truemotion1.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

/*
 * Duck TrueMotion 1.0 Decoder
 * Copyright (C) 2003 Alex Beregszaszi & Mike Melanson
 *
 * 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 truemotion1.c
 * Duck TrueMotion v1 Video Decoder by 
 * Alex Beregszaszi ([e-mail]) and
 * Mike Melanson ([e-mail])
 *
 * The TrueMotion v1 decoder presently only decodes 16-bit TM1 data and
 * outputs RGB555 data. 24-bit TM1 data is not supported yet.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "common.h"
#include "avcodec.h"
#include "dsputil.h"

#define printf(...) {} //(f)printf() usage is forbidden in libavcodec, use av_log
#define fprintf(...) {} 

#include "truemotion1data.h"

#define LE_16(x)  ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])

typedef struct TrueMotion1Context {
    AVCodecContext *avctx;
    AVFrame frame;
    AVFrame prev_frame;

    unsigned char *buf;
    int size;

    unsigned char *mb_change_bits;
    int mb_change_bits_row_size;
    unsigned char *index_stream;
    int index_stream_size;

    int flags;
    int x, y, w, h;
    
    uint32_t y_predictor_table[1024];
    uint32_t c_predictor_table[1024];
    
    int compression;
    int block_type;
    int block_width;
    int block_height;

    int16_t *ydt;
    int16_t *cdt;
    int16_t *fat_ydt;
    int16_t *fat_cdt;
    
    int last_deltaset, last_vectable;

    unsigned int *vert_pred;

} TrueMotion1Context;

#define FLAG_SPRITE         32
#define FLAG_KEYFRAME       16
#define FLAG_INTERFRAME      8
#define FLAG_INTERPOLATED    4

struct frame_header {
    uint8_t header_size;
    uint8_t compression;
    uint8_t deltaset;
    uint8_t vectable;
    uint16_t ysize;
    uint16_t xsize;
    uint16_t checksum;
    uint8_t version;
    uint8_t header_type;
    uint8_t flags;
    uint8_t control;
    uint16_t xoffset;
    uint16_t yoffset;
    uint16_t width;
    uint16_t height;
};

#define ALGO_NOP        0
#define ALGO_RGB16V     1
#define ALGO_RGB16H     2
#define ALGO_RGB24H     3

/* these are the various block sizes that can occupy a 4x4 block */
#define BLOCK_2x2  0
#define BLOCK_2x4  1
#define BLOCK_4x2  2
#define BLOCK_4x4  3

typedef struct comp_types {
    int algorithm;
    int block_width;
    int block_height;
    int block_type;
} comp_types;

/* { valid for metatype }, algorithm, num of deltas, horiz res, vert res */
static comp_types compression_types[17] = {
    { ALGO_NOP,    0, 0, 0 },

    { ALGO_RGB16V, 4, 4, BLOCK_4x4 },
    { ALGO_RGB16H, 4, 4, BLOCK_4x4 },
    { ALGO_RGB16V, 4, 2, BLOCK_4x2 },
    { ALGO_RGB16H, 4, 2, BLOCK_4x2 },

    { ALGO_RGB16V, 2, 4, BLOCK_2x4 },
    { ALGO_RGB16H, 2, 4, BLOCK_2x4 },
    { ALGO_RGB16V, 2, 2, BLOCK_2x2 },
    { ALGO_RGB16H, 2, 2, BLOCK_2x2 },

    { ALGO_NOP,    4, 4, BLOCK_4x4 },
    { ALGO_RGB24H, 4, 4, BLOCK_4x4 },
    { ALGO_NOP,    4, 2, BLOCK_4x2 },
    { ALGO_RGB24H, 4, 2, BLOCK_4x2 },

    { ALGO_NOP,    2, 4, BLOCK_2x4 },
    { ALGO_RGB24H, 2, 4, BLOCK_2x4 },
    { ALGO_NOP,    2, 2, BLOCK_2x2 },
    { ALGO_RGB24H, 2, 2, BLOCK_2x2 }
};

static void select_delta_tables(TrueMotion1Context *s, int delta_table_index)
{
    int i;

    if (delta_table_index > 3)
        return;

    s->ydt = ydts[delta_table_index];
    s->cdt = cdts[delta_table_index];
    s->fat_ydt = fat_ydts[delta_table_index];
    s->fat_cdt = fat_cdts[delta_table_index];

    /* Y skinny deltas need to be halved for some reason; maybe the
     * skinny Y deltas should be modified */
    for (i = 0; i < 8; i++)
    {
        /* drop the lsb before dividing by 2-- net effect: round down
         * when dividing a negative number (e.g., -3/2 = -2, not -1) */
        s->ydt[i] &= 0xFFFE;
        s->ydt[i] /= 2;
    }
}

