eacmv.c
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1 /*
2  * Electronic Arts CMV Video Decoder
3  * Copyright (c) 2007-2008 Peter Ross
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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.
11  *
12  * Libav 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.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
31 #include "libavutil/common.h"
32 #include "libavutil/intreadwrite.h"
33 #include "libavutil/imgutils.h"
34 #include "avcodec.h"
35 #include "internal.h"
36 
37 typedef struct CmvContext {
42  int width, height;
43  unsigned int palette[AVPALETTE_COUNT];
44 } CmvContext;
45 
47  CmvContext *s = avctx->priv_data;
48  s->avctx = avctx;
49  avctx->pix_fmt = AV_PIX_FMT_PAL8;
50  return 0;
51 }
52 
53 static void cmv_decode_intra(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
54  unsigned char *dst = s->frame.data[0];
55  int i;
56 
57  for (i=0; i < s->avctx->height && buf_end - buf >= s->avctx->width; i++) {
58  memcpy(dst, buf, s->avctx->width);
59  dst += s->frame.linesize[0];
60  buf += s->avctx->width;
61  }
62 }
63 
64 static void cmv_motcomp(unsigned char *dst, int dst_stride,
65  const unsigned char *src, int src_stride,
66  int x, int y,
67  int xoffset, int yoffset,
68  int width, int height){
69  int i,j;
70 
71  for(j=y;j<y+4;j++)
72  for(i=x;i<x+4;i++)
73  {
74  if (i+xoffset>=0 && i+xoffset<width &&
75  j+yoffset>=0 && j+yoffset<height) {
76  dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];
77  }else{
78  dst[j*dst_stride + i] = 0;
79  }
80  }
81 }
82 
83 static void cmv_decode_inter(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
84  const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);
85  int x,y,i;
86 
87  i = 0;
88  for(y=0; y<s->avctx->height/4; y++)
89  for(x=0; x<s->avctx->width/4 && buf_end - buf > i; x++) {
90  if (buf[i]==0xFF) {
91  unsigned char *dst = s->frame.data[0] + (y*4)*s->frame.linesize[0] + x*4;
92  if (raw+16<buf_end && *raw==0xFF) { /* intra */
93  raw++;
94  memcpy(dst, raw, 4);
95  memcpy(dst+s->frame.linesize[0], raw+4, 4);
96  memcpy(dst+2*s->frame.linesize[0], raw+8, 4);
97  memcpy(dst+3*s->frame.linesize[0], raw+12, 4);
98  raw+=16;
99  }else if(raw<buf_end) { /* inter using second-last frame as reference */
100  int xoffset = (*raw & 0xF) - 7;
101  int yoffset = ((*raw >> 4)) - 7;
102  if (s->last2_frame.data[0])
103  cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
104  s->last2_frame.data[0], s->last2_frame.linesize[0],
105  x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
106  raw++;
107  }
108  }else{ /* inter using last frame as reference */
109  int xoffset = (buf[i] & 0xF) - 7;
110  int yoffset = ((buf[i] >> 4)) - 7;
111  if (s->last_frame.data[0])
112  cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
113  s->last_frame.data[0], s->last_frame.linesize[0],
114  x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
115  }
116  i++;
117  }
118 }
119 
120 static void cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)
121 {
122  int pal_start, pal_count, i;
123 
124  if(buf_end - buf < 16) {
125  av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");
126  return;
127  }
128 
129  s->width = AV_RL16(&buf[4]);
130  s->height = AV_RL16(&buf[6]);
131  if (s->avctx->width!=s->width || s->avctx->height!=s->height)
133 
134  s->avctx->time_base.num = 1;
135  s->avctx->time_base.den = AV_RL16(&buf[10]);
136 
137  pal_start = AV_RL16(&buf[12]);
138  pal_count = AV_RL16(&buf[14]);
139 
140  buf += 16;
141  for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {
142  s->palette[i] = AV_RB24(buf);
143  buf += 3;
144  }
145 }
146 
147 #define EA_PREAMBLE_SIZE 8
148 #define MVIh_TAG MKTAG('M', 'V', 'I', 'h')
149 
151  void *data, int *got_frame,
152  AVPacket *avpkt)
153 {
154  const uint8_t *buf = avpkt->data;
155  int buf_size = avpkt->size;
156  CmvContext *s = avctx->priv_data;
157  const uint8_t *buf_end = buf + buf_size;
158 
159  if (buf_end - buf < EA_PREAMBLE_SIZE)
160  return AVERROR_INVALIDDATA;
161 
162  if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {
163  cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);
164  return buf_size;
165  }
166 
167  if (av_image_check_size(s->width, s->height, 0, s->avctx))
168  return -1;
169 
170  /* shuffle */
171  if (s->last2_frame.data[0])
172  avctx->release_buffer(avctx, &s->last2_frame);
174  FFSWAP(AVFrame, s->frame, s->last_frame);
175 
176  s->frame.reference = 1;
178  if (ff_get_buffer(avctx, &s->frame)<0) {
179  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
180  return -1;
181  }
182 
183  memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
184 
185  buf += EA_PREAMBLE_SIZE;
186  if ((buf[0]&1)) { // subtype
187  cmv_decode_inter(s, buf+2, buf_end);
188  s->frame.key_frame = 0;
190  }else{
191  s->frame.key_frame = 1;
193  cmv_decode_intra(s, buf+2, buf_end);
194  }
195 
196  *got_frame = 1;
197  *(AVFrame*)data = s->frame;
198 
199  return buf_size;
200 }
201 
203  CmvContext *s = avctx->priv_data;
204  if (s->frame.data[0])
205  s->avctx->release_buffer(avctx, &s->frame);
206  if (s->last_frame.data[0])
207  s->avctx->release_buffer(avctx, &s->last_frame);
208  if (s->last2_frame.data[0])
209  s->avctx->release_buffer(avctx, &s->last2_frame);
210 
211  return 0;
212 }
213 
215  .name = "eacmv",
216  .type = AVMEDIA_TYPE_VIDEO,
217  .id = AV_CODEC_ID_CMV,
218  .priv_data_size = sizeof(CmvContext),
222  .capabilities = CODEC_CAP_DR1,
223  .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),
224 };