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@273: vec = load yetilab.vector;
Chris@222: bf = load yetilab.vector.blockfuncs;
Chris@93: af = load yetilab.stream.audiofile;
Chris@264: win = load yetilab.signal.window;
Chris@93: fft = load yetilab.transform.fft;
Chris@273: mat = load yetilab.matrix;
Chris@158: ch = load yetilab.stream.channels;
Chris@8: 
Chris@291: //!!! todo: synchronized for everything with state assignment
Chris@291: 
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@260:                [vec.slice buf hop size,
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@284: streamContiguous rate framesize frames =
Chris@284:    (var remaining = frames;
Chris@284:     var buffered = mat.zeroSizeMatrix ();
Chris@284:     var position = 0;
Chris@284:     channels = mat.height (head frames); // so we don't need to keep a head ptr
Chris@284:     {
Chris@284:         get position () = position,
Chris@284:         get channels () = channels,
Chris@284:         get sampleRate () = rate,
Chris@284:         get finished? () = empty? remaining and mat.empty? buffered,
Chris@284:         get available () = 
Chris@284:             // Don't take length of frames -- we don't want to lose laziness.
Chris@284:             // If the caller cares that much, they can measure frames themselves
Chris@284:             if empty? remaining then
Chris@284:                 Known (mat.width buffered) 
Chris@284:             else
Chris@284:                 Unknown ()
Chris@284:             fi,
Chris@284:         read count =
Chris@284:            (framesFor samples acc =
Chris@284:                 if samples <= 0 or empty? remaining then
Chris@284:                     acc
Chris@284:                 else
Chris@284:                     this = head remaining;
Chris@284:                     remaining := tail remaining;
Chris@284:                     framesFor (samples - mat.width this) (acc ++ [this])
Chris@284:                 fi;
Chris@284:             source = mat.concat (Horizontal ()) (framesFor count [buffered]);
Chris@284:             toReturn = mat.columnSlice source 0 count;
Chris@284:             position := position + mat.width toReturn;
Chris@284:             buffered := mat.columnSlice source count (mat.width source);
Chris@284:             toReturn),
Chris@284:         close = \(),
Chris@284:     });
Chris@284: 
Chris@291: overlapAdd overlap frames =
Chris@285:    (ola fr acc =
Chris@291:         case fr of
Chris@291:         first::rest:
Chris@291:            (w = mat.width acc;
Chris@291:             pre = mat.columnSlice acc 0 (w - overlap);
Chris@291:             added = mat.sum first
Chris@291:                (mat.resizedTo (mat.size first)
Chris@291:                (mat.columnSlice acc (w - overlap) w));
Chris@291:             pre :: ola rest added);
Chris@291:          _:
Chris@291:             [acc];
Chris@291:         esac;
Chris@291:     case frames of
Chris@291:     first::rest:
Chris@291:         mat.concat (Horizontal ()) (ola rest first);
Chris@291:      _: 
Chris@291:         mat.zeroSizeMatrix ();
Chris@291:     esac);
Chris@285: 
Chris@284: streamOverlapping rate framesize hop frames =
Chris@284:    (var remaining = frames;
Chris@284:     var buffered = mat.zeroSizeMatrix ();
Chris@284:     var position = 0;
Chris@294: 
Chris@288:     factor = hop / (framesize/2);
Chris@290:     w = bf.scaled factor (win.hann framesize); // periodic window, not symmetric
Chris@284:     channels = mat.height (head frames); // so we don't need to keep a head ptr
Chris@294: 
Chris@291:     syncd = synchronized remaining;
Chris@294: 
Chris@294:     finished' () = syncd \(empty? remaining and mat.empty? buffered);
Chris@294: 
Chris@294:     read' count = 
Chris@294:        (framesFor samples acc =
Chris@294:             if samples <= 0 or empty? remaining then
Chris@294:                 acc
Chris@294:             else
Chris@294:                 this = mat.resizedTo { columns = framesize, rows = channels }
Chris@294:                    (mat.newMatrix (RowMajor ())
Chris@294:                        (map (bf.multiply w) (mat.asRows (head remaining))));
Chris@294:                 remaining := tail remaining;
Chris@294:                 framesFor (samples - hop) (acc ++ [this])
Chris@294:             fi;
Chris@294:         source = overlapAdd (framesize - hop)
Chris@294:            (framesFor count [buffered]);
Chris@294:         buffered := mat.columnSlice source count (mat.width source);
Chris@294:         mat.columnSlice source 0 count);
Chris@294: 
Chris@294:     // lose initial padding
Chris@294:     \() (read' (framesize - hop));
Chris@294:     
Chris@294:     {
Chris@294:         get position () = syncd \(position),
Chris@294:         get channels () = channels,
Chris@294:         get sampleRate () = rate,
Chris@294:         get finished? () = finished' (),
Chris@294:         get available () = if finished' () then Known 0 else Unknown () fi,
Chris@294:         read count = syncd
Chris@294:           \(data = read' count;
Chris@294:             position := position + mat.width data;
Chris@294:             data),
Chris@294:         close = \(),
Chris@294:     });
Chris@284:     
Chris@282: //!!! doc: convert frames back to a stream
Chris@282: streamed rate { framesize, hop } frames =
Chris@282:     if framesize == hop then
Chris@282:         streamContiguous rate framesize frames
Chris@282:     else
Chris@284:         streamOverlapping rate framesize hop frames
Chris@282:     fi;
Chris@282: 
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@294: frequencyDomainFrames parameters stream =
Chris@294:    (f = fft.realForward parameters.framesize;
Chris@294:     map f (windowedFrames parameters 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@284: 
Chris@285:     overlapAdd,
Chris@285: 
Chris@284:     streamed,
Chris@11: }
Chris@8: