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ffmpeg / libavcodec / pcxenc.c @ 2912e87a

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/*
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 * PC Paintbrush PCX (.pcx) image encoder
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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 Libav.
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 *
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 * Libav 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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 * Libav 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 Libav; 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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 * PCX image encoder
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 * @file
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 * @author Daniel Verkamp
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 * @sa http://www.qzx.com/pc-gpe/pcx.txt
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 */
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#include "avcodec.h"
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#include "bytestream.h"
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typedef struct PCXContext {
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    AVFrame picture;
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} PCXContext;
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static const uint32_t monoblack_pal[16] = { 0x000000, 0xFFFFFF };
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static av_cold int pcx_encode_init(AVCodecContext *avctx)
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{
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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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 * PCX run-length encoder
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 * @param dst output buffer
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 * @param dst_size size of output buffer
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 * @param src input buffer
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 * @param src_plane_size size of one plane of input buffer in bytes
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 * @param nplanes number of planes in input buffer
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 * @return number of bytes written to dst or -1 on error
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 * @bug will not work for nplanes != 1 && bpp != 8
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 */
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static int pcx_rle_encode(      uint8_t *dst, int dst_size,
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                          const uint8_t *src, int src_plane_size, int nplanes)
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{
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    int p;
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    const uint8_t *dst_start = dst;
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    // check worst-case upper bound on dst_size
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    if (dst_size < 2LL * src_plane_size * nplanes || src_plane_size <= 0)
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        return -1;
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    for (p = 0; p < nplanes; p++) {
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        int count = 1;
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        const uint8_t *src_plane = src + p;
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        const uint8_t *src_plane_end = src_plane + src_plane_size * nplanes;
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        uint8_t prev = *src_plane;
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        src_plane += nplanes;
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        for (; ; src_plane += nplanes) {
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            if (src_plane < src_plane_end && *src_plane == prev && count < 0x3F) {
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                // current byte is same as prev
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                ++count;
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            } else {
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                // output prev * count
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                if (count != 1 || prev >= 0xC0)
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                    *dst++ = 0xC0 | count;
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                *dst++ = prev;
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                if (src_plane == src_plane_end)
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                    break;
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                // start new run
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                count = 1;
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                prev = *src_plane;
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            }
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        }
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    }
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    return dst - dst_start;
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}
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static int pcx_encode_frame(AVCodecContext *avctx,
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                            unsigned char *buf, int buf_size, void *data)
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{
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    PCXContext *s = avctx->priv_data;
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    AVFrame *const pict = &s->picture;
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    const uint8_t *buf_start = buf;
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    const uint8_t *buf_end   = buf + buf_size;
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    int bpp, nplanes, i, y, line_bytes, written;
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    const uint32_t *pal = NULL;
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    const uint8_t *src;
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    *pict = *(AVFrame *)data;
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    pict->pict_type = FF_I_TYPE;
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    pict->key_frame = 1;
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    if (avctx->width > 65535 || avctx->height > 65535) {
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        av_log(avctx, AV_LOG_ERROR, "image dimensions do not fit in 16 bits\n");
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        return -1;
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    }
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    switch (avctx->pix_fmt) {
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    case PIX_FMT_RGB24:
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        bpp = 8;
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        nplanes = 3;
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        break;
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    case PIX_FMT_RGB8:
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    case PIX_FMT_BGR8:
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    case PIX_FMT_RGB4_BYTE:
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    case PIX_FMT_BGR4_BYTE:
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    case PIX_FMT_GRAY8:
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    case PIX_FMT_PAL8:
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        bpp = 8;
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        nplanes = 1;
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        pal = (uint32_t *)pict->data[1];
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        break;
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    case PIX_FMT_MONOBLACK:
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        bpp = 1;
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        nplanes = 1;
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        pal = monoblack_pal;
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        break;
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    default:
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        av_log(avctx, AV_LOG_ERROR, "unsupported pixfmt\n");
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        return -1;
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    }
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    line_bytes = (avctx->width * bpp + 7) >> 3;
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    line_bytes = (line_bytes + 1) & ~1;
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    bytestream_put_byte(&buf, 10);                  // manufacturer
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    bytestream_put_byte(&buf, 5);                   // version
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    bytestream_put_byte(&buf, 1);                   // encoding
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    bytestream_put_byte(&buf, bpp);                 // bits per pixel per plane
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    bytestream_put_le16(&buf, 0);                   // x min
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    bytestream_put_le16(&buf, 0);                   // y min
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    bytestream_put_le16(&buf, avctx->width - 1);    // x max
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    bytestream_put_le16(&buf, avctx->height - 1);   // y max
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    bytestream_put_le16(&buf, 0);                   // horizontal DPI
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    bytestream_put_le16(&buf, 0);                   // vertical DPI
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    for (i = 0; i < 16; i++)
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        bytestream_put_be24(&buf, pal ? pal[i] : 0);// palette (<= 16 color only)
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    bytestream_put_byte(&buf, 0);                   // reserved
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    bytestream_put_byte(&buf, nplanes);             // number of planes
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    bytestream_put_le16(&buf, line_bytes);          // scanline plane size in bytes
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    while (buf - buf_start < 128)
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        *buf++= 0;
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    src = pict->data[0];
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    for (y = 0; y < avctx->height; y++) {
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        if ((written = pcx_rle_encode(buf, buf_end - buf,
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                                      src, line_bytes, nplanes)) < 0) {
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            av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
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            return -1;
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        }
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        buf += written;
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        src += pict->linesize[0];
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    }
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    if (nplanes == 1 && bpp == 8) {
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        if (buf_end - buf < 257) {
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            av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
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            return -1;
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        }
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        bytestream_put_byte(&buf, 12);
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        for (i = 0; i < 256; i++) {
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            bytestream_put_be24(&buf, pal[i]);
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        }
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    }
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    return buf - buf_start;
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}
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AVCodec ff_pcx_encoder = {
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    "pcx",
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    AVMEDIA_TYPE_VIDEO,
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    CODEC_ID_PCX,
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    sizeof(PCXContext),
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    pcx_encode_init,
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    pcx_encode_frame,
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    NULL,
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    .pix_fmts = (const enum PixelFormat[]){
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        PIX_FMT_RGB24,
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        PIX_FMT_RGB8, PIX_FMT_BGR8, PIX_FMT_RGB4_BYTE, PIX_FMT_BGR4_BYTE, PIX_FMT_GRAY8, PIX_FMT_PAL8,
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        PIX_FMT_MONOBLACK,
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        PIX_FMT_NONE},
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    .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
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};