[Mp4-tech] IDR period and intra period

[Satendra]

All IDR frames are Intra frames, hence IDR is a subset of Intra.
But IDR has all features of Intra frames, and have some extra features.
Hence IDR is a superset of Intra in terms of features.
:-D
Best Regards
Satendra
On Tue, Mar 18, 2024 at 9:48 PM, <Ye-Kui.Wang nokia.com> wrote:
>  An important typo below:
>
> IDR is a subset (NOT superset) of Intra.
>
> BR, YK
>
>  ------------------------------
> *From:* mp4-tech-bounces lists.mpegif.org [mailto:
> mp4-tech-bounces lists.mpegif.org] *On Behalf Of *ext Satendra
> *Sent:* Tuesday, March 18, 2024 11:11 AM
> *To:* Venkat Subbiah
> *Cc:* ashfiqua tahseen; mp4-tech lists.mpegif.org
> *Subject:* Re: [Mp4-tech] IDR period and intra period
>
> Simple terminology
>
> IDR picture is a superset of Intra picture.
>
> IDR picture is an Intra picture, but it says that now onwards decoder can
> not use any of the previously decoded pictures as reference picture for
> inter decoding.
>
> Best Regards
> Satendra
>
>
> On Mon, Mar 17, 2024 at 10:43 PM, Venkat Subbiah <vsubbiah iavior.com>
> wrote:
>
> >
> >    1. What is the difference between an IDR picture and Intra
> >    picture?
> >
> > *instantaneous decoding refresh (IDR) picture*: A *coded picture *in
> > which all *slices *are *I *or *SI slices *that
> >
> > causes the *decoding process *to mark all *reference pictures *as
> > "unused for reference" immediately after
> >
> > decoding the IDR picture. After the decoding of an IDR picture all
> > following *coded pictures *in *decoding order*
> >
> > can be decoded without *inter prediction *from any *picture *decoded
> > prior to the IDR picture. The first *picture *of
> >
> > each *coded video sequence *is an IDR picture.
> >
> >
> >
> > Above is the definition of an IDR picture from the standard. As you can
> > see the focus of the definition is on "all picture all following *coded
> > pictures *in *decoding order*
> >
> > can be decoded without *inter prediction *from any *picture *decoded
> > prior to the IDR picture". This part might not be necessarily true for just
> > an I picture.
> >
> >
> >
> > *I slice*: A *slice *that is not an *SI slice *that is decoded using *prediction
> > *only from decoded samples within the
> >
> > same *slice*.
> >
> > Ø       Above again is a definition from the standard and as it reads
> > the only restriction about I slice is the prediction is only from decoded
> > samples within the same slice. And it does **not** say anything about
> > following picture.
> >
> >
> >
> > -Venkat
> >
> >
> >  ------------------------------
> >
> > *From:* mp4-tech-bounces lists.mpegif.org [mailto:
> > mp4-tech-bounces lists.mpegif.org] *On Behalf Of *ashfiqua tahseen
> > *Sent:* Friday, March 14, 2024 12:17 PM
> > *To:* mp4-tech lists.mpegif.org
> > *Subject:* [Mp4-tech] IDR period and intra period
> >
> >
> >
> > Hi,
> >
> >
> >
> > 1. What is the difference between an IDR picture and Intra picture? And
> > what is the difference between IDR period and intra period?
> >
> >
> >
> > 2. We can set different QP for I and P slice. I am just curious, in real
> > application, do the companies use different QP for tham?
> >
> >
> >
> > Any suggestion will be highly appreciated.
> >
> >
> >
> > With regards,
> >
> > Ashfiqua
> >
> >
> >  ------------------------------
> >
> > Never miss a thing. Make Yahoo your homepage.<http://us.rd.yahoo.com/evt=51438/*http:/www.yahoo.com/r/hs>
> >
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> >
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> >
>
>
>
> --
>
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>
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