PeerStreamer

/*

 * Electronic Arts TGQ Video Decoder

 * Copyright (c) 2007-2008 Peter Ross <pross@xvid.org>

 *

 * 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 St, Fifth Floor, Boston, MA  02110-1301  USA

 */

/**

 * @file

 * Electronic Arts TGQ Video Decoder

 * @author Peter Ross <pross@xvid.org>

 *

 * Technical details here:

 * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_TGQ

 */

#include "avcodec.h"

#define ALT_BITSTREAM_READER_LE

#include "get_bits.h"

#include "bytestream.h"

#include "dsputil.h"

#include "aandcttab.h"

typedef struct TgqContext {

    AVCodecContext *avctx;

    DSPContext dsp;

    AVFrame frame;

    int width,height;

    ScanTable scantable;

    int qtable[64];

    DECLARE_ALIGNED(16, DCTELEM, block)[6][64];

} TgqContext;

static av_cold int tgq_decode_init(AVCodecContext *avctx){

    TgqContext *s = avctx->priv_data;

    s->avctx = avctx;

    if(avctx->idct_algo==FF_IDCT_AUTO)

        avctx->idct_algo=FF_IDCT_EA;

    dsputil_init(&s->dsp, avctx);

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

    avctx->time_base = (AVRational){1, 15};

    avctx->pix_fmt = PIX_FMT_YUV420P;

    return 0;

}

static void tgq_decode_block(TgqContext *s, DCTELEM block[64], GetBitContext *gb){

    uint8_t *perm = s->scantable.permutated;

    int i,j,value;

    block[0] = get_sbits(gb,8) * s->qtable[0];

    for(i=1; i<64; ) {

        switch(show_bits(gb,3)) {

        case 4:

            block[perm[i++]] = 0;

        case 0:

            block[perm[i++]] = 0;

            skip_bits(gb,3);

            break;

        case 5:

        case 1:

            skip_bits(gb,2);

            value = get_bits(gb,6);

            for(j=0; j<value; j++)

                block[perm[i++]] = 0;

            break;

        case 6:

            skip_bits(gb,3);

            block[perm[i]] = -s->qtable[perm[i]];

            i++;

            break;

        case 2:

            skip_bits(gb,3);

            block[perm[i]] = s->qtable[perm[i]];

            i++;

            break;

        case 7: // 111b

        case 3: // 011b

            skip_bits(gb,2);

            if (show_bits(gb,6)==0x3F) {

                skip_bits(gb, 6);

                block[perm[i]] = get_sbits(gb,8)*s->qtable[perm[i]];

            }else{

                block[perm[i]] = get_sbits(gb,6)*s->qtable[perm[i]];

            }

            i++;

            break;

        }

    }

    block[0] += 128<<4;

}

static void tgq_idct_put_mb(TgqContext *s, DCTELEM (*block)[64], int mb_x, int mb_y){

    int linesize= s->frame.linesize[0];

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

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

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

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

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

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

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

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

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

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

    }

}

static inline void tgq_dconly(TgqContext *s, unsigned char *dst, int dst_stride, int dc){

    int level = av_clip_uint8((dc*s->qtable[0] + 2056)>>4);

    int j;

    for(j=0;j<8;j++)

        memset(dst+j*dst_stride, level, 8);

}

static void tgq_idct_put_mb_dconly(TgqContext *s, int mb_x, int mb_y, const int8_t *dc)

{

    int linesize= s->frame.linesize[0];

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

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

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

    tgq_dconly(s,dest_y                 , linesize, dc[0]);

    tgq_dconly(s,dest_y              + 8, linesize, dc[1]);

    tgq_dconly(s,dest_y + 8*linesize    , linesize, dc[2]);

    tgq_dconly(s,dest_y + 8*linesize + 8, linesize, dc[3]);

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

        tgq_dconly(s,dest_cb, s->frame.linesize[1], dc[4]);

        tgq_dconly(s,dest_cr, s->frame.linesize[2], dc[5]);

