[Mp4-tech] H264: is access unit delimiter required?

[Victor lyamtsev]

OK, so if I have to parse h264 stream, should I just start looking for the
NALU delimiters in RTP payload ( if I am using RTP as transport layer),  as
following?
next_bits (24) == 0x000001 && next_bites(32) == 0x000001 - for NALU start
next_bits(24) == 0x0 && next_bits(24) == 0x000001 - for NALU end
Thanks again,
-vl
On 10/24/07, Gary Sullivan <garysull windows.microsoft.com> wrote:
>
>  I am almost certain that the answer would be that the answer is No.  Part
> of the motivation behind some key aspects of the design of the video
> standard was to consider environments like RTP where some packets will be
> lost and it is therefore beneficial to ensure that slices can be decoded
> without dependency on a single copy of some picture header information that
> appears only once at the beginning of each picture in the transmission
> sequence.  If we assume that decoders include the functionality to decode
> individual slices when some information has been lost, the access unit
> delimiter would appear to serve no purpose in such an environment.
>
> Best Regards,
>
> Gary Sullivan
>
>  ------------------------------
> *From:* Victor lyamtsev [mailto:vlyamtsev gmail.com]
> *Sent:* Wednesday, October 24, 2023 7:32 AM
> *To:* mp4-tech lists.mpegif.org
> *Cc:* Gary Sullivan
> *Subject:* Re: [Mp4-tech] H264: is access unit delimiter required?
>
>  Does RTP transport require it?
> Thank you,
> -vl
>
>
> On 10/23/07, Gary Sullivan <garysull windows.microsoft.com> wrote:
> >
> >  Its presence is not required by the video standard.  However, its
> > presence may be required in some application-level specifications.
> >
> > Best Regards,
> >
> > Gary Sullivan
> >
> >  ------------------------------
> > *From:* mp4-tech-bounces lists.mpegif.org [mailto:mp4-tech-bounces lists.mpegif.org]
> > *On Behalf Of *Victor lyamtsev
> > *Sent:* Tuesday, October 23, 2023 7:31 AM
> > *To:* mp4-tech lists.mpegif.org
> > *Subject:* [Mp4-tech] H264: is access unit delimiter required?
> >
> >
> >  Hello,
> > Regarding parsing of H264 stream...
> > Do I have to start from searching for Access Unit delimiter to read NAL
> > unit? More to the point: is the Access Unit delimiter required by standard
> > and is it common practice to use it?
> > Thanks,
> > -vl
> >
> >
> >
> >
>
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