PeerStreamer

/*

 * PSX MDEC codec

 * Copyright (c) 2003 Michael Niedermayer

 *

 * 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

 *

 * based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>

 */

/**

 * @file mdec.c

 * PSX MDEC codec.

 * This is very similar to intra only MPEG1.

 */

#include "avcodec.h"

#include "dsputil.h"

#include "mpegvideo.h"

//#undef NDEBUG

//#include <assert.h>

typedef struct MDECContext{

    AVCodecContext *avctx;

    DSPContext dsp;

    AVFrame picture;

    PutBitContext pb;

    GetBitContext gb;

    ScanTable scantable;

    int version;

    int qscale;

    int last_dc[3];

    int mb_width;

    int mb_height;

    int mb_x, mb_y;

    DCTELEM __align8 block[6][64];

    uint16_t __align8 intra_matrix[64];

    int __align8 q_intra_matrix[64];

    uint8_t *bitstream_buffer;

    int bitstream_buffer_size;

    int block_last_index[6];

} MDECContext;

//very similar to mpeg1

static inline int mdec_decode_block_intra(MDECContext *a, DCTELEM *block, int n)

{

    int level, diff, i, j, run;

    int component;

    RLTable *rl = &rl_mpeg1;

    uint8_t * const scantable= a->scantable.permutated;

    const uint16_t *quant_matrix= ff_mpeg1_default_intra_matrix;

    const int qscale= a->qscale;

    /* DC coef */

    if(a->version==2){

        block[0]= 2*get_sbits(&a->gb, 10) + 1024;

    }else{

        component = (n <= 3 ? 0 : n - 4 + 1);

        diff = decode_dc(&a->gb, component);

        if (diff >= 0xffff)

            return -1;

        a->last_dc[component]+= diff;

        block[0] = a->last_dc[component]<<3;

    }

    i = 0;

    {

        OPEN_READER(re, &a->gb);

        /* now quantify & encode AC coefs */

        for(;;) {

            UPDATE_CACHE(re, &a->gb);

            GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);

            if(level == 127){

                break;

            } else if(level != 0) {

                i += run;

                j = scantable[i];

                level= (level*qscale*quant_matrix[j])>>3;

//                level= (level-1)|1;

                level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);

                LAST_SKIP_BITS(re, &a->gb, 1);

            } else {

                /* escape */

                run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);

                UPDATE_CACHE(re, &a->gb);

                level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);

                i += run;

                j = scantable[i];

                if(level<0){

                    level= -level;

                    level= (level*qscale*quant_matrix[j])>>3;

                    level= (level-1)|1;

                    level= -level;

                }else{

                    level= (level*qscale*quant_matrix[j])>>3;

                    level= (level-1)|1;

                }

            }

            if (i > 63){

                av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);

                return -1;

            }

            block[j] = level;

        }

        CLOSE_READER(re, &a->gb);

    }

    a->block_last_index[n] = i;

    return 0;

}

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

    int i;

    const int block_index[6]= {5,4,0,1,2,3};

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

    for(i=0; i<6; i++){

        if( mdec_decode_block_intra(a, block[ block_index[i] ], block_index[i]) < 0)

            return -1;

    }

    return 0;

}

static inline void idct_put(MDECContext *a, int mb_x, int mb_y){

    DCTELEM (*block)[64]= a->block;

    int linesize= a->picture.linesize[0];

    uint8_t *dest_y  = a->picture.data[0] + (mb_y * 16* linesize              ) + mb_x * 16;

    uint8_t *dest_cb = a->picture.data[1] + (mb_y * 8 * a->picture.linesize[1]) + mb_x * 8;

    uint8_t *dest_cr = a->picture.data[2] + (mb_y * 8 * a->picture.linesize[2]) + mb_x * 8;

    a->dsp.idct_put(dest_y                 , linesize, block[0]);

    a->dsp.idct_put(dest_y              + 8, linesize, block[1]);

    a->dsp.idct_put(dest_y + 8*linesize    , linesize, block[2]);

    a->dsp.idct_put(dest_y + 8*linesize + 8, linesize, block[3]);

    if(!(a->avctx->flags&CODEC_FLAG_GRAY)){

        a->dsp.idct_put(dest_cb, a->picture.linesize[1], block[4]);

        a->dsp.idct_put(dest_cr, a->picture.linesize[2], block[5]);

