diff options
author | 2002-01-04 05:57:00 +0000 | |
---|---|---|
committer | 2002-01-04 05:57:00 +0000 | |
commit | 0d8c217a2fc3ea543d559e6202b3eb3e1e6f614c (patch) | |
tree | 2643a25ebb64cfd5cfa8737d82a531800e549e7c /cyuv.c | |
parent | 69c1559ccb3cb3f30247354229af530f7f162ff1 (diff) |
integrated Tim Ferguson's native CYUV decoder
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@3970 b3059339-0415-0410-9bf9-f77b7e298cf2
Diffstat (limited to 'cyuv.c')
-rw-r--r-- | cyuv.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/cyuv.c b/cyuv.c new file mode 100644 index 0000000000..86d597af7d --- /dev/null +++ b/cyuv.c @@ -0,0 +1,85 @@ +/* ------------------------------------------------------------------------ + * Creative YUV Video Decoder + * + * Dr. Tim Ferguson, 2001. + * For more details on the algorithm: + * http://www.csse.monash.edu.au/~timf/videocodec.html + * + * This is a very simple predictive coder. A video frame is coded in YUV411 + * format. The first pixel of each scanline is coded using the upper four + * bits of its absolute value. Subsequent pixels for the scanline are coded + * using the difference between the last pixel and the current pixel (DPCM). + * The DPCM values are coded using a 16 entry table found at the start of the + * frame. Thus four bits per component are used and are as follows: + * UY VY YY UY VY YY UY VY... + * This code assumes the frame width will be a multiple of four pixels. This + * should probably be fixed. + * ------------------------------------------------------------------------ */ +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/types.h> +#include <unistd.h> + +/* ------------------------------------------------------------------------ + * This function decodes a buffer containing a CYUV encoded frame. + * + * buf - the input buffer to be decoded + * size - the size of the input buffer + * frame - the output frame buffer (UYVY format) + * width - the width of the output frame + * height - the height of the output frame + * bit_per_pixel - ignored for now: may be used later for conversions. + */ +void decode_cyuv(unsigned char *buf, int size, unsigned char *frame, int width, int height, int bit_per_pixel) +{ +int i, xpos, ypos, cur_Y = 0, cur_U = 0, cur_V = 0; +char *delta_y_tbl, *delta_c_tbl, *ptr; + + delta_y_tbl = buf + 16; + delta_c_tbl = buf + 32; + ptr = buf + (16 * 3); + + for(ypos = 0; ypos < height; ypos++) + for(xpos = 0; xpos < width; xpos += 4) + { + if(xpos == 0) /* first pixels in scanline */ + { + cur_U = *(ptr++); + cur_Y = (cur_U & 0x0f) << 4; + cur_U = cur_U & 0xf0; + *frame++ = cur_U; + *frame++ = cur_Y; + + cur_V = *(ptr++); + cur_Y = (cur_Y + delta_y_tbl[cur_V & 0x0f]) & 0xff; + cur_V = cur_V & 0xf0; + *frame++ = cur_V; + *frame++ = cur_Y; + } + else /* subsequent pixels in scanline */ + { + i = *(ptr++); + cur_U = (cur_U + delta_c_tbl[i >> 4]) & 0xff; + cur_Y = (cur_Y + delta_y_tbl[i & 0x0f]) & 0xff; + *frame++ = cur_U; + *frame++ = cur_Y; + + i = *(ptr++); + cur_V = (cur_V + delta_c_tbl[i >> 4]) & 0xff; + cur_Y = (cur_Y + delta_y_tbl[i & 0x0f]) & 0xff; + *frame++ = cur_V; + *frame++ = cur_Y; + } + + i = *(ptr++); + cur_Y = (cur_Y + delta_y_tbl[i & 0x0f]) & 0xff; + *frame++ = cur_U; + *frame++ = cur_Y; + + cur_Y = (cur_Y + delta_y_tbl[i >> 4]) & 0xff; + *frame++ = cur_V; + *frame++ = cur_Y; + } +} + |