PeerStreamer

/*

 * 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 truemotion2.c

 * Duck TrueMotion2 decoder.

 */

#include "avcodec.h"

#include "common.h"

#include "bitstream.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)

{

    if(code->recode)

        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, uint8_t *buf)

{

    uint32_t magic;

    uint8_t *obuf;

    int length;

    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 */

        int w, h, size, flags, xr, yr;

        length = AV_RL32(buf);

        buf += 4;

        init_get_bits(&ctx->gb, buf, 32 * 8);

        size = get_bits_long(&ctx->gb, 31);

        h = get_bits(&ctx->gb, 15);

        w = get_bits(&ctx->gb, 15);

        flags = get_bits_long(&ctx->gb, 31);

        yr = get_bits(&ctx->gb, 9);

        xr = get_bits(&ctx->gb, 9);

        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, uint8_t *buf, int stream_id) {

    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;

    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 */

    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++)

            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] - 128) - last[1];\

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

    last[0] = (int)CHR[stride + 0] - 128;\

    last[1] = (int)CHR[stride + 1] - 128;}

/* 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] + 128;

        }

        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;

    uint8_t *Y, *U, *V;

    int *src;

    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 = p->data[0];

    src = (ctx->cur?ctx->Y2:ctx->Y1);

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

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

            Y[i] = av_clip_uint8(*src++);

        }

        Y += p->linesize[0];

    }

    U = p->data[2];

    src = (ctx->cur?ctx->U2:ctx->U1);

    for(j = 0; j < (ctx->avctx->height + 1) >> 1; j++){

        for(i = 0; i < (ctx->avctx->width + 1) >> 1; i++){

            U[i] = av_clip_uint8(*src++);

        }

        U += p->linesize[2];

    }

    V = p->data[1];

    src = (ctx->cur?ctx->V2:ctx->V1);

    for(j = 0; j < (ctx->avctx->height + 1) >> 1; j++){

        for(i = 0; i < (ctx->avctx->width + 1) >> 1; i++){

            V[i] = av_clip_uint8(*src++);

        }

        V += p->linesize[1];

    }

    return keyframe;

}

static int decode_frame(AVCodecContext *avctx,

                        void *data, int *data_size,

                        uint8_t *buf, int buf_size)

{

    TM2Context * const l = avctx->priv_data;

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

    int skip, t;

    p->reference = 1;

    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");

        return -1;

    }

    l->dsp.bswap_buf((uint32_t*)buf, (uint32_t*)buf, buf_size >> 2);

    skip = tm2_read_header(l, buf);

    if(skip == -1)

        return -1;

    t = tm2_read_stream(l, buf + skip, TM2_C_HI);

    if(t == -1)

        return -1;

    skip += t;

    t = tm2_read_stream(l, buf + skip, TM2_C_LO);

    if(t == -1)

        return -1;

    skip += t;

    t = tm2_read_stream(l, buf + skip, TM2_L_HI);

    if(t == -1)

        return -1;

    skip += t;

    t = tm2_read_stream(l, buf + skip, TM2_L_LO);

    if(t == -1)

        return -1;

    skip += t;

    t = tm2_read_stream(l, buf + skip, TM2_UPD);

    if(t == -1)

        return -1;

    skip += t;

    t = tm2_read_stream(l, buf + skip, TM2_MOT);

    if(t == -1)

        return -1;

    skip += t;

    t = tm2_read_stream(l, buf + skip, TM2_TYPE);

    if(t == -1)

        return -1;

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

    if(p->key_frame)

        p->pict_type = FF_I_TYPE;

    else

        p->pict_type = FF_P_TYPE;

    l->cur = !l->cur;

    *data_size = sizeof(AVFrame);

    *(AVFrame*)data = l->pic;

    return buf_size;

}

static int decode_init(AVCodecContext *avctx){

    TM2Context * const l = avctx->priv_data;

    int i;

    if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {

        return -1;

    }

    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->has_b_frames = 0;

    avctx->pix_fmt = PIX_FMT_YUV420P;

    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 int decode_end(AVCodecContext *avctx){

    TM2Context * const l = avctx->priv_data;

    int i;

    if(l->last)

        av_free(l->last);

    if(l->clast)

        av_free(l->clast);

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

        if(l->tokens[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);

    }

    return 0;

}

AVCodec truemotion2_decoder = {

    "truemotion2",

    CODEC_TYPE_VIDEO,

    CODEC_ID_TRUEMOTION2,

    sizeof(TM2Context),

    decode_init,

    NULL,

    decode_end,

    decode_frame,

    CODEC_CAP_DR1,

};