frame: Initial version of the new frame API. Updates issue #4.

frame/frame.go

@@ -0,0 +1,57 @@
+// Package frame implements access to FLAC audio frames.
+package frame
+
+import "io"
+
+// A Frame contains the header and subframes of an audio frame. It holds the
+// encoded samples from a block (a part) of the audio stream. Each subframe
+// holding the samples from one of its channel.
+//
+// ref: https://www.xiph.org/flac/format.html#frame
+type Frame struct {
+	// Audio frame header.
+	Header
+	// One subframe per channel, containing encoded audio samples.
+	Subframes []Subframe
+	// Underlying io.Reader.
+	r io.Reader
+}
+
+// New creates a new Frame for accessing the audio samples of r. It reads and
+// parses an audio frame header. Call Frame.Parse to parse the audio samples of
+// its subframes, and Frame.Next to gain access to the next audio frame.
+func New(r io.Reader) (frame *Frame, err error) {
+	frame = &Frame{r: r}
+	err = frame.parseHeader()
+	if err != nil {
+		return nil, err
+	}
+	panic("not yet implemented.")
+}
+
+// Next returns access to the next audio frame. It reads and parses an audio
+// frame header. Call Frame.Parse to parse the audio samples of its subframes.
+func (frame *Frame) Next() (next *Frame, err error) {
+	panic("not yet implemented.")
+}
+
+// Parse reads and parses the audio samples of each subframe. If the samples are
+// interchannel correlated between the subframes, it decorrelates them.
+//
+// ref: https://www.xiph.org/flac/format.html#interchannel
+func (frame *Frame) Parse() error {
+	panic("not yet implemented.")
+}
+
+// A Header contains the basic properties of an audio frame, such as its sample
+// rate and channel count. To facilitate random access decoding each frame
+// header starts with a sync-code. This allows the decoder to synchronize and
+// locate the start of a frame header.
+//
+// ref: https://www.xiph.org/flac/format.html#frame_header
+type Header struct{}
+
+// parseHeader reads and parses the header of an audio frame.
+func (frame *Frame) parseHeader() error {
+	panic("not yet implemented.")
+}

frame/subframe.go

@@ -0,0 +1,22 @@
+package frame
+
+import "io"
+
+// A Subframe contains the encoded audio samples from one channel of an audio
+// block (a part of the audio stream).
+//
+// ref: https://www.xiph.org/flac/format.html#subframe
+type Subframe struct {
+	// Subframe header.
+	SubHeader
+	// Unencoded audio samples. Samples is initially nil, and gets populated by a
+	// call to Frame.Parse.
+	Samples []int32
+	// Underlying io.Reader.
+	r io.Reader
+}
+
+// A SubHeader specifies the prediction method and order of a subframe.
+//
+// ref: https://www.xiph.org/flac/format.html#subframe_header
+type SubHeader struct{}