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ffmpeg / libavcodec / tmv.c @ 72415b2a

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/*
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 * 8088flex TMV video decoder
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 * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * 8088flex TMV video decoder
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 * @file libavcodec/tmv.c
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 * @author Daniel Verkamp
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 * @sa http://www.oldskool.org/pc/8088_Corruption
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 */
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#include "avcodec.h"
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#include "cga_data.h"
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typedef struct TMVContext {
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    AVFrame pic;
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} TMVContext;
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static int tmv_decode_frame(AVCodecContext *avctx, void *data,
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                            int *data_size, AVPacket *avpkt)
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{
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    TMVContext *tmv    = avctx->priv_data;
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    const uint8_t *src = avpkt->data;
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    uint8_t *dst, *dst_char;
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    unsigned char_cols = avctx->width >> 3;
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    unsigned char_rows = avctx->height >> 3;
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    unsigned x, y, mask, char_y, fg, bg, c;
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    if (tmv->pic.data[0])
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        avctx->release_buffer(avctx, &tmv->pic);
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    if (avctx->get_buffer(avctx, &tmv->pic) < 0) {
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        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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        return -1;
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    }
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    if (avpkt->size < 2*char_rows*char_cols) {
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        av_log(avctx, AV_LOG_ERROR,
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               "Input buffer too small, truncated sample?\n");
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        *data_size = 0;
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        return -1;
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    }
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    tmv->pic.pict_type = FF_I_TYPE;
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    tmv->pic.key_frame = 1;
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    dst                = tmv->pic.data[0];
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    tmv->pic.palette_has_changed = 1;
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    memcpy(tmv->pic.data[1], ff_cga_palette, 16 * 4);
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    for (y = 0; y < char_rows; y++) {
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        for (x = 0; x < char_cols; x++) {
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            c  = *src++ * 8;
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            bg = *src  >> 4;
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            fg = *src++ & 0xF;
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            dst_char = dst + x * 8;
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            for (char_y = 0; char_y < 8; char_y++) {
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                for (mask = 0x80; mask; mask >>= 1) {
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                    *dst_char++ = ff_cga_font[c + char_y] & mask ? fg : bg;
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                }
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                dst_char += tmv->pic.linesize[0] - 8;
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            }
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        }
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        dst += tmv->pic.linesize[0] * 8;
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    }
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    *data_size = sizeof(AVFrame);
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    *(AVFrame *)data = tmv->pic;
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    return avpkt->size;
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}
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static av_cold int tmv_decode_close(AVCodecContext *avctx)
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{
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    TMVContext *tmv = avctx->priv_data;
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    if (tmv->pic.data[0])
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        avctx->release_buffer(avctx, &tmv->pic);
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    return 0;
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}
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AVCodec tmv_decoder = {
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    .name           = "tmv",
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    .type           = AVMEDIA_TYPE_VIDEO,
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    .id             = CODEC_ID_TMV,
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    .priv_data_size = sizeof(TMVContext),
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    .close          = tmv_decode_close,
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    .decode         = tmv_decode_frame,
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    .capabilities   = CODEC_CAP_DR1,
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    .long_name      = NULL_IF_CONFIG_SMALL("8088flex TMV"),
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};