/*
  * Electronic Arts CMV Video Decoder
  * Copyright (c) 2007-2008 Peter Ross
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 /**

  * @file

  * Electronic Arts CMV Video Decoder

  * by Peter Ross (pross@xvid.org)

  *
  * Technical details here:
  * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_CMV
  */
 

 #include "libavutil/common.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/imgutils.h"

 #include "avcodec.h"

 #include "internal.h"

 
 typedef struct CmvContext {
     AVCodecContext *avctx;

     AVFrame *last_frame;   ///< last
     AVFrame *last2_frame;  ///< second-last

     int width, height;
     unsigned int palette[AVPALETTE_COUNT];
 } CmvContext;
 
 static av_cold int cmv_decode_init(AVCodecContext *avctx){
     CmvContext *s = avctx->priv_data;

     s->avctx = avctx;

     avctx->pix_fmt = AV_PIX_FMT_PAL8;

 
     s->last_frame  = av_frame_alloc();
     s->last2_frame = av_frame_alloc();
     if (!s->last_frame || !s->last2_frame) {
         av_frame_free(&s->last_frame);
         av_frame_free(&s->last2_frame);
         return AVERROR(ENOMEM);
     }
 

     return 0;
 }
 

 static void cmv_decode_intra(CmvContext * s, AVFrame *frame,
                              const uint8_t *buf, const uint8_t *buf_end)
 {
     unsigned char *dst = frame->data[0];

     int i;
 

     for (i=0; i < s->avctx->height && buf_end - buf >= s->avctx->width; i++) {

         memcpy(dst, buf, s->avctx->width);

         dst += frame->linesize[0];

         buf += s->avctx->width;
     }
 }
 
 static void cmv_motcomp(unsigned char *dst, int dst_stride,
                         const unsigned char *src, int src_stride,
                         int x, int y,
                         int xoffset, int yoffset,
                         int width, int height){
     int i,j;
 
     for(j=y;j<y+4;j++)
     for(i=x;i<x+4;i++)
     {
         if (i+xoffset>=0 && i+xoffset<width &&
             j+yoffset>=0 && j+yoffset<height) {
             dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];
         }else{
             dst[j*dst_stride + i] = 0;
         }
     }
 }
 

 static void cmv_decode_inter(CmvContext *s, AVFrame *frame, const uint8_t *buf,
                              const uint8_t *buf_end)
 {

     const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);
     int x,y,i;
 
     i = 0;
     for(y=0; y<s->avctx->height/4; y++)

     for(x=0; x<s->avctx->width/4 && buf_end - buf > i; x++) {

         if (buf[i]==0xFF) {

             unsigned char *dst = frame->data[0] + (y*4)*frame->linesize[0] + x*4;

             if (raw+16<buf_end && *raw==0xFF) { /* intra */
                 raw++;
                 memcpy(dst, raw, 4);

                 memcpy(dst +     frame->linesize[0], raw+4, 4);
                 memcpy(dst + 2 * frame->linesize[0], raw+8, 4);
                 memcpy(dst + 3 * frame->linesize[0], raw+12, 4);

                 raw+=16;
             }else if(raw<buf_end) {  /* inter using second-last frame as reference */
                 int xoffset = (*raw & 0xF) - 7;
                 int yoffset = ((*raw >> 4)) - 7;

                 if (s->last2_frame->data[0])
                     cmv_motcomp(frame->data[0], frame->linesize[0],
                                 s->last2_frame->data[0], s->last2_frame->linesize[0],

                                 x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);

                 raw++;
             }
         }else{  /* inter using last frame as reference */
             int xoffset = (buf[i] & 0xF) - 7;
             int yoffset = ((buf[i] >> 4)) - 7;

             if (s->last_frame->data[0])
                 cmv_motcomp(frame->data[0], frame->linesize[0],

                             s->last_frame->data[0], s->last_frame->linesize[0],
                             x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);

         }
         i++;
     }
 }
 

 static int cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)

 {

     int pal_start, pal_count, i, ret, fps;

     if(buf_end - buf < 16) {

         av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");

         return AVERROR_INVALIDDATA;

     }
 
     s->width  = AV_RL16(&buf[4]);
     s->height = AV_RL16(&buf[6]);

     if (s->width  != s->avctx->width ||
         s->height != s->avctx->height) {

         av_frame_unref(s->last_frame);
         av_frame_unref(s->last2_frame);

     }

     ret = ff_set_dimensions(s->avctx, s->width, s->height);
     if (ret < 0)
         return ret;

     fps = AV_RL16(&buf[10]);
     if (fps > 0)
         s->avctx->time_base = (AVRational){ 1, fps };

 
     pal_start = AV_RL16(&buf[12]);
     pal_count = AV_RL16(&buf[14]);
 
     buf += 16;

     for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {

         s->palette[i] = 0xFFU << 24 | AV_RB24(buf);

         buf += 3;
     }

 
     return 0;

 }
 
 #define EA_PREAMBLE_SIZE 8
 #define MVIh_TAG MKTAG('M', 'V', 'I', 'h')
 
 static int cmv_decode_frame(AVCodecContext *avctx,

                             void *data, int *got_frame,

                             AVPacket *avpkt)

 {

     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     CmvContext *s = avctx->priv_data;
     const uint8_t *buf_end = buf + buf_size;

     AVFrame *frame = data;
     int ret;

     if (buf_end - buf < EA_PREAMBLE_SIZE)
         return AVERROR_INVALIDDATA;
 

     if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {

         unsigned size = AV_RL32(buf + 4);

         ret = cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);
         if (ret < 0)
             return ret;

         if (size > buf_end - buf - EA_PREAMBLE_SIZE)
             return -1;
         buf += size;

     }
 

     if (av_image_check_size(s->width, s->height, 0, s->avctx))

         return -1;
 

     if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)

         return ret;

     memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);

 
     buf += EA_PREAMBLE_SIZE;
     if ((buf[0]&1)) {  // subtype

         cmv_decode_inter(s, frame, buf+2, buf_end);
         frame->key_frame = 0;
         frame->pict_type = AV_PICTURE_TYPE_P;

     }else{

         frame->key_frame = 1;
         frame->pict_type = AV_PICTURE_TYPE_I;
         cmv_decode_intra(s, frame, buf+2, buf_end);

     }
 

     av_frame_unref(s->last2_frame);
     av_frame_move_ref(s->last2_frame, s->last_frame);
     if ((ret = av_frame_ref(s->last_frame, frame)) < 0)
         return ret;
 

     *got_frame = 1;

 
     return buf_size;
 }
 
 static av_cold int cmv_decode_end(AVCodecContext *avctx){
     CmvContext *s = avctx->priv_data;

 
     av_frame_free(&s->last_frame);
     av_frame_free(&s->last2_frame);

 
     return 0;
 }
 

 AVCodec ff_eacmv_decoder = {

     .name           = "eacmv",

     .long_name      = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_CMV,

     .priv_data_size = sizeof(CmvContext),
     .init           = cmv_decode_init,
     .close          = cmv_decode_end,
     .decode         = cmv_decode_frame,
     .capabilities   = CODEC_CAP_DR1,

 };