asv1.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

/*
 * ASUS V1/V2 codec
 * Copyright (c) 2003 Michael Niedermayer
 *
 * 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 asv1.c
 * ASUS V1/V2 codec.
 */

#include "avcodec.h"
#include "bitstream.h"
#include "dsputil.h"
#include "mpegvideo.h"

//#undef NDEBUG
//#include <assert.h>

#define VLC_BITS 6
#define ASV2_LEVEL_VLC_BITS 10

typedef struct ASV1Context{
    AVCodecContext *avctx;
    DSPContext dsp;
    AVFrame picture;
    PutBitContext pb;
    GetBitContext gb;
    ScanTable scantable;
    int inv_qscale;
    int mb_width;
    int mb_height;
    int mb_width2;
    int mb_height2;
    DECLARE_ALIGNED_8(DCTELEM, block[6][64]);
    DECLARE_ALIGNED_8(uint16_t, intra_matrix[64]);
    DECLARE_ALIGNED_8(int, q_intra_matrix[64]);
    uint8_t *bitstream_buffer;
    unsigned int bitstream_buffer_size;
} ASV1Context;

static const uint8_t scantab[64]={
    0x00,0x08,0x01,0x09,0x10,0x18,0x11,0x19,
    0x02,0x0A,0x03,0x0B,0x12,0x1A,0x13,0x1B,
    0x04,0x0C,0x05,0x0D,0x20,0x28,0x21,0x29,
    0x06,0x0E,0x07,0x0F,0x14,0x1C,0x15,0x1D,
    0x22,0x2A,0x23,0x2B,0x30,0x38,0x31,0x39,
    0x16,0x1E,0x17,0x1F,0x24,0x2C,0x25,0x2D,
    0x32,0x3A,0x33,0x3B,0x26,0x2E,0x27,0x2F,
    0x34,0x3C,0x35,0x3D,0x36,0x3E,0x37,0x3F,
};


static const uint8_t ccp_tab[17][2]={
    {0x2,2}, {0x7,5}, {0xB,5}, {0x3,5},
    {0xD,5}, {0x5,5}, {0x9,5}, {0x1,5},
    {0xE,5}, {0x6,5}, {0xA,5}, {0x2,5},
    {0xC,5}, {0x4,5}, {0x8,5}, {0x3,2},
    {0xF,5}, //EOB
};

static const uint8_t level_tab[7][2]={
    {3,4}, {3,3}, {3,2}, {0,3}, {2,2}, {2,3}, {2,4}
};

static const uint8_t dc_ccp_tab[8][2]={
    {0x1,2}, {0xD,4}, {0xF,4}, {0xC,4},
    {0x5,3}, {0xE,4}, {0x4,3}, {0x0,2},
};

static const uint8_t ac_ccp_tab[16][2]={
    {0x00,2}, {0x3B,6}, {0x0A,4}, {0x3A,6},
    {0x02,3}, {0x39,6}, {0x3C,6}, {0x38,6},
    {0x03,3}, {0x3D,6}, {0x08,4}, {0x1F,5},
    {0x09,4}, {0x0B,4}, {0x0D,4}, {0x0C,4},
};

static const uint8_t asv2_level_tab[63][2]={
    {0x3F,10},{0x2F,10},{0x37,10},{0x27,10},{0x3B,10},{0x2B,10},{0x33,10},{0x23,10},
    {0x3D,10},{0x2D,10},{0x35,10},{0x25,10},{0x39,10},{0x29,10},{0x31,10},{0x21,10},
    {0x1F, 8},{0x17, 8},{0x1B, 8},{0x13, 8},{0x1D, 8},{0x15, 8},{0x19, 8},{0x11, 8},
    {0x0F, 6},{0x0B, 6},{0x0D, 6},{0x09, 6},
    {0x07, 4},{0x05, 4},
    {0x03, 2},
    {0x00, 5},
    {0x02, 2},
    {0x04, 4},{0x06, 4},
    {0x08, 6},{0x0C, 6},{0x0A, 6},{0x0E, 6},
    {0x10, 8},{0x18, 8},{0x14, 8},{0x1C, 8},{0x12, 8},{0x1A, 8},{0x16, 8},{0x1E, 8},
    {0x20,10},{0x30,10},{0x28,10},{0x38,10},{0x24,10},{0x34,10},{0x2C,10},{0x3C,10},
    {0x22,10},{0x32,10},{0x2A,10},{0x3A,10},{0x26,10},{0x36,10},{0x2E,10},{0x3E,10},
};


static VLC ccp_vlc;
static VLC level_vlc;
static VLC dc_ccp_vlc;
static VLC ac_ccp_vlc;
static VLC asv2_level_vlc;

static void init_vlcs(ASV1Context *a){
    static int done = 0;

