1194 |
{2, 2}, {2, 2}, {1, 2}, {1, 2}, |
{2, 2}, {2, 2}, {1, 2}, {1, 2}, |
1195 |
}; |
}; |
1196 |
|
|
|
static __inline int |
|
|
get_coeff(Bitstream * bs, |
|
|
int *run, |
|
|
int *last, |
|
|
int intra, |
|
|
int short_video_header) |
|
|
{ |
|
|
|
|
|
uint32_t mode; |
|
|
const VLC *tab; |
|
|
int32_t level; |
|
|
|
|
|
if (short_video_header) // inter-VLCs will be used for both intra and inter blocks |
|
|
intra = 0; |
|
|
|
|
|
tab = &DCT3D[intra][BitstreamShowBits(bs, 12)]; |
|
|
|
|
|
if (tab->code == -1) |
|
|
goto error; |
|
|
|
|
|
BitstreamSkip(bs, tab->len); |
|
|
|
|
|
if (tab->code != ESCAPE) { |
|
|
if (!intra) { |
|
|
*run = (tab->code >> 4) & 255; |
|
|
level = tab->code & 15; |
|
|
*last = (tab->code >> 12) & 1; |
|
|
} else { |
|
|
*run = (tab->code >> 8) & 255; |
|
|
level = tab->code & 255; |
|
|
*last = (tab->code >> 16) & 1; |
|
|
} |
|
|
return BitstreamGetBit(bs) ? -level : level; |
|
|
} |
|
|
|
|
|
if (short_video_header) { |
|
|
// escape mode 4 - H.263 type, only used if short_video_header = 1 |
|
|
*last = BitstreamGetBit(bs); |
|
|
*run = BitstreamGetBits(bs, 6); |
|
|
level = BitstreamGetBits(bs, 8); |
|
|
|
|
|
if (level == 0 || level == 128) |
|
|
DEBUG1("Illegal LEVEL for ESCAPE mode 4:", level); |
|
|
|
|
|
return (level >= 128 ? -(256 - level) : level); |
|
|
} |
|
|
|
|
|
mode = BitstreamShowBits(bs, 2); |
|
|
|
|
|
if (mode < 3) { |
|
|
BitstreamSkip(bs, (mode == 2) ? 2 : 1); |
|
|
|
|
|
tab = &DCT3D[intra][BitstreamShowBits(bs, 12)]; |
|
|
if (tab->code == -1) |
|
|
goto error; |
|
|
|
|
|
BitstreamSkip(bs, tab->len); |
|
|
|
|
|
if (!intra) { |
|
|
*run = (tab->code >> 4) & 255; |
|
|
level = tab->code & 15; |
|
|
*last = (tab->code >> 12) & 1; |
|
|
} else { |
|
|
*run = (tab->code >> 8) & 255; |
|
|
level = tab->code & 255; |
|
|
*last = (tab->code >> 16) & 1; |
|
|
} |
|
|
|
|
|
if (mode < 2) // first escape mode, level is offset |
|
|
level += max_level[*last + (!intra << 1)][*run]; // need to add back the max level |
|
|
else if (mode == 2) // second escape mode, run is offset |
|
|
*run += max_run[*last + (!intra << 1)][level] + 1; |
|
|
|
|
|
return BitstreamGetBit(bs) ? -level : level; |
|
|
} |
|
|
// third escape mode - fixed length codes |
|
|
BitstreamSkip(bs, 2); |
|
|
*last = BitstreamGetBits(bs, 1); |
|
|
*run = BitstreamGetBits(bs, 6); |
|
|
BitstreamSkip(bs, 1); // marker |
|
|
level = BitstreamGetBits(bs, 12); |
|
|
BitstreamSkip(bs, 1); // marker |
|
|
|
|
|
return (level & 0x800) ? (level | (-1 ^ 0xfff)) : level; |
|
|
|
|
|
error: |
|
|
*run = VLC_ERROR; |
|
|
return 0; |
|
|
|
|
|
} |
|
|
|
|
1197 |
#endif /* _VLC_CODES_H */ |
#endif /* _VLC_CODES_H */ |