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 *last_frame;   ///< last
  40     AVFrame *last2_frame;  ///< second-last
  41     int width, height;
  42     unsigned int palette[AVPALETTE_COUNT];
  43 } CmvContext;
  44
  45 static av_cold int cmv_decode_init(AVCodecContext *avctx){
  46     CmvContext *s = avctx->priv_data;
  47     s->avctx = avctx;
  48     avctx->pix_fmt = AV_PIX_FMT_PAL8;
  49
  50     s->last_frame  = av_frame_alloc();
  51     s->last2_frame = av_frame_alloc();
  52     if (!s->last_frame || !s->last2_frame) {
  53         av_frame_free(&s->last_frame);
  54         av_frame_free(&s->last2_frame);
  55         return AVERROR(ENOMEM);
  56     }
  57
  58     return 0;
  59 }
  60
  61 static void cmv_decode_intra(CmvContext * s, AVFrame *frame,
  62                              const uint8_t *buf, const uint8_t *buf_end)
  63 {
  64     unsigned char *dst = frame->data[0];
  65     int i;
  66
  67     for (i=0; i < s->avctx->height && buf_end - buf >= s->avctx->width; i++) {
  68         memcpy(dst, buf, s->avctx->width);
  69         dst += frame->linesize[0];
  70         buf += s->avctx->width;
  71     }
  72 }
  73
  74 static void cmv_motcomp(unsigned char *dst, ptrdiff_t dst_stride,
  75                         const unsigned char *src, ptrdiff_t src_stride,
  76                         int x, int y,
  77                         int xoffset, int yoffset,
  78                         int width, int height){
  79     int i,j;
  80
  81     for(j=y;j<y+4;j++)
  82     for(i=x;i<x+4;i++)
  83     {
  84         if (i+xoffset>=0 && i+xoffset<width &&
  85             j+yoffset>=0 && j+yoffset<height) {
  86             dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];
  87         }else{
  88             dst[j*dst_stride + i] = 0;
  89         }
  90     }
  91 }
  92
  93 static void cmv_decode_inter(CmvContext *s, AVFrame *frame, const uint8_t *buf,
  94                              const uint8_t *buf_end)
  95 {
  96     const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);
  97     int x,y,i;
  98
  99     i = 0;
 100     for(y=0; y<s->avctx->height/4; y++)
 101     for(x=0; x<s->avctx->width/4 && buf_end - buf > i; x++) {
 102         if (buf[i]==0xFF) {
 103             unsigned char *dst = frame->data[0] + (y*4)*frame->linesize[0] + x*4;
 104             if (raw+16<buf_end && *raw==0xFF) { /* intra */
 105                 raw++;
 106                 memcpy(dst, raw, 4);
 107                 memcpy(dst +     frame->linesize[0], raw+4, 4);
 108                 memcpy(dst + 2 * frame->linesize[0], raw+8, 4);
 109                 memcpy(dst + 3 * frame->linesize[0], raw+12, 4);
 110                 raw+=16;
 111             }else if(raw<buf_end) {  /* inter using second-last frame as reference */
 112                 int xoffset = (*raw & 0xF) - 7;
 113                 int yoffset = ((*raw >> 4)) - 7;
 114                 if (s->last2_frame->data[0])
 115                     cmv_motcomp(frame->data[0], frame->linesize[0],
 116                                 s->last2_frame->data[0], s->last2_frame->linesize[0],
 117                                 x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
 118                 raw++;
 119             }
 120         }else{  /* inter using last frame as reference */
 121             int xoffset = (buf[i] & 0xF) - 7;
 122             int yoffset = ((buf[i] >> 4)) - 7;
 123             if (s->last_frame->data[0])
 124                 cmv_motcomp(frame->data[0], frame->linesize[0],
 125                             s->last_frame->data[0], s->last_frame->linesize[0],
 126                             x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
