[Mp4-tech] Ask for help in streaming H264 bitstream using RTP

[Herbert Thoma]

Basim Javed schrieb:
> dear Sir
> I have tried on this timing issue of H.264 with RTP enabled.As you stated,
> reciprocal of frame rate would be the display timingfor each frame;
> but when we encode with slice size=1000 bytes, do youthink:
> 1. it is a fixed frame rate. If yes, then how do we ensure? (whichparameter of encoder.cfg)

I am not very familiar with the JM reference software. But as far as I know the
JM encoder will produce fixed frame rate. (Well, it will produce the same timing
as the timing of the input YUV file.)
> 2. what are these SEI messages, and where they are and how tointerpret them on the
> receiver side, and how to effectively use them?

picture timing SEI messages are defined in Annex D.1.2 of the standard.
I don't know if the JM encoder can produce these SEI messages.
> 3. since now we get RTP packets, which contain NALU, which contain theslices,
> how do we understand the meaning of SEI messges?

again see Annex D.1.2
Regards,
 Herbert.
> On Tue, Mar 25, 2024 at 11:21 AM, Herbert Thoma<herbert.thoma iis.fraunhofer.de> wrote:> Felix schrieb:>> > Hi All:>  >>  >     I am trying to stream from a H264 bytestream file(a sequence of>  > NALUs in Annex B format).>>  A H.264 bytestream is not very well suited for streaming. It usually>  contains no timing information. A H.264 bitstream can contain timing>  information in so called picture timing SEI messages, but these SEI>  messages are not mandatory.>>  You might consider using a file format that contains timing information,>  e.g. the ISO file format (ISO/IEC 14496-12 + ISO/IEC 14496-15 for AVC).>>>  >     I come across some problems that you might help with.>  >     Some similar problems might have alreday been discussed on the>  > maillist before, but I sitll can not figure out the solution when>  > streaming a H264 bitstream file:>  >>  >    1.How to calculate the presentationTime for each frame:>  >>  >      The first frame's presentationTime is get from the 
wallclock by>  > "gettimeofday()", what about the following frames?>  >>  >    2.How to calculate the DurationTime?>  >>  >      DurationTime is usede to calculate the nextTime to send packet, how>  > to calculate it if I am streaming from a H264 bytestream file, rather>  > than from a live encoder? Is the DurationTime the reciprocal of Frame Rate?>>  The duration time of one AU is the reciprocal of the frame rate only>  if the bitstream is a constant frame rate bitstream.>>>  >    3.How to judge the current NALU Ends one AccessUnit in the function>  > currentNALUnitEndsAccessUnit()?>  >>  >      I found some clues in H264's standand document's section 7.4.1.2.4,>  > is it the right place?>>  Yes, the section 7.4.1.2.4 "Detection of the first VCL NAL unit of a primary>  coded picture" is the right place. However, your server needs to parse the>  H.264 bistream to the slice header level to access the needed information.>>  IMHO one of the following requirements has to be fulfi
lled to be able to>  stream from a H.264 bytestream:>>  - you need to know that the bitstream is fixed frame rate and you need to>   know that frame rate>>  or>>  - the bitstream contains picture timing SEI messages>>  Regards,>   Herbert.>>>  >    Any help will be apprecaiated!>  >    Thanks.>  >>  > B.R.>  > Felix.Xu>  >>  > ------------------------------------------------------------------------>  > ÑÅ»¢ÓÊÏ䣬ÄúµÄÖÕÉúÓÊÏ䣡 <http://cn.mail.yahoo.com/>>  >>  >>  > ------------------------------------------------------------------------>> >>  > _______________________________________________>  > NOTE: Please use clear subject lines for your posts. Include [audio, [video], [systems], [general] or another apppropriate identifier to indicate the type of question you have.>  >>  > Note: Conduct on the mailing list is subject to the Antitrust guidelines found at http://www.mpegif.org/public/documents/vault/mp-out-30042-Antitrust.php>>  -->  !!! Please note new phone and fax numbe
rs !!!>  Herbert Thoma>  Head of Video Group>  Multimedia Realtime Systems Department>  Fraunhofer IIS>  Am Wolfsmantel 33, 91058 Erlangen, Germany>  Phone: +49-9131-776-6130>  Fax:   +49-9131-776-6099>  email: tma iis.fhg.de>  www: http://www.iis.fhg.de/>>> _______________________________________________>  NOTE: Please use clear subject lines for your posts. Include [audio, [video], [systems], [general] or another apppropriate identifier to indicate the type of question you have.>>  Note: Conduct on the mailing list is subject to the Antitrust guidelines found at http://www.mpegif.org/public/documents/vault/mp-out-30042-Antitrust.php>
> 

-- 
!!! Please note new phone and fax numbers !!!
Herbert Thoma
Head of Video Group
Multimedia Realtime Systems Department
Fraunhofer IIS
Am Wolfsmantel 33, 91058 Erlangen, Germany
Phone: +49-9131-776-6130
Fax:   +49-9131-776-6099
email: tma iis.fhg.de
www: http://www.iis.fhg.de/