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Atari coding BBS
Re: adpcm or similar? |
Posted by: ray
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May,22.2006-19:09
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hi mikro,
as earx already pointed out, ADPCM is rather ineffective in terms of packing ratio. 1:4 is the maximum you can expect using 16bit samples while still providing a reasonable sound quality.
i also tried out some hacks/experiments trying to make up my own CPU-codec for the TT version of beams but finally decided for a mod conversion of loteks song as to me it seemed to be the most decent solution...to answer you question, i made up my own ADPCM codec compressing 8 bit samples -> 2 bit (thus also providing a ratio of 1:4, but with a lot more dynamic distortion than the usual 16->4bit compression, so the result basically sucked tbh). i also played around a bit with wavelets (again recently, when i came to finish BiQ) - some quickhacks on the peecee and in C, tho. but as it seems that the discrete wavelet transform isn't generally suited for audio-signals that well as it is the case with image signals, unless you are about to use some super sophisticated analyzation methods as mp2 does, leading to strong and noticeable artifacts with stronger quantization strengths, of course. i couldn't find any relieable information on this, so i can't tell whe ther there are wavelets suited better to natural/synthetic/whatever audio than daubechies and the mexican-hat?? maybe you should try check it out, as i assume a super-tight say 16-tap or more (??) - rough estimation, i'm sure you, or DSP-master earx know better. but come on, we are talking about simple 1D-signals - iDWT to be quite feasible in the 56k.
those were just some thoughts, so don't quote me on that ;)
regards, and good luck,
ray
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Posted by
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Date
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adpcm or similar?
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mikro
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May,21.2006-15:19
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Re: adpcm or similar?
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stghost
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May,21.2006-22:26
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Re: adpcm or similar?
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earx
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May,22.2006-09:20
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Re: adpcm or similar?
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mikro
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May,22.2006-12:38
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Re: adpcm or similar?
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earx
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May,22.2006-13:06
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Re: adpcm or similar?
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earx
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May,22.2006-13:24
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Re: adpcm or similar?
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ray
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May,22.2006-19:09
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Re: adpcm or similar?
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earx
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May,22.2006-22:48
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Re: adpcm or similar?
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gizmo
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May,23.2006-08:09
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Re: adpcm or similar?
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mikro
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May,23.2006-10:25
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Re: adpcm or similar?
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gizmo
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May,23.2006-20:23
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Re: adpcm or similar?
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earx
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May,23.2006-10:30
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Re: adpcm or similar?
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mikro
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May,23.2006-10:35
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Re: adpcm or similar?
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mikro
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May,27.2006-01:12
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Re: adpcm or similar?
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mikro
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May,27.2006-01:17
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Re: adpcm or similar?
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mikro
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May,27.2006-01:19
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Re: adpcm or similar?
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gizmo
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May,27.2006-10:45
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Re: adpcm or similar?
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mikro
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May,28.2006-14:24
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Re: adpcm or similar?
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earx
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May,29.2006-08:57
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Re: adpcm or similar?
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sqward
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May,29.2006-09:51
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Re: adpcm or similar?
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mikro
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May,29.2006-12:31
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Re: adpcm or similar?
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earx
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May,29.2006-13:18
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Re: adpcm or similar?
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sqward
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May,29.2006-14:13
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Re: adpcm or similar?
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sqward
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May,29.2006-14:19
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Re: adpcm or similar?
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mikro
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May,30.2006-13:45
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Re: adpcm or similar?
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earx
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May,30.2006-16:28
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Re: adpcm or similar?
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mikro
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May,31.2006-14:19
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Re: adpcm or similar?
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gwEm
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May,31.2006-17:59
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Re: adpcm or similar?
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ggn/KUA
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May,31.2006-22:26
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Re: adpcm or similar?
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gwEm
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Jun,06.2006-09:52
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Re: adpcm or similar?
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gwEm
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Jun,06.2006-10:03
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What's the anti-troll code? That's your personal code to be able to add comments and messages on the dhs.nu site.
Don't have a code or forgot it? Fix it here.
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