    if (!done) {
        done = 1;

        init_vlc(&ccp_vlc, VLC_BITS, 17,
                 &ccp_tab[0][1], 2, 1,
                 &ccp_tab[0][0], 2, 1, 1);
        init_vlc(&dc_ccp_vlc, VLC_BITS, 8,
                 &dc_ccp_tab[0][1], 2, 1,
                 &dc_ccp_tab[0][0], 2, 1, 1);
        init_vlc(&ac_ccp_vlc, VLC_BITS, 16,
                 &ac_ccp_tab[0][1], 2, 1,
                 &ac_ccp_tab[0][0], 2, 1, 1);
        init_vlc(&level_vlc,  VLC_BITS, 7,
                 &level_tab[0][1], 2, 1,
                 &level_tab[0][0], 2, 1, 1);
        init_vlc(&asv2_level_vlc, ASV2_LEVEL_VLC_BITS, 63,
                 &asv2_level_tab[0][1], 2, 1,
                 &asv2_level_tab[0][0], 2, 1, 1);
    }
}

//FIXME write a reversed bitstream reader to avoid the double reverse
static inline int asv2_get_bits(GetBitContext *gb, int n){
    return ff_reverse[ get_bits(gb, n) << (8-n) ];
}

static inline void asv2_put_bits(PutBitContext *pb, int n, int v){
    put_bits(pb, n, ff_reverse[ v << (8-n) ]);
}

static inline int asv1_get_level(GetBitContext *gb){
    int code= get_vlc2(gb, level_vlc.table, VLC_BITS, 1);

    if(code==3) return get_sbits(gb, 8);
    else        return code - 3;
}

static inline int asv2_get_level(GetBitContext *gb){
    int code= get_vlc2(gb, asv2_level_vlc.table, ASV2_LEVEL_VLC_BITS, 1);

    if(code==31) return (int8_t)asv2_get_bits(gb, 8);
    else         return code - 31;
}

static inline void asv1_put_level(PutBitContext *pb, int level){
    unsigned int index= level + 3;

    if(index <= 6) put_bits(pb, level_tab[index][1], level_tab[index][0]);
    else{
        put_bits(pb, level_tab[3][1], level_tab[3][0]);
        put_bits(pb, 8, level&0xFF);
    }
}

static inline void asv2_put_level(PutBitContext *pb, int level){
    unsigned int index= level + 31;

    if(index <= 62) put_bits(pb, asv2_level_tab[index][1], asv2_level_tab[index][0]);
    else{
        put_bits(pb, asv2_level_tab[31][1], asv2_level_tab[31][0]);
        asv2_put_bits(pb, 8, level&0xFF);
    }
}

static inline int asv1_decode_block(ASV1Context *a, DCTELEM block[64]){
    int i;

    block[0]= 8*get_bits(&a->gb, 8);

    for(i=0; i<11; i++){
        const int ccp= get_vlc2(&a->gb, ccp_vlc.table, VLC_BITS, 1);

        if(ccp){
            if(ccp == 16) break;
            if(ccp < 0 || i>=10){
                av_log(a->avctx, AV_LOG_ERROR, "coded coeff pattern damaged\n");
                return -1;
            }

            if(ccp&8) block[a->scantable.permutated[4*i+0]]= (asv1_get_level(&a->gb) * a->intra_matrix[4*i+0])>>4;
            if(ccp&4) block[a->scantable.permutated[4*i+1]]= (asv1_get_level(&a->gb) * a->intra_matrix[4*i+1])>>4;
            if(ccp&2) block[a->scantable.permutated[4*i+2]]= (asv1_get_level(&a->gb) * a->intra_matrix[4*i+2])>>4;
            if(ccp&1) block[a->scantable.permutated[4*i+3]]= (asv1_get_level(&a->gb) * a->intra_matrix[4*i+3])>>4;
        }
    }

    return 0;
}

static inline int asv2_decode_block(ASV1Context *a, DCTELEM block[64]){
    int i, count, ccp;

    count= asv2_get_bits(&a->gb, 4);

    block[0]= 8*asv2_get_bits(&a->gb, 8);

    ccp= get_vlc2(&a->gb, dc_ccp_vlc.table, VLC_BITS, 1);
    if(ccp){
        if(ccp&4) block[a->scantable.permutated[1]]= (asv2_get_level(&a->gb) * a->intra_matrix[1])>>4;
        if(ccp&2) block[a->scantable.permutated[2]]= (asv2_get_level(&a->gb) * a->intra_matrix[2])>>4;
        if(ccp&1) block[a->scantable.permutated[3]]= (asv2_get_level(&a->gb) * a->intra_matrix[3])>>4;
    }

    for(i=1; i<count+1; i++){
        const int ccp= get_vlc2(&a->gb, ac_ccp_vlc.table, VLC_BITS, 1);

