Audio books not recognized

[jgauthier 13]

Does emby support MP4 files for audio books? I can't figure out why these won't show up.

 

[Luke 37214]

Hi, no it’s currently audio files only.

[jgauthier 13]

They are audio files.    I don't know they're in an MP4 container, but there's no video.  I guess it must just be an audio track.

Maybe I can convert them.

 

Converting them is fine.  Strange way to deploy an audio book., But thanks for the answer!

Edited March 1 by jgauthier

[pwhodges 1538]

39 minutes ago, Luke said:

Hi, no it’s currently audio files only.

@Luke I have pointed out before that the mpeg4 standard originally (and still) specifies .mp4 as the extension whatever the content - i.e. even if the content is only audio.  Apple introduced the m4a and m4v variants which were later added to the standard - but mp4 remains valid for audio.

1 hour ago, jgauthier said:

Does emby support MP4 files for audio books? I can't figure out why these won't show up

For now you have to change the extension to m4a for Emby to recognise them.

Paul

[Gilgamesh_48 946]

2 minutes ago, pwhodges said:

@Luke I have pointed out before that the mpeg4 standard originally (and still) specifies .mp4 as the extension whatever the content - i.e. even if the content is only audio.  Apple introduced the m4a and m4v variants which were later added to the standard - but mp4 remains valid for audio.

For now you have to change the extension to m4a for Emby to recognise them.

Paul

I think you can also change them to mp3 extensions. I know you can change the extension of most mp3 files to mp4 to have them recognized as a video file and that allows them to be played and organized in a TV show type library (or movie) and played as shows. It was needed to handle audio books in multiple files with resume/FF/RW working correctly.

If it works mp3->mp4 then a file with no video should go mp4->mp3 as well. I have not done that in a long time, I quit using Emby for audio books, but I think, as long as there is no video track in the file changing the extension either to m4a or mp3 should be just fine.

[pwhodges 1538]

It's virtually certain that the mp4 files contain mp4 audio aka AAC.  Why would one change the extension to one which is conventionally (and correctly) used for a different, older, codec?

I mean, yes one can use the wrong extension, because many programs peek in the file to determine what they really are, but labelling an m4a file as mp3 makes no more sense than labelling a png image as jpg - and yes, I've seen that happen.

Paul

[speechles 1928]

If ffprobe is smart enough to know the extension is incorrect it will work that way. But if you change MP4->MP3 that will not work directly on devices, such as Roku, that trust the extension explicitly. With MP4 it is a container that can hold video or audio or both. With M4A it has the exact same properties as MP4 container except it can contain just audio. The M4V can contain just video but otherwise same properties as MP4. Renaming extensions is normally never done unless someone has them incorrect to begin with.

The Roku uses the extension to tell how to detect the format inside. Using the wrong  extension and Emby direct playing the file will end up badly (no streams available) since it doesn't involve ffmpeg which might correct things (provide a valid stream). The fallback of the audio player error correction might play it since it will ask for a full transcode of the audio to send to the Roku using HLS.

Edited March 1 by speechles

[jgauthier 13]

@pwhodges

Thanks for the tip.  changing the extension to m4a solved the issue.    thanks for your insight into this.