cyuv.c
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1 /*
2  * Creative YUV (CYUV) Video Decoder
3  * by Mike Melanson (melanson@pcisys.net)
4  * based on "Creative YUV (CYUV) stream format for AVI":
5  * http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt
6  *
7  * Copyright (C) 2003 the ffmpeg project
8  *
9  * This file is part of Libav.
10  *
11  * Libav is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU Lesser General Public
13  * License as published by the Free Software Foundation; either
14  * version 2.1 of the License, or (at your option) any later version.
15  *
16  * Libav is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19  * Lesser General Public License for more details.
20  *
21  * You should have received a copy of the GNU Lesser General Public
22  * License along with Libav; if not, write to the Free Software
23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24  */
25 
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 
35 #include "avcodec.h"
36 #include "dsputil.h"
37 #include "internal.h"
38 #include "libavutil/internal.h"
39 
40 
41 typedef struct CyuvDecodeContext {
43  int width, height;
46 
48 {
49  CyuvDecodeContext *s = avctx->priv_data;
50 
51  s->avctx = avctx;
52  s->width = avctx->width;
53  /* width needs to be divisible by 4 for this codec to work */
54  if (s->width & 0x3)
55  return -1;
56  s->height = avctx->height;
57  avctx->pix_fmt = AV_PIX_FMT_YUV411P;
58 
59  return 0;
60 }
61 
63  void *data, int *got_frame,
64  AVPacket *avpkt)
65 {
66  const uint8_t *buf = avpkt->data;
67  int buf_size = avpkt->size;
68  CyuvDecodeContext *s=avctx->priv_data;
69 
70  unsigned char *y_plane;
71  unsigned char *u_plane;
72  unsigned char *v_plane;
73  int y_ptr;
74  int u_ptr;
75  int v_ptr;
76 
77  /* prediction error tables (make it clear that they are signed values) */
78  const signed char *y_table = (const signed char*)buf + 0;
79  const signed char *u_table = (const signed char*)buf + 16;
80  const signed char *v_table = (const signed char*)buf + 32;
81 
82  unsigned char y_pred, u_pred, v_pred;
83  int stream_ptr;
84  unsigned char cur_byte;
85  int pixel_groups;
86 
87  if (avctx->codec_id == AV_CODEC_ID_AURA) {
88  y_table = u_table;
89  u_table = v_table;
90  }
91  /* sanity check the buffer size: A buffer has 3x16-bytes tables
92  * followed by (height) lines each with 3 bytes to represent groups
93  * of 4 pixels. Thus, the total size of the buffer ought to be:
94  * (3 * 16) + height * (width * 3 / 4) */
95  if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
96  av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
97  buf_size, 48 + s->height * (s->width * 3 / 4));
98  return -1;
99  }
100 
101  /* pixel data starts 48 bytes in, after 3x16-byte tables */
102  stream_ptr = 48;
103 
104  if (s->frame.data[0])
105  avctx->release_buffer(avctx, &s->frame);
106 
108  s->frame.reference = 0;
109  if (ff_get_buffer(avctx, &s->frame) < 0) {
110  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
111  return -1;
112  }
113 
114  y_plane = s->frame.data[0];
115  u_plane = s->frame.data[1];
116  v_plane = s->frame.data[2];
117 
118  /* iterate through each line in the height */
119  for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
120  y_ptr < (s->height * s->frame.linesize[0]);
121  y_ptr += s->frame.linesize[0] - s->width,
122  u_ptr += s->frame.linesize[1] - s->width / 4,
123  v_ptr += s->frame.linesize[2] - s->width / 4) {
124 
125  /* reset predictors */
126  cur_byte = buf[stream_ptr++];
127  u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
128  y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
129 
130  cur_byte = buf[stream_ptr++];
131  v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
132  y_pred += y_table[cur_byte & 0x0F];
133  y_plane[y_ptr++] = y_pred;
134 
135  cur_byte = buf[stream_ptr++];
136  y_pred += y_table[cur_byte & 0x0F];
137  y_plane[y_ptr++] = y_pred;
138  y_pred += y_table[(cur_byte & 0xF0) >> 4];
139  y_plane[y_ptr++] = y_pred;
140 
141  /* iterate through the remaining pixel groups (4 pixels/group) */
142  pixel_groups = s->width / 4 - 1;
143  while (pixel_groups--) {
144 
145  cur_byte = buf[stream_ptr++];
146  u_pred += u_table[(cur_byte & 0xF0) >> 4];
147  u_plane[u_ptr++] = u_pred;
148  y_pred += y_table[cur_byte & 0x0F];
149  y_plane[y_ptr++] = y_pred;
150 
151  cur_byte = buf[stream_ptr++];
152  v_pred += v_table[(cur_byte & 0xF0) >> 4];
153  v_plane[v_ptr++] = v_pred;
154  y_pred += y_table[cur_byte & 0x0F];
155  y_plane[y_ptr++] = y_pred;
156 
157  cur_byte = buf[stream_ptr++];
158  y_pred += y_table[cur_byte & 0x0F];
159  y_plane[y_ptr++] = y_pred;
160  y_pred += y_table[(cur_byte & 0xF0) >> 4];
161  y_plane[y_ptr++] = y_pred;
162 
163  }
164  }
165 
166  *got_frame = 1;
167  *(AVFrame*)data= s->frame;
168 
169  return buf_size;
170 }
171 
173 {
174  CyuvDecodeContext *s = avctx->priv_data;
175 
176  if (s->frame.data[0])
177  avctx->release_buffer(avctx, &s->frame);
178 
179  return 0;
180 }
181 
182 #if CONFIG_AURA_DECODER
183 AVCodec ff_aura_decoder = {
184  .name = "aura",
185  .type = AVMEDIA_TYPE_VIDEO,
186  .id = AV_CODEC_ID_AURA,
187  .priv_data_size = sizeof(CyuvDecodeContext),
191  .capabilities = CODEC_CAP_DR1,
192  .long_name = NULL_IF_CONFIG_SMALL("Auravision AURA"),
193 };
194 #endif
195 
196 #if CONFIG_CYUV_DECODER
197 AVCodec ff_cyuv_decoder = {
198  .name = "cyuv",
199  .type = AVMEDIA_TYPE_VIDEO,
200  .id = AV_CODEC_ID_CYUV,
201  .priv_data_size = sizeof(CyuvDecodeContext),
205  .capabilities = CODEC_CAP_DR1,
206  .long_name = NULL_IF_CONFIG_SMALL("Creative YUV (CYUV)"),
207 };
208 #endif