/*
  * Duck/ON2 TrueMotion 2 Decoder
  * Copyright (c) 2005 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

  * Duck TrueMotion2 decoder.
  */

 #include "avcodec.h"

 #include "get_bits.h"

 #include "dsputil.h"
 
 #define TM2_ESCAPE 0x80000000

 #define TM2_DELTAS 64

 /* Huffman-coded streams of different types of blocks */
 enum TM2_STREAMS{ TM2_C_HI = 0, TM2_C_LO, TM2_L_HI, TM2_L_LO,
      TM2_UPD, TM2_MOT, TM2_TYPE, TM2_NUM_STREAMS};
 /* Block types */
 enum TM2_BLOCKS{ TM2_HI_RES = 0, TM2_MED_RES, TM2_LOW_RES, TM2_NULL_RES,
                  TM2_UPDATE, TM2_STILL, TM2_MOTION};
 
 typedef struct TM2Context{
     AVCodecContext *avctx;
     AVFrame pic;
 
     GetBitContext gb;
     DSPContext dsp;

     /* TM2 streams */
     int *tokens[TM2_NUM_STREAMS];
     int tok_lens[TM2_NUM_STREAMS];
     int tok_ptrs[TM2_NUM_STREAMS];
     int deltas[TM2_NUM_STREAMS][TM2_DELTAS];
     /* for blocks decoding */
     int D[4];
     int CD[4];
     int *last;
     int *clast;

     /* data for current and previous frame */
     int *Y1, *U1, *V1, *Y2, *U2, *V2;
     int cur;
 } TM2Context;
 
 /**
 * Huffman codes for each of streams
 */
 typedef struct TM2Codes{

     VLC vlc; ///< table for FFmpeg bitstream reader

     int bits;
     int *recode; ///< table for converting from code indexes to values
     int length;
 } TM2Codes;
 
 /**
 * structure for gathering Huffman codes information
 */
 typedef struct TM2Huff{
     int val_bits; ///< length of literal
     int max_bits; ///< maximum length of code
     int min_bits; ///< minimum length of code
     int nodes; ///< total number of nodes in tree
     int num; ///< current number filled
     int max_num; ///< total number of codes
     int *nums; ///< literals
     uint32_t *bits; ///< codes
     int *lens; ///< codelengths
 } TM2Huff;
 
 static int tm2_read_tree(TM2Context *ctx, uint32_t prefix, int length, TM2Huff *huff)
 {
     if(length > huff->max_bits) {
         av_log(ctx->avctx, AV_LOG_ERROR, "Tree exceeded its given depth (%i)\n", huff->max_bits);
         return -1;
     }
 
     if(!get_bits1(&ctx->gb)) { /* literal */
         if (length == 0) {
             length = 1;
         }
         if(huff->num >= huff->max_num) {
             av_log(ctx->avctx, AV_LOG_DEBUG, "Too many literals\n");
             return -1;
         }
         huff->nums[huff->num] = get_bits_long(&ctx->gb, huff->val_bits);
         huff->bits[huff->num] = prefix;
         huff->lens[huff->num] = length;
         huff->num++;
         return 0;
     } else { /* non-terminal node */
         if(tm2_read_tree(ctx, prefix << 1, length + 1, huff) == -1)
             return -1;
         if(tm2_read_tree(ctx, (prefix << 1) | 1, length + 1, huff) == -1)
             return -1;
     }
     return 0;
 }
 
 static int tm2_build_huff_table(TM2Context *ctx, TM2Codes *code)
 {
     TM2Huff huff;
     int res = 0;

     huff.val_bits = get_bits(&ctx->gb, 5);
     huff.max_bits = get_bits(&ctx->gb, 5);
     huff.min_bits = get_bits(&ctx->gb, 5);
     huff.nodes = get_bits_long(&ctx->gb, 17);
     huff.num = 0;

