mirror of https://github.com/FFmpeg/FFmpeg.git
Originally committed as revision 8598 to svn://svn.ffmpeg.org/ffmpeg/trunkpull/126/head
Michael Niedermayer
18 years ago
parent
b56a8374b1
commit
1ca286e194
4 changed files with 132 additions and 58 deletions
@ -0,0 +1,96 @@ |
|||||||
|
/*
|
||||||
|
* RLE encoder |
||||||
|
* Copyright (c) 2007 Bobby Bingham |
||||||
|
* |
||||||
|
* 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 "avcodec.h" |
||||||
|
#include "rle.h" |
||||||
|
|
||||||
|
/**
|
||||||
|
* Count up to 127 consecutive pixels which are either all the same or |
||||||
|
* all differ from the previous and next pixels. |
||||||
|
* @param start Pointer to the first pixel |
||||||
|
* @param len Maximum number of pixels |
||||||
|
* @param bpp Bytes per pixel |
||||||
|
* @param same 1 if searching for identical pixel values. 0 for differing |
||||||
|
* @return Number of matching consecutive pixels found |
||||||
|
*/ |
||||||
|
static int count_pixels(const uint8_t *start, int len, int bpp, int same) |
||||||
|
{ |
||||||
|
const uint8_t *pos; |
||||||
|
int count = 1; |
||||||
|
|
||||||
|
for(pos = start + bpp; count < FFMIN(128, len); pos += bpp, count ++) { |
||||||
|
if(same != !memcmp(pos-bpp, pos, bpp)) { |
||||||
|
if(!same) { |
||||||
|
/* if bpp == 1, then 0 1 1 0 is more efficiently encoded as a single
|
||||||
|
* raw block of pixels. for larger bpp, RLE is as good or better */ |
||||||
|
if(bpp == 1 && count + 1 < FFMIN(128, len) && *pos != *(pos+1)) |
||||||
|
continue; |
||||||
|
|
||||||
|
/* if RLE can encode the next block better than as a raw block,
|
||||||
|
* back up and leave _all_ the identical pixels for RLE */ |
||||||
|
count --; |
||||||
|
} |
||||||
|
break; |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
return count; |
||||||
|
} |
||||||
|
|
||||||
|
/**
|
||||||
|
* RLE compress the row, with maximum size of out_size. Value before repeated bytes is (count ^ xor) + add. |
||||||
|
* @param outbuf Output buffer |
||||||
|
* @param out_size Maximum output size |
||||||
|
* @param ptr Input buffer |
||||||
|
* @param bpp Bytes per pixel |
||||||
|
* @param w Image width |
||||||
|
* @return Size of output in bytes, or -1 if larger than out_size |
||||||
|
*/ |
||||||
|
int ff_rle_encode(uint8_t *outbuf, int out_size, const uint8_t *ptr , int bpp, int w, int8_t add, uint8_t xor) |
||||||
|
{ |
||||||
|
int count, x; |
||||||
|
uint8_t *out; |
||||||
|
|
||||||
|
out = outbuf; |
||||||
|
|
||||||
|
|
||||||
|
for(x = 0; x < w; x += count) { |
||||||
|
/* see if we can encode the next set of pixels with RLE */ |
||||||
|
if((count = count_pixels(ptr, w-x, bpp, 1)) > 1) { |
||||||
|
if(out + bpp + 1 > outbuf + out_size) return -1; |
||||||
|
*out++ = (count ^ xor) + add; |
||||||
|
memcpy(out, ptr, bpp); |
||||||
|
out += bpp; |
||||||
|
} else { |
||||||
|
/* fall back on uncompressed */ |
||||||
|
count = count_pixels(ptr, w-x, bpp, 0); |
||||||
|
*out++ = count - 1; |
||||||
|
|
||||||
|
if(out + bpp*count > outbuf + out_size) return -1; |
||||||
|
memcpy(out, ptr, bpp * count); |
||||||
|
out += bpp * count; |
||||||
|
} |
||||||
|
|
||||||
|
ptr += count * bpp; |
||||||
|
} |
||||||
|
|
||||||
|
return out - outbuf; |
||||||
|
} |
||||||
@ -0,0 +1,27 @@ |
|||||||
|
/*
|
||||||
|
* RLE encoder |
||||||
|
* |
||||||
|
* 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 |
||||||
|
* |
||||||
|
*/ |
||||||
|
|
||||||
|
#ifndef RLE_H |
||||||
|
#define RLE_H |
||||||
|
|
||||||
|
int ff_rle_encode(uint8_t *outbuf, int out_size, const uint8_t *inbuf, int bpp, int w, int8_t add, uint8_t xor); |
||||||
|
|
||||||
|
#endif /* RLE_H */ |
||||||
Loading…
Reference in new issue