roqvideoenc.c

mediastreamer2是开源的网络传输媒体流的库

/*
 * RoQ Video Encoder.
 *
 * Copyright (C) 2007 Vitor Sessak <[e-mail]>
 * Copyright (C) 2004-2007 Eric Lasota
 *    Based on RoQ specs (C) 2001 Tim Ferguson
 *
 * 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 roqvideoenc.c
 * Id RoQ encoder by Vitor. Based on the Switchblade3 library and the
 * Switchblade3 FFmpeg glue by Eric Lasota.
 */

/*
 * COSTS:
 * Level 1:
 *  SKIP - 2 bits
 *  MOTION - 2 + 8 bits
 *  CODEBOOK - 2 + 8 bits
 *  SUBDIVIDE - 2 + combined subcel cost
 *
 * Level 2:
 *  SKIP - 2 bits
 *  MOTION - 2 + 8 bits
 *  CODEBOOK - 2 + 8 bits
 *  SUBDIVIDE - 2 + 4*8 bits
 *
 * Maximum cost: 138 bits per cel
 *
 * Proper evaluation requires LCD fraction comparison, which requires
 * Squared Error (SE) loss * savings increase
 *
 * Maximum savings increase: 136 bits
 * Maximum SE loss without overflow: 31580641
 * Components in 8x8 supercel: 192
 * Maximum SE precision per component: 164482
 *    >65025, so no truncation is needed (phew)
 */

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

#include "roqvideo.h"
#include "bytestream.h"
#include "elbg.h"

#define CHROMA_BIAS 1

/**
 * Maximum number of generated 4x4 codebooks. Can't be 256 to workaround a
 * Quake 3 bug.
 */
#define MAX_CBS_4x4 255

#define MAX_CBS_2x2 256 ///< Maximum number of 2x2 codebooks.

/* The cast is useful when multiplying it by INT_MAX */
#define ROQ_LAMBDA_SCALE ((uint64_t) FF_LAMBDA_SCALE)

/* Macroblock support functions */
static void unpack_roq_cell(roq_cell *cell, uint8_t u[4*3])
{
    memcpy(u  , cell->y, 4);
    memset(u+4, cell->u, 4);
    memset(u+8, cell->v, 4);
}

static void unpack_roq_qcell(uint8_t cb2[], roq_qcell *qcell, uint8_t u[4*4*3])
{
    int i,cp;
    static const int offsets[4] = {0, 2, 8, 10};

    for (cp=0; cp<3; cp++)
        for (i=0; i<4; i++) {
            u[4*4*cp + offsets[i]  ] = cb2[qcell->idx[i]*2*2*3 + 4*cp  ];
            u[4*4*cp + offsets[i]+1] = cb2[qcell->idx[i]*2*2*3 + 4*cp+1];
            u[4*4*cp + offsets[i]+4] = cb2[qcell->idx[i]*2*2*3 + 4*cp+2];
            u[4*4*cp + offsets[i]+5] = cb2[qcell->idx[i]*2*2*3 + 4*cp+3];
        }
}


static void enlarge_roq_mb4(uint8_t base[3*16], uint8_t u[3*64])
{
    int x,y,cp;

    for(cp=0; cp<3; cp++)
        for(y=0; y<8; y++)
            for(x=0; x<8; x++)
                *u++ = base[(y/2)*4 + (x/2) + 16*cp];
}

static inline int square(int x)
{
    return x*x;
}

static inline int eval_sse(uint8_t *a, uint8_t *b, int count)
{
    int diff=0;

    while(count--)
        diff += square(*b++ - *a++);

    return diff;
}

// FIXME Could use DSPContext.sse, but it is not so speed critical (used
// just for motion estimation).
static int block_sse(uint8_t **buf1, uint8_t **buf2, int x1, int y1, int x2,
                     int y2, int *stride1, int *stride2, int size)
{
    int i, k;
    int sse=0;

    for (k=0; k<3; k++) {
        int bias = (k ? CHROMA_BIAS : 4);
        for (i=0; i<size; i++)
            sse += bias*eval_sse(buf1[k] + (y1+i)*stride1[k] + x1,
                                 buf2[k] + (y2+i)*stride2[k] + x2, size);
    }

    return sse;
}

static int eval_motion_dist(RoqContext *enc, int x, int y, motion_vect vect,
                             int size)
{
    int mx=vect.d[0];
    int my=vect.d[1];

    if (mx < -7 || mx > 7)
        return INT_MAX;

    if (my < -7 || my > 7)
        return INT_MAX;

    mx += x;
    my += y;

    if ((unsigned) mx > enc->width-size || (unsigned) my > enc->height-size)
        return INT_MAX;

    return block_sse(enc->frame_to_enc->data, enc->last_frame->data, x, y,
                     mx, my,
                     enc->frame_to_enc->linesize, enc->last_frame->linesize,
                     size);
}

