Max Optimum File Size

[Fabe]

I created a file that is 912 KB in ebup format. It has 170 chapters, about 460,000 words. Is this too large to run smoothly in ereaders and smart phones?

Plus: individual files range from 4 to 24 KB with 14 being about average.

[troymc]

I don't know of any limit for the overall size of the epub, and the epub spec itself does not impose any file-size limits.

But I do that that ADE based ereaders limit the individual files to 300k (at least the older ones like the Sony's did - don't know if this has changed yet).

So if that epub is one 900+ KB xhtml file, then yes, older ereaders will not be able to open it.


IMHO, it's much better to break out each chapter as individual files, or, if you have small chapters in larger sections, then make each section an individual file.

I don't know of any negative impact from have lots of small files. I'm sure someone here has different ideas though!



Troy

[theducks]

Originally Posted by troymc

I don't know of any limit for the overall size of the epub, and the epub spec itself does not impose any file-size limits.

But I do that that ADE based ereaders limit the individual files to 300k (at least the older ones like the Sony's did - don't know if this has changed yet).

So if that epub is one 900+ KB xhtml file, then yes, older ereaders will not be able to open it.


IMHO, it's much better to break out each chapter as individual files, or, if you have small chapters in larger sections, then make each section an individual file.

I don't know of any negative impact from have lots of small files. I'm sure someone here has different ideas though!



Troy

It offends those folks that think every book should just be one huge linear file, with no chapter breaks (ADE based readers start a clean page).
The advantage is, when using the TOC (or link), to change from chapter low to chapter high is just 1 small file load. The other way, the reader has to search the entire file for the anchor point

[AlexBell]

Originally Posted by Fabe

I created a file that is 912 KB in ebup format. It has 170 chapters, about 460,000 words. Is this too large to run smoothly in ereaders and smart phones?

For what it is worth I have uploaded an ePub version of Lorna Doone by R.D. Blackmore to the MR library. The original upload contained an HTML file which was 296Kb uncompressed on disk, and several other HTML files. The ePub version would open with ADE and the Sony desktop reader, and on my Cybook Gen3. But it would not open on my Sony PRS650 - all the Sony showed was a File Error message.

I split the 296Kb HTML file into two parts (the largest of which was 264Kb uncompressed on disk) and recompiled the ePub. My Sony reader will now open it.

There have been responses on this forum to the effect that it's the size of the compressed file which counts and that some compression programs are more efficient than others, and that some files compress more easily than others, but I don't know any details.

My practice, for what it is worth, will be to keep uncompressed HTML files less than 264Kb, and check the ePub on my Sony reader before I upload it.

Regards, Alex

[Jellby]

Originally Posted by AlexBell

There have been responses on this forum to the effect that it's the size of the compressed file which counts

It's both, the (old) Sony has a limit of 300 kB uncompressed and 100 kB compressed for individual text files inside an ePUB.

As I said elsewhere I'm not sure if it's "k" for "kilo" (300 × 1000 = 300000 bytes) or "ki" for "kibi" (300 × 1024 = 307200 bytes). If it's the former, then a 296 kiB (296 × 1024 = 303104 bytes) would be too much already.

[HarryT]

Originally Posted by AlexBell

My practice, for what it is worth, will be to keep uncompressed HTML files less than 264Kb, and check the ePub on my Sony reader before I upload it.

Regards, Alex

You might wish to consider making each chapter of the book a separate HTML file; this is the standard practice with ePub books. Using small "flows" (separate HTML files) will improve performance on many devices.

[AlexBell]

Originally Posted by HarryT

You might wish to consider making each chapter of the book a separate HTML file; this is the standard practice with ePub books. Using small "flows" (separate HTML files) will improve performance on many devices.

I guess I'm just too lazy, Harry. Lorna Doone has 75 smallish chapters. It seemed easier to group them by 10s. The problem was that the last file was chapters 61 to 75. When I made it 61 to 70 and 71 to 75 it worked.

Regards, Alex

[AlexBell]

Originally Posted by Jellby

It's both, the (old) Sony has a limit of 300 kB uncompressed and 100 kB compressed for individual text files inside an ePUB.

As I said elsewhere I'm not sure if it's "k" for "kilo" (300 × 1000 = 300000 bytes) or "ki" for "kibi" (300 × 1024 = 307200 bytes). If it's the former, then a 296 kiB (296 × 1024 = 303104 bytes) would be too much already.

Thanks, Jellby. That makes more sense to me than it did when I first read it. If indeed it is 'kibi' then 300Kb/1024=292kb uncompressed. I still think I'll keep the files <280kb

Regards, Alex