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ffmpeg / libavcodec / bfi.c @ 72415b2a

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/*
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 * Brute Force & Ignorance (BFI) video decoder
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 * Copyright (c) 2008 Sisir Koppaka
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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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 * @file libavcodec/bfi.c
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 * @brief Brute Force & Ignorance (.bfi) video decoder
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 * @author Sisir Koppaka ( sisir.koppaka at gmail dot com )
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 * @sa http://wiki.multimedia.cx/index.php?title=BFI
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 */
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#include "libavutil/common.h"
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#include "avcodec.h"
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#include "bytestream.h"
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typedef struct BFIContext {
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    AVCodecContext *avctx;
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    AVFrame frame;
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    uint8_t *dst;
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} BFIContext;
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static av_cold int bfi_decode_init(AVCodecContext * avctx)
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{
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    BFIContext *bfi = avctx->priv_data;
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    avctx->pix_fmt = PIX_FMT_PAL8;
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    bfi->dst = av_mallocz(avctx->width * avctx->height);
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    return 0;
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}
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static int bfi_decode_frame(AVCodecContext * avctx, void *data,
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                            int *data_size, AVPacket *avpkt)
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{
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    const uint8_t *buf = avpkt->data;
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    int buf_size = avpkt->size;
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    BFIContext *bfi = avctx->priv_data;
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    uint8_t *dst = bfi->dst;
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    uint8_t *src, *dst_offset, colour1, colour2;
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    uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;
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    uint32_t *pal;
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    int i, j, height = avctx->height;
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    if (bfi->frame.data[0])
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        avctx->release_buffer(avctx, &bfi->frame);
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    bfi->frame.reference = 1;
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    if (avctx->get_buffer(avctx, &bfi->frame) < 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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    /* Set frame parameters and palette, if necessary */
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    if (!avctx->frame_number) {
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        bfi->frame.pict_type = FF_I_TYPE;
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        bfi->frame.key_frame = 1;
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        /* Setting the palette */
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        if(avctx->extradata_size>768) {
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            av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n");
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            return -1;
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        }
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        pal = (uint32_t *) bfi->frame.data[1];
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        for (i = 0; i < avctx->extradata_size / 3; i++) {
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            int shift = 16;
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            *pal = 0;
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            for (j = 0; j < 3; j++, shift -= 8)
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                *pal +=
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                    ((avctx->extradata[i * 3 + j] << 2) |
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                    (avctx->extradata[i * 3 + j] >> 4)) << shift;
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            pal++;
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        }
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        bfi->frame.palette_has_changed = 1;
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    } else {
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        bfi->frame.pict_type = FF_P_TYPE;
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        bfi->frame.key_frame = 0;
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    }
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    buf += 4; //Unpacked size, not required.
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    while (dst != frame_end) {
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        static const uint8_t lentab[4]={0,2,0,1};
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        unsigned int byte = *buf++, av_uninit(offset);
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        unsigned int code = byte >> 6;
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        unsigned int length = byte & ~0xC0;
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        /* Get length and offset(if required) */
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        if (length == 0) {
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            if (code == 1) {
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                length = bytestream_get_byte(&buf);
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                offset = bytestream_get_le16(&buf);
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            } else {
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                length = bytestream_get_le16(&buf);
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                if (code == 2 && length == 0)
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                    break;
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            }
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        } else {
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            if (code == 1)
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                offset = bytestream_get_byte(&buf);
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        }
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        /* Do boundary check */
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        if (dst + (length<<lentab[code]) > frame_end)
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            break;
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        switch (code) {
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        case 0:                //Normal Chain
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            bytestream_get_buffer(&buf, dst, length);
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            dst += length;
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            break;
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        case 1:                //Back Chain
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            dst_offset = dst - offset;
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            length *= 4;        //Convert dwords to bytes.
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            if (dst_offset < bfi->dst)
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                break;
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            while (length--)
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                *dst++ = *dst_offset++;
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            break;
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        case 2:                //Skip Chain
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            dst += length;
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            break;
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        case 3:                //Fill Chain
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            colour1 = bytestream_get_byte(&buf);
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            colour2 = bytestream_get_byte(&buf);
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            while (length--) {
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                *dst++ = colour1;
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                *dst++ = colour2;
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            }
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            break;
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        }
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    }
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    src = bfi->dst;
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    dst = bfi->frame.data[0];
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    while (height--) {
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        memcpy(dst, src, avctx->width);
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        src += avctx->width;
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        dst += bfi->frame.linesize[0];
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    }
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    *data_size = sizeof(AVFrame);
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    *(AVFrame *) data = bfi->frame;
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    return buf_size;
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}
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static av_cold int bfi_decode_close(AVCodecContext * avctx)
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{
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    BFIContext *bfi = avctx->priv_data;
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    if (bfi->frame.data[0])
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        avctx->release_buffer(avctx, &bfi->frame);
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    av_free(bfi->dst);
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    return 0;
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}
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AVCodec bfi_decoder = {
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    .name = "bfi",
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    .type = AVMEDIA_TYPE_VIDEO,
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    .id = CODEC_ID_BFI,
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    .priv_data_size = sizeof(BFIContext),
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    .init = bfi_decode_init,
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    .close = bfi_decode_close,
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    .decode = bfi_decode_frame,
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    .capabilities = CODEC_CAP_DR1,
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    .long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
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};