Documentation
¶
Overview ¶
Package apen reads and writes native Monkey's Audio framing: the descriptor, format header, and mandatory seek table a .ape file opens with, the run of frames behind them, and the APEv2 tag most files carry after the audio.
A frame carries neither its length nor its block count, so unlike every self-framing format here nothing can be recovered by scanning: the seek table is the index, and it is exact. That makes seeking a table lookup and makes a file whose table is unusable undecodable rather than degraded. It is also why the muxer needs a destination it can seek: the table and the totals in front of the audio are only knowable once the audio has gone out.
The package is named apen rather than ape because the registry imports codec/ape alongside it (the flacn precedent). The public container name and error prefix are "ape" either way.
Index ¶
Constants ¶
const MatchNeed = ape.MatchNeed
MatchNeed is the sniff window Match wants.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Demuxer ¶
type Demuxer struct {
// contains filtered or unexported fields
}
Demuxer reads one Monkey's Audio track from a native .ape source.
func NewDemuxer ¶
func NewDemuxer(src container.Source, opts *DemuxerOptions) (*Demuxer, error)
NewDemuxer parses the header of a native Monkey's Audio source and positions on the first frame. The returned Demuxer implements container.Seeker, container.Warner, and container.Tagger.
func (*Demuxer) ReadPacket ¶
ReadPacket yields one frame, with the block count and alignment the decoder needs in front of it. Packet data is reused across calls.
func (*Demuxer) SeekSample ¶
SeekSample repositions to the frame containing the target sample and returns that frame's first sample; format.Media pre-rolls the remainder. The seek table makes this exact arithmetic rather than a search, at the cost of a frame's worth of pre-roll, which the deep levels make long.
type DemuxerOptions ¶
type DemuxerOptions struct {
// Strict turns tolerated damage (the Warnings list) into errors.
Strict bool
}
DemuxerOptions configures parsing.
type Muxer ¶
type Muxer struct {
// contains filtered or unexported fields
}
Muxer writes one Monkey's Audio track as a native .ape stream.
NeedsSeek reports true: the file opens with a descriptor whose fields (the frame count, the final frame's length, the file's MD5) are only known once the audio has gone out, and with a seek table that is the format's only index -- a frame states neither its length nor its position, so a .ape without a filled table is not a degraded stream but an unreadable one. There is no streaming form to fall back to.
func NewMuxer ¶
func NewMuxer(w io.Writer, opts *MuxerOptions) *Muxer
NewMuxer returns a Monkey's Audio muxer writing to w. Begin fails unless w can actually seek; callers should check NeedsSeek and provide a file.
func (*Muxer) Begin ¶
Begin validates the track and writes the descriptor, the format header, and the seek table's reservation.
func (*Muxer) End ¶
End writes the trailing word, the tag block, and the totals: the seek table, the format header's frame counts, and the descriptor's byte counts and MD5.
type MuxerOptions ¶
type MuxerOptions struct {
// Tags are written as an APEv2 block after the audio, which is where a
// .ape file conventionally carries them and where the demuxer reads them.
Tags []container.Tag
}
MuxerOptions configures writing.
Source Files