EPUB vs AZW3

[1v4n0]

Hello,

From the "inside" (i.e. from within an editor) AZW3 ebooks look very similar to EPUBs. Same code, same files, more or less. EPUBs have a "content.opf" file, whereas the one in the AZW3 is called "metadata.opf", but they are very similar too.

So what are differences between the two? What does a converter do? I know that simply changing the extension won't work, but it doesn't seem to be much more complicated.

I got a feeling the answer might be very technical, but I'm willing to study

Thanks,

i

[DiapDealer]

Originally Posted by 1v4n0

Hello,

From the "inside" (i.e. from within an editor) AZW3 ebooks look very similar to EPUBs. Same code, same files, more or less. EPUBs have a "content.opf" file, whereas the one in the AZW3 is called "metadata.opf", but they are very similar too.

So what are differences between the two? What does a converter do? I know that simply changing the extension won't work, but it doesn't seem to be much more complicated.

I got a feeling the answer might be very technical, but I'm willing to study

Thanks,

i

There are no "files" inside a binary azw3. That's the main differnce. Any editor has extracted the records from the binary database and put them into files and arranged/presented them in the manner you see (either that, or you're actually looking at the source EPUB that's included with Kindlegen's output). Conversion is a rather large undertaking, actually. The binary headers must be constructed, the content put into records and all links converted from hrefs/ids to physical offsets. AZW3s are more like epubs in structure than regular-old mobi to be sure. But what you're looking at in an editor is not the "inside" of an AZW3. It's the conversion of the KF8 format into a familiar OEBPS structure that you can then tweak and rebuild.

[DaleDe]

Originally Posted by 1v4n0

Hello,

From the "inside" (i.e. from within an editor) AZW3 ebooks look very similar to EPUBs. Same code, same files, more or less. EPUBs have a "content.opf" file, whereas the one in the AZW3 is called "metadata.opf", but they are very similar too.

So what are differences between the two? What does a converter do? I know that simply changing the extension won't work, but it doesn't seem to be much more complicated.

I got a feeling the answer might be very technical, but I'm willing to study

Thanks,

i

A good place to start is our wiki. See KF8.

Dale

[Section8]

You might also look at the kindleunpack calibre plugin. It will "repackage" an azw3 as the equivalent epub (as you say they are internally similar) without a full conversion.

[1v4n0]

Thanks everyone.

@DiapDealer Got it, I didn't know. What is exactly a "Binary database"? Some not-human-readable machine-language?

@Section8 yeah I had tried that once. That's also why I thought AZW3 were very similar to EPUBs

[DaleDe]

Originally Posted by 1v4n0

Thanks everyone.

@DiapDealer Got it, I didn't know. What is exactly a "Binary database"? Some not-human-readable machine-language?

A binary database is a compiled file built by a computer. It is compared here to a pure text database such as a text file or tagged file. ePub is a collection of text files inside a zip container. The reading program must load an individual file and parse the tags to create the screen display. KF8 is a single file with binary pointers to the various sections of the eBook. The reading program follows the pointers to find the entries. The KF8 file must be built with a Computer program that compiles the database from the source files.

See our wiki for more on this. The compiled format of all Amazon file formats is based on PDB container format.

Dale