PeerStreamer

/*

 * CamStudio decoder

 * Copyright (c) 2006 Reimar Doeffinger

 *

 * 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

 */

#include <stdio.h>

#include <stdlib.h>

#include "avcodec.h"

#if CONFIG_ZLIB

#include <zlib.h>

#endif

#include "libavutil/lzo.h"

typedef struct {

    AVFrame pic;

    int linelen, height, bpp;

    unsigned int decomp_size;

    unsigned char* decomp_buf;

} CamStudioContext;

static void copy_frame_default(AVFrame *f, const uint8_t *src,

                               int linelen, int height) {

    int i;

    uint8_t *dst = f->data[0];

    dst += (height - 1) * f->linesize[0];

    for (i = height; i; i--) {

        memcpy(dst, src, linelen);

        src += linelen;

        dst -= f->linesize[0];

    }

}

static void add_frame_default(AVFrame *f, const uint8_t *src,

                              int linelen, int height) {

    int i, j;

    uint8_t *dst = f->data[0];

    dst += (height - 1) * f->linesize[0];

    for (i = height; i; i--) {

        for (j = linelen; j; j--)

            *dst++ += *src++;

        dst -= f->linesize[0] + linelen;

    }

}

#ifndef WORDS_BIGENDIAN

#define copy_frame_16 copy_frame_default

#define copy_frame_32 copy_frame_default

#define add_frame_16 add_frame_default

#define add_frame_32 add_frame_default

#else

static void copy_frame_16(AVFrame *f, const uint8_t *src,

                          int linelen, int height) {

    int i, j;

    uint8_t *dst = f->data[0];

    dst += (height - 1) * f->linesize[0];

    for (i = height; i; i--) {

        for (j = linelen / 2; j; j--) {

          dst[0] = src[1];

          dst[1] = src[0];

          src += 2;

          dst += 2;

        }

        dst -= f->linesize[0] + linelen;

    }

}

static void copy_frame_32(AVFrame *f, const uint8_t *src,

                          int linelen, int height) {

    int i, j;

    uint8_t *dst = f->data[0];

    dst += (height - 1) * f->linesize[0];

    for (i = height; i; i--) {

        for (j = linelen / 4; j; j--) {

          dst[0] = src[3];

          dst[1] = src[2];

          dst[2] = src[1];

          dst[3] = src[0];

          src += 4;

          dst += 4;

        }

        dst -= f->linesize[0] + linelen;

    }

}

static void add_frame_16(AVFrame *f, const uint8_t *src,

                         int linelen, int height) {

    int i, j;

    uint8_t *dst = f->data[0];

    dst += (height - 1) * f->linesize[0];

    for (i = height; i; i--) {

        for (j = linelen / 2; j; j--) {

          dst[0] += src[1];

          dst[1] += src[0];

          src += 2;

          dst += 2;

        }

        dst -= f->linesize[0] + linelen;

    }

}

static void add_frame_32(AVFrame *f, const uint8_t *src,

                         int linelen, int height) {

    int i, j;

    uint8_t *dst = f->data[0];

    dst += (height - 1) * f->linesize[0];

    for (i = height; i; i--) {

        for (j = linelen / 4; j; j--) {

          dst[0] += src[3];

          dst[1] += src[2];

          dst[2] += src[1];

          dst[3] += src[0];

          src += 4;

          dst += 4;

        }

        dst -= f->linesize[0] + linelen;

    }

}

#endif

static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,

                        const uint8_t *buf, int buf_size) {

    CamStudioContext *c = avctx->priv_data;

    AVFrame *picture = data;

    if (buf_size < 2) {

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

        return -1;

    }

    if (c->pic.data[0])

        avctx->release_buffer(avctx, &c->pic);

    c->pic.reference = 1;

    c->pic.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_READABLE |

                          FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;

    if (avctx->get_buffer(avctx, &c->pic) < 0) {

        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

        return -1;