     /* check for correct codes parameters */
     if((huff.val_bits < 1) || (huff.val_bits > 32) ||
        (huff.max_bits < 0) || (huff.max_bits > 32)) {
         av_log(ctx->avctx, AV_LOG_ERROR, "Incorrect tree parameters - literal length: %i, max code length: %i\n",
                huff.val_bits, huff.max_bits);
         return -1;
     }
     if((huff.nodes < 0) || (huff.nodes > 0x10000)) {
         av_log(ctx->avctx, AV_LOG_ERROR, "Incorrect number of Huffman tree nodes: %i\n", huff.nodes);
         return -1;
     }
     /* one-node tree */
     if(huff.max_bits == 0)
         huff.max_bits = 1;

     /* allocate space for codes - it is exactly ceil(nodes / 2) entries */
     huff.max_num = (huff.nodes + 1) >> 1;
     huff.nums = av_mallocz(huff.max_num * sizeof(int));
     huff.bits = av_mallocz(huff.max_num * sizeof(uint32_t));
     huff.lens = av_mallocz(huff.max_num * sizeof(int));

     if(tm2_read_tree(ctx, 0, 0, &huff) == -1)
         res = -1;

     if(huff.num != huff.max_num) {
         av_log(ctx->avctx, AV_LOG_ERROR, "Got less codes than expected: %i of %i\n",
                huff.num, huff.max_num);
         res = -1;
     }

     /* convert codes to vlc_table */
     if(res != -1) {
         int i;

         res = init_vlc(&code->vlc, huff.max_bits, huff.max_num,
                     huff.lens, sizeof(int), sizeof(int),
                     huff.bits, sizeof(uint32_t), sizeof(uint32_t), 0);
         if(res < 0) {
             av_log(ctx->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
             res = -1;

         } else

             res = 0;
         if(res != -1) {
             code->bits = huff.max_bits;
             code->length = huff.max_num;
             code->recode = av_malloc(code->length * sizeof(int));
             for(i = 0; i < code->length; i++)
                 code->recode[i] = huff.nums[i];
         }
     }
     /* free allocated memory */
     av_free(huff.nums);
     av_free(huff.bits);
     av_free(huff.lens);

     return res;
 }
 
 static void tm2_free_codes(TM2Codes *code)
 {

     av_free(code->recode);

     if(code->vlc.table)
         free_vlc(&code->vlc);
 }
 
 static inline int tm2_get_token(GetBitContext *gb, TM2Codes *code)
 {
     int val;
     val = get_vlc2(gb, code->vlc.table, code->bits, 1);
     return code->recode[val];
 }
 

 static inline int tm2_read_header(TM2Context *ctx, const uint8_t *buf)

 {
     uint32_t magic;

     const uint8_t *obuf;

     obuf = buf;

     magic = AV_RL32(buf);

     buf += 4;

     if(magic == 0x00000100) { /* old header */
 /*      av_log (ctx->avctx, AV_LOG_ERROR, "TM2 old header: not implemented (yet)\n"); */
         return 40;
     } else if(magic == 0x00000101) { /* new header */
         return 40;
     } else {
         av_log (ctx->avctx, AV_LOG_ERROR, "Not a TM2 header: 0x%08X\n", magic);
         return -1;
     }

     return buf - obuf;

 }
 
 static int tm2_read_deltas(TM2Context *ctx, int stream_id) {
     int d, mb;
     int i, v;

     d = get_bits(&ctx->gb, 9);
     mb = get_bits(&ctx->gb, 5);

     if((d < 1) || (d > TM2_DELTAS) || (mb < 1) || (mb > 32)) {
         av_log(ctx->avctx, AV_LOG_ERROR, "Incorrect delta table: %i deltas x %i bits\n", d, mb);
         return -1;
     }

     for(i = 0; i < d; i++) {
         v = get_bits_long(&ctx->gb, mb);
         if(v & (1 << (mb - 1)))
             ctx->deltas[stream_id][i] = v - (1 << mb);
         else
             ctx->deltas[stream_id][i] = v;
     }
     for(; i < TM2_DELTAS; i++)
         ctx->deltas[stream_id][i] = 0;

     return 0;
 }
 

 static int tm2_read_stream(TM2Context *ctx, const uint8_t *buf, int stream_id, int buf_size)
 {

     int i;
     int cur = 0;
     int skip = 0;
     int len, toks;
     TM2Codes codes;

