conv based speed stft

[futz12]

No description provided.

[tencent-adm]

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[github-actions]

Please enable github action in YOUR FORKED REPO to make code-format workflow work

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 98.52941% with 1 line in your changes missing coverage. Please review.

Project coverage is 94.13%. Comparing base (02fcca2) to head (c6ab155).
Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
src/layer/spectrogram.cpp	98.52%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5989      +/-   ##
==========================================
- Coverage   95.40%   94.13%   -1.28%     
==========================================
  Files         819      685     -134     
  Lines      264046   221001   -43045     
==========================================
- Hits       251922   208032   -43890     
- Misses      12124    12969     +845     

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[github-actions]

The binary size change of libncnn.so (bytes)

architecture	base size	pr size	difference
x86_64	16448264	16452352	+4088 ⚠️
armhf	7322360	7326236	+3876 ⚠️
aarch64	10703744	10703960	+216 ⚠️