        if(ccp){
            if(ccp&8) block[a->scantable.permutated[4*i+0]]= (asv2_get_level(&a->gb) * a->intra_matrix[4*i+0])>>4;
            if(ccp&4) block[a->scantable.permutated[4*i+1]]= (asv2_get_level(&a->gb) * a->intra_matrix[4*i+1])>>4;
            if(ccp&2) block[a->scantable.permutated[4*i+2]]= (asv2_get_level(&a->gb) * a->intra_matrix[4*i+2])>>4;
            if(ccp&1) block[a->scantable.permutated[4*i+3]]= (asv2_get_level(&a->gb) * a->intra_matrix[4*i+3])>>4;
        }
    }

    return 0;
}

static inline void asv1_encode_block(ASV1Context *a, DCTELEM block[64]){
    int i;
    int nc_count=0;

    put_bits(&a->pb, 8, (block[0] + 32)>>6);
    block[0]= 0;

    for(i=0; i<10; i++){
        const int index= scantab[4*i];
        int ccp=0;

        if( (block[index + 0] = (block[index + 0]*a->q_intra_matrix[index + 0] + (1<<15))>>16) ) ccp |= 8;
        if( (block[index + 8] = (block[index + 8]*a->q_intra_matrix[index + 8] + (1<<15))>>16) ) ccp |= 4;
        if( (block[index + 1] = (block[index + 1]*a->q_intra_matrix[index + 1] + (1<<15))>>16) ) ccp |= 2;
        if( (block[index + 9] = (block[index + 9]*a->q_intra_matrix[index + 9] + (1<<15))>>16) ) ccp |= 1;

        if(ccp){
            for(;nc_count; nc_count--)
                put_bits(&a->pb, ccp_tab[0][1], ccp_tab[0][0]);

            put_bits(&a->pb, ccp_tab[ccp][1], ccp_tab[ccp][0]);

            if(ccp&8) asv1_put_level(&a->pb, block[index + 0]);
            if(ccp&4) asv1_put_level(&a->pb, block[index + 8]);
            if(ccp&2) asv1_put_level(&a->pb, block[index + 1]);
            if(ccp&1) asv1_put_level(&a->pb, block[index + 9]);
        }else{
            nc_count++;
        }
    }
    put_bits(&a->pb, ccp_tab[16][1], ccp_tab[16][0]);
}

static inline void asv2_encode_block(ASV1Context *a, DCTELEM block[64]){
    int i;
    int count=0;

    for(count=63; count>3; count--){
        const int index= scantab[count];

        if( (block[index]*a->q_intra_matrix[index] + (1<<15))>>16 )
            break;
    }

    count >>= 2;

    asv2_put_bits(&a->pb, 4, count);
    asv2_put_bits(&a->pb, 8, (block[0] + 32)>>6);
    block[0]= 0;

    for(i=0; i<=count; i++){
        const int index= scantab[4*i];
        int ccp=0;

        if( (block[index + 0] = (block[index + 0]*a->q_intra_matrix[index + 0] + (1<<15))>>16) ) ccp |= 8;
        if( (block[index + 8] = (block[index + 8]*a->q_intra_matrix[index + 8] + (1<<15))>>16) ) ccp |= 4;
        if( (block[index + 1] = (block[index + 1]*a->q_intra_matrix[index + 1] + (1<<15))>>16) ) ccp |= 2;
        if( (block[index + 9] = (block[index + 9]*a->q_intra_matrix[index + 9] + (1<<15))>>16) ) ccp |= 1;

        assert(i || ccp<8);
        if(i) put_bits(&a->pb, ac_ccp_tab[ccp][1], ac_ccp_tab[ccp][0]);
        else  put_bits(&a->pb, dc_ccp_tab[ccp][1], dc_ccp_tab[ccp][0]);

        if(ccp){
            if(ccp&8) asv2_put_level(&a->pb, block[index + 0]);
            if(ccp&4) asv2_put_level(&a->pb, block[index + 8]);
            if(ccp&2) asv2_put_level(&a->pb, block[index + 1]);
            if(ccp&1) asv2_put_level(&a->pb, block[index + 9]);
        }
    }
}

static inline int decode_mb(ASV1Context *a, DCTELEM block[6][64]){
    int i;

    a->dsp.clear_blocks(block[0]);

    if(a->avctx->codec_id == CODEC_ID_ASV1){
        for(i=0; i<6; i++){
            if( asv1_decode_block(a, block[i]) < 0)
                return -1;
        }
    }else{
        for(i=0; i<6; i++){
            if( asv2_decode_block(a, block[i]) < 0)
                return -1;
        }
    }
    return 0;
}

static inline int encode_mb(ASV1Context *a, DCTELEM block[6][64]){
    int i;