www.pudn.com > ffmpeg_src2007.rar > 8bps.c

/* 
 * Quicktime Planar RGB (8BPS) Video Decoder 
 * Copyright (C) 2003 Roberto Togni 
 * 
 * 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 
 * 
 */ 
 
/** 
 * @file 8bps.c 
 * QT 8BPS Video Decoder by Roberto Togni  
 * For more information about the 8BPS format, visit: 
 *   http://www.pcisys.net/~melanson/codecs/ 
 * 
 * Supports: PAL8 (RGB 8bpp, paletted) 
 *         : BGR24 (RGB 24bpp) (can also output it as RGBA32) 
 *         : RGBA32 (RGB 32bpp, 4th plane is probably alpha and it's ignored) 
 * 
 */ 
 
#include  
#include  
 
#include "common.h" 
#include "avcodec.h" 
 
 
const enum PixelFormat pixfmt_rgb24[] = {PIX_FMT_BGR24, PIX_FMT_RGBA32, -1}; 
 
/* 
 * Decoder context 
 */ 
typedef struct EightBpsContext { 
 
        AVCodecContext *avctx; 
        AVFrame pic; 
 
        unsigned char planes; 
        unsigned char planemap[4]; 
} EightBpsContext; 
 
 
/* 
 * 
 * Decode a frame 
 * 
 */ 
static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, uint8_t *buf, int buf_size) 
{ 
        EightBpsContext * const c = (EightBpsContext *)avctx->priv_data; 
        unsigned char *encoded = (unsigned char *)buf; 
        unsigned char *pixptr, *pixptr_end; 
        unsigned int height = avctx->height; // Real image height 
        unsigned int dlen, p, row; 
        unsigned char *lp, *dp; 
        unsigned char count; 
        unsigned int px_inc; 
        unsigned int planes = c->planes; 
        unsigned char *planemap = c->planemap; 
 
        if(c->pic.data[0]) 
                avctx->release_buffer(avctx, &c->pic); 
 
        c->pic.reference = 0; 
        c->pic.buffer_hints = FF_BUFFER_HINTS_VALID; 
        if(avctx->get_buffer(avctx, &c->pic) < 0){ 
                av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 
                return -1; 
        } 
 
        /* Set data pointer after line lengths */ 
        dp = encoded + planes * (height << 1); 
 
        /* Ignore alpha plane, don't know what to do with it */ 
        if (planes == 4) 
                planes--; 
 
        px_inc = planes + (avctx->pix_fmt == PIX_FMT_RGBA32); 
 
        for (p = 0; p < planes; p++) { 
                /* Lines length pointer for this plane */ 
                lp = encoded + p * (height << 1); 
 
                /* Decode a plane */ 
                for(row = 0; row < height; row++) { 
                        pixptr = c->pic.data[0] + row * c->pic.linesize[0] + planemap[p]; 
                        pixptr_end = pixptr + c->pic.linesize[0]; 
                        dlen = be2me_16(*(unsigned short *)(lp+row*2)); 
                        /* Decode a row of this plane */ 
                        while(dlen > 0) { 
                                if(dp + 1 >= buf+buf_size) return -1; 
                                if ((count = *dp++) <= 127) { 
                                        count++; 
                                        dlen -= count + 1; 
                                        if (pixptr + count * px_inc > pixptr_end) 
                                            break; 
                                        if(dp + count > buf+buf_size) return -1; 
                                        while(count--) { 
                                                *pixptr = *dp++; 
                                                pixptr += px_inc; 
                                        } 
                                } else { 
                                        count = 257 - count; 
                                        if (pixptr + count * px_inc > pixptr_end) 
                                            break; 
                                        while(count--) { 
                                                *pixptr = *dp; 
                                                pixptr += px_inc; 
                                        } 
                                        dp++; 
                                        dlen -= 2; 
                                } 
                        } 
                } 
        } 
 
        if (avctx->palctrl) { 
                memcpy (c->pic.data[1], avctx->palctrl->palette, AVPALETTE_SIZE); 
                if (avctx->palctrl->palette_changed) { 
                        c->pic.palette_has_changed = 1; 
                        avctx->palctrl->palette_changed = 0; 
                } else 
                        c->pic.palette_has_changed = 0; 
        } 
 
        *data_size = sizeof(AVFrame); 
        *(AVFrame*)data = c->pic; 
 
        /* always report that the buffer was completely consumed */ 
        return buf_size; 
} 
 
 
/* 
 * 
 * Init 8BPS decoder 
 * 
 */ 
static int decode_init(AVCodecContext *avctx) 
{ 
        EightBpsContext * const c = (EightBpsContext *)avctx->priv_data; 
 
        c->avctx = avctx; 
        avctx->has_b_frames = 0; 
 
        c->pic.data[0] = NULL; 
 
    if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) { 
        return 1; 
    } 
 
        switch (avctx->bits_per_sample) { 
                case 8: 
                        avctx->pix_fmt = PIX_FMT_PAL8; 
                        c->planes = 1; 
                        c->planemap[0] = 0; // 1st plane is palette indexes 
                        if (avctx->palctrl == NULL) { 
                                av_log(avctx, AV_LOG_ERROR, "Error: PAL8 format but no palette from demuxer.\n"); 
                                return -1; 
                        } 
                        break; 
                case 24: 
                        avctx->pix_fmt = avctx->get_format(avctx, pixfmt_rgb24); 
                        c->planes = 3; 
                        c->planemap[0] = 2; // 1st plane is red 
                        c->planemap[1] = 1; // 2nd plane is green 
                        c->planemap[2] = 0; // 3rd plane is blue 
                        break; 
                case 32: 
                        avctx->pix_fmt = PIX_FMT_RGBA32; 
                        c->planes = 4; 
#ifdef WORDS_BIGENDIAN 
                        c->planemap[0] = 1; // 1st plane is red 
                        c->planemap[1] = 2; // 2nd plane is green 
                        c->planemap[2] = 3; // 3rd plane is blue 
                        c->planemap[3] = 0; // 4th plane is alpha??? 
#else 
                        c->planemap[0] = 2; // 1st plane is red 
                        c->planemap[1] = 1; // 2nd plane is green 
                        c->planemap[2] = 0; // 3rd plane is blue 
                        c->planemap[3] = 3; // 4th plane is alpha??? 
#endif 
                        break; 
                default: 
                        av_log(avctx, AV_LOG_ERROR, "Error: Unsupported color depth: %u.\n", avctx->bits_per_sample); 
                        return -1; 
        } 
 
  return 0; 
} 
 
 
 
 
/* 
 * 
 * Uninit 8BPS decoder 
 * 
 */ 
static int decode_end(AVCodecContext *avctx) 
{ 
        EightBpsContext * const c = (EightBpsContext *)avctx->priv_data; 
 
        if (c->pic.data[0]) 
                avctx->release_buffer(avctx, &c->pic); 
 
        return 0; 
} 
 
 
 
AVCodec eightbps_decoder = { 
        "8bps", 
        CODEC_TYPE_VIDEO, 
        CODEC_ID_8BPS, 
        sizeof(EightBpsContext), 
        decode_init, 
        NULL, 
        decode_end, 
        decode_frame, 
        CODEC_CAP_DR1, 
};