PeerStreamer

/*

 * LCL (LossLess Codec Library) Codec

 * Copyright (c) 2002-2004 Roberto Togni

 *

 * 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

 */

/**

 * @file

 * LCL (LossLess Codec Library) Video Codec

 * Decoder for MSZH and ZLIB codecs

 * Experimental encoder for ZLIB RGB24

 *

 * Fourcc: MSZH, ZLIB

 *

 * Original Win32 dll:

 * Ver2.23 By Kenji Oshima 2000.09.20

 * avimszh.dll, avizlib.dll

 *

 * A description of the decoding algorithm can be found here:

 *   http://www.pcisys.net/~melanson/codecs

 *

 * Supports: BGR24 (RGB 24bpp)

 *

 */

#include <stdio.h>

#include <stdlib.h>

#include "avcodec.h"

#include "lcl.h"

#include <zlib.h>

/*

 * Decoder context

 */

typedef struct LclEncContext {

    AVCodecContext *avctx;

    AVFrame pic;

    // Image type

    int imgtype;

    // Compression type

    int compression;

    // Flags

    int flags;

    z_stream zstream;

} LclEncContext;

/*

 *

 * Encode a frame

 *

 */

static int encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){

    LclEncContext *c = avctx->priv_data;

    AVFrame *pict = data;

    AVFrame * const p = &c->pic;

    int i;

    int zret; // Zlib return code

    *p = *pict;

    p->pict_type= AV_PICTURE_TYPE_I;

    p->key_frame= 1;

    if(avctx->pix_fmt != PIX_FMT_BGR24){

        av_log(avctx, AV_LOG_ERROR, "Format not supported!\n");

        return -1;

    }

    zret = deflateReset(&c->zstream);

    if (zret != Z_OK) {

        av_log(avctx, AV_LOG_ERROR, "Deflate reset error: %d\n", zret);

        return -1;

    }

    c->zstream.next_out = buf;

    c->zstream.avail_out = buf_size;

    for(i = avctx->height - 1; i >= 0; i--) {

        c->zstream.next_in = p->data[0]+p->linesize[0]*i;

        c->zstream.avail_in = avctx->width*3;

        zret = deflate(&c->zstream, Z_NO_FLUSH);

        if (zret != Z_OK) {

            av_log(avctx, AV_LOG_ERROR, "Deflate error: %d\n", zret);

            return -1;

        }

    }

    zret = deflate(&c->zstream, Z_FINISH);

    if (zret != Z_STREAM_END) {

        av_log(avctx, AV_LOG_ERROR, "Deflate error: %d\n", zret);

        return -1;

    }

    return c->zstream.total_out;

}

/*

 *

 * Init lcl encoder

 *

 */

static av_cold int encode_init(AVCodecContext *avctx)

{

    LclEncContext *c = avctx->priv_data;

    int zret; // Zlib return code

    c->avctx= avctx;

    assert(avctx->width && avctx->height);

    avctx->extradata= av_mallocz(8);

    avctx->coded_frame= &c->pic;

    // Will be user settable someday

    c->compression = 6;

    c->flags = 0;

    c->imgtype = IMGTYPE_RGB24;

    avctx->bits_per_coded_sample= 24;

    avctx->extradata[0]= 4;

    avctx->extradata[1]= 0;

    avctx->extradata[2]= 0;

    avctx->extradata[3]= 0;

    avctx->extradata[4]= c->imgtype;

    avctx->extradata[5]= c->compression;

    avctx->extradata[6]= c->flags;

    avctx->extradata[7]= CODEC_ZLIB;

    c->avctx->extradata_size= 8;

    c->zstream.zalloc = Z_NULL;

    c->zstream.zfree = Z_NULL;

    c->zstream.opaque = Z_NULL;

    zret = deflateInit(&c->zstream, c->compression);

    if (zret != Z_OK) {

        av_log(avctx, AV_LOG_ERROR, "Deflate init error: %d\n", zret);

        return 1;

    }

    return 0;

}

/*

 *

 * Uninit lcl encoder

 *

 */

static av_cold int encode_end(AVCodecContext *avctx)

{

    LclEncContext *c = avctx->priv_data;

    av_freep(&avctx->extradata);

    deflateEnd(&c->zstream);

    return 0;

}

AVCodec ff_zlib_encoder = {

    "zlib",

    AVMEDIA_TYPE_VIDEO,

    CODEC_ID_ZLIB,

    sizeof(LclEncContext),

    encode_init,

    encode_frame,

    encode_end,

    .pix_fmts = (const enum PixelFormat[]) { PIX_FMT_BGR24, PIX_FMT_NONE },

    .long_name = NULL_IF_CONFIG_SMALL("LCL (LossLess Codec Library) ZLIB"),

};