zmbv.c

ffmpeg源码分析

/*
 * Zip Motion Blocks Video (ZMBV) decoder
 * Copyright (c) 2006 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 */

/**
 * @file zmbv.c
 * Zip Motion Blocks Video decoder
 */

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

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

#ifdef CONFIG_ZLIB
#include <zlib.h>
#endif

#define ZMBV_KEYFRAME 1
#define ZMBV_DELTAPAL 2

enum ZmbvFormat {
    ZMBV_FMT_NONE  = 0,
    ZMBV_FMT_1BPP  = 1,
    ZMBV_FMT_2BPP  = 2,
    ZMBV_FMT_4BPP  = 3,
    ZMBV_FMT_8BPP  = 4,
    ZMBV_FMT_15BPP = 5,
    ZMBV_FMT_16BPP = 6,
    ZMBV_FMT_24BPP = 7,
    ZMBV_FMT_32BPP = 8
};

/*
 * Decoder context
 */
typedef struct ZmbvContext {
    AVCodecContext *avctx;
    AVFrame pic;

    int bpp;
    unsigned int decomp_size;
    uint8_t* decomp_buf;
    uint8_t pal[768];
    uint8_t *prev, *cur;
    int width, height;
    int fmt;
    int comp;
    int flags;
    int bw, bh, bx, by;
    int decomp_len;
#ifdef CONFIG_ZLIB
    z_stream zstream;
#endif
    int (*decode_intra)(struct ZmbvContext *c);
    int (*decode_xor)(struct ZmbvContext *c);
} ZmbvContext;

/**
 * Decode XOR'ed frame - 8bpp version
 */

static int zmbv_decode_xor_8(ZmbvContext *c)
{
    uint8_t *src = c->decomp_buf;
    uint8_t *output, *prev;
    int8_t *mvec;
    int x, y;
    int d, dx, dy, bw2, bh2;
    int block;
    int i, j;
    int mx, my;

    output = c->cur;
    prev = c->prev;

    if(c->flags & ZMBV_DELTAPAL){
        for(i = 0; i < 768; i++)
            c->pal[i] ^= *src++;
    }

    mvec = (int8_t*)src;
    src += ((c->bx * c->by * 2 + 3) & ~3);

    block = 0;
    for(y = 0; y < c->height; y += c->bh) {
        bh2 = ((c->height - y) > c->bh) ? c->bh : (c->height - y);
        for(x = 0; x < c->width; x += c->bw) {
            uint8_t *out, *tprev;

            d = mvec[block] & 1;
            dx = mvec[block] >> 1;
            dy = mvec[block + 1] >> 1;
            block += 2;

            bw2 = ((c->width - x) > c->bw) ? c->bw : (c->width - x);

            /* copy block - motion vectors out of bounds are used to zero blocks */
            out = output + x;
            tprev = prev + x + dx + dy * c->width;
            mx = x + dx;
            my = y + dy;
            for(j = 0; j < bh2; j++){
                if((my + j < 0) || (my + j >= c->height)) {
                    memset(out, 0, bw2);
                } else {
                    for(i = 0; i < bw2; i++){
                        if((mx + i < 0) || (mx + i >= c->width))
                            out[i] = 0;
                        else
                            out[i] = tprev[i];
                    }
                }
                out += c->width;
                tprev += c->width;
            }

            if(d) { /* apply XOR'ed difference */
                out = output + x;
                for(j = 0; j < bh2; j++){
                    for(i = 0; i < bw2; i++)
                        out[i] ^= *src++;
                    out += c->width;
                }
            }
        }
        output += c->width * c->bh;
        prev += c->width * c->bh;
    }
    if(src - c->decomp_buf != c->decomp_len)
        av_log(c->avctx, AV_LOG_ERROR, "Used %i of %i bytes\n", src-c->decomp_buf, c->decomp_len);
    return 0;
}

/**
 * Decode XOR'ed frame - 15bpp and 16bpp version
 */

static int zmbv_decode_xor_16(ZmbvContext *c)
{
    uint8_t *src = c->decomp_buf;
    uint16_t *output, *prev;
    int8_t *mvec;
    int x, y;
    int d, dx, dy, bw2, bh2;
    int block;
    int i, j;
    int mx, my;

    output = (uint16_t*)c->cur;
    prev = (uint16_t*)c->prev;

    mvec = (int8_t*)src;
    src += ((c->bx * c->by * 2 + 3) & ~3);

    block = 0;
    for(y = 0; y < c->height; y += c->bh) {
        bh2 = ((c->height - y) > c->bh) ? c->bh : (c->height - y);
        for(x = 0; x < c->width; x += c->bw) {
            uint16_t *out, *tprev;

            d = mvec[block] & 1;
            dx = mvec[block] >> 1;
            dy = mvec[block + 1] >> 1;
            block += 2;

            bw2 = ((c->width - x) > c->bw) ? c->bw : (c->width - x);

