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 
38 
39 typedef struct CyuvDecodeContext {
41  int width, height;
44 
46 {
47  CyuvDecodeContext *s = avctx->priv_data;
48 
49  s->avctx = avctx;
50  s->width = avctx->width;
51  /* width needs to be divisible by 4 for this codec to work */
52  if (s->width & 0x3)
53  return -1;
54  s->height = avctx->height;
55  avctx->pix_fmt = PIX_FMT_YUV411P;
56 
57  return 0;
58 }
59 
61  void *data, int *data_size,
62  AVPacket *avpkt)
63 {
64  const uint8_t *buf = avpkt->data;
65  int buf_size = avpkt->size;
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  const signed char *y_table = (const signed char*)buf + 0;
77  const signed char *u_table = (const signed char*)buf + 16;
78  const signed char *v_table = (const signed char*)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  if (avctx->codec_id == CODEC_ID_AURA) {
86  y_table = u_table;
87  u_table = v_table;
88  }
89  /* sanity check the buffer size: A buffer has 3x16-bytes tables
90  * followed by (height) lines each with 3 bytes to represent groups
91  * of 4 pixels. Thus, the total size of the buffer ought to be:
92  * (3 * 16) + height * (width * 3 / 4) */
93  if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
94  av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
95  buf_size, 48 + s->height * (s->width * 3 / 4));
96  return -1;
97  }
98 
99  /* pixel data starts 48 bytes in, after 3x16-byte tables */
100  stream_ptr = 48;
101 
102  if (s->frame.data[0])
103  avctx->release_buffer(avctx, &s->frame);
104 
106  s->frame.reference = 0;
107  if (avctx->get_buffer(avctx, &s->frame) < 0) {
108  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
109  return -1;
110  }
111 
112  y_plane = s->frame.data[0];
113  u_plane = s->frame.data[1];
114  v_plane = s->frame.data[2];
115 
116  /* iterate through each line in the height */
117  for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
118  y_ptr < (s->height * s->frame.linesize[0]);
119  y_ptr += s->frame.linesize[0] - s->width,
120  u_ptr += s->frame.linesize[1] - s->width / 4,
121  v_ptr += s->frame.linesize[2] - s->width / 4) {
122 
123  /* reset predictors */
124  cur_byte = buf[stream_ptr++];
125  u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
126  y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
127 
128  cur_byte = buf[stream_ptr++];
129  v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
130  y_pred += y_table[cur_byte & 0x0F];
131  y_plane[y_ptr++] = y_pred;
132 
133  cur_byte = buf[stream_ptr++];
134  y_pred += y_table[cur_byte & 0x0F];
135  y_plane[y_ptr++] = y_pred;
136  y_pred += y_table[(cur_byte & 0xF0) >> 4];
137  y_plane[y_ptr++] = y_pred;
138 
139  /* iterate through the remaining pixel groups (4 pixels/group) */
140  pixel_groups = s->width / 4 - 1;
141  while (pixel_groups--) {
142 
143  cur_byte = buf[stream_ptr++];
144  u_pred += u_table[(cur_byte & 0xF0) >> 4];
145  u_plane[u_ptr++] = u_pred;
146  y_pred += y_table[cur_byte & 0x0F];
147  y_plane[y_ptr++] = y_pred;
148 
149  cur_byte = buf[stream_ptr++];
150  v_pred += v_table[(cur_byte & 0xF0) >> 4];
151  v_plane[v_ptr++] = v_pred;
152  y_pred += y_table[cur_byte & 0x0F];
153  y_plane[y_ptr++] = y_pred;
154 
155  cur_byte = buf[stream_ptr++];
156  y_pred += y_table[cur_byte & 0x0F];
157  y_plane[y_ptr++] = y_pred;
158  y_pred += y_table[(cur_byte & 0xF0) >> 4];
159  y_plane[y_ptr++] = y_pred;
160 
161  }
162  }
163 
164  *data_size=sizeof(AVFrame);
165  *(AVFrame*)data= s->frame;
166 
167  return buf_size;
168 }
169 
171 {
172  CyuvDecodeContext *s = avctx->priv_data;
173 
174  if (s->frame.data[0])
175  avctx->release_buffer(avctx, &s->frame);
176 
177  return 0;
178 }
179 
180 #if CONFIG_AURA_DECODER
181 AVCodec ff_aura_decoder = {
182  .name = "aura",
183  .type = AVMEDIA_TYPE_VIDEO,
184  .id = CODEC_ID_AURA,
185  .priv_data_size = sizeof(CyuvDecodeContext),
189  .capabilities = CODEC_CAP_DR1,
190  .long_name = NULL_IF_CONFIG_SMALL("Auravision AURA"),
191 };
192 #endif
193 
194 #if CONFIG_CYUV_DECODER
195 AVCodec ff_cyuv_decoder = {
196  .name = "cyuv",
197  .type = AVMEDIA_TYPE_VIDEO,
198  .id = CODEC_ID_CYUV,
199  .priv_data_size = sizeof(CyuvDecodeContext),
203  .capabilities = CODEC_CAP_DR1,
204  .long_name = NULL_IF_CONFIG_SMALL("Creative YUV (CYUV)"),
205 };
206 #endif