#ifdef WORDS_BIGENDIAN
static int make_ydt_entry(int p2, int p1, int16_t *ydt)
#else
static int make_ydt_entry(int p1, int p2, int16_t *ydt)
#endif
{
    int lo, hi;
    
    lo = ydt[p1];
    lo += (lo << 5) + (lo << 10);
    hi = ydt[p2];
    hi += (hi << 5) + (hi << 10);
    return ((lo + (hi << 16)) << 1);
}

#ifdef WORDS_BIGENDIAN
static int make_cdt_entry(int p2, int p1, int16_t *cdt)
#else
static int make_cdt_entry(int p1, int p2, int16_t *cdt)
#endif
{
    int r, b, lo;
    
    b = cdt[p2];
    r = cdt[p1] << 10;
    lo = b + r;
    return ((lo + (lo << 16)) << 1);
}

static void gen_vector_table(TrueMotion1Context *s, uint8_t *sel_vector_table)
{
    int len, i, j;
    unsigned char delta_pair;
    
    for (i = 0; i < 1024; i += 4)
    {
        len = *sel_vector_table++ / 2;
        for (j = 0; j < len; j++)
        {
            delta_pair = *sel_vector_table++;
            s->y_predictor_table[i+j] = 0xfffffffe & 
                make_ydt_entry(delta_pair >> 4, delta_pair & 0xf, s->ydt);
            s->c_predictor_table[i+j] = 0xfffffffe & 
                make_cdt_entry(delta_pair >> 4, delta_pair & 0xf, s->cdt);
        }
        s->y_predictor_table[i+(j-1)] |= 1;
        s->c_predictor_table[i+(j-1)] |= 1;
    }
}

/* Returns the number of bytes consumed from the bytestream. Returns -1 if
 * there was an error while decoding the header */ 
static int truemotion1_decode_header(TrueMotion1Context *s)
{
    int i;
    struct frame_header header;
    uint8_t header_buffer[128];  /* logical maximum size of the header */
    uint8_t *sel_vector_table;

    /* There is 1 change bit per 4 pixels, so each change byte represents
     * 32 pixels; divide width by 4 to obtain the number of change bits and
     * then round up to the nearest byte. */
    s->mb_change_bits_row_size = ((s->avctx->width >> 2) + 7) >> 3;

    header.header_size = ((s->buf[0] >> 5) | (s->buf[0] << 3)) & 0x7f;
    if (s->buf[0] < 0x10)
    {
        printf("invalid header size\n");
        return -1;
    }

    /* unscramble the header bytes with a XOR operation */
    memset(header_buffer, 0, 128);
    for (i = 1; i < header.header_size; i++)
    header_buffer[i - 1] = s->buf[i] ^ s->buf[i + 1];
    header.compression = header_buffer[0];
    header.deltaset = header_buffer[1];
    header.vectable = header_buffer[2];
    header.ysize = LE_16(&header_buffer[3]);
    header.xsize = LE_16(&header_buffer[5]);
    header.checksum = LE_16(&header_buffer[7]);
    header.version = header_buffer[9];
    header.header_type = header_buffer[10];
    header.flags = header_buffer[11];
    header.control = header_buffer[12];

    /* Version 2 */
    if (header.version >= 2)
    {
        if (header.header_type > 3)
        {
            av_log(s->avctx, AV_LOG_ERROR, "truemotion1: invalid header type\n");
            return -1;
        } else if ((header.header_type == 2) || (header.header_type == 3)) {
            s->flags = header.flags;
            if (!(s->flags & FLAG_INTERFRAME))
                s->flags |= FLAG_KEYFRAME;
        } else
            s->flags = FLAG_KEYFRAME;
    } else /* Version 1 */
        s->flags = FLAG_KEYFRAME;
    
    if (s->flags & FLAG_SPRITE) {
        s->w = header.width;
        s->h = header.height;
        s->x = header.xoffset;
        s->y = header.yoffset;
    } else {
        s->w = header.xsize;
        s->h = header.ysize;
        if (header.header_type < 2) {
            if ((s->w < 213) && (s->h >= 176))
                s->flags |= FLAG_INTERPOLATED;
        }
    }

    if (header.compression > 17) {
        printf("invalid compression type (%d)\n", header.compression);
        return -1;
    }
    
    if ((header.deltaset != s->last_deltaset) || 
        (header.vectable != s->last_vectable))
        select_delta_tables(s, header.deltaset);

    if ((header.compression & 1) && header.header_type)
        sel_vector_table = pc_tbl2;
    else {
        if (header.vectable < 4)
            sel_vector_table = tables[header.vectable - 1];
        else {
            printf("invalid vector table id (%d)\n", header.vectable);
            return -1;
        }
    }