Files extension transcoding - Just a comment.


I´ve been testing file extensions. I was supposed that AAC lossy was not transcoded by Sobsonic server. Only lossless codecs and some not very ususal lossy formats.

But I´ve noticed, testing the cache of the mobile app, that using the same codec, M4A files are transcoded, but AAC files aren´t.

I´ve converted all my M4A files on my collection, to AAC. Just a quick one file extension change. (Around 4500 files) Just to avoid transcoding. And I´ve resynched.

Have someone noticed something similar with any other codec or extension?

Thank you!


  • gravelldgravelld Administrator

    This might be helpful:

    Note: visitors from the future! The below may have been changed by the time you read this.

    Currently, if the extension of the file is not one of "aac", "flac", "mp3", "ogg", "oga", "opus", "wav" then the file will be transcoded. We use ffmpeg to transcode any such file to a FLAC and stream that.

    I'm not sure on the historical reasons for transcoding MP4 but I guess it might relate to support in certain players for the MP4 container format (given that AAC is deemed not to require transcoding and is likely to be the same internal audio format), e.g. browsers or apps.

  • Thank you!!!! Perfectly clear now.

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