[FFmpeg-devel] [PATCH] E-AC-3 spectral extension

[Michael Niedermayer]

On Tue, Jun 02, 2009 at 08:28:42PM +0000, Loren Merritt wrote:
> On Tue, 2 Jun 2009, Michael Niedermayer wrote:
>> On Mon, Jun 01, 2009 at 11:37:08PM -0400, Justin Ruggles wrote:
>>> Michael Niedermayer wrote:
>>>
>>>> about the PRNG, well just decode a AC3 with 2 different PRNGS and 
>>>> compare
>>>> by how much they differ
>>>
>>> LFG vs. MLFG
>>> stddev:   14.99 PSNR: 72.80 bytes:  3999744/  3999744
>>>
>>> Nero vs. FFAC3
>>> stddev:   19.75 PSNR: 70.41 bytes:  3998720/  3999744
>>
>> nice, so we are down to a stddev of ~4.76 that looks alot healthier 
>> already
>> than the >100 of before, still its a little larger than what it should be,
>> of course that might be a issue in nero as well instead of our decoder ...
>
> Nitpick: assuming independence, it's variance that's additive, not stddev.
> The amount of nero vs ffac3 difference that isn't explained by RNG is
> sqrt(19.75**2 - 14.99**2) = 12.86

of course
i mixed them up ... math and headache dont mix too well
thanks for correcting that mistake


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