ID3v2.4 change to 2.3 unicode character conversion error occurred.

[Mapaler]

Use IdSharp example or use library in my program, if ID3v2.4 change to 2.3, unicode character change to ??? ,and will fail forever, unless delet ID3V2, but 2.3 change to 2.4 is correct.

[judwhite]

@Mapaler Thanks for the report, I'll test over here using some multi-byte characters.

If you have an example ID3v2.4 tag (just the tag header without the MP3 data) please attach that portion in case it's an edge case in the original 2.4 tag.

[Mapaler]

I download them from osu! beatmap.(It's a good game and powerd by C#)

(Following these download on mirror. download and unzip them.)

This one is ID3v2.4 , and convert to 2.3 don't correct.

• 
  Make Up! Make Up!

These two are ID#v2.3 , but only load in IdSharp correctly, can't correct save at 2.3.

• 
  End of Dream
• 
  Hinarin's Relation of Misfortune

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And they are ID3v2.4

• 
  IOSYS - Candid Telling You
• 
  Nanamori-chu Goraku-bu - My Pace de Ikimashou (TV Size)
• 
  Innocent Key - Grilled Bird
• 
  Katou Emiri - Kaerimichi (TV Size)
• 
  Demetori - Innocent Treasures
• 
  IOSYS - The Lovely, Freezing, Tomboyish Bath, Cirno's Hot Spring
• 
  Ryu- - I'm so Happy
• 
  fripSide - future gazer (TV Size)
• 
  IOSYS - Kanbu de Todomatte Sugu Tokeru ~ Kyouki no Udongein
• 
  IOSYS - Utage wa Eien ni
• 
  Pal4 music team - Back to Dream
• 
  IOSYS - Utage wa Eien ni SHD
• 
  Tatsh feat Hatsuki Yura - Eternal Wind
• 
  Boom - How Do You Do (Nightcore Remix)
• 
  Beniiro Litmus - Rin to Shite Saku Hana no Gotoku (Full Ver)
• 
  Hajime Hyakkoku - Virtual love
• 
  U - Clu Clu Lovely Day
• 
  Yuduki - Dear You (Vocal Version)
• 
  Toyosaki Aki - Guitar ni Kubittake (Full ver)
• 
  Nana Takahashi - Shuwa Supa Daisakusen
• 
  Hatsune Miku - Uta ni Katachi wa Nai Keredo
• 
  Hatsune Miku - Game of Life
• 
  Aimee B - Fallen Angel
• 
  Nico Nico Douga - Dr. KBC