/*
  * Zip Motion Blocks Video (ZMBV) encoder
  * Copyright (c) 2006 Konstantin Shishkov
  *
  * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**

  * @file

  * Zip Motion Blocks Video encoder
  */
 
 #include <stdio.h>
 #include <stdlib.h>
 

 #include "libavutil/intreadwrite.h"

 #include "avcodec.h"
 
 #include <zlib.h>
 
 #define ZMBV_KEYFRAME 1
 #define ZMBV_DELTAPAL 2
 
 #define ZMBV_BLOCK 16
 
 /**
  * Encoder context
  */
 typedef struct ZmbvEncContext {
     AVCodecContext *avctx;
     AVFrame pic;
 
     int range;
     uint8_t *comp_buf, *work_buf;
     uint8_t pal[768];
     uint32_t pal2[256]; //for quick comparisons
     uint8_t *prev;
     int pstride;
     int comp_size;
     int keyint, curfrm;
     z_stream zstream;
 } ZmbvEncContext;
 

 static int score_tab[256];
 

 /** Block comparing function
  * XXX should be optimized and moved to DSPContext
  * TODO handle out of edge ME
  */

 static inline int block_cmp(uint8_t *src, int stride, uint8_t *src2, int stride2,
                             int bw, int bh, int *xored)

 {
     int sum = 0;
     int i, j;

     uint8_t histogram[256] = {0};

     *xored = 0;

     for(j = 0; j < bh; j++){

         for(i = 0; i < bw; i++){
             int t = src[i] ^ src2[i];
             histogram[t]++;
             *xored |= t;
         }

         src += stride;
         src2 += stride2;
     }

     for(i = 1; i < 256; i++)
         sum += score_tab[histogram[i]];

     return sum;
 }
 
 /** Motion estimation function
  * TODO make better ME decisions
  */

 static int zmbv_me(ZmbvEncContext *c, uint8_t *src, int sstride, uint8_t *prev,
                    int pstride, int x, int y, int *mx, int *my, int *xored)

 {

     int dx, dy, tx, ty, tv, bv, bw, bh;

 
     *mx = *my = 0;

     bw = FFMIN(ZMBV_BLOCK, c->avctx->width - x);
     bh = FFMIN(ZMBV_BLOCK, c->avctx->height - y);

     bv = block_cmp(src, sstride, prev, pstride, bw, bh, xored);

     if(!bv) return 0;

     for(ty = FFMAX(y - c->range, 0); ty < FFMIN(y + c->range, c->avctx->height - bh); ty++){
         for(tx = FFMAX(x - c->range, 0); tx < FFMIN(x + c->range, c->avctx->width - bw); tx++){

             if(tx == x && ty == y) continue; // we already tested this block
             dx = tx - x;
             dy = ty - y;

             tv = block_cmp(src, sstride, prev + dx + dy*pstride, pstride, bw, bh, xored);

             if(tv < bv){
                  bv = tv;
                  *mx = dx;
                  *my = dy;
                  if(!bv) return 0;
              }
          }
     }
     return bv;
 }
 
 static int encode_frame(AVCodecContext *avctx, uint8_t *buf, int buf_size, void *data)
 {

     ZmbvEncContext * const c = avctx->priv_data;

     AVFrame *pict = data;
     AVFrame * const p = &c->pic;
     uint8_t *src, *prev;
     uint32_t *palptr;
     int len = 0;
     int keyframe, chpal;
     int fl;
     int work_size = 0;
     int bw, bh;
     int i, j;
 
     keyframe = !c->curfrm;

     c->curfrm++;

     if(c->curfrm == c->keyint)
         c->curfrm = 0;
     *p = *pict;

     p->pict_type= keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;

     p->key_frame= keyframe;
     chpal = !keyframe && memcmp(p->data[1], c->pal2, 1024);
 
