AAC files: the ADTS frames of ISO/IEC 14496-3, Annex 1.A, with the ID3v2 tags that often come before them.
The duration comes from the first of these that the file has:
The reading is strict: the audio starts right after the tags. The :except option leaves out the quirks of the tags that it names.
AAC files: the ADTS frames of ISO/IEC 14496-3, Annex 1.A, with the ID3v2 tags that often come before them. The duration comes from the first of these that the file has: - the samples of every frame, when the view holds the whole file - the average length of the first frames and the size of the file - the TLEN frame of a tag The reading is strict: the audio starts right after the tags. The :except option leaves out the quirks of the tags that it names.
(frame-header view p)The header of the ADTS frame at p in view, or nil when no valid
header is there.
The header is a map of :mpeg, which is 2 or 4, :profile, :sample-rate, :channels, :samples, :length, :crc? and :vbr?. The length of the frame is in bytes, with the header. The channels are 0 when the audio itself says how many, and :vbr? is whether the buffer fullness is 0x7FF, which marks a variable bitrate.
The header of the ADTS frame at `p` in `view`, or nil when no valid header is there. The header is a map of :mpeg, which is 2 or 4, :profile, :sample-rate, :channels, :samples, :length, :crc? and :vbr?. The length of the frame is in bytes, with the header. The channels are 0 when the audio itself says how many, and :vbr? is whether the buffer fullness is 0x7FF, which marks a variable bitrate.
(read view)(read view opts)The AAC file in view, read with opts, as a map of the keys below,
each absent when the file doesn't have it, as mp4/read gives them.
The :except of opts is the ids of the quirks to leave out. When the
view lacks bytes, the reading throws an exception that holds their
ranges.
The AAC file in `view`, read with `opts`, as a map of the keys below, each absent when the file doesn't have it, as mp4/read gives them. - :id3 are the ID3v2 tags, and :tags what they say, as id3/named gives it - :codecs is the RFC 6381 codecs string, e.g. "mp4a.40.2" - :media-start is where the first frame starts - :sample-rate, :channels and :vbr? of the first frame, as frame-header gives them, without channels when the audio says them. Of HE-AAC, they're those of its core, which plays at twice the rate, and in stereo with parametric stereo, as the audio alone tells. - :duration is in seconds - :chapters, from the CHAP and CTOC frames, as id3/chapters gives them - :artwork, a map of :type, :data and :description The :except of `opts` is the ids of the quirks to leave out. When the view lacks bytes, the reading throws an exception that holds their ranges.
(report file)The diagnostics of the read file, with those of its tags. Each
diagnostic has its message.
The diagnostics of the read `file`, with those of its tags. Each diagnostic has its message.
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