1bf676a434df1b1cb12ee9515432ab848c49d3ee
[libav.git] / libavcodec / cyuv.c
1 /*
2 *
3 * Copyright (C) 2003 the ffmpeg project
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * Creative YUV (CYUV) Video Decoder
20 * by Mike Melanson (melanson@pcisys.net)
21 * based on "Creative YUV (CYUV) stream format for AVI":
22 * http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt
23 *
24 */
25
26 /**
27 * @file cyuv.c
28 * Creative YUV (CYUV) Video Decoder.
29 */
30
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <unistd.h>
35
36 #include "common.h"
37 #include "avcodec.h"
38 #include "dsputil.h"
39 #include "mpegvideo.h"
40 #include "bswap.h"
41
42
43 typedef struct CyuvDecodeContext {
44 AVCodecContext *avctx;
45 int width, height;
46 AVFrame frame;
47 } CyuvDecodeContext;
48
49 static int cyuv_decode_init(AVCodecContext *avctx)
50 {
51 CyuvDecodeContext *s = avctx->priv_data;
52
53 s->avctx = avctx;
54 s->width = avctx->width;
55 s->height = avctx->height;
56 avctx->pix_fmt = PIX_FMT_YUV411P;
57 avctx->has_b_frames = 0;
58
59 return 0;
60 }
61
62 static int cyuv_decode_frame(AVCodecContext *avctx,
63 void *data, int *data_size,
64 uint8_t *buf, int buf_size)
65 {
66 CyuvDecodeContext *s=avctx->priv_data;
67
68 unsigned char *y_plane;
69 unsigned char *u_plane;
70 unsigned char *v_plane;
71 int y_ptr;
72 int u_ptr;
73 int v_ptr;
74
75 /* prediction error tables (make it clear that they are signed values) */
76 signed char *y_table = buf + 0;
77 signed char *u_table = buf + 16;
78 signed char *v_table = buf + 32;
79
80 unsigned char y_pred, u_pred, v_pred;
81 int stream_ptr;
82 unsigned char cur_byte;
83 int pixel_groups;
84
85 *data_size = 0;
86
87 /* sanity check the buffer size: A buffer has 3x16-bytes tables
88 * followed by (height) lines each with 3 bytes to represent groups
89 * of 4 pixels. Thus, the total size of the buffer ought to be:
90 * (3 * 16) + height * (width * 3 / 4) */
91 if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
92 printf ("ffmpeg: cyuv: got a buffer with %d bytes when %d were expected\n",
93 buf_size,
94 48 + s->height * (s->width * 3 / 4));
95 return -1;
96 }
97
98 /* pixel data starts 48 bytes in, after 3x16-byte tables */
99 stream_ptr = 48;
100
101 s->frame.reference = 0;
102 if(avctx->get_buffer(avctx, &s->frame) < 0) {
103 fprintf(stderr, "get_buffer() failed\n");
104 return -1;
105 }
106
107 y_plane = s->frame.data[0];
108 u_plane = s->frame.data[1];
109 v_plane = s->frame.data[2];
110
111 /* iterate through each line in the height */
112 for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
113 y_ptr < (s->height * s->frame.linesize[0]);
114 y_ptr += s->frame.linesize[0] - s->width,
115 u_ptr += s->frame.linesize[1] - s->width / 4,
116 v_ptr += s->frame.linesize[2] - s->width / 4) {
117
118 /* reset predictors */
119 cur_byte = buf[stream_ptr++];
120 u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
121 y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
122
123 cur_byte = buf[stream_ptr++];
124 v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
125 y_pred += y_table[cur_byte & 0x0F];
126 y_plane[y_ptr++] = y_pred;
127
128 cur_byte = buf[stream_ptr++];
129 y_pred += y_table[cur_byte & 0x0F];
130 y_plane[y_ptr++] = y_pred;
131 y_pred += y_table[(cur_byte & 0xF0) >> 4];
132 y_plane[y_ptr++] = y_pred;
133
134 /* iterate through the remaining pixel groups (4 pixels/group) */
135 pixel_groups = s->width / 4 - 1;
136 while (pixel_groups--) {
137
138 cur_byte = buf[stream_ptr++];
139 u_pred += u_table[(cur_byte & 0xF0) >> 4];
140 u_plane[u_ptr++] = u_pred;
141 y_pred += y_table[cur_byte & 0x0F];
142 y_plane[y_ptr++] = y_pred;
143
144 cur_byte = buf[stream_ptr++];
145 v_pred += v_table[(cur_byte & 0xF0) >> 4];
146 v_plane[v_ptr++] = v_pred;
147 y_pred += y_table[cur_byte & 0x0F];
148 y_plane[y_ptr++] = y_pred;
149
150 cur_byte = buf[stream_ptr++];
151 y_pred += y_table[cur_byte & 0x0F];
152 y_plane[y_ptr++] = y_pred;
153 y_pred += y_table[(cur_byte & 0xF0) >> 4];
154 y_plane[y_ptr++] = y_pred;
155
156 }
157 }
158
159 *data_size=sizeof(AVFrame);
160 *(AVFrame*)data= s->frame;
161
162 avctx->release_buffer(avctx, &s->frame);
163
164 return buf_size;
165 }
166
167 static int cyuv_decode_end(AVCodecContext *avctx)
168 {
169 /* CyuvDecodeContext *s = avctx->priv_data;*/
170
171 return 0;
172 }
173
174 AVCodec cyuv_decoder = {
175 "cyuv",
176 CODEC_TYPE_VIDEO,
177 CODEC_ID_CYUV,
178 sizeof(CyuvDecodeContext),
179 cyuv_decode_init,
180 NULL,
181 cyuv_decode_end,
182 cyuv_decode_frame,
183 0,
184 NULL
185 };
186