Chris@8: 
Chris@93: module yetilab.stream.framer;
Chris@8: 
Chris@25: /**
Chris@25:  * Framer expresses a stream (or a file) as a lazy list of (possibly
Chris@158:  * overlapping) frames of data.
Chris@25:  */
Chris@25: 
Chris@222: vec = load yetilab.vector.vector;
Chris@222: bf = load yetilab.vector.blockfuncs;
Chris@93: af = load yetilab.stream.audiofile;
Chris@93: win = load yetilab.transform.window;
Chris@93: fft = load yetilab.transform.fft;
Chris@158: mat = load yetilab.matrix.matrix;
Chris@158: ch = load yetilab.stream.channels;
Chris@8: 
Chris@32: blockList framesize stream =
Chris@14:     if stream.finished? then
Chris@158:         stream.close ();
Chris@160:         []
Chris@13:     else
Chris@158:         mat.resizedTo { rows = stream.channels, columns = framesize }
Chris@158:            (stream.read framesize)
Chris@32:             :. \(blockList framesize stream);
Chris@13:     fi;
Chris@13: 
Chris@47: overlappingBlockList size hop stream valid buffer =
Chris@29:    (
Chris@158:     m = stream.read hop;
Chris@158:     obtained = mat.width m;
Chris@23: 
Chris@32:     // Retain framesize - hop samples from old buffer, add hop samples
Chris@29:     // (zero-padded if necessary) just read
Chris@158:     buffer = map2
Chris@158:         do buf row:
Chris@218:             vec.concat
Chris@218:                [vec.rangeOf hop (size-hop) buf,
Chris@218:                 vec.resizedTo hop (mat.getRow row m)];
Chris@158:         done buffer [0..stream.channels-1];
Chris@23: 
Chris@23:     // Number of "valid" elements (not tail-end zero-padding) left in buffer
Chris@24:     remaining = valid - (hop - obtained);
Chris@23: 
Chris@23:     if remaining <= 0 then
Chris@23:         stream.close ();
Chris@23:         [];
Chris@12:     else
Chris@163:         mat.newMatrix (RowMajor ()) buffer
Chris@158:             :. \(overlappingBlockList size hop stream remaining buffer);
Chris@23:     fi);
Chris@14: 
Chris@32: frames { framesize, hop } stream =
Chris@32:     if framesize == hop then
Chris@32:         blockList framesize stream
Chris@30:     else
Chris@32:         overlappingBlockList framesize hop stream 
Chris@218:             framesize (map \(vec.zeros framesize) [0..stream.channels-1]);
Chris@30:     fi;
Chris@14: 
Chris@158: monoFrames params stream =
Chris@158:     map ch.mixedDown (frames params stream);
Chris@158: 
Chris@49: windowedFrames { framesize, hop, window } stream =
Chris@49:    (win = window framesize;
Chris@158:     map (bf.multiply win) (monoFrames { framesize, hop } stream));
Chris@49: 
Chris@49: frequencyDomainFrames { framesize, hop } stream =
Chris@49:    (f = fft.realForward framesize;
Chris@49:     map f (windowedFrames { framesize, hop, window = win.hann } stream));
Chris@23: 
Chris@11: { 
Chris@30:     frames,
Chris@158:     monoFrames,
Chris@49:     windowedFrames,
Chris@49:     frequencyDomainFrames,
Chris@49: 
Chris@49:     framesOfFile parameters filename =
Chris@146:         frames parameters (af.open filename),
Chris@49: 
Chris@158:     monoFramesOfFile parameters filename =
Chris@158:         monoFrames parameters (af.open filename),
Chris@158: 
Chris@49:     windowedFramesOfFile parameters filename = 
Chris@146:         windowedFrames parameters (af.open filename),
Chris@49: 
Chris@49:     frequencyDomainFramesOfFile parameters filename = 
Chris@146:         frequencyDomainFrames parameters (af.open filename),
Chris@11: }
Chris@8: