libavcodec/eacmv.c

   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 libavcodec/eacmv.c
  24  * Electronic Arts CMV Video Decoder
  25  * by Peter Ross (suxen_drol at hotmail dot com)
  26  *
  27  * Technical details here:
  28  * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_CMV
  29  */
  30
  31 #include "libavutil/intreadwrite.h"
  32 #include "avcodec.h"
  33
  34 typedef struct CmvContext {
  35     AVCodecContext *avctx;
  36     AVFrame frame;        ///< current
  37     AVFrame last_frame;   ///< last
  38     AVFrame last2_frame;  ///< second-last
  39     int width, height;
  40     unsigned int palette[AVPALETTE_COUNT];
  41 } CmvContext;
  42
  43 static av_cold int cmv_decode_init(AVCodecContext *avctx){
  44     CmvContext *s = avctx->priv_data;
  45     s->avctx = avctx;
  46     avctx->pix_fmt = PIX_FMT_PAL8;
  47     return 0;
  48 }
  49
  50 static void cmv_decode_intra(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
  51     unsigned char *dst = s->frame.data[0];
  52     int i;
  53
  54     for (i=0; i < s->avctx->height && buf+s->avctx->width<=buf_end; i++) {
  55         memcpy(dst, buf, s->avctx->width);
  56         dst += s->frame.linesize[0];
  57         buf += s->avctx->width;
  58     }
  59 }
  60
  61 static void cmv_motcomp(unsigned char *dst, int dst_stride,
  62                         const unsigned char *src, int src_stride,
  63                         int x, int y,
  64                         int xoffset, int yoffset,
  65                         int width, int height){
  66     int i,j;
  67
  68     for(j=y;j<y+4;j++)
  69     for(i=x;i<x+4;i++)
  70     {
  71         if (i+xoffset>=0 && i+xoffset<width &&
  72             j+yoffset>=0 && j+yoffset<height) {
  73             dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];
  74         }else{
  75             dst[j*dst_stride + i] = 0;
  76         }
  77     }
  78 }
  79
  80 static void cmv_decode_inter(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
  81     const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);
  82     int x,y,i;
  83
  84     i = 0;
  85     for(y=0; y<s->avctx->height/4; y++)
  86     for(x=0; x<s->avctx->width/4 && buf+i<buf_end; x++) {
  87         if (buf[i]==0xFF) {
  88             unsigned char *dst = s->frame.data[0] + (y*4)*s->frame.linesize[0] + x*4;
  89             if (raw+16<buf_end && *raw==0xFF) { /* intra */
  90                 raw++;
  91                 memcpy(dst, raw, 4);
  92                 memcpy(dst+s->frame.linesize[0], raw+4, 4);
  93                 memcpy(dst+2*s->frame.linesize[0], raw+8, 4);
  94                 memcpy(dst+3*s->frame.linesize[0], raw+12, 4);
  95                 raw+=16;
  96             }else if(raw<buf_end) {  /* inter using second-last frame as reference */
  97                 int xoffset = (*raw & 0xF) - 7;
  98                 int yoffset = ((*raw >> 4)) - 7;
  99                 cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
 100                             s->last2_frame.data[0], s->last2_frame.linesize[0],
 101                             x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
 102                 raw++;
 103             }
 104         }else{  /* inter using last frame as reference */
 105             int xoffset = (buf[i] & 0xF) - 7;
 106             int yoffset = ((buf[i] >> 4)) - 7;
 107             cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
 108                       s->last_frame.data[0], s->last_frame.linesize[0],
 109                       x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
 110         }
 111         i++;
 112     }
 113 }
 114
 115 static void cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)
 116 {
 117     int pal_start, pal_count, i;
 118
 119     if(buf+16>=buf_end) {
 120         av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");
 121         return;
 122     }
 123
 124     s->width  = AV_RL16(&buf[4]);
 125     s->height = AV_RL16(&buf[6]);
 126     if (s->avctx->width!=s->width || s->avctx->height!=s->height)
 127         avcodec_set_dimensions(s->avctx, s->width, s->height);
 128
 129     s->avctx->time_base.num = 1;
 130     s->avctx->time_base.den = AV_RL16(&buf[10]);
 131
 132     pal_start = AV_RL16(&buf[12]);
 133     pal_count = AV_RL16(&buf[14]);
 134
 135     buf += 16;
 136     for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf+2<buf_end; i++) {
 137         s->palette[i] = AV_RB24(buf);
 138         buf += 3;
 139     }
 140 }
 141
 142 #define EA_PREAMBLE_SIZE 8
 143 #define MVIh_TAG MKTAG('M', 'V', 'I', 'h')
 144
 145 static int cmv_decode_frame(AVCodecContext *avctx,
 146                             void *data, int *data_size,
 147                             AVPacket *avpkt)
 148 {
 149     const uint8_t *buf = avpkt->data;
 150     int buf_size = avpkt->size;
 151     CmvContext *s = avctx->priv_data;
 152     const uint8_t *buf_end = buf + buf_size;
 153
 154     if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {
 155         cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);
 156         return buf_size;
 157     }
 158
 159     if (avcodec_check_dimensions(s->avctx, s->width, s->height))
 160         return -1;
 161
 162     /* shuffle */
 163     if (s->last2_frame.data[0])
 164         avctx->release_buffer(avctx, &s->last2_frame);
 165     FFSWAP(AVFrame, s->last_frame, s->last2_frame);
 166     FFSWAP(AVFrame, s->frame, s->last_frame);
 167
 168     s->frame.reference = 1;
 169     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
 170     if (avctx->get_buffer(avctx, &s->frame)<0) {
 171         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 172         return -1;
 173     }
 174
 175     memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
 176
 177     buf += EA_PREAMBLE_SIZE;
 178     if ((buf[0]&1)) {  // subtype
 179         cmv_decode_inter(s, buf+2, buf_end);
 180         s->frame.key_frame = 0;
 181         s->frame.pict_type = FF_P_TYPE;
 182     }else{
 183         s->frame.key_frame = 1;
 184         s->frame.pict_type = FF_I_TYPE;
 185         cmv_decode_intra(s, buf+2, buf_end);
 186     }
 187
 188     *data_size = sizeof(AVFrame);
 189     *(AVFrame*)data = s->frame;
 190
 191     return buf_size;
 192 }
 193
 194 static av_cold int cmv_decode_end(AVCodecContext *avctx){
 195     CmvContext *s = avctx->priv_data;
 196     if (s->frame.data[0])
 197         s->avctx->release_buffer(avctx, &s->frame);
 198     if (s->last_frame.data[0])
 199         s->avctx->release_buffer(avctx, &s->last_frame);
 200     if (s->last2_frame.data[0])
 201         s->avctx->release_buffer(avctx, &s->last2_frame);
 202
 203     return 0;
 204 }
 205
 206 AVCodec eacmv_decoder = {
 207     "eacmv",
 208     CODEC_TYPE_VIDEO,
 209     CODEC_ID_CMV,
 210     sizeof(CmvContext),
 211     cmv_decode_init,
 212     NULL,
 213     cmv_decode_end,
 214     cmv_decode_frame,
 215     CODEC_CAP_DR1,
 216     .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),
 217 };