Subject: [AVT] Where can I get ISO/IEC 1172 from

From: Deepak Kotian <[email-masked]>
Date: Wed, 27 Aug 2003 03:12:35 +0530

Hi,

    I want to implement RFC 2250 for MPEG1 Video and Audio ES.
    Helix( RealOne forum) say that I would need ISO/IEC 1172 for RFC 
    implementation. Where can I get ISO/IEC 1172 from, any inputs on this one please

Here is the extract of the document from real networks
***********************
·       MPEG-1
Helix Universal Server delivers ISO/IEC 1172 compliant video and system bit 
streams over RTSP/RTP. RealOne Player and QuickTime Player, for example, 
can play MPEG-1 streams. Helix Universal Server delivers MPEG-1 content 
with file extensions of mpa, mpg, mpeg, mpv, mps, m2v, m1v, and mpe
***********************

Thanks and Regards
Deepak

  ----- Original Message ----- 
  From: Deepak Kotian 
  To: [email-masked] 
  Cc: [email-masked] 
  Sent: Tuesday, August 26, 2003 8:26 PM
  Subject: Re: [AVT] RTP timestamp calculation for MPEG1 Video and Audio ES so that itworks with RTSP client like RealOne/QuickTime

  Hi,

  >>There is also an interoperablity statement for >>RTP/RTSP in the real 
  >>networks site. Sorry, I am not able to cite the >>exact document at 
  >>present. try downloading from their website.

  Just to add.
  About this documents, there seems to be no 
  document with the RealOne guys for the timestamp calculation,etc. I checked with them at the helix forum.

  Thanks and Regards
  Deepak

  ----- Original Message ----- 
    From: Deepak Kotian 
    To: [email-masked] 
    Cc: [email-masked] 
    Sent: Tuesday, August 26, 2003 7:33 PM
    Subject: Re: [AVT] RTP timestamp calculation for MPEG1 Video and Audio ES so that itworks with RTSP client like RealOne/QuickTime

    Hi,

    Thanks for the inputs.
    But, these RFCs do not mention about the PTS or DTS timestamp
    calculation, it seems the RTP timestamp is derived from PTS or DTS
    of headers. Which is usually 33 bits, that too is mystery to me as
    the RTP timestamp is 32 bits. 
    That is what I have heard.

    Is there a very simple implementation where Minimal RTSP server
    is implemented and works with RealOne via RTP for both MPEG1 audio 
    and video Elementary stream.
    The helix source is really very big to understand quickly.
    Some more inputs would be of great help.

    Thanks and Regards
    Deepak

      ----- Original Message ----- 
      From: Neo Anderson 
      To: [email-masked] 
      Cc: [email-masked] 
      Sent: Tuesday, August 26, 2003 11:14 AM
      Subject: Re: [AVT] RTP timestamp calculation for MPEG1 Video and Audio ES so that itworks with RTSP client like RealOne/QuickTime

          Hi,

          Since you have mentioned the documents yourself, I think they 
          provide sufficient information for interop with realone. Check out 
          rfc3550 too.

          We need to provide the timestamp with the proper clock rates 
          mentioned for the specific media type payload format (rfc2250).

          For example, if the clock is 90kHz, practically, multiply the 
          timestamp in seconds by 90000. This is the RTP  timestamp value to be 
          transmitted in the packet. Check out the clock rates carefully for 
          each media type and associated payload format is used.

          Take care of putting proper NTP and RTP timestamp correlation while 
          sending SR packets.

          There is also an interoperablity statement for RTP/RTSP in the real 
          networks site. Sorry, I am not able to cite the exact document at 
          present. try downloading from their website.

          --Neo
          Get your own Free E-mail at Witch Wisdom http://www.witchwisdom.com
          __________________
          http://www.zzn.com

---

From: Deepak Kotian <[email-masked]>
Date: Wed, 27 Aug 2003 08:33:54 +0530

Thanks for the input.
So, basically it is difficult to get it.
Can someone in the forum have a handy document for calculation of RTP timestamp with reference
to PTS/DTS for Video and Audio ES.

Any help on this would be great.

Thanks and Regards
Deepak
  ----- Original Message ----- 
  From: Sandy (Alexander) MacInnis 
  To: Deepak Kotian ; [email-masked] 
  Sent: Wednesday, August 27, 2003 6:09 AM
  Subject: Re: [AVT] Where can I get ISO/IEC 1172 from

  The MPEG-1 standard is ISO/IEC 11172 (not 1172). That looks like a typo.

  The systems part is 11172-1, video is 11172-2, and audio is 11172-3.

  These standards are copyrighted by ISO/IEC, and they are available in hard copy from the national standards bodies and IEC.

  There may be some people with bootleg non-final soft copies, but as far as I know they are not permitted to be distributed due to copyright.

