Razor12911
25-08-2015, 11:01
Hi guys. I am here to explain and give extra information about precomp.
First of all, a whole lot of newbies think that precomp compresses files, "If you use precomp you get better results", well I am here to clarify that.
Pecomp is not a compressor, it's more like a decompressor with the aim of decompressesing zlib and deflate streams that exist in a certain file meaning the output is suppose to be bigger than input.
Q: Why must the output be bigger than input?
A: So that there must be a lot of repetitions and similarities within the file that when you apply step or stronger compression such as LZMA which targets those repetition and similarities to make the output much smaller.
Q: Why does precomp take so long to process a file?
A: Data is represented as binary zeroes and ones, there are so many of them within a file, precomp has to scan for headers/traces of zlib or deflate streams then decompress them then looks for another.
Q: Why does precomp stop working sometimes.
A: it may be cause by a false detected stream within the file and when precomp tries to decompress it, an exception is raised because the stream was falsely detected via file headers.
Q: What if there were no streams detected?
A: Then do not use precomp for that particular file.
Q: How to know the count of streams found?
A: After precomp has processed a file, it shows a summary.
Q: How to know before precomp finishes that the results will be excellent?
A1: use verbose command -v. Turn it on.
A2: look at the temp file, original file and current progress, if temp is bigger than original file while precomp is still working then expect great results but if temp is more or less equal in comparison to original file and progress percentage agrees with the division of both then it is wise to stop process and remove precomp from method.
First of all, a whole lot of newbies think that precomp compresses files, "If you use precomp you get better results", well I am here to clarify that.
Pecomp is not a compressor, it's more like a decompressor with the aim of decompressesing zlib and deflate streams that exist in a certain file meaning the output is suppose to be bigger than input.
Q: Why must the output be bigger than input?
A: So that there must be a lot of repetitions and similarities within the file that when you apply step or stronger compression such as LZMA which targets those repetition and similarities to make the output much smaller.
Q: Why does precomp take so long to process a file?
A: Data is represented as binary zeroes and ones, there are so many of them within a file, precomp has to scan for headers/traces of zlib or deflate streams then decompress them then looks for another.
Q: Why does precomp stop working sometimes.
A: it may be cause by a false detected stream within the file and when precomp tries to decompress it, an exception is raised because the stream was falsely detected via file headers.
Q: What if there were no streams detected?
A: Then do not use precomp for that particular file.
Q: How to know the count of streams found?
A: After precomp has processed a file, it shows a summary.
Q: How to know before precomp finishes that the results will be excellent?
A1: use verbose command -v. Turn it on.
A2: look at the temp file, original file and current progress, if temp is bigger than original file while precomp is still working then expect great results but if temp is more or less equal in comparison to original file and progress percentage agrees with the division of both then it is wise to stop process and remove precomp from method.