PeerStreamer

/*

 * BMP image format

 * Copyright (c) 2005 Mans Rullgard

 *

 * This library 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 of the License, or (at your option) any later version.

 *

 * This library 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 this library; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "avcodec.h"

#include "bitstream.h"

#include "bswap.h"

typedef struct BMPContext {

    AVFrame picture;

} BMPContext;

#define BMP_RGB       0

#define BMP_RLE8      1

#define BMP_RLE4      2

#define BMP_BITFIELDS 3

#define read16(bits) bswap_16(get_bits(bits, 16))

#define read32(bits) bswap_32(get_bits_long(bits, 32))

static int bmp_decode_init(AVCodecContext *avctx){

    BMPContext *s = avctx->priv_data;

    avcodec_get_frame_defaults((AVFrame*)&s->picture);

    avctx->coded_frame = (AVFrame*)&s->picture;

    return 0;

}

static int bmp_decode_frame(AVCodecContext *avctx,

                            void *data, int *data_size,

                            uint8_t *buf, int buf_size)

{

    BMPContext *s = avctx->priv_data;

    AVFrame *picture = data;

    AVFrame *p = &s->picture;

    GetBitContext bits;

    unsigned int fsize, hsize;

    int width, height;

    unsigned int depth;

    unsigned int comp;

    unsigned int ihsize;

    int i, j, n, linesize;

    uint32_t rgb[3];

    uint8_t *ptr;

    int dsize;

    if(buf_size < 14){

        av_log(avctx, AV_LOG_ERROR, "buf size too small (%d)\n", buf_size);

        return -1;

    }

    init_get_bits(&bits, buf, buf_size);

    if(get_bits(&bits, 16) != 0x424d){ /* 'BM' */

        av_log(avctx, AV_LOG_ERROR, "bad magic number\n");

        return -1;

    }

    fsize = read32(&bits);

    if(buf_size < fsize){

        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",

               buf_size, fsize);

        return -1;

    }

    skip_bits(&bits, 16);       /* reserved1 */

    skip_bits(&bits, 16);       /* reserved2 */

    hsize = read32(&bits); /* header size */

    if(fsize <= hsize){

        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",

               fsize, hsize);

        return -1;

    }

    ihsize = read32(&bits);       /* more header size */

    if(ihsize + 14 > hsize){

        av_log(avctx, AV_LOG_ERROR, "invalid header size %d\n", hsize);

        return -1;

    }

    width = read32(&bits);

    height = read32(&bits);

    if(read16(&bits) != 1){ /* planes */

        av_log(avctx, AV_LOG_ERROR, "invalid BMP header\n");

        return -1;

    }

    depth = read16(&bits);

    if(ihsize > 16)

        comp = read32(&bits);

    else

        comp = BMP_RGB;

    if(comp != BMP_RGB && comp != BMP_BITFIELDS){

        av_log(avctx, AV_LOG_ERROR, "BMP coding %d not supported\n", comp);

        return -1;

    }

    if(comp == BMP_BITFIELDS){

        skip_bits(&bits, 20 * 8);

        rgb[0] = read32(&bits);

        rgb[1] = read32(&bits);

        rgb[2] = read32(&bits);

    }

    avctx->codec_id = CODEC_ID_BMP;

    avctx->width = width;

    avctx->height = height > 0? height: -height;

    avctx->pix_fmt = PIX_FMT_NONE;

    switch(depth){

    case 32:

        if(comp == BMP_BITFIELDS){

            rgb[0] = (rgb[0] >> 15) & 3;

            rgb[1] = (rgb[1] >> 15) & 3;

            rgb[2] = (rgb[2] >> 15) & 3;

            if(rgb[0] + rgb[1] + rgb[2] != 3 ||

               rgb[0] == rgb[1] || rgb[0] == rgb[2] || rgb[1] == rgb[2]){

                break;

            }

        } else {

            rgb[0] = 2;

            rgb[1] = 1;

            rgb[2] = 0;

        }

        avctx->pix_fmt = PIX_FMT_BGR24;

        break;

    case 24:

        avctx->pix_fmt = PIX_FMT_BGR24;

        break;

    case 16:

        if(comp == BMP_RGB)

            avctx->pix_fmt = PIX_FMT_RGB555;

        break;

    default:

        av_log(avctx, AV_LOG_ERROR, "depth %d not supported\n", depth);

        return -1;

    }

    if(avctx->pix_fmt == PIX_FMT_NONE){

        av_log(avctx, AV_LOG_ERROR, "unsupported pixel format\n");

        return -1;

    }

    p->reference = 0;

    if(avctx->get_buffer(avctx, p) < 0){

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

        return -1;

    }

    p->pict_type = FF_I_TYPE;

    p->key_frame = 1;

    buf += hsize;

    dsize = buf_size - hsize;

    n = avctx->width * (depth / 8);

    if(n * avctx->height > dsize){

        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",

               dsize, n * avctx->height);

        return -1;

    }

    if(height > 0){

        ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];

        linesize = -p->linesize[0];

    } else {

        ptr = p->data[0];

        linesize = p->linesize[0];

    }

    switch(depth){

    case 24:

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

            memcpy(ptr, buf, n);

            buf += n;

            ptr += linesize;

        }

        break;

    case 16:

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

            uint16_t *src = (uint16_t *) buf;

            uint16_t *dst = (uint16_t *) ptr;

            for(j = 0; j < avctx->width; j++)

                *dst++ = le2me_16(*src++);

            buf += n;

            ptr += linesize;

        }

        break;

    case 32:

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

            uint8_t *src = buf;

            uint8_t *dst = ptr;

            for(j = 0; j < avctx->width; j++){

                dst[0] = src[rgb[2]];

                dst[1] = src[rgb[1]];

                dst[2] = src[rgb[0]];

                dst += 3;

                src += 4;

            }

            buf += n;

            ptr += linesize;

        }

        break;

    default:

        av_log(avctx, AV_LOG_ERROR, "BMP decoder is broken\n");

        return -1;

    }

    *picture = s->picture;

    *data_size = sizeof(AVPicture);

    return buf_size;

}

AVCodec bmp_decoder = {

    "bmp",

    CODEC_TYPE_VIDEO,

    CODEC_ID_BMP,

    sizeof(BMPContext),

    bmp_decode_init,

    NULL,

    NULL,

    bmp_decode_frame

};