FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
eacmv.c
Go to the documentation of this file.
1 /*
2  * Electronic Arts CMV Video Decoder
3  * Copyright (c) 2007-2008 Peter Ross
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * Electronic Arts CMV Video Decoder
25  * by Peter Ross (pross@xvid.org)
26  *
27  * Technical details here:
28  * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_CMV
29  */
30 
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 {
39  AVFrame *last_frame; ///< last
40  AVFrame *last2_frame; ///< second-last
41  int width, height;
42  unsigned int palette[AVPALETTE_COUNT];
43 } CmvContext;
44 
46  CmvContext *s = avctx->priv_data;
47 
48  s->avctx = avctx;
49  avctx->pix_fmt = AV_PIX_FMT_PAL8;
50 
53  if (!s->last_frame || !s->last2_frame) {
56  return AVERROR(ENOMEM);
57  }
58 
59  return 0;
60 }
61 
63  const uint8_t *buf, const uint8_t *buf_end)
64 {
65  unsigned char *dst = frame->data[0];
66  int i;
67 
68  for (i=0; i < s->avctx->height && buf_end - buf >= s->avctx->width; i++) {
69  memcpy(dst, buf, s->avctx->width);
70  dst += frame->linesize[0];
71  buf += s->avctx->width;
72  }
73 }
74 
75 static void cmv_motcomp(unsigned char *dst, int dst_stride,
76  const unsigned char *src, int src_stride,
77  int x, int y,
78  int xoffset, int yoffset,
79  int width, int height){
80  int i,j;
81 
82  for(j=y;j<y+4;j++)
83  for(i=x;i<x+4;i++)
84  {
85  if (i+xoffset>=0 && i+xoffset<width &&
86  j+yoffset>=0 && j+yoffset<height) {
87  dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];
88  }else{
89  dst[j*dst_stride + i] = 0;
90  }
91  }
92 }
93 
95  const uint8_t *buf_end)
96 {
97  const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);
98  int x,y,i;
99 
100  i = 0;
101  for(y=0; y<s->avctx->height/4; y++)
102  for(x=0; x<s->avctx->width/4 && buf_end - buf > i; x++) {
103  if (buf[i]==0xFF) {
104  unsigned char *dst = frame->data[0] + (y*4)*frame->linesize[0] + x*4;
105  if (raw+16<buf_end && *raw==0xFF) { /* intra */
106  raw++;
107  memcpy(dst, raw, 4);
108  memcpy(dst + frame->linesize[0], raw+4, 4);
109  memcpy(dst + 2 * frame->linesize[0], raw+8, 4);
110  memcpy(dst + 3 * frame->linesize[0], raw+12, 4);
111  raw+=16;
112  }else if(raw<buf_end) { /* inter using second-last frame as reference */
113  int xoffset = (*raw & 0xF) - 7;
114  int yoffset = ((*raw >> 4)) - 7;
115  if (s->last2_frame->data[0])
116  cmv_motcomp(frame->data[0], frame->linesize[0],
117  s->last2_frame->data[0], s->last2_frame->linesize[0],
118  x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
119  raw++;
120  }
121  }else{ /* inter using last frame as reference */
122  int xoffset = (buf[i] & 0xF) - 7;
123  int yoffset = ((buf[i] >> 4)) - 7;
124  if (s->last_frame->data[0])
125  cmv_motcomp(frame->data[0], frame->linesize[0],
126  s->last_frame->data[0], s->last_frame->linesize[0],
127  x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
128  }
129  i++;
130  }
131 }
132 
133 static void cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)
134 {
135  int pal_start, pal_count, i;
136 
137  if(buf_end - buf < 16) {
138  av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");
139  return;
140  }
141 
142  s->width = AV_RL16(&buf[4]);
143  s->height = AV_RL16(&buf[6]);
144  if (s->avctx->width!=s->width || s->avctx->height!=s->height) {
148  }
149 
150  s->avctx->time_base.num = 1;
151  s->avctx->time_base.den = AV_RL16(&buf[10]);
152 
153  pal_start = AV_RL16(&buf[12]);
154  pal_count = AV_RL16(&buf[14]);
155 
156  buf += 16;
157  for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {
158  s->palette[i] = 0xFFU << 24 | AV_RB24(buf);
159  buf += 3;
160  }
161 }
162 
163 #define EA_PREAMBLE_SIZE 8
164 #define MVIh_TAG MKTAG('M', 'V', 'I', 'h')
165 
167  void *data, int *got_frame,
168  AVPacket *avpkt)
169 {
170  const uint8_t *buf = avpkt->data;
171  int buf_size = avpkt->size;
172  CmvContext *s = avctx->priv_data;
173  const uint8_t *buf_end = buf + buf_size;
174  AVFrame *frame = data;
175  int ret;
176 
177  if (buf_end - buf < EA_PREAMBLE_SIZE)
178  return AVERROR_INVALIDDATA;
179 
180  if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {
181  unsigned size = AV_RL32(buf + 4);
182  cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);
183  if (size > buf_end - buf - EA_PREAMBLE_SIZE)
184  return -1;
185  buf += size;
186  }
187 
188  if (av_image_check_size(s->width, s->height, 0, s->avctx))
189  return -1;
190 
191  if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
192  return ret;
193 
194  memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);
195 
196  buf += EA_PREAMBLE_SIZE;
197  if ((buf[0]&1)) { // subtype
198  cmv_decode_inter(s, frame, buf+2, buf_end);
199  frame->key_frame = 0;
200  frame->pict_type = AV_PICTURE_TYPE_P;
201  }else{
202  frame->key_frame = 1;
203  frame->pict_type = AV_PICTURE_TYPE_I;
204  cmv_decode_intra(s, frame, buf+2, buf_end);
205  }
206 
209  if ((ret = av_frame_ref(s->last_frame, frame)) < 0)
210  return ret;
211 
212  *got_frame = 1;
213 
214  return buf_size;
215 }
216 
218  CmvContext *s = avctx->priv_data;
219 
222 
223  return 0;
224 }
225 
227  .name = "eacmv",
228  .type = AVMEDIA_TYPE_VIDEO,
229  .id = AV_CODEC_ID_CMV,
230  .priv_data_size = sizeof(CmvContext),
234  .capabilities = CODEC_CAP_DR1,
235  .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),
236 };