    }

}

static int decode_frame(AVCodecContext *avctx,

                        void *data, int *data_size,

                        uint8_t *buf, int buf_size)

{

    MDECContext * const a = avctx->priv_data;

    AVFrame *picture = data;

    AVFrame * const p= (AVFrame*)&a->picture;

    int i;

    if(p->data[0])

        avctx->release_buffer(avctx, p);

    p->reference= 0;

    if(avctx->get_buffer(avctx, p) < 0){

        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

        return -1;

    }

    p->pict_type= I_TYPE;

    p->key_frame= 1;

    a->last_dc[0]=

    a->last_dc[1]=

    a->last_dc[2]= 0;

    a->bitstream_buffer= av_fast_realloc(a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);

    for(i=0; i<buf_size; i+=2){

        a->bitstream_buffer[i]  = buf[i+1];

        a->bitstream_buffer[i+1]= buf[i  ];

    }

    init_get_bits(&a->gb, a->bitstream_buffer, buf_size*8);

    /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */

    skip_bits(&a->gb, 32);

    a->qscale=  get_bits(&a->gb, 16);

    a->version= get_bits(&a->gb, 16);

//    printf("qscale:%d (0x%X), version:%d (0x%X)\n", a->qscale, a->qscale, a->version, a->version);

    for(a->mb_x=0; a->mb_x<a->mb_width; a->mb_x++){

        for(a->mb_y=0; a->mb_y<a->mb_height; a->mb_y++){

            if( decode_mb(a, a->block) <0)

                return -1;

            idct_put(a, a->mb_x, a->mb_y);

        }

    }

//    p->quality= (32 + a->inv_qscale/2)/a->inv_qscale;

//    memset(p->qscale_table, p->quality, p->qstride*a->mb_height);

    *picture= *(AVFrame*)&a->picture;

    *data_size = sizeof(AVPicture);

    emms_c();

    return (get_bits_count(&a->gb)+31)/32*4;

}

static void mdec_common_init(AVCodecContext *avctx){

    MDECContext * const a = avctx->priv_data;

    dsputil_init(&a->dsp, avctx);

    a->mb_width   = (avctx->coded_width  + 15) / 16;

    a->mb_height  = (avctx->coded_height + 15) / 16;

    avctx->coded_frame= (AVFrame*)&a->picture;

    a->avctx= avctx;

}

static int decode_init(AVCodecContext *avctx){

    MDECContext * const a = avctx->priv_data;

    AVFrame *p= (AVFrame*)&a->picture;

    mdec_common_init(avctx);

    init_vlcs();

    ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);

/*

    for(i=0; i<64; i++){

        int index= ff_zigzag_direct[i];

        a->intra_matrix[i]= 64*ff_mpeg1_default_intra_matrix[index] / a->inv_qscale;

    }

*/

    p->qstride= a->mb_width;

    p->qscale_table= av_mallocz( p->qstride * a->mb_height);

    avctx->pix_fmt= PIX_FMT_YUV420P;

    return 0;

}

static int decode_end(AVCodecContext *avctx){

    MDECContext * const a = avctx->priv_data;

    av_freep(&a->bitstream_buffer);

    av_freep(&a->picture.qscale_table);

    a->bitstream_buffer_size=0;

    return 0;

}

AVCodec mdec_decoder = {

    "mdec",

    CODEC_TYPE_VIDEO,

    CODEC_ID_MDEC,

    sizeof(MDECContext),

    decode_init,

    NULL,

    decode_end,

    decode_frame,

    CODEC_CAP_DR1,

};