            /* copy block - motion vectors out of bounds are used to zero blocks */
            out = output + x;
            tprev = prev + x + dx + dy * c->width;
            mx = x + dx;
            my = y + dy;
            for(j = 0; j < bh2; j++){
                if((my + j < 0) || (my + j >= c->height)) {
                    memset(out, 0, bw2 * 2);
                } else {
                    for(i = 0; i < bw2; i++){
                        if((mx + i < 0) || (mx + i >= c->width))
                            out[i] = 0;
                        else
                            out[i] = tprev[i];
                    }
                }
                out += c->width;
                tprev += c->width;
            }

            if(d) { /* apply XOR'ed difference */
                out = output + x;
                for(j = 0; j < bh2; j++){
                    for(i = 0; i < bw2; i++) {
                        out[i] ^= *((uint16_t*)src);
                        src += 2;
                    }
                    out += c->width;
                }
            }
        }
        output += c->width * c->bh;
        prev += c->width * c->bh;
    }
    if(src - c->decomp_buf != c->decomp_len)
        av_log(c->avctx, AV_LOG_ERROR, "Used %i of %i bytes\n", src-c->decomp_buf, c->decomp_len);
    return 0;
}

#ifdef ZMBV_ENABLE_24BPP
/**
 * Decode XOR'ed frame - 24bpp version
 */

static int zmbv_decode_xor_24(ZmbvContext *c)
{
    uint8_t *src = c->decomp_buf;
    uint8_t *output, *prev;
    int8_t *mvec;
    int x, y;
    int d, dx, dy, bw2, bh2;
    int block;
    int i, j;
    int mx, my;
    int stride;

    output = c->cur;
    prev = c->prev;

    stride = c->width * 3;
    mvec = (int8_t*)src;
    src += ((c->bx * c->by * 2 + 3) & ~3);

    block = 0;
    for(y = 0; y < c->height; y += c->bh) {
        bh2 = ((c->height - y) > c->bh) ? c->bh : (c->height - y);
        for(x = 0; x < c->width; x += c->bw) {
            uint8_t *out, *tprev;

            d = mvec[block] & 1;
            dx = mvec[block] >> 1;
            dy = mvec[block + 1] >> 1;
            block += 2;

            bw2 = ((c->width - x) > c->bw) ? c->bw : (c->width - x);

            /* copy block - motion vectors out of bounds are used to zero blocks */
            out = output + x * 3;
            tprev = prev + (x + dx) * 3 + dy * stride;
            mx = x + dx;
            my = y + dy;
            for(j = 0; j < bh2; j++){
                if((my + j < 0) || (my + j >= c->height)) {
                    memset(out, 0, bw2 * 3);
                } else {
                    for(i = 0; i < bw2; i++){
                        if((mx + i < 0) || (mx + i >= c->width)) {
                            out[i * 3 + 0] = 0;
                            out[i * 3 + 1] = 0;
                            out[i * 3 + 2] = 0;
                        } else {
                            out[i * 3 + 0] = tprev[i * 3 + 0];
                            out[i * 3 + 1] = tprev[i * 3 + 1];
                            out[i * 3 + 2] = tprev[i * 3 + 2];
                        }
                    }
                }
                out += stride;
                tprev += stride;
            }

            if(d) { /* apply XOR'ed difference */
                out = output + x * 3;
                for(j = 0; j < bh2; j++){
                    for(i = 0; i < bw2; i++) {
                        out[i * 3 + 0] ^= *src++;
                        out[i * 3 + 1] ^= *src++;
                        out[i * 3 + 2] ^= *src++;
                    }
                    out += stride;
                }
            }
        }
        output += stride * c->bh;
        prev += stride * c->bh;
    }
    if(src - c->decomp_buf != c->decomp_len)
        av_log(c->avctx, AV_LOG_ERROR, "Used %i of %i bytes\n", src-c->decomp_buf, c->decomp_len);
    return 0;
}
#endif //ZMBV_ENABLE_24BPP

/**
 * Decode XOR'ed frame - 32bpp version
 */

static int zmbv_decode_xor_32(ZmbvContext *c)
{
    uint8_t *src = c->decomp_buf;
    uint32_t *output, *prev;
    int8_t *mvec;
    int x, y;
    int d, dx, dy, bw2, bh2;
    int block;
    int i, j;
    int mx, my;

    output = (uint32_t*)c->cur;
    prev = (uint32_t*)c->prev;

    mvec = (int8_t*)src;
    src += ((c->bx * c->by * 2 + 3) & ~3);

    block = 0;
    for(y = 0; y < c->height; y += c->bh) {
        bh2 = ((c->height - y) > c->bh) ? c->bh : (c->height - y);
        for(x = 0; x < c->width; x += c->bw) {
            uint32_t *out, *tprev;

            d = mvec[block] & 1;
            dx = mvec[block] >> 1;
            dy = mvec[block + 1] >> 1;
            block += 2;

            bw2 = ((c->width - x) > c->bw) ? c->bw : (c->width - x);

            /* copy block - motion vectors out of bounds are used to zero blocks */
            out = output + x;
            tprev = prev + x + dx + dy * c->width;
            mx = x + dx;
            my = y + dy;
            for(j = 0; j < bh2; j++){