The purpose of this frame is to carry a short audio clip which represents the information carried by another ID3v2 frame that is present in the same tag.
To avoid these audio clips being confused with the main audio content of the file the ID3v2 unsynchronisation scheme must be used if the audio clip uses an MPEG audio format. If the unsynchronisation scheme is not appropriate for the audio format then the scrambling scheme defined in section 5 must be applied to the audio clip data.
<ID3v2.3 or ID3v2.4 frame header, ID: "ATXT"> Text encoding $xx MIME type <text string> $00 Flags %0000000a Equivalent text <text string according to encoding> $00 (00) Audio data <binary data>
The Frame ID for the audio-text frame shall be set to "ATXT" using ISO-8859-1 character encoding.
The MIME type shall be represented as a terminated string encoded using ISO-8859-1 character encoding. Where the MIME type corresponds to MPEG 1/2 layer I, II and III, MPEG 2.5 or AAC audio the ID3v2 unsynchronisation scheme should be applied, either to the audio-text frame or to the tag which contains it. For other MIME types the scrambling scheme defined in the Appendix should be applied to the audio data.
- Flag a - Scrambling flag
This flag shall be set if the scrambling method defined in Section 5 has been applied to the audio data, or not set if no scrambling has been applied.
The Equivalent text field carries a null terminated string encoded according to the Text encoding byte as defined by the ID3v2 specifications [1], [2]. This text must be semantically equivalent to the spoken narrative in the audio clip and should match the text and encoding used by another ID3v2 frame in the tag.
The Audio data carries an audio clip which provides the audio description. The encoding of the audio data shall match the MIME type field and the data shall be scrambled if the scrambling flag is set.
More than one audio-text frame may be present in a tag but each must carry a unique string in the Equivalent text field.