OriginalThe original file is synced unchanged, without any conversion.
Specified output formatThe file is always converted to the format specified in the Encoder settings of the Encoder selected in the Handheld Options.
Specified output format only when necessaryThe file is only converted when it is not supported by the target device, as defined by the supported file types listed in the Handheld Options > "File, Paths, & More > Supported Types".
Specified output format only when necessary (including high bitrates)The file is only converted when it is not supported by the target device, as defined by the supported file types listed in the Handheld Options > "File, Paths, & More > Supported Types",
or the file type is supported but the bitrate is significantly higher than the output bitrate specified in the Encoder settings of the Encoder selected in the Handheld Options.
Note 1: A file will not be converted if a copy of it already exists in the Audio Cache location as defined in "Options > File Location > Conversion Cache > Audio", regardless of the Bitrate of the cached file. The Audio Conversion Cache functionality can be turned off by selecting the "None (do not create cache)" setting in that option.
Note 2: A file will also not be converted if it already exists on the Device itself, regardless of the Bitrate of the existing file.
Note 3: The file will also not be converted if the target Bitrate is close to the existing Bitrate. For example, a 203 Kbps VBR MP3 file will not be converted if the encoder settings call for a 192 Kbps CBR conversion. Files in the range 160 to 192 Kbps will not be converted with 160 Kbps CBR conversion settings, but will all be converted with 128 Kbps CBR conversion settings.
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Reference:
https://yabb.jriver.com/interact/index.php/topic,103512.msg719640.html#msg719640 where it was tested by Imeric.
If someone tests that the functionality still works that way, and if the above wording makes sense to everyone, I'll update the
Handheld Sync Options Wiki.
If it doesn't work, something is broken or settings are wrong.
If the above wording still doesn't make sense, please write a description that does make sense to you, and I'll consider using that.