    }

    // decompress data

    switch ((buf[0] >> 1) & 7) {

        case 0: { // lzo compression

            int outlen = c->decomp_size, inlen = buf_size - 2;

            if (av_lzo1x_decode(c->decomp_buf, &outlen, &buf[2], &inlen))

                av_log(avctx, AV_LOG_ERROR, "error during lzo decompression\n");

            break;

        }

        case 1: { // zlib compression

#if CONFIG_ZLIB

            unsigned long dlen = c->decomp_size;

            if (uncompress(c->decomp_buf, &dlen, &buf[2], buf_size - 2) != Z_OK)

                av_log(avctx, AV_LOG_ERROR, "error during zlib decompression\n");

            break;

#else

            av_log(avctx, AV_LOG_ERROR, "compiled without zlib support\n");

            return -1;

#endif

        }

        default:

            av_log(avctx, AV_LOG_ERROR, "unknown compression\n");

            return -1;

    }

    // flip upside down, add difference frame

    if (buf[0] & 1) { // keyframe

        c->pic.pict_type = FF_I_TYPE;

        c->pic.key_frame = 1;

        switch (c->bpp) {

          case 16:

              copy_frame_16(&c->pic, c->decomp_buf, c->linelen, c->height);

              break;

          case 32:

              copy_frame_32(&c->pic, c->decomp_buf, c->linelen, c->height);

              break;

          default:

              copy_frame_default(&c->pic, c->decomp_buf, c->linelen, c->height);

        }

    } else {

        c->pic.pict_type = FF_P_TYPE;

        c->pic.key_frame = 0;

        switch (c->bpp) {

          case 16:

              add_frame_16(&c->pic, c->decomp_buf, c->linelen, c->height);

              break;

          case 32:

              add_frame_32(&c->pic, c->decomp_buf, c->linelen, c->height);

              break;

          default:

              add_frame_default(&c->pic, c->decomp_buf, c->linelen, c->height);

        }

    }

    *picture = c->pic;

    *data_size = sizeof(AVFrame);

    return buf_size;

}

static av_cold int decode_init(AVCodecContext *avctx) {

    CamStudioContext *c = avctx->priv_data;

    if (avcodec_check_dimensions(avctx, avctx->height, avctx->width) < 0) {

        return 1;

    }

    switch (avctx->bits_per_coded_sample) {

        case 16: avctx->pix_fmt = PIX_FMT_RGB555; break;

        case 24: avctx->pix_fmt = PIX_FMT_BGR24; break;

        case 32: avctx->pix_fmt = PIX_FMT_RGB32; break;

        default:

            av_log(avctx, AV_LOG_ERROR,

                   "CamStudio codec error: invalid depth %i bpp\n",

                   avctx->bits_per_coded_sample);

             return 1;

    }

    c->bpp = avctx->bits_per_coded_sample;

    c->pic.data[0] = NULL;

    c->linelen = avctx->width * avctx->bits_per_coded_sample / 8;

    c->height = avctx->height;

    c->decomp_size = c->height * c->linelen;

    c->decomp_buf = av_malloc(c->decomp_size + AV_LZO_OUTPUT_PADDING);

    if (!c->decomp_buf) {

        av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");

        return 1;

    }

    return 0;

}

static av_cold int decode_end(AVCodecContext *avctx) {

    CamStudioContext *c = avctx->priv_data;

    av_freep(&c->decomp_buf);

    if (c->pic.data[0])

        avctx->release_buffer(avctx, &c->pic);

    return 0;

}

AVCodec cscd_decoder = {

    "camstudio",

    CODEC_TYPE_VIDEO,

    CODEC_ID_CSCD,

    sizeof(CamStudioContext),

    decode_init,

    NULL,

    decode_end,

    decode_frame,

    CODEC_CAP_DR1,

    .long_name = NULL_IF_CONFIG_SMALL("CamStudio"),

};