    }

}

static void tgq_decode_mb(TgqContext *s, int mb_y, int mb_x, const uint8_t **bs, const uint8_t *buf_end){

    int mode;

    int i;

    int8_t dc[6];

    mode = bytestream_get_byte(bs);

    if (mode>buf_end-*bs) {

        av_log(s->avctx, AV_LOG_ERROR, "truncated macroblock\n");

        return;

    }

    if (mode>12) {

        GetBitContext gb;

        init_get_bits(&gb, *bs, mode*8);

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

            tgq_decode_block(s, s->block[i], &gb);

        tgq_idct_put_mb(s, s->block, mb_x, mb_y);

    }else{

        if (mode==3) {

            memset(dc, (*bs)[0], 4);

            dc[4] = (*bs)[1];

            dc[5] = (*bs)[2];

        }else if (mode==6) {

            memcpy(dc, *bs, 6);

        }else if (mode==12) {

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

                dc[i] = (*bs)[i*2];

        }else{

            av_log(s->avctx, AV_LOG_ERROR, "unsupported mb mode %i\n", mode);

        }

        tgq_idct_put_mb_dconly(s, mb_x, mb_y, dc);

    }

    *bs += mode;

}

static void tgq_calculate_qtable(TgqContext *s, int quant){

    int i,j;

    const int a = (14*(100-quant))/100 + 1;

    const int b = (11*(100-quant))/100 + 4;

    for(j=0;j<8;j++)

    for(i=0;i<8;i++)

        if (s->avctx->idct_algo==FF_IDCT_EA)

            s->qtable[j*8+i] = ((a*(j+i)/(7+7) + b)*ff_inv_aanscales[j*8+i])>>(14-4);

        else

            s->qtable[j*8+i] = (a*(j+i)/(7+7) + b)<<3;

}

static int tgq_decode_frame(AVCodecContext *avctx,

                            void *data, int *data_size,

                            AVPacket *avpkt){

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    const uint8_t *buf_start = buf;

    const uint8_t *buf_end = buf + buf_size;

    TgqContext *s = avctx->priv_data;

    int x,y;

    int big_endian = AV_RL32(&buf[4]) > 0x000FFFFF;

    buf += 8;

    if(8>buf_end-buf) {

        av_log(avctx, AV_LOG_WARNING, "truncated header\n");

        return -1;

    }

    s->width  = big_endian ? AV_RB16(&buf[0]) : AV_RL16(&buf[0]);

    s->height = big_endian ? AV_RB16(&buf[2]) : AV_RL16(&buf[2]);

    if (s->avctx->width!=s->width || s->avctx->height!=s->height) {

        avcodec_set_dimensions(s->avctx, s->width, s->height);

        if (s->frame.data[0])

            avctx->release_buffer(avctx, &s->frame);

    }

    tgq_calculate_qtable(s, buf[4]);

    buf += 8;

    if (!s->frame.data[0]) {

        s->frame.key_frame = 1;

        s->frame.pict_type = FF_I_TYPE;

        s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;

        if (avctx->get_buffer(avctx, &s->frame)) {

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

            return -1;

        }

    }

    for (y=0; y<(avctx->height+15)/16; y++)

    for (x=0; x<(avctx->width+15)/16; x++)

        tgq_decode_mb(s, y, x, &buf, buf_end);

    *data_size = sizeof(AVFrame);

    *(AVFrame*)data = s->frame;

    return buf-buf_start;

}

static av_cold int tgq_decode_end(AVCodecContext *avctx){

    TgqContext *s = avctx->priv_data;

    if (s->frame.data[0])

        s->avctx->release_buffer(avctx, &s->frame);

    return 0;

}

AVCodec ff_eatgq_decoder = {

    "eatgq",

    AVMEDIA_TYPE_VIDEO,

    CODEC_ID_TGQ,

    sizeof(TgqContext),

    tgq_decode_init,

    NULL,

    tgq_decode_end,

    tgq_decode_frame,

    CODEC_CAP_DR1,

    .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts TGQ video"),

};