     /* get stream length in dwords */

     len = AV_RB32(buf); buf += 4; cur += 4;

     skip = len * 4 + 4;

     if(len == 0)
         return 4;

     if (len >= INT_MAX/4-1 || len < 0 || len > buf_size) {
         av_log(ctx->avctx, AV_LOG_ERROR, "Error, invalid stream size.\n");
         return -1;
     }
 

     toks = AV_RB32(buf); buf += 4; cur += 4;

     if(toks & 1) {

         len = AV_RB32(buf); buf += 4; cur += 4;

         if(len == TM2_ESCAPE) {

             len = AV_RB32(buf); buf += 4; cur += 4;

         }
         if(len > 0) {

             init_get_bits(&ctx->gb, buf, (skip - cur) * 8);

             if(tm2_read_deltas(ctx, stream_id) == -1)
                 return -1;
             buf += ((get_bits_count(&ctx->gb) + 31) >> 5) << 2;
             cur += ((get_bits_count(&ctx->gb) + 31) >> 5) << 2;
         }
     }
     /* skip unused fields */

     if(AV_RB32(buf) == TM2_ESCAPE) {

         buf += 4; cur += 4; /* some unknown length - could be escaped too */
     }
     buf += 4; cur += 4;
     buf += 4; cur += 4; /* unused by decoder */

     if(skip < cur)
         return -1;

     init_get_bits(&ctx->gb, buf, (skip - cur) * 8);

     if(tm2_build_huff_table(ctx, &codes) == -1)
         return -1;
     buf += ((get_bits_count(&ctx->gb) + 31) >> 5) << 2;
     cur += ((get_bits_count(&ctx->gb) + 31) >> 5) << 2;

     toks >>= 1;
     /* check if we have sane number of tokens */
     if((toks < 0) || (toks > 0xFFFFFF)){
         av_log(ctx->avctx, AV_LOG_ERROR, "Incorrect number of tokens: %i\n", toks);
         tm2_free_codes(&codes);
         return -1;
     }
     ctx->tokens[stream_id] = av_realloc(ctx->tokens[stream_id], toks * sizeof(int));
     ctx->tok_lens[stream_id] = toks;

     len = AV_RB32(buf); buf += 4; cur += 4;

     if(len > 0) {

         init_get_bits(&ctx->gb, buf, (skip - cur) * 8);

         for(i = 0; i < toks; i++) {
             if (get_bits_left(&ctx->gb) <= 0) {
                 av_log(ctx->avctx, AV_LOG_ERROR, "Incorrect number of tokens: %i\n", toks);
                 return -1;
             }

             ctx->tokens[stream_id][i] = tm2_get_token(&ctx->gb, &codes);

         }

     } else {

         for(i = 0; i < toks; i++)
             ctx->tokens[stream_id][i] = codes.recode[0];

     }
     tm2_free_codes(&codes);

     return skip;
 }
 
 static inline int GET_TOK(TM2Context *ctx,int type) {
     if(ctx->tok_ptrs[type] >= ctx->tok_lens[type]) {
         av_log(ctx->avctx, AV_LOG_ERROR, "Read token from stream %i out of bounds (%i>=%i)\n", type, ctx->tok_ptrs[type], ctx->tok_lens[type]);
         return 0;
     }
     if(type <= TM2_MOT)
         return ctx->deltas[type][ctx->tokens[type][ctx->tok_ptrs[type]++]];
     return ctx->tokens[type][ctx->tok_ptrs[type]++];
 }
 
