Duck TrueMotion 2 video decoder, courtesy of Konstantin Shishkov

Originally committed as revision 4638 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 889 insertions, 0 deletions

diff --git a/libavcodec/truemotion2.c b/libavcodec/truemotion2.c
new file mode 100644
index 0000000000..5392eb22b1
--- /dev/null
+++ b/libavcodec/truemotion2.c
@@ -0,0 +1,889 @@
+/*
+ * Duck/ON2 TrueMotion 2 Decoder
+ * Copyright (c) 2005 Konstantin Shishkov
+ *
+ * This library 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 of the License, or (at your option) any later version.
+ *
+ * This library 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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 32
+/* 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 = LE_32(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 = LE_32(buf);
+        buf += 4;
+        
+        init_get_bits(&ctx->gb, buf, 32);
+        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 = BE_32(buf); buf += 4; cur += 4;
+    skip = len * 4 + 4;
+    
+    if(len == 0)
+        return 4;
+    
+    toks = BE_32(buf); buf += 4; cur += 4;
+    if(toks & 1) {
+        len = BE_32(buf); buf += 4; cur += 4;
+        if(len == TM2_ESCAPE) {
+            len = BE_32(buf); buf += 4; cur += 4;
+        }
+        if(len > 0) {
+            init_get_bits(&ctx->gb, buf, skip - cur);
+            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(BE_32(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);
+    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 = BE_32(buf); buf += 4; cur += 4;
+    if(len > 0) {
+        init_get_bits(&ctx->gb, buf, skip - cur);
+        for(i = 0; i < toks; i++)
+            ctx->tokens[stream_id][i] = tm2_get_token(&ctx->gb, &codes);
+    } else {
+        memset(ctx->tokens[stream_id], 0, toks * sizeof(int));
+    }
+    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] = 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) >> 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] = 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] = 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] = 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;
+    if(avctx->get_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->height, avctx->width) < 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,
+};