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make ModeAlphabet read-only and use a custom mode alphabet 

only locally in unpack_modes()

Originally committed as revision 13964 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Stefan Gehrer 2008-06-25 14:14:58 +00:00
parent 181782ae46
commit e8e4743591
1 changed files with 15 additions and 9 deletions
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24
libavcodec/vp3.c
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@ -172,11 +172,8 @@ typedef struct Vp3Fragment {
#define MODE_COPY 8
/* There are 6 preset schemes, plus a free-form scheme */
static int ModeAlphabet[7][CODING_MODE_COUNT] =
static const int ModeAlphabet[6][CODING_MODE_COUNT] =
{
/* this is the custom scheme */
{ 0, 0, 0, 0, 0, 0, 0, 0 },
/* scheme 1: Last motion vector dominates */
{ MODE_INTER_LAST_MV, MODE_INTER_PRIOR_LAST,
MODE_INTER_PLUS_MV, MODE_INTER_NO_MV,
@ -877,6 +874,7 @@ static int unpack_modes(Vp3DecodeContext *s, GetBitContext *gb)
int current_macroblock;
int current_fragment;
int coding_mode;
int custom_mode_alphabet[CODING_MODE_COUNT];
debug_vp3(" vp3: unpacking encoding modes\n");
@ -896,12 +894,17 @@ static int unpack_modes(Vp3DecodeContext *s, GetBitContext *gb)
if (scheme == 0) {
debug_modes(" custom mode alphabet ahead:\n");
for (i = 0; i < 8; i++)
ModeAlphabet[scheme][get_bits(gb, 3)] = i;
custom_mode_alphabet[get_bits(gb, 3)] = i;
}
for (i = 0; i < 8; i++)
debug_modes(" mode[%d][%d] = %d\n", scheme, i,
ModeAlphabet[scheme][i]);
for (i = 0; i < 8; i++) {
if(scheme)
debug_modes(" mode[%d][%d] = %d\n", scheme, i,
ModeAlphabet[scheme-1][i]);
else
debug_modes(" mode[0][%d] = %d\n", i,
custom_mode_alphabet[i]);
}
/* iterate through all of the macroblocks that contain 1 or more
* coded fragments */
@ -921,8 +924,11 @@ static int unpack_modes(Vp3DecodeContext *s, GetBitContext *gb)
/* mode 7 means get 3 bits for each coding mode */
if (scheme == 7)
coding_mode = get_bits(gb, 3);
else if(scheme == 0)
coding_mode = custom_mode_alphabet
[get_vlc2(gb, s->mode_code_vlc.table, 3, 3)];
else
coding_mode = ModeAlphabet[scheme]
coding_mode = ModeAlphabet[scheme-1]
[get_vlc2(gb, s->mode_code_vlc.table, 3, 3)];
s->macroblock_coding[current_macroblock] = coding_mode;