 /* blocks decoding routines */
 
 /* common Y, U, V pointers initialisation */

 #define TM2_INIT_POINTERS() \

     int *last, *clast; \
     int *Y, *U, *V;\
     int Ystride, Ustride, Vstride;\
 \
     Ystride = ctx->avctx->width;\
     Vstride = (ctx->avctx->width + 1) >> 1;\
     Ustride = (ctx->avctx->width + 1) >> 1;\
     Y = (ctx->cur?ctx->Y2:ctx->Y1) + by * 4 * Ystride + bx * 4;\
     V = (ctx->cur?ctx->V2:ctx->V1) + by * 2 * Vstride + bx * 2;\
     U = (ctx->cur?ctx->U2:ctx->U1) + by * 2 * Ustride + bx * 2;\
     last = ctx->last + bx * 4;\
     clast = ctx->clast + bx * 4;
 

 #define TM2_INIT_POINTERS_2() \

     int *Yo, *Uo, *Vo;\
     int oYstride, oUstride, oVstride;\
 \
     TM2_INIT_POINTERS();\
     oYstride = Ystride;\
     oVstride = Vstride;\
     oUstride = Ustride;\
     Yo = (ctx->cur?ctx->Y1:ctx->Y2) + by * 4 * oYstride + bx * 4;\
     Vo = (ctx->cur?ctx->V1:ctx->V2) + by * 2 * oVstride + bx * 2;\
     Uo = (ctx->cur?ctx->U1:ctx->U2) + by * 2 * oUstride + bx * 2;
 
 /* recalculate last and delta values for next blocks */
 #define TM2_RECALC_BLOCK(CHR, stride, last, CD) {\

     CD[0] = CHR[1] - last[1];\

     CD[1] = (int)CHR[stride + 1] - (int)CHR[1];\

     last[0] = (int)CHR[stride + 0];\
     last[1] = (int)CHR[stride + 1];}

 
 /* common operations - add deltas to 4x4 block of luma or 2x2 blocks of chroma */
 static inline void tm2_apply_deltas(TM2Context *ctx, int* Y, int stride, int *deltas, int *last)
 {
     int ct, d;
     int i, j;

     for(j = 0; j < 4; j++){
         ct = ctx->D[j];
         for(i = 0; i < 4; i++){
             d = deltas[i + j * 4];
             ct += d;
             last[i] += ct;

             Y[i] = av_clip_uint8(last[i]);

         }
         Y += stride;
         ctx->D[j] = ct;
     }
 }
 
 static inline void tm2_high_chroma(int *data, int stride, int *last, int *CD, int *deltas)
 {
     int i, j;
     for(j = 0; j < 2; j++){
         for(i = 0; i < 2; i++){
             CD[j] += deltas[i + j * 2];
             last[i] += CD[j];

             data[i] = last[i];

         }
         data += stride;
     }
 }
 
 static inline void tm2_low_chroma(int *data, int stride, int *clast, int *CD, int *deltas, int bx)
 {
     int t;
     int l;
     int prev;
 
     if(bx > 0)
         prev = clast[-3];
     else
         prev = 0;
     t = (CD[0] + CD[1]) >> 1;

     l = (prev - CD[0] - CD[1] + clast[1]) >> 1;

     CD[1] = CD[0] + CD[1] - t;
     CD[0] = t;
     clast[0] = l;

     tm2_high_chroma(data, stride, clast, CD, deltas);
 }
 
 static inline void tm2_hi_res_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
 {
     int i;
     int deltas[16];
     TM2_INIT_POINTERS();
 
     /* hi-res chroma */
     for(i = 0; i < 4; i++) {
         deltas[i] = GET_TOK(ctx, TM2_C_HI);
         deltas[i + 4] = GET_TOK(ctx, TM2_C_HI);
     }
     tm2_high_chroma(U, Ustride, clast, ctx->CD, deltas);
     tm2_high_chroma(V, Vstride, clast + 2, ctx->CD + 2, deltas + 4);

     /* hi-res luma */
     for(i = 0; i < 16; i++)
         deltas[i] = GET_TOK(ctx, TM2_L_HI);

     tm2_apply_deltas(ctx, Y, Ystride, deltas, last);
 }
 
 static inline void tm2_med_res_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
 {
     int i;
     int deltas[16];
     TM2_INIT_POINTERS();

