by MiPi » Tue Apr 22, 2014 6:17 am
I've found it in some other forum and verified it manually (tagged m4a file in Win7 explorer and looked inside the file in hexa editor).
Yes, it is moov.udta.Xtra. The format inside this atom is nearly the same as in WMA/WMV tags, in fact, Xtra works here only as the envelope for some standard WMA tags.
I'm going to implement reading these tags and probably edit/preserve them in case they are already present (i.e. write both - standard and Xtra tag - to avoid the situation, that Win. explorer will show different values, as rating, from MM4). Standard M4A tags (as 'rate') have definitely higher priority, conversion from windows rating scale will be the same as we do for WMA/WMV.
I've found it in some other forum and verified it manually (tagged m4a file in Win7 explorer and looked inside the file in hexa editor).
Yes, it is moov.udta.Xtra. The format inside this atom is nearly the same as in WMA/WMV tags, in fact, Xtra works here only as the envelope for some standard WMA tags.
I'm going to implement reading these tags and probably edit/preserve them in case they are already present (i.e. write both - standard and Xtra tag - to avoid the situation, that Win. explorer will show different values, as rating, from MM4). Standard M4A tags (as 'rate') have definitely higher priority, conversion from windows rating scale will be the same as we do for WMA/WMV.