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ffmpeg / libavcodec / pcx.c @ dae0d1e2

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/*
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 * PC Paintbrush PCX (.pcx) image decoder
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 * Copyright (c) 2007, 2008 Ivo van Poorten
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 *
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 * This decoder does not support CGA palettes. I am unable to find samples
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 * and Netpbm cannot generate them.
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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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#include "avcodec.h"
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#include "bytestream.h"
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#include "get_bits.h"
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typedef struct PCXContext {
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    AVFrame picture;
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} PCXContext;
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static av_cold int pcx_init(AVCodecContext *avctx) {
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    PCXContext *s = avctx->priv_data;
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    avcodec_get_frame_defaults(&s->picture);
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    avctx->coded_frame= &s->picture;
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    return 0;
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}
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/**
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 * @return advanced src pointer
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 */
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static const uint8_t *pcx_rle_decode(const uint8_t *src, uint8_t *dst,
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                            unsigned int bytes_per_scanline, int compressed) {
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    unsigned int i = 0;
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    unsigned char run, value;
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    if (compressed) {
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        while (i<bytes_per_scanline) {
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            run = 1;
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            value = *src++;
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            if (value >= 0xc0) {
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                run = value & 0x3f;
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                value = *src++;
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            }
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            while (i<bytes_per_scanline && run--)
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                dst[i++] = value;
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        }
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    } else {
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        memcpy(dst, src, bytes_per_scanline);
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        src += bytes_per_scanline;
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    }
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    return src;
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}
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static void pcx_palette(const uint8_t **src, uint32_t *dst, unsigned int pallen) {
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    unsigned int i;
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    for (i=0; i<pallen; i++)
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        *dst++ = bytestream_get_be24(src);
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    memset(dst, 0, (256 - pallen) * sizeof(*dst));
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}
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static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
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                            AVPacket *avpkt) {
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    const uint8_t *buf = avpkt->data;
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    int buf_size = avpkt->size;
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    PCXContext * const s = avctx->priv_data;
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    AVFrame *picture = data;
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    AVFrame * const p = &s->picture;
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    int compressed, xmin, ymin, xmax, ymax;
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    unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
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                 bytes_per_scanline;
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    uint8_t *ptr;
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    uint8_t const *bufstart = buf;
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    if (buf[0] != 0x0a || buf[1] > 5) {
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        av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
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        return -1;
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    }
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    compressed = buf[2];
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    xmin = AV_RL16(buf+ 4);
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    ymin = AV_RL16(buf+ 6);
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    xmax = AV_RL16(buf+ 8);
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    ymax = AV_RL16(buf+10);
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    if (xmax < xmin || ymax < ymin) {
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        av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
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        return -1;
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    }
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    w = xmax - xmin + 1;
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    h = ymax - ymin + 1;
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    bits_per_pixel     = buf[3];
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    bytes_per_line     = AV_RL16(buf+66);
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    nplanes            = buf[65];
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    bytes_per_scanline = nplanes * bytes_per_line;
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    if (bytes_per_scanline < w * bits_per_pixel * nplanes / 8) {
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        av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
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        return -1;
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    }
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    switch ((nplanes<<8) + bits_per_pixel) {
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        case 0x0308:
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            avctx->pix_fmt = PIX_FMT_RGB24;
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            break;
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        case 0x0108:
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        case 0x0104:
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        case 0x0102:
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        case 0x0101:
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        case 0x0401:
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        case 0x0301:
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        case 0x0201:
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            avctx->pix_fmt = PIX_FMT_PAL8;
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            break;
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        default:
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            av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
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            return -1;
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    }
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    buf += 128;
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    if (p->data[0])
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        avctx->release_buffer(avctx, p);
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    if (avcodec_check_dimensions(avctx, w, h))
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        return -1;
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    if (w != avctx->width || h != avctx->height)
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        avcodec_set_dimensions(avctx, w, h);
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    if (avctx->get_buffer(avctx, p) < 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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    p->pict_type = FF_I_TYPE;
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    ptr    = p->data[0];
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    stride = p->linesize[0];
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    if (nplanes == 3 && bits_per_pixel == 8) {
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        uint8_t scanline[bytes_per_scanline];
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        for (y=0; y<h; y++) {
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            buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
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            for (x=0; x<w; x++) {
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                ptr[3*x  ] = scanline[x                    ];
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                ptr[3*x+1] = scanline[x+ bytes_per_line    ];
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                ptr[3*x+2] = scanline[x+(bytes_per_line<<1)];
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            }
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            ptr += stride;
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        }
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    } else if (nplanes == 1 && bits_per_pixel == 8) {
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        uint8_t scanline[bytes_per_scanline];
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        const uint8_t *palstart = bufstart + buf_size - 769;
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        for (y=0; y<h; y++, ptr+=stride) {
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            buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
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            memcpy(ptr, scanline, w);
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        }
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        if (buf != palstart) {
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            av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
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            buf = palstart;
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        }
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        if (*buf++ != 12) {
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            av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
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            return -1;
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        }
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    } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */
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        uint8_t scanline[bytes_per_scanline];
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        GetBitContext s;
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        for (y=0; y<h; y++) {
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            init_get_bits(&s, scanline, bytes_per_scanline<<3);
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            buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
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            for (x=0; x<w; x++)
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                ptr[x] = get_bits(&s, bits_per_pixel);
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            ptr += stride;
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        }
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    } else {    /* planar, 4, 8 or 16 colors */
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        uint8_t scanline[bytes_per_scanline];
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        int i;
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        for (y=0; y<h; y++) {
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            buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
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            for (x=0; x<w; x++) {
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                int m = 0x80 >> (x&7), v = 0;
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                for (i=nplanes - 1; i>=0; i--) {
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                    v <<= 1;
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                    v  += !!(scanline[i*bytes_per_line + (x>>3)] & m);
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                }
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                ptr[x] = v;
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            }
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            ptr += stride;
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        }
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    }
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    if (nplanes == 1 && bits_per_pixel == 8) {
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        pcx_palette(&buf, (uint32_t *) p->data[1], 256);
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    } else if (bits_per_pixel < 8) {
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        const uint8_t *palette = bufstart+16;
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        pcx_palette(&palette, (uint32_t *) p->data[1], 16);
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    }
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    *picture = s->picture;
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    *data_size = sizeof(AVFrame);
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    return buf - bufstart;
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}
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static av_cold int pcx_end(AVCodecContext *avctx) {
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    PCXContext *s = avctx->priv_data;
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    if(s->picture.data[0])
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        avctx->release_buffer(avctx, &s->picture);
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    return 0;
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}
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AVCodec pcx_decoder = {
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    "pcx",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_PCX,
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    sizeof(PCXContext),
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    pcx_init,
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    NULL,
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    pcx_end,
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    pcx_decode_frame,
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    CODEC_CAP_DR1,
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    NULL,
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    .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
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};