PeerStreamer

/*

 * PC Paintbrush PCX (.pcx) image encoder

 * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>

 *

 * 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

 */

/**

 * PCX image encoder

 * @file

 * @author Daniel Verkamp

 * @sa http://www.qzx.com/pc-gpe/pcx.txt

 */

#include "avcodec.h"

#include "bytestream.h"

typedef struct PCXContext {

    AVFrame picture;

} PCXContext;

static const uint32_t monoblack_pal[16] = { 0x000000, 0xFFFFFF };

static av_cold int pcx_encode_init(AVCodecContext *avctx)

{

    PCXContext *s = avctx->priv_data;

    avcodec_get_frame_defaults(&s->picture);

    avctx->coded_frame = &s->picture;

    return 0;

}

/**

 * PCX run-length encoder

 * @param dst output buffer

 * @param dst_size size of output buffer

 * @param src input buffer

 * @param src_plane_size size of one plane of input buffer in bytes

 * @param nplanes number of planes in input buffer

 * @return number of bytes written to dst or -1 on error

 * @bug will not work for nplanes != 1 && bpp != 8

 */

static int pcx_rle_encode(      uint8_t *dst, int dst_size,

                          const uint8_t *src, int src_plane_size, int nplanes)

{

    int p;

    const uint8_t *dst_start = dst;

    // check worst-case upper bound on dst_size

    if (dst_size < 2LL * src_plane_size * nplanes || src_plane_size <= 0)

        return -1;

    for (p = 0; p < nplanes; p++) {

        int count = 1;

        const uint8_t *src_plane = src + p;

        const uint8_t *src_plane_end = src_plane + src_plane_size * nplanes;

        uint8_t prev = *src_plane;

        src_plane += nplanes;

        for (; ; src_plane += nplanes) {

            if (src_plane < src_plane_end && *src_plane == prev && count < 0x3F) {

                // current byte is same as prev

                ++count;

            } else {

                // output prev * count

                if (count != 1 || prev >= 0xC0)

                    *dst++ = 0xC0 | count;

                *dst++ = prev;

                if (src_plane == src_plane_end)

                    break;

                // start new run

                count = 1;

                prev = *src_plane;

            }

        }

    }

    return dst - dst_start;

}

static int pcx_encode_frame(AVCodecContext *avctx,

                            unsigned char *buf, int buf_size, void *data)

{

    PCXContext *s = avctx->priv_data;

    AVFrame *const pict = &s->picture;

    const uint8_t *buf_start = buf;

    const uint8_t *buf_end   = buf + buf_size;

    int bpp, nplanes, i, y, line_bytes, written;

    const uint32_t *pal = NULL;

    const uint8_t *src;

    *pict = *(AVFrame *)data;

    pict->pict_type = AV_PICTURE_TYPE_I;

    pict->key_frame = 1;

    if (avctx->width > 65535 || avctx->height > 65535) {

        av_log(avctx, AV_LOG_ERROR, "image dimensions do not fit in 16 bits\n");

        return -1;

    }

    switch (avctx->pix_fmt) {

    case PIX_FMT_RGB24:

        bpp = 8;

        nplanes = 3;

        break;

    case PIX_FMT_RGB8:

    case PIX_FMT_BGR8:

    case PIX_FMT_RGB4_BYTE:

    case PIX_FMT_BGR4_BYTE:

    case PIX_FMT_GRAY8:

    case PIX_FMT_PAL8:

        bpp = 8;

        nplanes = 1;

        pal = (uint32_t *)pict->data[1];

        break;

    case PIX_FMT_MONOBLACK:

        bpp = 1;

        nplanes = 1;

        pal = monoblack_pal;

        break;

    default:

        av_log(avctx, AV_LOG_ERROR, "unsupported pixfmt\n");

        return -1;

    }

    line_bytes = (avctx->width * bpp + 7) >> 3;

    line_bytes = (line_bytes + 1) & ~1;

    bytestream_put_byte(&buf, 10);                  // manufacturer

    bytestream_put_byte(&buf, 5);                   // version

    bytestream_put_byte(&buf, 1);                   // encoding

    bytestream_put_byte(&buf, bpp);                 // bits per pixel per plane

    bytestream_put_le16(&buf, 0);                   // x min

    bytestream_put_le16(&buf, 0);                   // y min

    bytestream_put_le16(&buf, avctx->width - 1);    // x max

    bytestream_put_le16(&buf, avctx->height - 1);   // y max

    bytestream_put_le16(&buf, 0);                   // horizontal DPI

    bytestream_put_le16(&buf, 0);                   // vertical DPI

    for (i = 0; i < 16; i++)

        bytestream_put_be24(&buf, pal ? pal[i] : 0);// palette (<= 16 color only)

    bytestream_put_byte(&buf, 0);                   // reserved

    bytestream_put_byte(&buf, nplanes);             // number of planes

    bytestream_put_le16(&buf, line_bytes);          // scanline plane size in bytes

    while (buf - buf_start < 128)

        *buf++= 0;

    src = pict->data[0];

    for (y = 0; y < avctx->height; y++) {

        if ((written = pcx_rle_encode(buf, buf_end - buf,

                                      src, line_bytes, nplanes)) < 0) {

            av_log(avctx, AV_LOG_ERROR, "buffer too small\n");

            return -1;

        }

        buf += written;

        src += pict->linesize[0];

    }

    if (nplanes == 1 && bpp == 8) {

        if (buf_end - buf < 257) {

            av_log(avctx, AV_LOG_ERROR, "buffer too small\n");

            return -1;

        }

        bytestream_put_byte(&buf, 12);

        for (i = 0; i < 256; i++) {

            bytestream_put_be24(&buf, pal[i]);

        }

    }

    return buf - buf_start;

}

AVCodec ff_pcx_encoder = {

    "pcx",

    AVMEDIA_TYPE_VIDEO,

    CODEC_ID_PCX,

    sizeof(PCXContext),

    pcx_encode_init,

    pcx_encode_frame,

    NULL,

    .pix_fmts = (const enum PixelFormat[]){

        PIX_FMT_RGB24,

        PIX_FMT_RGB8, PIX_FMT_BGR8, PIX_FMT_RGB4_BYTE, PIX_FMT_BGR4_BYTE, PIX_FMT_GRAY8, PIX_FMT_PAL8,

        PIX_FMT_MONOBLACK,

        PIX_FMT_NONE},

    .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),

};