  --Sandy MacInnis
  Broadcom
  (Chair of MPEG-1 Systems and MPEG-2 Systems at the time they were developed.)

  At 02:42 PM 8/26/2003, Deepak Kotian wrote:

    Hi,

     
    Thanks and Regards
    Deepak

---

From: "Sandy (Alexander) MacInnis" <[email-masked]>
Date: Tue, 26 Aug 2003 17:39:24 -0700

The MPEG-1 standard is ISO/IEC 11172 (not 1172). That looks like a
typo.

The systems part is 11172-1, video is 11172-2, and audio is
11172-3.

These standards are copyrighted by ISO/IEC, and they are available in
hard copy from the national standards bodies and IEC.

There may be some people with bootleg non-final soft copies, but as far
as I know they are not permitted to be distributed due to
copyright.

--Sandy MacInnis

Broadcom

(Chair of MPEG-1 Systems and MPEG-2 Systems at the time they were
developed.)

Hi,

I want to implement RFC 2250
for MPEG1 Video and Audio ES.

Helix( RealOne forum) say
that I would need ISO/IEC 1172
for RFC

implementation. Where can I
get ISO/IEC 1172
from, any inputs on this one
please

Here is the extract of the document from real
networks

***********************

·       MPEG-1

Helix Universal Server delivers ISO/IEC 1172 compliant video and system
bit

***********************

Thanks and Regards

Deepak

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt

---

From: Deepak Kotian <[email-masked]>
Date: Thu, 28 Aug 2003 00:14:48 +0530

The cost seems to be 44,00 swiss francs, I do not have that
much of budget to shell on this right now.
Unless there is some other way to get it.

I  just need a proper RTP timestamp calcualation for MPEG1 audio
and Video ES considering various frames and I think someone in the group
should have some handy docuement on it.
Can someone share it generously.

Thanks and Regards
Deepak

----- Original Message -----
From: "Colin Perkins" <[email-masked]>
To: "Deepak Kotian" <[email-masked]>
Cc: "Sandy (Alexander) MacInnis" <[email-masked]>; <[email-masked]>
Sent: Wednesday, August 27, 2003 11:23 PM
Subject: Re: [AVT] Where can I get ISO/IEC 1172 from

I believe you can now buy copies of ISO standards online, available for
download as PDF files. See
http://www.iso.ch/iso/en/prods-services/ISOstore/store.html

Colin

On Wednesday, Aug 27, 2003, at 04:03 Europe/London, Deepak Kotian wrote:

> There may be some people with bootleg non-final soft copies, but as
> far as I know they are not permitted to be distributed due to
> copyright.
>
> --Sandy MacInnis
> Broadcom
--
Colin Perkins
http://csperkins.org/

---

From: "Sandy (Alexander) MacInnis" <[email-masked]>
Date: Wed, 27 Aug 2003 12:01:20 -0700

The MPEG-1 Systems standard doesn't say anything directly about RTP.

Fundamentally, it specifies a formal timing model for determining the 
conformance of bit streams, and this timing model uses time stamps.

There are 3 types of time stamps included:

- SCR (System Clock Reference) - this is in effect a sample of the stream's 
(i.e. sender's) time base as it applies to the compressed stream. To the 
receiver it means, in effect, "When you get this, the time is the value in 
this SCR".

- PTS (Presentation Time Stamp) - indicates the presentation (i.e. display) 
time of a picture. This is always delayed from the time the compressed data 
at the start of a picture arrives, since there is a non-negative delay in 
the compressed data buffer and it takes time to transfer a picture across a 
finite rate channel.

- DTS (Decoding Time Stamp) - indicates the decoding time of a picture, in 
case it is different from the PTS. This is really to easy conformance 
testing, decoders don't need to make use of it. DTS != PTS in the case of I 
and P pictures in streams that may have B pictures, due to the re-ordering 
delay that is inherent in the use of B pictures.

All of these refer to an idealized decoder model called an STD (System 
Target Decoder); there are significant differences between the STD model 
and most real decoders. For example, in the STD, pictures are decoded 
instantaneously, and they are displayed instantaneously (not with raster 
scan). Those differences are not relevant to an encoder - the requirements 
of the stream are set by the standard, not by individual decoders. However 
decoders typically have to make some adjustments to account for the time 
required to decode pictures, etc.

All of the time stamps (SCR, PTS, DTS) are samples of same underlying time 
base. This is fundamental to the way MPEG Systems works (MPEG-1, MPEG-2 
Transport, and MPEG-2 Program streams).

--Sandy

At 11:35 AM 8/27/2003, Deepak Kotian wrote:
>Thanks for the link.
>I assume, it will really help for RTP timestamp calculation
>for realTime video generated from encoder boards.
>
>Thanks and Regards
>Deepak

---

From: Deepak Kotian <[email-masked]>
Date: Thu, 28 Aug 2003 00:05:32 +0530

Thanks for the link.

