Maximum size of HTML file for Sony

[AlexBell]

A couple of months ago I uploaded Lorna Doone by R.D. Blackmore. It opened without problem using ADE desktop and with my Cybook Gen3, but when I loaded it on to my new Sony PRS 650 it refused to open, and just gave me a Page Error! message - though it did open with the Sony desktop reader.

With help from Perilous on the Sony forum I split an HTML file which was 296Kb on disk into two, loaded version 2 on to my Sony Reader, and found that it works.

There is an HTML file in the ebook which is 264Kb on disk. So it looks as though the maximum size for an HTML file in an ePub for a Sony reader is more than 264Kb and less than 296Kb.

Regards, Alex

[Jellby]

I think it was something like 300KB uncompressed and 100KB compressed, and it may be 300×1000 rather than 300×1024.

[Valloric]

What Jellby said, plus I think someone around here tested this to the KB and narrowed it down to ~280KB uncompressed. My memory could be playing tricks on me though.

[AlexBell]

Originally Posted by Jellby

I think it was something like 300KB uncompressed and 100KB compressed, and it may be 300×1000 rather than 300×1024.

Thanks to you both, but I think my experience shows that 300kb on disk is more than the Sony reader can handle. My Sony reader could not handle a 296Kb uncompressed file even though the Cybook could, and both desktop readers could.

I think I read somewhere that the magic number is 290Kb, but in future I'll try to use files less than 264Kb - and test the ebook on the Sony before I upload it.

It would be nice if other people who develop ePubs could post the maximum size of uncompressed HTML files that they have found that Sony readers can handle.

Regards, Alex

[opitzs]

Would that be of any use? If it also has to be < 100kb compressed? I mean you can create files that compress good or bad, and the uncompressed file size would be no indicator if it works...

[AlexBell]

Originally Posted by opitzs

Would that be of any use? If it also has to be < 100kb compressed? I mean you can create files that compress good or bad, and the uncompressed file size would be no indicator if it works...

Thanks, opitzs. I know next to nothing about compression methods, and always use Winzip. I guess all I've shown is that 264kb HTML file will work on a Sony when the file is compressed with Winzip

Regards, Alex

[Valloric]

Originally Posted by AlexBell

I guess all I've shown is that 264kb HTML file will work on a Sony when the file is compressed with Winzip

No, all you've shown is that that particular file, when compressed, will work on the Sony. Other files that are 264kb may or may not compress to something smaller than 100kb. It depends entirely on how compressible is the content of the file.

[AlexBell]

Originally Posted by Valloric

No, all you've shown is that that particular file, when compressed, will work on the Sony. Other files that are 264kb may or may not compress to something smaller than 100kb. It depends entirely on how compressible is the content of the file.

I'm sorry, I don't quite understand. What factors would make a file more or less compressible?

Regards, Alex

[Jellby]

Originally Posted by AlexBell

I'm sorry, I don't quite understand. What factors would make a file more or less compressible?

The contents. In an extreme case, a file that's just 1MB of "AAAAA..." will compress very efficiently, a file with the first 1024 digits of pi a bit less. But both, being basically ASCII text will be more compressible than a 1MB JPG, which is already compressed.

[AlexBell]

Thanks to you both.

Regards, Alex