[opus] MDCT implementation and his overlapped relationship

[Diego Alejandro Parra Guzman]

Dear all

In the paper section describes how CELT and SILK had implemented a look/up
head delay of (2.5ms), (5ms) respectively ,  could you explain me>

1) those values are fixed.
1)  how you  guarantee those values independent of the architecture's
performance.

Thanks so much


On Tue, Apr 18, 2017 at 10:05 AM, Diego Alejandro Parra Guzman <
daparrag at correo.udistrital.edu.co> wrote:

> thanks you so much for your answer.
>
> On Thu, Apr 13, 2017 at 8:59 AM, Jean-Marc Valin <jmvalin at jmvalin.ca>
> wrote:
>
>> Hi Diego,
>>
>> You might find figure 3 or this paper useful:
>> https://jmvalin.ca/papers/aes135_opus_celt.pdf
>>
>> It shows the MDCT window for a 5 ms frame, but the (non-zero) overlap is
>> always 120 samples regarless of the frame size. You can either see it as
>> partial overlap, or as a full-overlap with a window that has zeros on
>> the sides.
>>
>> Cheers,
>>
>>         Jean-Marc
>>
>> On 11/04/17 05:04 AM, Diego Alejandro Parra Guzman wrote:
>> > Dear all
>> >
>> > I'm working on the implementation of the MDCT for the processor
>> > ARM-Cortex-M4 I'm trying  to replicate the behavior of the MDCT
>> > for several overlapped values however I realized that current
>> > implementation of the MDCT is very close to the theory only in case in
>> > which we have and overlap exactly equal to N/2 where N is the size of
>> > the input vector as is shown in the examples  for celt.
>> >
>> > could you explain me if the implementation had been thought for
>> > different overlapped values, or instead the implementation uses only the
>> > overlap equal to N/2.
>> >
>> > Additional I want to know in case of overlapped values different to N/2
>> > which values had been considered.
>> >
>> > Thanks for you support.
>> >
>> > --
>> > Diego Alejandro Parra Guzmán
>> > Estudiante de ingeniería electrónica
>> > Universidad distrital FJC
>> >
>> >
>> > _______________________________________________
>> > opus mailing list
>> > opus at xiph.org
>> > http://lists.xiph.org/mailman/listinfo/opus
>> >
>>
>
>
>
> --
> Diego Alejandro Parra Guzmán
> Estudiante de ingeniería electrónica
> Universidad distrital FJC
>



-- 
Diego Alejandro Parra Guzmán
Estudiante de ingeniería electrónica
Universidad distrital FJC
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