     /* low-res chroma */
     deltas[0] = GET_TOK(ctx, TM2_C_LO);
     deltas[1] = deltas[2] = deltas[3] = 0;
     tm2_low_chroma(U, Ustride, clast, ctx->CD, deltas, bx);
 
     deltas[0] = GET_TOK(ctx, TM2_C_LO);
     deltas[1] = deltas[2] = deltas[3] = 0;
     tm2_low_chroma(V, Vstride, clast + 2, ctx->CD + 2, deltas, bx);
 
     /* hi-res luma */
     for(i = 0; i < 16; i++)
         deltas[i] = GET_TOK(ctx, TM2_L_HI);

     tm2_apply_deltas(ctx, Y, Ystride, deltas, last);
 }
 
 static inline void tm2_low_res_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
 {
     int i;
     int t1, t2;
     int deltas[16];
     TM2_INIT_POINTERS();
 
     /* low-res chroma */
     deltas[0] = GET_TOK(ctx, TM2_C_LO);
     deltas[1] = deltas[2] = deltas[3] = 0;
     tm2_low_chroma(U, Ustride, clast, ctx->CD, deltas, bx);
 
     deltas[0] = GET_TOK(ctx, TM2_C_LO);
     deltas[1] = deltas[2] = deltas[3] = 0;
     tm2_low_chroma(V, Vstride, clast + 2, ctx->CD + 2, deltas, bx);
 
     /* low-res luma */
     for(i = 0; i < 16; i++)
         deltas[i] = 0;

     deltas[ 0] = GET_TOK(ctx, TM2_L_LO);
     deltas[ 2] = GET_TOK(ctx, TM2_L_LO);
     deltas[ 8] = GET_TOK(ctx, TM2_L_LO);
     deltas[10] = GET_TOK(ctx, TM2_L_LO);

     if(bx > 0)
         last[0] = (last[-1] - ctx->D[0] - ctx->D[1] - ctx->D[2] - ctx->D[3] + last[1]) >> 1;
     else
         last[0] = (last[1]  - ctx->D[0] - ctx->D[1] - ctx->D[2] - ctx->D[3])>> 1;
     last[2] = (last[1] + last[3]) >> 1;
 
     t1 = ctx->D[0] + ctx->D[1];
     ctx->D[0] = t1 >> 1;
     ctx->D[1] = t1 - (t1 >> 1);
     t2 = ctx->D[2] + ctx->D[3];
     ctx->D[2] = t2 >> 1;
     ctx->D[3] = t2 - (t2 >> 1);

     tm2_apply_deltas(ctx, Y, Ystride, deltas, last);
 }
 
 static inline void tm2_null_res_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
 {
     int i;
     int ct;
     int left, right, diff;
     int deltas[16];
     TM2_INIT_POINTERS();

     /* null chroma */
     deltas[0] = deltas[1] = deltas[2] = deltas[3] = 0;
     tm2_low_chroma(U, Ustride, clast, ctx->CD, deltas, bx);
 
     deltas[0] = deltas[1] = deltas[2] = deltas[3] = 0;
     tm2_low_chroma(V, Vstride, clast + 2, ctx->CD + 2, deltas, bx);

     /* null luma */
     for(i = 0; i < 16; i++)
         deltas[i] = 0;
 
     ct = ctx->D[0] + ctx->D[1] + ctx->D[2] + ctx->D[3];

     if(bx > 0)
         left = last[-1] - ct;
     else
         left = 0;

     right = last[3];
     diff = right - left;
     last[0] = left + (diff >> 2);
     last[1] = left + (diff >> 1);
     last[2] = right - (diff >> 2);
     last[3] = right;
     {
         int tp = left;

         ctx->D[0] = (tp + (ct >> 2)) - left;
         left += ctx->D[0];
         ctx->D[1] = (tp + (ct >> 1)) - left;
         left += ctx->D[1];
         ctx->D[2] = ((tp + ct) - (ct >> 2)) - left;
         left += ctx->D[2];
         ctx->D[3] = (tp + ct) - left;
     }
     tm2_apply_deltas(ctx, Y, Ystride, deltas, last);
 }
 
 static inline void tm2_still_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
 {
     int i, j;
     TM2_INIT_POINTERS_2();
 
