DDS, BSA and NIF compression

[thisisbleep]

I have been compressing all of the files after installing the STEP mods, to see if I can improve the performance, but I have been encountering problems.

 

I used DDSopt to compress the texture files using the default settings and maximum compression (6.07 GB reduced to 5.45 GB), SMCO to compress the meshes (524 MB reduced to 512 MB) and DDSopt to compress the BSA files, which has caused problems.

 

The BSA files which were compressed using the maximum compression do not work, when launching the game it shows the Skyrim logo and nothing else happens. I also tried to use the 8 compression setting, after seeing a comment when searching on this forum about the same issue, but that causes repeat errors with reading the BSA files in DDSopt. I found that checking the "forced" option helps, but does not entirely eliminate it. The Dragonborn.bsa has problems, it processes the file and when re-constructing has the error every time at the end, when using the 8 compression setting and the file is an onimous 666 MB. BSAopt is the same as DDSopt, it outputs the same file sizes with the same problems.

 

I tested a few of the first BSA files, which were compressed with the 8 setting (Chesko_WearableLanterns.nsa, Chesko_WearableLantern_Candle_DG.bsa, Clanking Armor.bsa, ClimatesOfTamriel.bsa and Convenient Horses.bsa), but the game still does not load. Is it possible to optimise BSA files which come from the modding community or can I only optimise the official files?

 

Also, since using SMCO to compress the meshes one of the meshes on the loading and start screen is broken, it has added a nice red box. I presume that this is caused by one of the meshes, I have re-run the SMCO NIF program, but it says that all of the files have been already optimised. When starting a new game I did not notice any other damaged textures or meshes.

 

 

 

 

 

EDIT: As I suspected, it was the "No Smoke on Loading Screen" which was effected and replacing the original NIF file has fixed that. So I just have a problem with compressing the BSA files now.

[Aiyen]

Touching the meshes is almost always a very bad idea. Regardless of what some people want you to think. You should only ever do it if you are 100% sure of what you are doing and why.

 

In general for compression then it can go wrong. And if it does then the resource will not be loadable by the game.

Also some resources like certain textures will not like if you even add compression at all, so it is not really a good idea to do so.

Also any program that just "does it on everything at once" is bound to cause more work then doing it piece wise one mod folder at a time, and testing properly.

[Kelmych]

We aren't sure why Skyrim can't read some of the vanilla BSAs that DDSopt/BSAopt has recompressed. It might be because it can't handle the higher compression used, but there hasn't been any testing of this. Ethatron has done some work a while ago on a tool for optimizing meshes, but it is incomplete and he has not had time to work on any of his utilities since the beginning of this year.

[thisisbleep]

That is a shame, when using the maximum compression in DDSopt it reduced the ~20 GB of BSA files by about 3 GB.

 

I will check the Papyrus logs later and see if it is recording any errors or giving a reason why it is not loading them.

 

 

Would there be a performance benefit from unpacking all of the files?

[EssArrBee]

The performance benefit is negligible since the BSAs are on disk which is around 1,000,000 clock cycles to access and adding in decompression from the archive is maybe ~1000 clock cycles. One million vs one million one thousand is nothing when dealing with billions of cycles a second and multi-cores. This BSAs performance thing is a hold over from the Oblivion days because of it's single core dependence.