/**
 * Returns distortion between two macroblocks
 */
static inline int squared_diff_macroblock(uint8_t a[], uint8_t b[], int size)
{
    int cp, sdiff=0;

    for(cp=0;cp<3;cp++) {
        int bias = (cp ? CHROMA_BIAS : 4);
        sdiff += bias*eval_sse(a, b, size*size);
        a += size*size;
        b += size*size;
    }

    return sdiff;
}

typedef struct
{
    int eval_dist[4];
    int best_bit_use;
    int best_coding;

    int subCels[4];
    motion_vect motion;
    int cbEntry;
} subcel_evaluation_t;

typedef struct
{
    int eval_dist[4];
    int best_coding;

    subcel_evaluation_t subCels[4];

    motion_vect motion;
    int cbEntry;

    int sourceX, sourceY;
} cel_evaluation_t;

typedef struct
{
    int numCB4;
    int numCB2;
    int usedCB2[MAX_CBS_2x2];
    int usedCB4[MAX_CBS_4x4];
    uint8_t unpacked_cb2[MAX_CBS_2x2*2*2*3];
    uint8_t unpacked_cb4[MAX_CBS_4x4*4*4*3];
    uint8_t unpacked_cb4_enlarged[MAX_CBS_4x4*8*8*3];
} roq_codebooks_t;

/**
 * Temporary vars
 */
typedef struct
{
    cel_evaluation_t *cel_evals;

    int f2i4[MAX_CBS_4x4];
    int i2f4[MAX_CBS_4x4];
    int f2i2[MAX_CBS_2x2];
    int i2f2[MAX_CBS_2x2];

    int mainChunkSize;

    int numCB4;
    int numCB2;

    roq_codebooks_t codebooks;

    int *closest_cb2;
    int used_option[4];
} roq_tempdata_t;

/**
 * Initializes cel evaluators and sets their source coordinates
 */
static void create_cel_evals(RoqContext *enc, roq_tempdata_t *tempData)
{
    int n=0, x, y, i;

    tempData->cel_evals = av_malloc(enc->width*enc->height/64 * sizeof(cel_evaluation_t));

    /* Map to the ROQ quadtree order */
    for (y=0; y<enc->height; y+=16)
        for (x=0; x<enc->width; x+=16)
            for(i=0; i<4; i++) {
                tempData->cel_evals[n  ].sourceX = x + (i&1)*8;
                tempData->cel_evals[n++].sourceY = y + (i&2)*4;
            }
}

/**
 * Get macroblocks from parts of the image
 */
static void get_frame_mb(AVFrame *frame, int x, int y, uint8_t mb[], int dim)
{
    int i, j, cp;

    for (cp=0; cp<3; cp++) {
        int stride = frame->linesize[cp];
        for (i=0; i<dim; i++)
            for (j=0; j<dim; j++)
                *mb++ = frame->data[cp][(y+i)*stride + x + j];
    }
}

/**
 * Find the codebook with the lowest distortion from an image
 */
static int index_mb(uint8_t cluster[], uint8_t cb[], int numCB,
                    int *outIndex, int dim)
{
    int i, lDiff = INT_MAX, pick=0;

    /* Diff against the others */
    for (i=0; i<numCB; i++) {
        int diff = squared_diff_macroblock(cluster, cb + i*dim*dim*3, dim);
        if (diff < lDiff) {
            lDiff = diff;
            pick = i;
        }
    }

    *outIndex = pick;
    return lDiff;
}

#define EVAL_MOTION(MOTION) \
    do { \
        diff = eval_motion_dist(enc, j, i, MOTION, blocksize); \
            \
        if (diff < lowestdiff) { \
            lowestdiff = diff; \
            bestpick = MOTION; \
        } \
    } while(0)

static void motion_search(RoqContext *enc, int blocksize)
{
    static const motion_vect offsets[8] = {
        {{ 0,-1}},
        {{ 0, 1}},
        {{-1, 0}},
        {{ 1, 0}},
        {{-1, 1}},
        {{ 1,-1}},
        {{-1,-1}},
        {{ 1, 1}},
    };

    int diff, lowestdiff, oldbest;
    int off[3];
    motion_vect bestpick = {{0,0}};
    int i, j, k, offset;

    motion_vect *last_motion;
    motion_vect *this_motion;
    motion_vect vect, vect2;

    int max=(enc->width/blocksize)*enc->height/blocksize;

    if (blocksize == 4) {
        last_motion = enc->last_motion4;
        this_motion = enc->this_motion4;
    } else {
        last_motion = enc->last_motion8;
        this_motion = enc->this_motion8;
    }

    for (i=0; i<enc->height; i+=blocksize)
        for (j=0; j<enc->width; j+=blocksize) {
            lowestdiff = eval_motion_dist(enc, j, i, (motion_vect) {{0,0}},
                                          blocksize);
            bestpick.d[0] = 0;
            bestpick.d[1] = 0;

            if (blocksize == 4)
                EVAL_MOTION(enc->this_motion8[(i/8)*(enc->width/8) + j/8]);

            offset = (i/blocksize)*enc->width/blocksize + j/blocksize;
            if (offset < max && offset >= 0)
                EVAL_MOTION(last_motion[offset]);

            offset++;
            if (offset < max && offset >= 0)
                EVAL_MOTION(last_motion[offset]);

            offset = (i/blocksize + 1)*enc->width/blocksize + j/blocksize;
            if (offset < max && offset >= 0)