[FFmpeg-devel] [PATCH] RDFT for Bink and QDM2

Alex Converse alex.converse
Sat Jan 17 19:29:13 CET 2009


Attached is my RDFT patch with all the feedback applied. Also attached
is a patch that makes use of it in QDM2 decoding. I thought I had
unwrapped the math perfectly but it looks like things changed for the
better.

Also new is a flag for FFT sign convention. This is because the
inverse transform is not the same as the forward transform with the
opposite sign convention, scaled.

The reference files are decoded with the binary coder from the qt63 dlls.

$ tests/tiny_psnr ../qdm2/nadasurf_popular_dl.wav old.wav 2 0 44
stddev: 1305.89 PSNR: 34.00 bytes: 39632896/ 39632896
$ tests/tiny_psnr ../qdm2/nadasurf_popular_dl.wav new.wav 2 0 44
stddev: 1145.39 PSNR: 35.14 bytes: 39632896/ 39632896
$ tests/tiny_psnr ../qdm2/switzler084d_dl.wav old.wav 2 0 44
stddev:  377.46 PSNR: 44.78 bytes: 20660224/ 20660224
$ tests/tiny_psnr ../qdm2/switzler084d_dl.wav new.wav 2 0 44
stddev:  305.00 PSNR: 46.63 bytes: 20660224/ 20660224
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