Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Yet another ISO question
#1
hey guys, i made the iso file of my FFXII dvd successfully with ImgBurn (Thanks ShadowLady),

and now i'll try to compress it with Linuz plugin,

the default size is 3.78 GB, i chose the 'compress better' option, what do you guys think the size will be?

(kinda junk question, sorry)
Indonesian GAMER
Reply

Sponsored links

#2
Who knows. It depends on what kind of compression the data of the game already had and if the data of the game is easily compressed. For example video files can get almost 0 compression. Just do it and see.
[Image: newsig.jpg]
Reply
#3
Ok, the result is 3.78 GB >> 3.49 GBOhmy
uhh, what's the FFXII.ISO.BZ2.table file?
Indonesian GAMER
Reply
#4
(10-28-2009, 01:50 PM)Clouddd Wrote: Ok, the result is 3.78 GB >> 3.49 GBOhmy
uhh, what's the FFXII.ISO.BZ2.table file?

Most games are already compressed to squeeze as much as they can onto the DVD, and attempting to compress a compressed file generally results in something like that Tongue

And I have absolutely no idea that that .table file is.
"This thread should be closed immediately, it causes parallel imagination and multiprocess hallucination" --ardhi
Reply
#5
(10-28-2009, 02:16 PM)echosierra Wrote:
(10-28-2009, 01:50 PM)Clouddd Wrote: Ok, the result is 3.78 GB >> 3.49 GBOhmy
uhh, what's the FFXII.ISO.BZ2.table file?

Most games are already compressed to squeeze as much as they can onto the DVD, and attempting to compress a compressed file generally results in something like that Tongue

And I have absolutely no idea that that .table file is.

A little history first.

Today's public compression programs (with exceptions in video media) treat the whole file as 1 piece of sequential media. That means to get a few bytes in the middle of a 2GB file, you have to decompress 1GB of data, *and throw it away*. Time waster.

PCSX2 Compression routines don't try to swallow that much. We put compressed blocks of 65536 bytes to 1 megabyte (original size) back-to-back in our files.
Note I said "original size". We prefer smaller sizes come out after compression. But we can't predict what the size of each compressed block is.

Enter the .table file. It's simply a pointer to the start of each of those compressed blocks. A positional read of the .table file, followed by a positional read of the compressed file, and we have our block.

As for .BZ2, that's a compression routine. Found in use in Linux. Used by us.

Sorry, no pop quiz. Tongue
Reply
#6
Hmmm I understand the public compression programs meeding to decompress the data making it slower, but what do you think about NTFS compression against the PCSX2 one? doesnt seem like either has much of an overhead when reading the files.
Core i5 3570k -- Geforce GTX 670  --  Windows 7 x64
Reply
#7
(10-28-2009, 03:08 PM)efp Wrote:
(10-28-2009, 02:16 PM)echosierra Wrote:
(10-28-2009, 01:50 PM)Clouddd Wrote: Ok, the result is 3.78 GB >> 3.49 GBOhmy
uhh, what's the FFXII.ISO.BZ2.table file?

Most games are already compressed to squeeze as much as they can onto the DVD, and attempting to compress a compressed file generally results in something like that Tongue

And I have absolutely no idea that that .table file is.

A little history first.

Today's public compression programs (with exceptions in video media) treat the whole file as 1 piece of sequential media. That means to get a few bytes in the middle of a 2GB file, you have to decompress 1GB of data, *and throw it away*. Time waster.

PCSX2 Compression routines don't try to swallow that much. We put compressed blocks of 65536 bytes to 1 megabyte (original size) back-to-back in our files.
Note I said "original size". We prefer smaller sizes come out after compression. But we can't predict what the size of each compressed block is.

Enter the .table file. It's simply a pointer to the start of each of those compressed blocks. A positional read of the .table file, followed by a positional read of the compressed file, and we have our block.

As for .BZ2, that's a compression routine. Found in use in Linux. Used by us.

Sorry, no pop quiz. Tongue

Do you discard compressed chunks that come out about the same size as the original and keep the uncompressed data intact? Not sure if the BZ2 format supports something like this, or if you're even following the standard that closely.

Just curious.
"This thread should be closed immediately, it causes parallel imagination and multiprocess hallucination" --ardhi
Reply
#8
Some games have big dummy files (sometimes even called Dummy.dat) which get compressed to a tiny size (because they only have repetitive information). I don't remember exactly which games have them, but I sometimes have managed to compress games and save 1 Gb or more.
Reply
#9
(10-29-2009, 12:55 AM)echosierra Wrote: Do you discard compressed chunks that come out about the same size as the original and keep the uncompressed data intact? Not sure if the BZ2 format supports something like this, or if you're even following the standard that closely.

Just curious.

Both GZIP and BZ2 support that idea (both have 'Magic' test headers just to confirm they're compressed streams instead of plain data), but EFPCDVD didn't use the idea to avoid cases where data looks just like a compressed stream... but isn't.
It's something to consider... just as soon as I get a computer that can run PCSX2 again.
Reply
#10
wow, it's kinda hard to understand the explanation here guys, but i appreciate your help.

Quote:It's something to consider... just as soon as I get a computer that can run PCSX2 again.

Tongue
Indonesian GAMER
Reply




Users browsing this thread: 1 Guest(s)