PeerStreamer

/*

 * Intel Indeo 2 codec

 * Copyright (c) 2005 Konstantin Shishkov

 *

 * 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

 * Intel Indeo 2 decoder.

 */

#define ALT_BITSTREAM_READER_LE

#include "avcodec.h"

#include "get_bits.h"

#include "indeo2data.h"

#include "libavutil/common.h"

typedef struct Ir2Context{

    AVCodecContext *avctx;

    AVFrame picture;

    GetBitContext gb;

    int decode_delta;

} Ir2Context;

#define CODE_VLC_BITS 14

static VLC ir2_vlc;

/* Indeo 2 codes are in range 0x01..0x7F and 0x81..0x90 */

static inline int ir2_get_code(GetBitContext *gb)

{

    return get_vlc2(gb, ir2_vlc.table, CODE_VLC_BITS, 1) + 1;

}

static int ir2_decode_plane(Ir2Context *ctx, int width, int height, uint8_t *dst, int stride,

                             const uint8_t *table)

{

    int i;

    int j;

    int out = 0;

    int c;

    int t;

    if(width&1)

        return -1;

    /* first line contain absolute values, other lines contain deltas */

    while (out < width){

        c = ir2_get_code(&ctx->gb);

        if(c >= 0x80) { /* we have a run */

            c -= 0x7F;

            if(out + c*2 > width)

                return -1;

            for (i = 0; i < c * 2; i++)

                dst[out++] = 0x80;

        } else { /* copy two values from table */

            dst[out++] = table[c * 2];

            dst[out++] = table[(c * 2) + 1];

        }

    }

    dst += stride;

    for (j = 1; j < height; j++){

        out = 0;

        while (out < width){

            c = ir2_get_code(&ctx->gb);

            if(c >= 0x80) { /* we have a skip */

                c -= 0x7F;

                if(out + c*2 > width)

                    return -1;

                for (i = 0; i < c * 2; i++) {

                    dst[out] = dst[out - stride];

                    out++;

                }

            } else { /* add two deltas from table */

                t = dst[out - stride] + (table[c * 2] - 128);

                t= av_clip_uint8(t);

                dst[out] = t;

                out++;

                t = dst[out - stride] + (table[(c * 2) + 1] - 128);

                t= av_clip_uint8(t);

                dst[out] = t;

                out++;

            }

        }

        dst += stride;

    }

    return 0;

}

static int ir2_decode_plane_inter(Ir2Context *ctx, int width, int height, uint8_t *dst, int stride,

                             const uint8_t *table)

{

    int j;

    int out = 0;

    int c;

    int t;

    if(width&1)

        return -1;

    for (j = 0; j < height; j++){

        out = 0;

        while (out < width){

            c = ir2_get_code(&ctx->gb);

            if(c >= 0x80) { /* we have a skip */

                c -= 0x7F;

                out += c * 2;

            } else { /* add two deltas from table */

                t = dst[out] + (((table[c * 2] - 128)*3) >> 2);

                t= av_clip_uint8(t);

                dst[out] = t;

                out++;

                t = dst[out] + (((table[(c * 2) + 1] - 128)*3) >> 2);

                t= av_clip_uint8(t);

                dst[out] = t;

                out++;

            }

        }

        dst += stride;

    }

    return 0;

}

static int ir2_decode_frame(AVCodecContext *avctx,

                        void *data, int *data_size,

                        AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    Ir2Context * const s = avctx->priv_data;

    AVFrame *picture = data;

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

    int start;

    if(p->data[0])

        avctx->release_buffer(avctx, p);

    p->reference = 1;

    p->buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;

    if (avctx->reget_buffer(avctx, p)) {

        av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");

        return -1;

    }

    s->decode_delta = buf[18];

    /* decide whether frame uses deltas or not */

#ifndef ALT_BITSTREAM_READER_LE

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

        buf[i] = av_reverse[buf[i]];

#endif

    start = 48; /* hardcoded for now */

    init_get_bits(&s->gb, buf + start, buf_size - start);

    if (s->decode_delta) { /* intraframe */

        ir2_decode_plane(s, avctx->width, avctx->height,

                         s->picture.data[0], s->picture.linesize[0], ir2_luma_table);

        /* swapped U and V */

        ir2_decode_plane(s, avctx->width >> 2, avctx->height >> 2,

                         s->picture.data[2], s->picture.linesize[2], ir2_luma_table);

        ir2_decode_plane(s, avctx->width >> 2, avctx->height >> 2,

                         s->picture.data[1], s->picture.linesize[1], ir2_luma_table);

    } else { /* interframe */

        ir2_decode_plane_inter(s, avctx->width, avctx->height,

                         s->picture.data[0], s->picture.linesize[0], ir2_luma_table);

        /* swapped U and V */

        ir2_decode_plane_inter(s, avctx->width >> 2, avctx->height >> 2,

                         s->picture.data[2], s->picture.linesize[2], ir2_luma_table);

        ir2_decode_plane_inter(s, avctx->width >> 2, avctx->height >> 2,

                         s->picture.data[1], s->picture.linesize[1], ir2_luma_table);

    }

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

    *data_size = sizeof(AVPicture);

    return buf_size;

}

static av_cold int ir2_decode_init(AVCodecContext *avctx){

    Ir2Context * const ic = avctx->priv_data;

    static VLC_TYPE vlc_tables[1 << CODE_VLC_BITS][2];

    ic->avctx = avctx;

    avctx->pix_fmt= PIX_FMT_YUV410P;

    ir2_vlc.table = vlc_tables;

    ir2_vlc.table_allocated = 1 << CODE_VLC_BITS;

#ifdef ALT_BITSTREAM_READER_LE

        init_vlc(&ir2_vlc, CODE_VLC_BITS, IR2_CODES,

                 &ir2_codes[0][1], 4, 2,

                 &ir2_codes[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC | INIT_VLC_LE);

#else

        init_vlc(&ir2_vlc, CODE_VLC_BITS, IR2_CODES,

                 &ir2_codes[0][1], 4, 2,

                 &ir2_codes[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);

#endif

    return 0;

}

static av_cold int ir2_decode_end(AVCodecContext *avctx){

    Ir2Context * const ic = avctx->priv_data;

    AVFrame *pic = &ic->picture;

    if (pic->data[0])

        avctx->release_buffer(avctx, pic);

    return 0;

}

AVCodec ff_indeo2_decoder = {

    "indeo2",

    AVMEDIA_TYPE_VIDEO,

    CODEC_ID_INDEO2,

    sizeof(Ir2Context),

    ir2_decode_init,

    NULL,

    ir2_decode_end,

    ir2_decode_frame,

    CODEC_CAP_DR1,

    .long_name = NULL_IF_CONFIG_SMALL("Intel Indeo 2"),

};