     /* update chroma */
     for(j = 0; j < 2; j++){
         for(i = 0; i < 2; i++){
             U[i] = Uo[i];
             V[i] = Vo[i];
         }
         U += Ustride; V += Vstride;
         Uo += oUstride; Vo += oVstride;
     }
     U -= Ustride * 2;
     V -= Vstride * 2;
     TM2_RECALC_BLOCK(U, Ustride, clast, ctx->CD);
     TM2_RECALC_BLOCK(V, Vstride, (clast + 2), (ctx->CD + 2));
 
     /* update deltas */
     ctx->D[0] = Yo[3] - last[3];
     ctx->D[1] = Yo[3 + oYstride] - Yo[3];
     ctx->D[2] = Yo[3 + oYstride * 2] - Yo[3 + oYstride];
     ctx->D[3] = Yo[3 + oYstride * 3] - Yo[3 + oYstride * 2];
 
     for(j = 0; j < 4; j++){
         for(i = 0; i < 4; i++){
             Y[i] = Yo[i];
             last[i] = Yo[i];
         }
         Y += Ystride;
         Yo += oYstride;
     }
 }
 
 static inline void tm2_update_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
 {
     int i, j;
     int d;
     TM2_INIT_POINTERS_2();

     /* update chroma */
     for(j = 0; j < 2; j++){
         for(i = 0; i < 2; i++){
             U[i] = Uo[i] + GET_TOK(ctx, TM2_UPD);
             V[i] = Vo[i] + GET_TOK(ctx, TM2_UPD);
         }
         U += Ustride; V += Vstride;
         Uo += oUstride; Vo += oVstride;
     }
     U -= Ustride * 2;
     V -= Vstride * 2;
     TM2_RECALC_BLOCK(U, Ustride, clast, ctx->CD);
     TM2_RECALC_BLOCK(V, Vstride, (clast + 2), (ctx->CD + 2));
 
     /* update deltas */
     ctx->D[0] = Yo[3] - last[3];
     ctx->D[1] = Yo[3 + oYstride] - Yo[3];
     ctx->D[2] = Yo[3 + oYstride * 2] - Yo[3 + oYstride];
     ctx->D[3] = Yo[3 + oYstride * 3] - Yo[3 + oYstride * 2];
 
     for(j = 0; j < 4; j++){
         d = last[3];
         for(i = 0; i < 4; i++){
             Y[i] = Yo[i] + GET_TOK(ctx, TM2_UPD);
             last[i] = Y[i];
         }
         ctx->D[j] = last[3] - d;
         Y += Ystride;
         Yo += oYstride;
     }
 }
 
 static inline void tm2_motion_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
 {
     int i, j;
     int mx, my;
     TM2_INIT_POINTERS_2();
 
     mx = GET_TOK(ctx, TM2_MOT);
     my = GET_TOK(ctx, TM2_MOT);

     Yo += my * oYstride + mx;
     Uo += (my >> 1) * oUstride + (mx >> 1);
     Vo += (my >> 1) * oVstride + (mx >> 1);

     /* copy chroma */
     for(j = 0; j < 2; j++){
         for(i = 0; i < 2; i++){
             U[i] = Uo[i];
             V[i] = Vo[i];
         }
         U += Ustride; V += Vstride;
         Uo += oUstride; Vo += oVstride;
     }
     U -= Ustride * 2;
     V -= Vstride * 2;
     TM2_RECALC_BLOCK(U, Ustride, clast, ctx->CD);
     TM2_RECALC_BLOCK(V, Vstride, (clast + 2), (ctx->CD + 2));
 
