add a -partition_limit option to limit the number of bits used by intra4x4

Although it degrades quality, this option is useful to avoid the 512k
limit for partition #0.
If not enough to reach the lower bound of 4bits per macroblock header,
one should also limit the number of segments used (down to -segments 1)

See the man file for extra details.

Change-Id: Ia59ffac13176c85b809ddd6340d37b54ee9487ea
This commit is contained in:
Pascal Massimino
2011-08-23 15:58:22 -07:00
parent cd12b4b0ac
commit 900286e091
8 changed files with 56 additions and 8 deletions

View File

@ -676,6 +676,9 @@ static void HelpLong(void) {
printf(" -sharpness <int> ....... "
"filter sharpness (0:most .. 7:least sharp)\n");
printf(" -strong ................ use strong filter instead of simple.\n");
printf(" -partition_limit <int> . limit quality to fit the 512k limit on\n");
printf(" "
"the first partition (0=no degradation ... 100=full)\n");
printf(" -alpha_comp <int> ...... set the transparency-compression\n");
printf(" -noalpha ............... discard any transparency information.\n");
printf(" -pass <int> ............ analysis pass number (1..10)\n");
@ -712,10 +715,15 @@ static const char* const kErrorMessages[] = {
"BITSTREAM_OUT_OF_MEMORY: Out of memory re-allocating byte buffer",
"NULL_PARAMETER: NULL parameter passed to function",
"INVALID_CONFIGURATION: configuration is invalid",
"BAD_DIMENSION: Bad picture dimension",
"PARTITION0_OVERFLOW: Partition #0 is too big to fit 512k",
"PARTITION_OVERFLOW: Partition is too big to fir 16M",
"BAD_WRITE: Picture writer returned an error"
"BAD_DIMENSION: Bad picture dimension. Maximum width and height "
"allowed is 16383 pixels.",
"PARTITION0_OVERFLOW: Partition #0 is too big to fit 512k.\n"
"To reduce the size of this partition, try using less segments "
"with the -segments option, and eventually reduce the number of "
"header bits using -partition_limit. More details are available "
"in the manual (`man cwebp`)",
"PARTITION_OVERFLOW: Partition is too big to fit 16M",
"BAD_WRITE: Picture writer returned an I/O error"
};
//-----------------------------------------------------------------------------
@ -789,6 +797,8 @@ int main(int argc, const char *argv[]) {
config.preprocessing = strtol(argv[++c], NULL, 0);
} else if (!strcmp(argv[c], "-segments") && c < argc - 1) {
config.segments = strtol(argv[++c], NULL, 0);
} else if (!strcmp(argv[c], "-partition_limit") && c < argc - 1) {
config.partition_limit = strtol(argv[++c], NULL, 0);
} else if (!strcmp(argv[c], "-alpha_comp") && c < argc - 1) {
config.alpha_compression = strtol(argv[++c], NULL, 0);
} else if (!strcmp(argv[c], "-noalpha")) {