     fl = (keyframe ? ZMBV_KEYFRAME : 0) | (chpal ? ZMBV_DELTAPAL : 0);
     *buf++ = fl; len++;
     if(keyframe){
         deflateReset(&c->zstream);
         *buf++ = 0; len++; // hi ver
         *buf++ = 1; len++; // lo ver
         *buf++ = 1; len++; // comp
         *buf++ = 4; len++; // format - 8bpp
         *buf++ = ZMBV_BLOCK; len++; // block width
         *buf++ = ZMBV_BLOCK; len++; // block height
     }
     palptr = (uint32_t*)p->data[1];
     src = p->data[0];
     prev = c->prev;
     if(chpal){
         uint8_t tpal[3];
         for(i = 0; i < 256; i++){

             AV_WB24(tpal, palptr[i]);

             c->work_buf[work_size++] = tpal[0] ^ c->pal[i * 3 + 0];
             c->work_buf[work_size++] = tpal[1] ^ c->pal[i * 3 + 1];
             c->work_buf[work_size++] = tpal[2] ^ c->pal[i * 3 + 2];
             c->pal[i * 3 + 0] = tpal[0];
             c->pal[i * 3 + 1] = tpal[1];
             c->pal[i * 3 + 2] = tpal[2];
         }
         memcpy(c->pal2, p->data[1], 1024);
     }
     if(keyframe){
         for(i = 0; i < 256; i++){

             AV_WB24(c->pal+(i*3), palptr[i]);

         }
         memcpy(c->work_buf, c->pal, 768);
         memcpy(c->pal2, p->data[1], 1024);
         work_size = 768;
         for(i = 0; i < avctx->height; i++){
             memcpy(c->work_buf + work_size, src, avctx->width);
             src += p->linesize[0];
             work_size += avctx->width;
         }
     }else{

         int x, y, bh2, bw2, xored;

         uint8_t *tsrc, *tprev;
         uint8_t *mv;

         int mx, my;

 
         bw = (avctx->width + ZMBV_BLOCK - 1) / ZMBV_BLOCK;
         bh = (avctx->height + ZMBV_BLOCK - 1) / ZMBV_BLOCK;
         mv = c->work_buf + work_size;
         memset(c->work_buf + work_size, 0, (bw * bh * 2 + 3) & ~3);
         work_size += (bw * bh * 2 + 3) & ~3;
         /* for now just XOR'ing */
         for(y = 0; y < avctx->height; y += ZMBV_BLOCK) {
             bh2 = FFMIN(avctx->height - y, ZMBV_BLOCK);
             for(x = 0; x < avctx->width; x += ZMBV_BLOCK, mv += 2) {
                 bw2 = FFMIN(avctx->width - x, ZMBV_BLOCK);
 
                 tsrc = src + x;
                 tprev = prev + x;
 

                 zmbv_me(c, tsrc, p->linesize[0], tprev, c->pstride, x, y, &mx, &my, &xored);

                 mv[0] = (mx << 1) | !!xored;

                 mv[1] = my << 1;
                 tprev += mx + my * c->pstride;

                 if(xored){

                     for(j = 0; j < bh2; j++){
                         for(i = 0; i < bw2; i++)
                             c->work_buf[work_size++] = tsrc[i] ^ tprev[i];
                         tsrc += p->linesize[0];
                         tprev += c->pstride;
                     }
                 }
             }
             src += p->linesize[0] * ZMBV_BLOCK;
             prev += c->pstride * ZMBV_BLOCK;
         }
     }
     /* save the previous frame */
     src = p->data[0];
     prev = c->prev;
     for(i = 0; i < avctx->height; i++){
         memcpy(prev, src, avctx->width);
         prev += c->pstride;
         src += p->linesize[0];
     }
 
     c->zstream.next_in = c->work_buf;
     c->zstream.avail_in = work_size;
     c->zstream.total_in = 0;
 
     c->zstream.next_out = c->comp_buf;
     c->zstream.avail_out = c->comp_size;
     c->zstream.total_out = 0;

     if(deflate(&c->zstream, Z_SYNC_FLUSH) != Z_OK){

         av_log(avctx, AV_LOG_ERROR, "Error compressing data\n");
         return -1;
     }
 
     memcpy(buf, c->comp_buf, c->zstream.total_out);
     return len + c->zstream.total_out;
 }
 
