[Mp4-tech] [Audio] Delay in eAAC+ Decoding

[Heiko Purnhagen]

> Dear Heiko,
>
> Thanks.
>
> I could observe 2048 samples difference as compared to
> AAC+  and
> the difference between eAAC+ and AAC is (962 + 2048)
> samples.  This can be observed by removing the first
> (2048 + 962) samples in both the channels of the
> output of eAAC+.

The additional delay of 1 frame (2048 samples) is due to the error
resilience mechanisms that are included in 3GPP's eAAC+ decoder but are
not within the scope of the MPEG-4 HE-AAC v1 and v2 profiles.
Best regards
     Heiko
>
> Thanks in advance for further info.
> Best regards,
> Datta
>
> --- Heiko Purnhagen <purnhage tnt.uni-hannover.de>
> wrote:
>
>> Dattaguru B.N. wrote:
>> > Dear Experts,
>> >
>> > Can anybody please let me know the reason for the
>> > delay in case of eAAC+ decoding as compared to
>> AAC.  I
>> > know there is some delay introduced by AAC+ as
>> > compared to AAC (962 samples).  But with eAAC+ the
>> > delay is no where related with 962 samples.  Can
>> > anybody please help me in understanding the reason
>> for
>> > the delay.
>>
>> Both AAC+ and eAAC+ decoders (to use the 3GPP
>> naming) should have
>> exactly the same additional delay of 962 samples
>> when compared to the
>> AAC core decoder at fs/2. What delays do you
>> observe?
>>
>> Best regards
>>
>>       Heiko
>>
>>
>> >
>> > Thanks in advance
>> > Best Regards,
>> > Datta
>> >
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