On Tue, Nov 17, 2015 at 04:08:29AM +0300, Даниил Чередник wrote: > Thank you for answer. > > If I understood available ATRAC1 docs, the purpose of this delay line is > just to compensate delay of 1st QMF because for 1st and 2nd band we have > two QMF but for 3rd band just one. > > About test, yes for some reason this patch brakes it. I will try to find > out. Sorry, I should have done it before.
np if the changed / new version is more correct then please also provide a new reference file for the fate samples with a new filename and update the fate test so it uses the new file thanks > > I tried to decode "The Four Seasons, Concerto Alla Rustica in G - Winter- > Largo.aea" sample, the results are: > without patch: https://yadi.sk/i/PCFplrafkWEFC > with patch: https://yadi.sk/i/iLUR188gkWEFn > On zoomed spectrogram it is possible to find aliasing if decode without > patch. I can share decoded wav file if needed. > > > > On Mon, Nov 16, 2015 at 3:45 AM, Michael Niedermayer <mich...@niedermayer.cc > > wrote: > > > On Sat, Nov 14, 2015 at 02:59:30AM +0300, Даниил Чередник wrote: > > > Hello! > > > > > > I have noticed if decode > > > > > https://samples.ffmpeg.org/A-codecs/ATRAC1/Test%20tones%20disc%20-%20Chirp.aea > > > file by ffmpeg we got aliasing near 11025Hz. Screenshots: > > > https://yadi.sk/i/r-95jZkKkSnbu https://yadi.sk/i/PV92LNESkSnby > > > > > > I was tried to solve it: > > > > > > ATRAC1 - hybrid codec, has two stacked QMF and splits the signal into 3 > > > band before MDCT. Thereby we need to compensate delay of one QMF to > > > achieve reconstruction. > > > There is a delay line but it looks like delay for 23 sample is not > > correct. > > > I have done some experiments and got 39 should be right delay. Results of > > > decoding with patch: https://yadi.sk/i/yooaIQrmkSncB > > > https://yadi.sk/i/CUXsH7-CkSncK > > > > > > > > To be honest I am not a prof in math and it would be great if someone > > > recheck it from math perspective. > > > > i dont think math can help here > > whatever a format requires that has to be done, this could even be > > wrong from a math point of view of a ideal transform > > > > > > > > > > There is a patch in attach. > > > > the patch also affects the atrac1 fate test > > have you checked if the new output for that test is better than the > > old ? > > > > make V=2 fate-atrac1 > > > > also have you looked at other files, is this improving all files ? > > any that get worse ? > > > > > > [...] > > > > -- > > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB > > > > Many that live deserve death. And some that die deserve life. Can you give > > it to them? Then do not be too eager to deal out death in judgement. For > > even the very wise cannot see all ends. -- Gandalf > > > > _______________________________________________ > > ffmpeg-devel mailing list > > ffmpeg-devel@ffmpeg.org > > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > > > > > > -- > Daniil Cherednik > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB The greatest way to live with honor in this world is to be what we pretend to be. -- Socrates
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