 
 /**
  * Init zmbv encoder
  */

 static av_cold int encode_init(AVCodecContext *avctx)

 {

     ZmbvEncContext * const c = avctx->priv_data;

     int zret; // Zlib return code

     int i;

     int lvl = 9;
 

     for(i=1; i<256; i++)

         score_tab[i]= -i * log(i/(double)(ZMBV_BLOCK*ZMBV_BLOCK)) * (256/M_LN2);

     c->avctx = avctx;
 
     c->curfrm = 0;
     c->keyint = avctx->keyint_min;
     c->range = 8;
     if(avctx->me_range > 0)
         c->range = FFMIN(avctx->me_range, 127);
 
     if(avctx->compression_level >= 0)
         lvl = avctx->compression_level;
     if(lvl < 0 || lvl > 9){
         av_log(avctx, AV_LOG_ERROR, "Compression level should be 0-9, not %i\n", lvl);
         return -1;
     }
 
     // Needed if zlib unused or init aborted before deflateInit
     memset(&(c->zstream), 0, sizeof(z_stream));
     c->comp_size = avctx->width * avctx->height + 1024 +
         ((avctx->width + ZMBV_BLOCK - 1) / ZMBV_BLOCK) * ((avctx->height + ZMBV_BLOCK - 1) / ZMBV_BLOCK) * 2 + 4;
     if ((c->work_buf = av_malloc(c->comp_size)) == NULL) {
         av_log(avctx, AV_LOG_ERROR, "Can't allocate work buffer.\n");
         return -1;
     }
     /* Conservative upper bound taken from zlib v1.2.1 source via lcl.c */
     c->comp_size = c->comp_size + ((c->comp_size + 7) >> 3) +
                            ((c->comp_size + 63) >> 6) + 11;
 
     /* Allocate compression buffer */
     if ((c->comp_buf = av_malloc(c->comp_size)) == NULL) {
         av_log(avctx, AV_LOG_ERROR, "Can't allocate compression buffer.\n");
         return -1;
     }

     c->pstride = FFALIGN(avctx->width, 16);

     if ((c->prev = av_malloc(c->pstride * avctx->height)) == NULL) {
         av_log(avctx, AV_LOG_ERROR, "Can't allocate picture.\n");
         return -1;
     }
 
     c->zstream.zalloc = Z_NULL;
     c->zstream.zfree = Z_NULL;
     c->zstream.opaque = Z_NULL;
     zret = deflateInit(&(c->zstream), lvl);
     if (zret != Z_OK) {
         av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
         return -1;
     }
 

     avctx->coded_frame = (AVFrame*)&c->pic;
 

     return 0;
 }
 
 
 
 /**

  * Uninit zmbv encoder

  */

 static av_cold int encode_end(AVCodecContext *avctx)

 {

     ZmbvEncContext * const c = avctx->priv_data;

 
     av_freep(&c->comp_buf);
     av_freep(&c->work_buf);
 
     deflateEnd(&(c->zstream));
     av_freep(&c->prev);
 
     return 0;
 }
 

 AVCodec ff_zmbv_encoder = {

     .name           = "zmbv",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = CODEC_ID_ZMBV,
     .priv_data_size = sizeof(ZmbvEncContext),
     .init           = encode_init,
     .encode         = encode_frame,
     .close          = encode_end,

     .pix_fmts = (const enum PixelFormat[]){PIX_FMT_PAL8, PIX_FMT_NONE},

     .long_name = NULL_IF_CONFIG_SMALL("Zip Motion Blocks Video"),

 };