Fixed gradual unalignment error & padding

src/matlab/spectral_analysis/dtDefaultBlockBoundaries.m

@@ -7,9 +7,15 @@
     blocks = zeros(0,2);
 
     %frames_per_s = Fs/advance_samples;
-
+    first = true;
     while(StopBlock_s < (file_len_s - Advance_s - shift_samples_s))
-        StopBlock_s = min(StartBlock_s + block_len_s + 2 * block_pad_s, file_len_s);
+        if (first)
+            StopBlock_s = min(StartBlock_s + block_len_s + block_pad_s, file_len_s);
+            first = false;
+        else
+            StopBlock_s = min(StartBlock_s + block_len_s + 2 * block_pad_s, file_len_s);
+        end
+
 
         %fprintf('Processing raw block from %.10f to %.10f\n', StartBlock_s, StopBlock_s);
         blocks = vertcat(blocks, [StartBlock_s, StopBlock_s]);
@@ -21,7 +27,7 @@
 
         %StartBlock_s = Indices.timeidx(end) + Advance_s - shift_samples_s;
         %StartBlock_s = StopBlock_s - shift_samples_s;
-        StartBlock_s = StartBlock_s + block_len_s - shift_samples_s;
+        StartBlock_s = max(StopBlock_s - shift_samples_s - 2 * block_pad_s, 0);
     end
 end
 

src/matlab/user_interface/dtPlotSpecgram.m

@@ -212,7 +212,16 @@
 shift_samples = 0;
 shift_samples_s = shift_samples / header.fs;
 
-block_pad_s = 1 / thr.high_cutoff_Hz;
+% Padding the number of samples/frame allows for the full block length
+% to be generated with full FFT frames.
+% Because of how SNR is calculated, we have n_bad_snr_frames poorly
+% rendered pixels at the end of a block.
+% TODO: There likely does not need to be any padding at the beginning, but
+% the padding currently is equal on both sides. Maybe remove pre-padding
+% elsewhere in code.
+n_bad_snr_frames = 1;
+block_pad_frames = Length_samples + n_bad_snr_frames;
+block_pad_s = block_pad_frames * Length_s/Length_samples; % 1 / thr.high_cutoff_Hz;
 
 % Determine what padding is needed.
 % padding will be added to each side of the current
@@ -302,8 +311,9 @@
     %fprintf('Block(%.4f - %.4f) = TimeIdx(%.4f - %.4f)\n', blkstart_s, blkend_s, Indices_blk.timeidx(1), Indices_blk.timeidx(end));
 
     % Plot spectrogram with image().
+    snr_dB_blk = snr_dB_blk(:, 1:floor((Indices_blk.FrameLastComplete - n_bad_snr_frames)));
     if (strcmp(FilterBank,'linear'))
-        ImageH(hidx) = image(Indices_blk.timeidx, frequencyAxis, snr_dB_blk, 'Parent', AxisH);
+        ImageH(hidx) = image(Indices_blk.timeidx(1:floor((Indices_blk.FrameLastComplete - n_bad_snr_frames))), frequencyAxis, snr_dB_blk, 'Parent', AxisH);
     elseif (strcmp(FilterBank,'constantQ'))
         ImageH(hidx) = image(Indices_blk.timeidx, log10(frequencyAxis), snr_dB_blk, 'Parent', AxisH);
     end
@@ -333,7 +343,8 @@
 end
 
 fclose(handle);
-set(AxisH, 'XLim', [Start_s, Stop_s]);
+% Padding was added to Stop_s earlier and now must be deducted
+set(AxisH, 'XLim', [Start_s, Stop_s - block_pad_s]);
 set(AxisH, 'YDir', 'normal');
 if strcmp(FilterBank, 'linear')
     set(AxisH, 'YLim', [frequencyAxis(1), frequencyAxis(end)]);

src/matlab/user_interface/dtTonalAnnotate.m

@@ -2125,7 +2125,9 @@ function annotationFilenameToClipboard_Callback(hObject, eventdata, handles)
 
 % Images will painted on top of any preview or selected points, 
 % Reorder, placing images at end of list
-axisChildren = get(axisH, 'Children');
+% "fliplr" is to ensure that the earlier block is rendered above
+% the latter: this hides visual artifacts of the snr averaging filter
+axisChildren = fliplr(get(axisH, 'Children')')';
 axisIndcs = 1:length(axisChildren);
 % Locate the images in the list of children
 imageIndcs = zeros(length(handles.image), 1);