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/****************************************************************************** |
/****************************************************************************** |
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* * |
* * |
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* bitstream.c * |
* mbcoding.c * |
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* * |
* * |
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* Copyright (C) 2001 - Peter Ross <pross@cs.rmit.edu.au> * |
* Copyright (C) 2002 - Michael Militzer <isibaar@xvid.org> * |
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* * |
* * |
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* For more information visit the XviD homepage: http://www.xvid.org * |
* For more information visit the XviD homepage: http://www.xvid.org * |
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* * |
* * |
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* * |
* * |
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* Revision history: * |
* Revision history: * |
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* * |
* * |
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* 14.04.2002 bframe encoding |
* 14.04.2002 bframe encoding * |
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* 08.03.2002 initial version; isibaar * |
* 08.03.2002 initial version; isibaar * |
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* * |
* * |
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******************************************************************************/ |
******************************************************************************/ |
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#define ABS(X) (((X)>0)?(X):-(X)) |
#define ABS(X) (((X)>0)?(X):-(X)) |
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#define CLIP(X,A) (X > A) ? (A) : (X) |
#define CLIP(X,A) (X > A) ? (A) : (X) |
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VLC intra_table[65536]; |
VLC intra_table[524032]; |
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VLC inter_table[65536]; |
VLC inter_table[524032]; |
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VLC DCT3Dintra[4096]; |
VLC DCT3Dintra[4096]; |
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VLC DCT3Dinter[4096]; |
VLC DCT3Dinter[4096]; |
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static int16_t clip_table[4096]; |
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void init_vlc_tables(void) |
void init_vlc_tables(void) |
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{ |
{ |
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vlc[0] = intra_table; |
vlc[0] = intra_table; |
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vlc[1] = inter_table; |
vlc[1] = inter_table; |
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// initialize the clipping table |
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for(i = -2048; i < 2048; i++) { |
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clip_table[i + 2048] = i; |
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if(i < -255) |
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clip_table[i + 2048] = -255; |
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if(i > 255) |
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clip_table[i + 2048] = 255; |
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} |
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// generate encoding vlc lookup tables |
// generate encoding vlc lookup tables |
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// the lookup table idea is taken from the excellent fame project by Vivien Chapellier |
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for(i = 0; i < 4; i++) { |
for(i = 0; i < 4; i++) { |
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intra = i % 2; |
intra = i % 2; |
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last = i / 2; |
last = i / 2; |
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coeff_ptr = coeff_vlc[last + 2 * intra]; |
coeff_ptr = coeff_vlc[last + 2 * intra]; |
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for(k = -255; k < 256; k++) { // level |
for(k = -2047; k < 2048; k++) { // level |
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int8_t *max_level_ptr = max_level[last + 2 * intra]; |
int8_t *max_level_ptr = max_level[last + 2 * intra]; |
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int8_t *max_run_ptr = max_run[last + 2 * intra]; |
int8_t *max_run_ptr = max_run[last + 2 * intra]; |
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j = intra; |
j = intra; |
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last = intra; |
last = intra; |
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while((v = qcoeff[zigzag[j]]) == 0) j++; |
while(j < 64 && (v = qcoeff[zigzag[j]]) == 0) j++; |
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do { |
do { |
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// count zeroes |
vlc = table + 64 * 2047 + (v << 6) + j - last; |
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vlc = table + 64*255 + (clip_table[2048+v] << 6) + j - last; |
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last = ++j; |
last = ++j; |
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// count zeroes |
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while(j < 64 && (v = qcoeff[zigzag[j]]) == 0) j++; |
while(j < 64 && (v = qcoeff[zigzag[j]]) == 0) j++; |
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// write code |
// write code |
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if(j != 64) { |
if(j != 64) { |
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BitstreamPutBits(bs, vlc->code, vlc->len); |
BitstreamPutBits(bs, vlc->code, vlc->len); |
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} else { |
} else { |
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vlc += 64*511; |
vlc += 64 * 4095; |
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BitstreamPutBits(bs, vlc->code, vlc->len); |
BitstreamPutBits(bs, vlc->code, vlc->len); |
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break; |
break; |
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} |
} |