= row_dec
;
269 /* 2-color encoding */
270 for (pixel_y
= 0; pixel_y
< 4; pixel_y
++) {
271 for (pixel_x
= 0; pixel_x
< 4; pixel_x
++, flags
>>= 1)
272 pixels
[pixel_ptr
++] = colors
[(flags
& 0x1) ^ 1];
273 pixel_ptr
-= row_dec
;
277 /* otherwise, it's a 1-color block */
278 colors
[0] = (byte_b
<< 8) | byte_a
;
280 for (pixel_y
= 0; pixel_y
< 4; pixel_y
++) {
281 for (pixel_x
= 0; pixel_x
< 4; pixel_x
++)
282 pixels
[pixel_ptr
++] = colors
[0];
283 pixel_ptr
-= row_dec
;
287 block_ptr
+= block_inc
;
293 static int msvideo1_decode_frame(AVCodecContext
*avctx
,
294 void *data
, int *got_frame
,
297 const uint8_t *buf
= avpkt
->data
;
298 int buf_size
= avpkt
->size
;
299 Msvideo1Context
*s
= avctx
->priv_data
;
305 if ((ret
= ff_reget_buffer(avctx
, s
->frame
)) < 0)
309 const uint8_t *pal
= av_packet_get_side_data(avpkt
, AV_PKT_DATA_PALETTE
, NULL
);
312 memcpy(s
->pal
, pal
, AVPALETTE_SIZE
);
313 s
->frame
->palette_has_changed
= 1;
318 msvideo1_decode_8bit(s
);
320 msvideo1_decode_16bit(s
);
322 if ((ret
= av_frame_ref(data
, s
->frame
)) < 0)
327 /* report that the buffer was completely consumed */
331 static av_cold
int msvideo1_decode_end(AVCodecContext
*avctx
)
333 Msvideo1Context
*s
= avctx
->priv_data
;
335 av_frame_free(&s
->frame
);
340 AVCodec ff_msvideo1_decoder
= {
342 .long_name
= NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
343 .type
= AVMEDIA_TYPE_VIDEO
,
344 .id
= AV_CODEC_ID_MSVIDEO1
,
345 .priv_data_size
= sizeof(Msvideo1Context
),
346 .init
= msvideo1_decode_init
,
347 .close
= msvideo1_decode_end
,
348 .decode
= msvideo1_decode_frame
,
349 .capabilities
= CODEC_CAP_DR1
,