Thanks and Regards
Deepak

----- Original Message -----
From: "Colin Perkins" <[email-masked]>
To: "Deepak Kotian" <[email-masked]>
Cc: "Sandy (Alexander) MacInnis" <[email-masked]>; <[email-masked]>
Sent: Wednesday, August 27, 2003 11:23 PM
Subject: Re: [AVT] Where can I get ISO/IEC 1172 from

Colin

--
Colin Perkins
http://csperkins.org/

---

From: Colin Perkins <[email-masked]>
Date: Wed, 27 Aug 2003 18:53:41 +0100

Colin

-- 
Colin Perkins
http://csperkins.org/

---

From: Deepak Kotian <[email-masked]>
Date: Thu, 28 Aug 2003 08:20:24 +0530

Thanks for inputs.
Just telling you the backgorund.
I have an encoder which sends out Video ES and Audio ES, I want
to send it out in RTP format to play it on RealOne player. We have
supported RTSP Minimal server and RealOne player plays Video with some
breaks
and latency and 2 sec audio after 1 minute. Do not know the exact reason.
So, we are doubting the RTP timestamp calculation which is not
clear from the RFC. We have done encapsulation as per RFC 2250.

Any suggestions on this

List my query/problem in a simpler way.

1.  Where do I source the Time to be fed in RTP timestamp field in the
      RTP header in my case, should it be PTS/DTS/SCR. This is mainly for
      MPEG1 for Video ES
      Is there some calculation needed for the same.

2.   Also, If the calculation is to be done from MPEG1 headers, the SCR/PTS
field
      seems to of 33 bits, how do we fit it in 32 bit timestamp of RTP.

3.  Should the SCR or PTS or DTS be multiplied by 90 and fed in the RTP
timestamp.

4.  Is there a special way to calculate time for B-Frame for Video ES.

Can one over here kindly give their  view on these queries.

Thanks and Regards
Deepak

---

From: Aaron Colwell <[email-masked]>
Date: Thu, 28 Aug 2003 09:29:14 -0700 (PDT)

comments inline

>       Is there some calculation needed for the same.

If you look at the RTP RFCs (RFC 1889 or RFC 3550) you will see that it 
says "The timestamp reflects the sampling instant of the first octet in 
the RTP data packet". This statement implies PTS. Later in that section it 
specifically talks about MPEG. It says 
  "Consecutive RTP packets MAY contain timestamps that are not monotonic 
   if the data is not transmitted in the order it was sampled, as in the 
   case of MPEG interpolated video frames."

This again implies PTS because in the case where B frames are used the PTS 
timestamps are not monotonically increasing when the frames are 
transmitted in decode order.

>       seems to of 33 bits, how do we fit it in 32 bit timestamp of RTP.
Drop the 33rd bit. Doing this will just cause the RTP timestamp to wrap 
faster than the MPEG timestamp.

> 3.  Should the SCR or PTS or DTS be multiplied by 90 and fed in the RTP
I'm not 100% sure about this, but I believe that the PTS sample rate is 
90kHz. That is the same sample rate that the RTP timestamps should be in 
for MPEG. You should not need to modify the timestamps in any way other 
than adding the random offset specified in the RTP spec.

> 4.  Is there a special way to calculate time for B-Frame for Video ES.
See my answer for 1. Just use the PTS timestamps.

Aaron

---

From: Deepak Kotian <[email-masked]>
Date: Fri, 29 Aug 2003 00:24:55 +0530

Thanks very much for an excellent response.
We will check this one out and see how it works for us.

1. Also, the RFC 2250 does not say much about how to clearly
encapsulate the MPEG1 Audio ES, frag_offset, frame sync and
timestamp for the same.
Can one give more details on it.
I calculated the as per one of the post, the loading in RealOne
seems faster, but there seems to be audio being played for the
same.

2. Which RFC/document would be good reference for details of MPEG1 system
and
    audio/video ES header details and how MPEG1 packetization
    is done,etc.

Could one please let me know.

Thanks and  Regards
Deepak

----- Original Message -----
From: "Aaron Colwell" <[email-masked]>
To: "Deepak Kotian" <[email-masked]>
Cc: "Sandy (Alexander) MacInnis" <[email-masked]>; "Colin Perkins"
<[email-masked]>; <[email-masked]>
Sent: Thursday, August 28, 2003 9:59 PM
Subject: Re: [AVT] Where can I get ISO/IEC 1172 from

> > > the compressed data buffer and it takes time to transfer a picture
across
> > a
> > > testing, decoders don't need to make use of it. DTS != PTS in the case
of
> > I