libavcodec/eacmv.c

   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
  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 {
  38     AVCodecContext *avctx;
  39     AVFrame frame;        ///< current
  40     AVFrame last_frame;   ///< last
  41     AVFrame last2_frame;  ///< second-last
  42     int width, height;
  43     unsigned int palette[AVPALETTE_COUNT];
  44 } CmvContext;
  45
  46 static av_cold int cmv_decode_init(AVCodecContext *avctx){
  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             cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
 112                       s->last_frame.data[0], s->last_frame.linesize[0],
 113                       x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
 114         }
 115         i++;
 116     }
 117 }
 118
 119 static void cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)
 120 {
 121     int pal_start, pal_count, i;
 122
 123     if(buf_end - buf < 16) {
 124         av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");
 125         return;
 126     }
 127
 128     s->width  = AV_RL16(&buf[4]);
 129     s->height = AV_RL16(&buf[6]);
 130     if (s->avctx->width!=s->width || s->avctx->height!=s->height)
 131         avcodec_set_dimensions(s->avctx, s->width, s->height);
 132
 133     s->avctx->time_base.num = 1;
 134     s->avctx->time_base.den = AV_RL16(&buf[10]);
 135
 136     pal_start = AV_RL16(&buf[12]);
 137     pal_count = AV_RL16(&buf[14]);
 138
 139     buf += 16;
 140     for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {
 141         s->palette[i] = AV_RB24(buf);
 142         buf += 3;
 143     }
 144 }
 145
 146 #define EA_PREAMBLE_SIZE 8
 147 #define MVIh_TAG MKTAG('M', 'V', 'I', 'h')
 148
 149 static int cmv_decode_frame(AVCodecContext *avctx,
 150                             void *data, int *got_frame,
 151                             AVPacket *avpkt)
 152 {
 153     const uint8_t *buf = avpkt->data;
 154     int buf_size = avpkt->size;
 155     CmvContext *s = avctx->priv_data;
 156     const uint8_t *buf_end = buf + buf_size;
 157
 158     if (buf_end - buf < EA_PREAMBLE_SIZE)
 159         return AVERROR_INVALIDDATA;
 160
 161     if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {
 162         cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);
 163         return buf_size;
 164     }
 165
 166     if (av_image_check_size(s->width, s->height, 0, s->avctx))
 167         return -1;
 168
 169     /* shuffle */
 170     if (s->last2_frame.data[0])
 171         avctx->release_buffer(avctx, &s->last2_frame);
 172     FFSWAP(AVFrame, s->last_frame, s->last2_frame);
 173     FFSWAP(AVFrame, s->frame, s->last_frame);
 174
 175     s->frame.reference = 1;
 176     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
 177     if (ff_get_buffer(avctx, &s->frame)<0) {
 178         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 179         return -1;
 180     }
 181
 182     memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
 183
 184     buf += EA_PREAMBLE_SIZE;
 185     if ((buf[0]&1)) {  // subtype
 186         cmv_decode_inter(s, buf+2, buf_end);
 187         s->frame.key_frame = 0;
 188         s->frame.pict_type = AV_PICTURE_TYPE_P;
 189     }else{
 190         s->frame.key_frame = 1;
 191         s->frame.pict_type = AV_PICTURE_TYPE_I;
 192         cmv_decode_intra(s, buf+2, buf_end);
 193     }
 194
 195     *got_frame = 1;
 196     *(AVFrame*)data = s->frame;
 197
 198     return buf_size;
 199 }
 200
 201 static av_cold int cmv_decode_end(AVCodecContext *avctx){
 202     CmvContext *s = avctx->priv_data;
 203     if (s->frame.data[0])
 204         s->avctx->release_buffer(avctx, &s->frame);
 205     if (s->last_frame.data[0])
 206         s->avctx->release_buffer(avctx, &s->last_frame);
 207     if (s->last2_frame.data[0])
 208         s->avctx->release_buffer(avctx, &s->last2_frame);
 209
 210     return 0;
 211 }
 212
 213 AVCodec ff_eacmv_decoder = {
 214     .name           = "eacmv",
 215     .type           = AVMEDIA_TYPE_VIDEO,
 216     .id             = AV_CODEC_ID_CMV,
 217     .priv_data_size = sizeof(CmvContext),
 218     .init           = cmv_decode_init,
 219     .close          = cmv_decode_end,
 220     .decode         = cmv_decode_frame,
 221     .capabilities   = CODEC_CAP_DR1,
 222     .long_name      = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),
 223 };