     /* copy luma */
     for(j = 0; j < 4; j++){
         for(i = 0; i < 4; i++){
             Y[i] = Yo[i];
         }
         Y += Ystride;
         Yo += oYstride;
     }
     /* calculate deltas */
     Y -= Ystride * 4;
     ctx->D[0] = Y[3] - last[3];
     ctx->D[1] = Y[3 + Ystride] - Y[3];
     ctx->D[2] = Y[3 + Ystride * 2] - Y[3 + Ystride];
     ctx->D[3] = Y[3 + Ystride * 3] - Y[3 + Ystride * 2];
     for(i = 0; i < 4; i++)
         last[i] = Y[i + Ystride * 3];
 }
 
 static int tm2_decode_blocks(TM2Context *ctx, AVFrame *p)
 {
     int i, j;
     int bw, bh;
     int type;
     int keyframe = 1;

     int *Y, *U, *V;
     uint8_t *dst;

     bw = ctx->avctx->width >> 2;
     bh = ctx->avctx->height >> 2;
 
     for(i = 0; i < TM2_NUM_STREAMS; i++)
         ctx->tok_ptrs[i] = 0;

     if (ctx->tok_lens[TM2_TYPE]<bw*bh){
         av_log(ctx->avctx,AV_LOG_ERROR,"Got %i tokens for %i blocks\n",ctx->tok_lens[TM2_TYPE],bw*bh);
         return -1;
     }

     memset(ctx->last, 0, 4 * bw * sizeof(int));
     memset(ctx->clast, 0, 4 * bw * sizeof(int));
 
     for(j = 0; j < bh; j++) {
         memset(ctx->D, 0, 4 * sizeof(int));
         memset(ctx->CD, 0, 4 * sizeof(int));
         for(i = 0; i < bw; i++) {
             type = GET_TOK(ctx, TM2_TYPE);
             switch(type) {
             case TM2_HI_RES:
                 tm2_hi_res_block(ctx, p, i, j);
                 break;
             case TM2_MED_RES:
                 tm2_med_res_block(ctx, p, i, j);
                 break;
             case TM2_LOW_RES:
                 tm2_low_res_block(ctx, p, i, j);
                 break;
             case TM2_NULL_RES:
                 tm2_null_res_block(ctx, p, i, j);
                 break;
             case TM2_UPDATE:
                 tm2_update_block(ctx, p, i, j);
                 keyframe = 0;
                 break;
             case TM2_STILL:
                 tm2_still_block(ctx, p, i, j);
                 keyframe = 0;
                 break;
             case TM2_MOTION:
                 tm2_motion_block(ctx, p, i, j);
                 keyframe = 0;
                 break;
             default:
                 av_log(ctx->avctx, AV_LOG_ERROR, "Skipping unknown block type %i\n", type);
             }
         }
     }

 
     /* copy data from our buffer to AVFrame */

     Y = (ctx->cur?ctx->Y2:ctx->Y1);
     U = (ctx->cur?ctx->U2:ctx->U1);
     V = (ctx->cur?ctx->V2:ctx->V1);
     dst = p->data[0];

     for(j = 0; j < ctx->avctx->height; j++){
         for(i = 0; i < ctx->avctx->width; i++){

             int y = Y[i], u = U[i >> 1], v = V[i >> 1];
             dst[3*i+0] = av_clip_uint8(y + v);
             dst[3*i+1] = av_clip_uint8(y);
             dst[3*i+2] = av_clip_uint8(y + u);

         }

         Y += ctx->avctx->width;
         if (j & 1) {
             U += ctx->avctx->width >> 1;
             V += ctx->avctx->width >> 1;

         }

         dst += p->linesize[0];

     }

     return keyframe;
 }
 

 static const int tm2_stream_order[TM2_NUM_STREAMS] = {
     TM2_C_HI, TM2_C_LO, TM2_L_HI, TM2_L_LO, TM2_UPD, TM2_MOT, TM2_TYPE
 };
 

 static int decode_frame(AVCodecContext *avctx,

                         void *data, int *data_size,

                         AVPacket *avpkt)

