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/intreadwrite.h"
32 #include "libavutil/imgutils.h"
33 #include "avcodec.h"
34 
35 typedef struct CmvContext {
40  int width, height;
41  unsigned int palette[AVPALETTE_COUNT];
42 } CmvContext;
43 
45  CmvContext *s = avctx->priv_data;
46  s->avctx = avctx;
47  avctx->pix_fmt = PIX_FMT_PAL8;
48  return 0;
49 }
50 
51 static void cmv_decode_intra(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
52  unsigned char *dst = s->frame.data[0];
53  int i;
54 
55  for (i=0; i < s->avctx->height && buf_end - buf >= s->avctx->width; i++) {
56  memcpy(dst, buf, s->avctx->width);
57  dst += s->frame.linesize[0];
58  buf += s->avctx->width;
59  }
60 }
61 
62 static void cmv_motcomp(unsigned char *dst, int dst_stride,
63  const unsigned char *src, int src_stride,
64  int x, int y,
65  int xoffset, int yoffset,
66  int width, int height){
67  int i,j;
68 
69  for(j=y;j<y+4;j++)
70  for(i=x;i<x+4;i++)
71  {
72  if (i+xoffset>=0 && i+xoffset<width &&
73  j+yoffset>=0 && j+yoffset<height) {
74  dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];
75  }else{
76  dst[j*dst_stride + i] = 0;
77  }
78  }
79 }
80 
81 static void cmv_decode_inter(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
82  const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);
83  int x,y,i;
84 
85  i = 0;
86  for(y=0; y<s->avctx->height/4; y++)
87  for(x=0; x<s->avctx->width/4 && buf_end - buf > i; x++) {
88  if (buf[i]==0xFF) {
89  unsigned char *dst = s->frame.data[0] + (y*4)*s->frame.linesize[0] + x*4;
90  if (raw+16<buf_end && *raw==0xFF) { /* intra */
91  raw++;
92  memcpy(dst, raw, 4);
93  memcpy(dst+s->frame.linesize[0], raw+4, 4);
94  memcpy(dst+2*s->frame.linesize[0], raw+8, 4);
95  memcpy(dst+3*s->frame.linesize[0], raw+12, 4);
96  raw+=16;
97  }else if(raw<buf_end) { /* inter using second-last frame as reference */
98  int xoffset = (*raw & 0xF) - 7;
99  int yoffset = ((*raw >> 4)) - 7;
100  if (s->last2_frame.data[0])
101  cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
102  s->last2_frame.data[0], s->last2_frame.linesize[0],
103  x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
104  raw++;
105  }
106  }else{ /* inter using last frame as reference */
107  int xoffset = (buf[i] & 0xF) - 7;
108  int yoffset = ((buf[i] >> 4)) - 7;
109  if (s->last_frame.data[0])
110  cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
111  s->last_frame.data[0], s->last_frame.linesize[0],
112  x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
113  }
114  i++;
115  }
116 }
117 
118 static void cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)
119 {
120  int pal_start, pal_count, i;
121 
122  if(buf_end - buf < 16) {
123  av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");
124  return;
125  }
126 
127  s->width = AV_RL16(&buf[4]);
128  s->height = AV_RL16(&buf[6]);
129  if (s->avctx->width!=s->width || s->avctx->height!=s->height)
131 
132  s->avctx->time_base.num = 1;
133  s->avctx->time_base.den = AV_RL16(&buf[10]);
134 
135  pal_start = AV_RL16(&buf[12]);
136  pal_count = AV_RL16(&buf[14]);
137 
138  buf += 16;
139  for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {
140  s->palette[i] = AV_RB24(buf);
141  buf += 3;
142  }
143 }
144 
145 #define EA_PREAMBLE_SIZE 8
146 #define MVIh_TAG MKTAG('M', 'V', 'I', 'h')
147 
149  void *data, int *data_size,
150  AVPacket *avpkt)
151 {
152  const uint8_t *buf = avpkt->data;
153  int buf_size = avpkt->size;
154  CmvContext *s = avctx->priv_data;
155  const uint8_t *buf_end = buf + buf_size;
156 
157  if (buf_end - buf < EA_PREAMBLE_SIZE)
158  return AVERROR_INVALIDDATA;
159 
160  if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {
161  cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);
162  return buf_size;
163  }
164 
165  if (av_image_check_size(s->width, s->height, 0, s->avctx))
166  return -1;
167 
168  /* shuffle */
169  if (s->last2_frame.data[0])
170  avctx->release_buffer(avctx, &s->last2_frame);
172  FFSWAP(AVFrame, s->frame, s->last_frame);
173 
174  s->frame.reference = 1;
176  if (avctx->get_buffer(avctx, &s->frame)<0) {
177  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
178  return -1;
179  }
180 
181  memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
182 
183  buf += EA_PREAMBLE_SIZE;
184  if ((buf[0]&1)) { // subtype
185  cmv_decode_inter(s, buf+2, buf_end);
186  s->frame.key_frame = 0;
188  }else{
189  s->frame.key_frame = 1;
191  cmv_decode_intra(s, buf+2, buf_end);
192  }
193 
194  *data_size = sizeof(AVFrame);
195  *(AVFrame*)data = s->frame;
196 
197  return buf_size;
198 }
199 
201  CmvContext *s = avctx->priv_data;
202  if (s->frame.data[0])
203  s->avctx->release_buffer(avctx, &s->frame);
204  if (s->last_frame.data[0])
205  s->avctx->release_buffer(avctx, &s->last_frame);
206  if (s->last2_frame.data[0])
207  s->avctx->release_buffer(avctx, &s->last2_frame);
208 
209  return 0;
210 }
211 
213  .name = "eacmv",
214  .type = AVMEDIA_TYPE_VIDEO,
215  .id = CODEC_ID_CMV,
216  .priv_data_size = sizeof(CmvContext),
220  .capabilities = CODEC_CAP_DR1,
221  .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),
222 };