/*

 * 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 "libavutil/attributes.h"

#define BITSTREAM_READER_LE

#include "libavutil/mem_internal.h"

#include "aandcttab.h"

#include "avcodec.h"

#include "bytestream.h"

#include "codec_internal.h"

#include "copy_block.h"

#include "decode.h"

#include "eaidct.h"

#include "get_bits.h"

typedef struct TgqContext {

    AVCodecContext *avctx;

    AVFrame *last_frame;

    int width, height;

    int qtable[64];

    DECLARE_ALIGNED(16, int16_t, block)[6][64];

} TgqContext;

static av_cold int tgq_decode_init(AVCodecContext *avctx)

{

    TgqContext *s = avctx->priv_data;

    s->avctx = avctx;

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

    avctx->pix_fmt   = AV_PIX_FMT_YUV420P;

    s->last_frame = av_frame_alloc();

    if (!s->last_frame)

        return AVERROR(ENOMEM);

    return 0;

}

static int tgq_decode_block(TgqContext *s, int16_t block[64], GetBitContext *gb)

{

    const uint8_t *scantable = ff_zigzag_direct;

    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:

            if (i >= 63)

                return AVERROR_INVALIDDATA;

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

            av_fallthrough;

        case 0:

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

            skip_bits(gb, 3);

            break;

        case 5:

        case 1:

            skip_bits(gb, 2);

            value = get_bits(gb, 6);

            if (value > 64 - i)

                return AVERROR_INVALIDDATA;

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

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

            break;

        case 6:

            skip_bits(gb, 3);

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

            i++;

            break;

        case 2:

            skip_bits(gb, 3);

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

            i++;

            break;

        case 7: // 111b

        case 3: // 011b

            skip_bits(gb, 2);

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

                skip_bits(gb, 6);

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

            } else {

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

            }

            i++;

            break;

        }

    }

    block[0] += 128 << 4;

    return 0;

}

static void tgq_idct_put_mb(TgqContext *s, int16_t (*block)[64], AVFrame *frame,

                            int mb_x, int mb_y)

{

    ptrdiff_t linesize = frame->linesize[0];

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

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

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

    ff_ea_idct_put_c(dest_y                   , linesize, block[0]);

    ff_ea_idct_put_c(dest_y                + 8, linesize, block[1]);

    ff_ea_idct_put_c(dest_y + 8 * linesize    , linesize, block[2]);

    ff_ea_idct_put_c(dest_y + 8 * linesize + 8, linesize, block[3]);

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

         ff_ea_idct_put_c(dest_cb, frame->linesize[1], block[4]);

         ff_ea_idct_put_c(dest_cr, frame->linesize[2], block[5]);

    }

}

static inline void tgq_dconly(TgqContext *s, unsigned char *dst,

                              ptrdiff_t 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, AVFrame *frame,

                                   int mb_x, int mb_y, const int8_t *dc)

{

    ptrdiff_t linesize = frame->linesize[0];

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

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

    uint8_t *dest_cr = frame->data[2] + (mb_y * 8  * 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 & AV_CODEC_FLAG_GRAY)) {

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

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

    }

}

static int tgq_decode_mb(TgqContext *s, GetByteContext *gbyte,

                         AVFrame *frame, int mb_y, int mb_x)

{

    int mode;

    int i;

    mode = bytestream2_get_byte(gbyte);

    if (mode > 12) {

        GetBitContext gb;

        int ret = init_get_bits8(&gb, gbyte->buffer, FFMIN(bytestream2_get_bytes_left(gbyte), mode));

        if (ret < 0)

            return ret;

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

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

            if (ret < 0)

                return ret;

        }

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

        bytestream2_skip(gbyte, mode);

    } else {

        int8_t dc[6];

        if (mode == 1) {

            int x, y;

            int mv = bytestream2_get_byte(gbyte);

            int mv_x = mv >> 4;

            int mv_y = mv & 0x0F;

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

                av_log(s->avctx, AV_LOG_ERROR, "missing reference frame\n");

                return -1;

