cljrdec.c

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/*
 * Cirrus Logic AccuPak (CLJR) decoder
 * Copyright (c) 2003 Alex Beregszaszi
 *
 * 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
 * Cirrus Logic AccuPak decoder.
 */

#include "avcodec.h"
#include "get_bits.h"
#include "internal.h"

static int decode_frame(AVCodecContext *avctx,
                        void *data, int *got_frame,
                        AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size       = avpkt->size;
    GetBitContext gb;
    AVFrame * const p = data;
    int x, y, ret;

    if (avctx->height <= 0 || avctx->width <= 0) {
        av_log(avctx, AV_LOG_ERROR, "Invalid width or height\n");
        return AVERROR_INVALIDDATA;
    }

    if (buf_size / avctx->height < avctx->width) {
        av_log(avctx, AV_LOG_ERROR,
               "Resolution larger than buffer size. Invalid header?\n");
        return AVERROR_INVALIDDATA;
    }

    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
        return ret;
    p->pict_type = AV_PICTURE_TYPE_I;
    p->key_frame = 1;

    init_get_bits(&gb, buf, buf_size * 8);

    for (y = 0; y < avctx->height; y++) {
        uint8_t *luma = &p->data[0][y * p->linesize[0]];
        uint8_t *cb   = &p->data[1][y * p->linesize[1]];
        uint8_t *cr   = &p->data[2][y * p->linesize[2]];
        for (x = 0; x < avctx->width; x += 4) {
            luma[3] = (get_bits(&gb, 5)*33) >> 2;
            luma[2] = (get_bits(&gb, 5)*33) >> 2;
            luma[1] = (get_bits(&gb, 5)*33) >> 2;
            luma[0] = (get_bits(&gb, 5)*33) >> 2;
            luma += 4;
            *(cb++) = get_bits(&gb, 6) << 2;
            *(cr++) = get_bits(&gb, 6) << 2;
        }
    }

    *got_frame = 1;

    return buf_size;
}

static av_cold int decode_init(AVCodecContext *avctx)
{
    avctx->pix_fmt = AV_PIX_FMT_YUV411P;
    return 0;
}

AVCodec ff_cljr_decoder = {
    .name           = "cljr",
    .long_name      = NULL_IF_CONFIG_SMALL("Cirrus Logic AccuPak"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_CLJR,
    .init           = decode_init,
    .decode         = decode_frame,
    .capabilities   = AV_CODEC_CAP_DR1,
};