Hi Rishi and Jamie,
Thanks again for your replies.
We will write an opaque data parser for H.264 for our
needs.
Best regards,
Carol.
-----Original Message-----
From: ext Rishi Mathew [mailto:rmathew real.com]
Sent: Wednesday, August 15, 2007 7:48 PM
To: Jamie Gordon; Chen Carol.I (Nokia-TP-MSW/Dallas)
Cc: nokia-private-devhelixcommunity.org;
datatype-devhelixcommunity.org
Subject: Re: [datatype-dev] Question about H264 Profile
info
Carol,
The Helix Server does not do Opaquedata parsing. As Jamie
says, if you
are seeing a fmtp line in SDP with little information, then
it is
because the encoder which generated the content only made
that much
information available.
If you want to handle these cases, and figure out which
decoder to load
for different kinds of H.264 content, then you have to write
an
Opaquedata parser. This operation is similar to what exists
for
RealMedia which can have different 4ccs for different codecs
embedded
within a RM file.
Cheers,
Rishi.
At 03:10 PM 8/15/2007, Jamie Gordon wrote:
>Carol.i.Chennokia.com wrote:
>>Hi Jamie,
>>Thanks for your response.
>>Here is the problem we are having:
>>When we stream a H.264 clip from Helix Mobile
Server, we get something
>>like this in the SDP:
>> a=fmtp:96
>>
>>a=OpaqueData:buffer;"AAAAKWF2Y0MBTQAo/+EAEmdNAC
iadAoP0IAHoxQAco4sQgEAB
>>Gj
>>uPIA="
>>We are checking for the profile-level-id from the
fmtp parameters, but
>>in this case can't obtain it. We want to be able to
determine the
>>profile and decide which decoder to use (or whether
to even pass it to
>>decoder). Currently there's a H.264 Main profile
clip that is crashing
>>our decoders. We would like to be able to prevent
that.
>Only hinted H.264 is supported, which means the fmtp,
etc. is created
>by the encoder or hinting tool, *not* the server.
>
>if the content is hinted and the hint track does not
contain correct
>expected SDP info, then you will need to look into the
encoder you are
>using.
>
>If the content is unhinted, it is possible that you are
using a version
>of the mp4 plugin that attempts to allow the client-side
packetization
>rather than simply erring out. If that is the case, this
is not a
>supported or tested usage configuration. It will
certainly not work
>with any non-helix clients and may or may not work well
with helix
clients.
>The mime type advertised in the SDP would be different
than the
>standard mime type in this case, since it is a different
streaming
>profile and configuration than the standard
packetization.
>
>Jamie
>
>>Some questions I hope you can help us with:
>>(1) Does the Helix Mobile Server actually parse the
opaque data in
>>H.264 contents to obtain profile-level-id and send
this as fmtp
>>parameter in the SDP?
>> -- (a) If so, does it parse every time? (and
what might cause it
>>to fail this time?)
>> -- (b) If only sometimes, under what conditions
will it parse or
>>not parse?
>> -- (c) Can the opaque data be relied on to get
the profile info
>>for all H.264 clips?
>> -- (d) Is this code reusable for the DNA Helix
client software?
>>(2) Does the answers to the same questions apply to
H.263 as well,
>>when Opaque data is received instead of
profile-level-id from SDP ?
>>Thanks again,
>> Carol.
>>
>>-----Original Message-----
>>From: ext Jamie Gordon [mailto:jgordonreal.com]
Sent: Tuesday, August
>>14, 2007 3:05 PM
>>To: Chen Carol.I (Nokia-TP-MSW/Dallas)
>>Cc: nokia-private-devhelixcommunity.org;
>>datatype-devhelixcommunity.org
>>Subject: Re: [datatype-dev] Question about H264
Profile info That code
>>should not be used on the server.
>>datatype/mp4/fileformat/h264packetizer.cpp is client
side code and is
>>not meant to be compiled into a server build.
>>Helix DNA Server open source server does not include
H.264 support.
>>Helix Mobile Server includes support for hinted
h.264 content only.
>>Thanks,
>>Jamie
>>Carol.i.Chennokia.com wrote:
>>>Hi,
>>>
>>>We are having issues getting Profile level
information of H264 clips
>>>from SDP during streaming.
>>>
>>>The fmtp parameters we get from the SDP is
something like this:
>>> a=fmtp:96
>>>
>>>An example of a more complete fmtp line that
we're expecting:
>>> a=fmtp:96* profile-level-id=4D400D*;
>>>parameter-sets=Z01ADZZUCwSn/gACAAIB,aO44gA==;
packetization-mode=1
>>>
>>>The code for writing the profile-level-id etc.
seem to be in:
>>>
/datatype/mp4/fileformat/h264packetizer.cpp
>>> H264Packetizer::AddHeaderSDPData()
>>>
>>>However, is the server does not seem to be
extracting these
>>>information from the opaque data and adding it
to the SDP for some
>>H264 clips.
>>>We need the profile info for codec
configuration. If we can't depend
>>>on the server to provide us with the info, I
would add a parser for
>>>opaque data to retrieve it in:
>>>
>>>
CH264PayloadFormatPluginDevice::CreatePayloadFormat()
>>>
>>>Any comments, suggestions? Is there another way
to reliably obtain
>>>profile level information?
>>>
>>>Thanks,
>>> Carol.
>>>
>>>
>>>------------------------------------------------
---------------------
>>>-
>>>--
>>>
>>>_______________________________________________
>>>Datatype-dev mailing list
>>>Datatype-devhelixcommunity.org
>>>http://lists.helixcommunity.org/mailman/listinfo/da
tatype-dev
>
>_______________________________________________
>Datatype-dev mailing list
>Datatype-devhelixcommunity.org
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tatype-dev
Rishi Mathew
Helix Community
RealNetworks, Inc.
rmathewreal.com
http://www.helixcommuni
ty.org
http://www.realnetworks.com/products/support/devsupp
ort.html
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