            }

            if (mv_x >= 8) mv_x -= 16;

            if (mv_y >= 8) mv_y -= 16;

            x = mb_x * 16 - mv_x;

            y = mb_y * 16 - mv_y;

            if (x < 0 || x + 16 > s->width || y < 0 || y + 16 > s->height) {

                av_log(s->avctx, AV_LOG_ERROR, "invalid motion vector\n");

                return -1;

            }

            copy_block16(frame->data[0] + (mb_y * 16 * frame->linesize[0]) + mb_x * 16,

                         s->last_frame->data[0] + y * s->last_frame->linesize[0] + x,

                         frame->linesize[0], s->last_frame->linesize[0], 16);

            for (int p = 1; p < 3; p++)

                copy_block8(frame->data[p] + (mb_y * 8 * frame->linesize[p]) + mb_x * 8,

                            s->last_frame->data[p] + (y >> 1) * s->last_frame->linesize[p] + (x >> 1),

                            frame->linesize[p], s->last_frame->linesize[p], 8);

            frame->flags &= ~AV_FRAME_FLAG_KEY;

            return 0;

        } else if (mode == 3) {

            memset(dc, bytestream2_get_byte(gbyte), 4);

            dc[4] = bytestream2_get_byte(gbyte);

            dc[5] = bytestream2_get_byte(gbyte);

        } else if (mode == 6) {

            if (bytestream2_get_buffer(gbyte, dc, 6) != 6)

                return AVERROR_INVALIDDATA;

        } else if (mode == 12) {

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

                dc[i] = bytestream2_get_byte(gbyte);

                bytestream2_skip(gbyte, 1);

            }

        } else {

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

            return -1;

        }

        tgq_idct_put_mb_dconly(s, frame, mb_x, mb_y, dc);

    }

    return 0;

}

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++)

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

                                    ff_inv_aanscales[j * 8 + i]) >> (14 - 4);

}

static int tgq_decode_frame(AVCodecContext *avctx, AVFrame *frame,

                            int *got_frame, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size       = avpkt->size;

    TgqContext *s      = avctx->priv_data;

    GetByteContext gbyte;

    int x, y, ret;

    int big_endian;

    if (buf_size < 16) {

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

        return AVERROR_INVALIDDATA;

    }

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

    bytestream2_init(&gbyte, buf + 8, buf_size - 8);

    if (big_endian) {

        s->width  = bytestream2_get_be16u(&gbyte);

        s->height = bytestream2_get_be16u(&gbyte);

    } else {

        s->width  = bytestream2_get_le16u(&gbyte);

        s->height = bytestream2_get_le16u(&gbyte);

    }

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

        av_frame_unref(s->last_frame);

        ret = ff_set_dimensions(s->avctx, s->width, s->height);

        if (ret < 0)

            return ret;

    }

    tgq_calculate_qtable(s, bytestream2_get_byteu(&gbyte));

    bytestream2_skipu(&gbyte, 3);

    int mb_width  = FFALIGN(avctx->width,  16) >> 4;

    int mb_height = FFALIGN(avctx->height, 16) >> 4;

    if (bytestream2_get_bytes_left(&gbyte) < mb_width * mb_height)

        return AVERROR_INVALIDDATA;

    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

        return ret;

    frame->flags |= AV_FRAME_FLAG_KEY;

    for (y = 0; y < mb_height; y++)

        for (x = 0; x < mb_width; x++)

            if (tgq_decode_mb(s, &gbyte, frame, y, x) < 0)

                return AVERROR_INVALIDDATA;

    if ((ret = av_frame_replace(s->last_frame, frame)) < 0)

        return ret;

    *got_frame = 1;

    return avpkt->size;

}

static av_cold int tgq_decode_close(AVCodecContext *avctx)

{

    TgqContext *s = avctx->priv_data;

    av_frame_free(&s->last_frame);

    return 0;

}

const FFCodec ff_eatgq_decoder = {

    .p.name         = "eatgq",

    CODEC_LONG_NAME("Electronic Arts TGQ video"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_TGQ,

    .priv_data_size = sizeof(TgqContext),

    .init           = tgq_decode_init,

    .close          = tgq_decode_close,

    FF_CODEC_DECODE_CB(tgq_decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

};