Feature request - join multi part downloads

[ErgoPraxis]

In certain cases, the full book download link is unavailable which forces downloading the book onto parts.

Joining the resulting mp4 files is trivial. See second half of comment for bash command examples using ffmpeg (https://github.com/jvatic/audible-downloader/issues/26#issuecomment-1859221572).

However, Audible adds a short audio accouncement to the end of each part announcing something like "this book has been broken into parts to make the download faster. You have reached the end of a part but not the book [...]"

To make the join seemless, solving how to remove this announcement would be needed. Some possible ideas

• Assume a specific duration and cut that portion off before the join. This is problematuc however since we can't garantee the same length is universal throughout Audible. Also, we couldn't garantee this announcmemt wouldn't change in the future.
• Use chapter markers to cut the last chapter. I suspect this is how the audible native app works since I've never heard the announce on their app. Does the code pull chapter markers? I haven't looked.

[jvatic]

Thank you for filing this feature request @ErgoPraxis!

Yes, removing the announcement will likely be a bit tricky, and I think the second option you've suggested should work. The chapter markers aren't currently being pulled in, and ffmpeg can be used for that.

Another consideration is to ensure the chapter markers of the concatenated files are all seamlessly merged.