 127         }
 128         i++;
 129     }
 130 }
 131
 132 static int cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)
 133 {
 134     int pal_start, pal_count, i, ret, fps;
 135
 136     if(buf_end - buf < 16) {
 137         av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");
 138         return AVERROR_INVALIDDATA;
 139     }
 140
 141     s->width  = AV_RL16(&buf[4]);
 142     s->height = AV_RL16(&buf[6]);
 143
 144     if (s->width  != s->avctx->width ||
 145         s->height != s->avctx->height) {
 146         av_frame_unref(s->last_frame);
 147         av_frame_unref(s->last2_frame);
 148     }
 149
 150     ret = ff_set_dimensions(s->avctx, s->width, s->height);
 151     if (ret < 0)
 152         return ret;
 153
 154     fps = AV_RL16(&buf[10]);
 155     if (fps > 0)
 156         s->avctx->framerate = (AVRational){ fps, 1 };
 157
 158     pal_start = AV_RL16(&buf[12]);
 159     pal_count = AV_RL16(&buf[14]);
 160
 161     buf += 16;
 162     for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {
 163         s->palette[i] = AV_RB24(buf);
 164         buf += 3;
 165     }
 166
 167     return 0;
 168 }
 169
 170 #define EA_PREAMBLE_SIZE 8
 171 #define MVIh_TAG MKTAG('M', 'V', 'I', 'h')
 172
 173 static int cmv_decode_frame(AVCodecContext *avctx,
 174                             void *data, int *got_frame,
 175                             AVPacket *avpkt)
 176 {
 177     const uint8_t *buf = avpkt->data;
 178     int buf_size = avpkt->size;
 179     CmvContext *s = avctx->priv_data;
 180     const uint8_t *buf_end = buf + buf_size;
 181     AVFrame *frame = data;
 182     int ret;
 183
 184     if (buf_end - buf < EA_PREAMBLE_SIZE)
 185         return AVERROR_INVALIDDATA;
 186
 187     if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {
 188         ret = cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);
 189         if (ret < 0)
 190             return ret;
 191         return buf_size;
 192     }
 193
 194     if (av_image_check_size(s->width, s->height, 0, s->avctx))
 195         return -1;
 196
 197     if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) {
 198         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 199         return ret;
 200     }
 201
 202     memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);
 203
 204     buf += EA_PREAMBLE_SIZE;
 205     if ((buf[0]&1)) {  // subtype
 206         cmv_decode_inter(s, frame, buf+2, buf_end);
 207         frame->key_frame = 0;
 208         frame->pict_type = AV_PICTURE_TYPE_P;
 209     }else{
 210         frame->key_frame = 1;
 211         frame->pict_type = AV_PICTURE_TYPE_I;
 212         cmv_decode_intra(s, frame, buf+2, buf_end);
 213     }
 214
 215     av_frame_unref(s->last2_frame);
 216     av_frame_move_ref(s->last2_frame, s->last_frame);
 217     if ((ret = av_frame_ref(s->last_frame, frame)) < 0)
 218         return ret;
 219
 220     *got_frame = 1;
 221
 222     return buf_size;
 223 }
 224
 225 static av_cold int cmv_decode_end(AVCodecContext *avctx){
 226     CmvContext *s = avctx->priv_data;
 227
 228     av_frame_free(&s->last_frame);
 229     av_frame_free(&s->last2_frame);
 230
 231     return 0;
 232 }
 233
 234 AVCodec ff_eacmv_decoder = {
 235     .name           = "eacmv",
 236     .long_name      = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),
 237     .type           = AVMEDIA_TYPE_VIDEO,
 238     .id             = AV_CODEC_ID_CMV,
 239     .priv_data_size = sizeof(CmvContext),
 240     .init           = cmv_decode_init,
 241     .close          = cmv_decode_end,
 242     .decode         = cmv_decode_frame,
 243     .capabilities   = AV_CODEC_CAP_DR1,
 244 };