[Mp4-tech] Re: [HE-AAC] PS conformance test

[=?gb2312?B?0Oy+p8P3?=]

Hi Datta,
In 14496-4:2004/Amd 11:2006, it states:
"A conformant HE-AAC v2 profile decoder that receives a PS enhanced data stream shall output the mono signal in the two output channels until a first ps_data() element with enable_ps_header==1 is received, ensuring that the PS data can be decoded correctly."
Hope this helps,
Jingming
Dear Alex,
3GPP recommmends ODG test for PS Conformance unlike MPEG!
ISO also provides Conformance tool for validating PS in similar way as that of SBR.
I have query on PS Conformance.  If you see the PS conformance streams, they have PS data starting only
from the middle of the stream.  If my decoder searches for presence of PS only in the first frame and in
audioConfig info,  it will not be able to detect PS!
Can experts, please let me know how to handle such a scenario.  If I were to support these kind of (PS flagged
in the middle of the stream) should I have to create stereo always?  If so, how can we support Mono (AACLC and SBR)
streams?  Or if I say my decoder is eAACPlus decoder, its output will be always stereo?
Thanks in advance,
Datta
----- Original Message ----
From: Andy Quan <zhengyuan.quan gmail.com>
To: Alex Converse <alexc improvsys.com>
Cc: mp4-tech lists.mpegif.org
Sent: Sunday, 25 May, 2008 12:06:26 PM
Subject: Re: [Mp4-tech] [HE-AAC] PS conformance test
Many thanks!
On 5/24/08, Alex Converse <alexc improvsys.com> wrote:
> Andy Quan wrote:
> > Does ISO have conformance testing specification for aac+ v2 decoder?
> > Anybody knows its name?
> >
> >
> Parametric stereo conformance is covered in 14496-4:2004/Amd 11:2006 and Cor
> 2:2007
>
> > I find that 3GPP TS 26406 has introduced a set of testing vectors and
> > set ODG score as its metric. However, unlike ISO SBR testing, this
> > 3GPP testing method is not dedicated for PS tools as there is no such
> > a testing framework that can block errors from LC+SBR.
> >
> >
> The decoder conformance procedure is similar to SBR. But your mention of ODG
> makes me think that you may be referring to encode. For encode all the ISO
> spec is going to tell you is if you have a properly formatted bitstream. For
> decode 26.406v7.0.0 defers to ISO.
>
> Regards,
> Alex Converse
>

--
Regards,
Andy Quan
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