 {

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

     TM2Context * const l = avctx->priv_data;
     AVFrame * const p= (AVFrame*)&l->pic;

     int i, skip, t;

     uint8_t *swbuf;

     swbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
     if(!swbuf){
         av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
         return -1;
     }

     p->reference = 3;

     p->buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
     if(avctx->reget_buffer(avctx, p) < 0){

         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

         av_free(swbuf);

         return -1;
     }
 

     l->dsp.bswap_buf((uint32_t*)swbuf, (const uint32_t*)buf, buf_size >> 2);
     skip = tm2_read_header(l, swbuf);

     if(skip == -1){
         av_free(swbuf);

         return -1;

     }

     for(i = 0; i < TM2_NUM_STREAMS; i++){

         t = tm2_read_stream(l, swbuf + skip, tm2_stream_order[i], buf_size);

         if(t == -1){

             av_free(swbuf);

             return -1;
         }
         skip += t;
     }

     p->key_frame = tm2_decode_blocks(l, p);
     if(p->key_frame)

         p->pict_type = AV_PICTURE_TYPE_I;

     else

         p->pict_type = AV_PICTURE_TYPE_P;

     l->cur = !l->cur;
     *data_size = sizeof(AVFrame);
     *(AVFrame*)data = l->pic;

     av_free(swbuf);

     return buf_size;
 }
 

 static av_cold int decode_init(AVCodecContext *avctx){

     TM2Context * const l = avctx->priv_data;
     int i;
 
     if((avctx->width & 3) || (avctx->height & 3)){
         av_log(avctx, AV_LOG_ERROR, "Width and height must be multiple of 4\n");
         return -1;
     }

     l->avctx = avctx;
     l->pic.data[0]=NULL;

     avctx->pix_fmt = PIX_FMT_BGR24;

     avcodec_get_frame_defaults(&l->pic);

 
     dsputil_init(&l->dsp, avctx);

     l->last = av_malloc(4 * sizeof(int) * (avctx->width >> 2));
     l->clast = av_malloc(4 * sizeof(int) * (avctx->width >> 2));

     for(i = 0; i < TM2_NUM_STREAMS; i++) {
         l->tokens[i] = NULL;
         l->tok_lens[i] = 0;
     }

     l->Y1 = av_malloc(sizeof(int) * avctx->width * avctx->height);
     l->U1 = av_malloc(sizeof(int) * ((avctx->width + 1) >> 1) * ((avctx->height + 1) >> 1));
     l->V1 = av_malloc(sizeof(int) * ((avctx->width + 1) >> 1) * ((avctx->height + 1) >> 1));
     l->Y2 = av_malloc(sizeof(int) * avctx->width * avctx->height);
     l->U2 = av_malloc(sizeof(int) * ((avctx->width + 1) >> 1) * ((avctx->height + 1) >> 1));
     l->V2 = av_malloc(sizeof(int) * ((avctx->width + 1) >> 1) * ((avctx->height + 1) >> 1));
     l->cur = 0;

     return 0;
 }
 

 static av_cold int decode_end(AVCodecContext *avctx){

     TM2Context * const l = avctx->priv_data;

     AVFrame *pic = &l->pic;

     int i;
 

     av_free(l->last);
     av_free(l->clast);

     for(i = 0; i < TM2_NUM_STREAMS; i++)

         av_free(l->tokens[i]);

     if(l->Y1){
         av_free(l->Y1);
         av_free(l->U1);
         av_free(l->V1);
         av_free(l->Y2);
         av_free(l->U2);
         av_free(l->V2);
     }

 
     if (pic->data[0])
         avctx->release_buffer(avctx, pic);
 

     return 0;
 }
 

 AVCodec ff_truemotion2_decoder = {

     .name           = "truemotion2",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = CODEC_ID_TRUEMOTION2,
     .priv_data_size = sizeof(TM2Context),
     .init           = decode_init,
     .close          = decode_end,
     .decode         = decode_frame,
     .capabilities   = CODEC_CAP_DR1,

     .long_name = NULL_IF_CONFIG_SMALL("Duck TrueMotion 2.0"),

 };