MobiMetadata

MobiMetadata is a .NET library you can use to read strongly typed metadata from mobi/azw files (with no drm) and save all images - including HD images from the azw.res/azw6 file - to a stream of your choice.

MobiMetadata targets .NET 6.0, is fully async, and uses a lot of recent language features. But the documentation is what you're reading here, the code is pretty much uncommented, and there's no Nuget package. Clone it, compile it, and hack away.

How to use.

var stream = File.Open(azwFile);
var hdStream = File.Open(azwResFile);

var metadata = new MobiMetadata();

// This will read all properties and records (except for image records) in all headers 
await metadata.ReadMetadataAsync(stream);

var title = metadata.MobiHeader.FullName;
var updatedTitle = metadata.MobiHeader.ExthHeader.UpdatedTitle;
var publisher = metadata.MobiHeader.ExthHeader.Publisher;

// Read the image records in both the azw and azw.res file (if you don't have an azw.res 
// file available pass null to this method). Note that this doesn't read the actual image
// data, just the containing records 
await metadata.SetImageRecordsAsync(hdStream);

// Save the cover if available. The MergedCoverRecord contains the HD cover if available, 
// else the SD cover or null if no cover record was found. 
if (metadata.MergedCoverRecord != null)
{
    await metadata.MergedCoverRecord.WriteDataAsync(yourCoverStream);
}

// Loop through pages
for (int i = 0; i < = metadata.MergedImageRecords.Count; i++)
{
    // Similar to MergedCoverRecord this contains the HD image if available, else the SD image. 
    await metadata.MergedImageRecords[i].WriteDataAsync(yourPageStream);
}

Have a look at the CbzMage source code (the Engine classes and MetadataManager) for more examples. Here is a page with lots of information about the various headers and properties.

If you have any questions use Discussions. If you want to report a bug use Issues.

Credits.

The parser is originally copied from the Mobi Metadata Reader by Limey. I cleaned it up, modernized it, fixed the FullName parsing, and added support for retrieving SD and HD images, the rest is Limey's work. This Stack Overflow post was very helpful when figuring out how to extract cover images. The structure of the Azw6 header was gleaned from UnpackKindleS