Problems parsing SDP file for RTP type 33

[Ben Barker]

Hi,

I have two SDP files. On points to an Mpeg4 multicast stream, the
other to a Mpeg 2 DVB stream.

If I try to access the former with the following sdp:

v=0
m=video <port> RTP/AVP 96
c=IN IP4 <mcaddress>
a=rtpmap:96 MP4V-ES/90000
a=source-filter: incl IN IP4 <mcaddress>  <source_address>

All works fine, and from the command line I see that the SDP has been
properly parsed:

FFmpeg version git-b319052, Copyright (c) 2000-2011 the FFmpeg developers
  built on Aug 15 2011 16:42:18 with gcc 4.1.2 20070626 (Red Hat 4.1.2-14)
  configuration:
  libavutil    50. 37. 0 / 50. 37. 0
  libavcore     0. 16. 1 /  0. 16. 1
  libavcodec   52.109. 0 / 52.109. 0
  libavformat  52. 97. 0 / 52. 97. 0
  libavdevice  52.  2. 3 / 52.  2. 3
  libavfilter   1. 74. 0 /  1. 74. 0
  libswscale    0. 12. 0 /  0. 12. 0
found ssm_source..<source_address>
found ssm_source....<source_address>

At which point streaming starts.

If however I try to access my Mpeg2 stream using the following sdp:

v=0
m=video <port> RTP/AVP 33
c=IN IP4 <multicast_address>
a=rtpmap:96 MP4V-ES/90000
a=source-filter: incl IN IP4 <multicast_address> <source_address>

Then ffmpeg returns:


FFmpeg version git-b319052, Copyright (c) 2000-2011 the FFmpeg developers
  built on Aug 15 2011 16:42:18 with gcc 4.1.2 20070626 (Red Hat 4.1.2-14)
  configuration:
  libavutil    50. 37. 0 / 50. 37. 0
  libavcore     0. 16. 1 /  0. 16. 1
  libavcodec   52.109. 0 / 52.109. 0
  libavformat  52. 97. 0 / 52. 97. 0
  libavdevice  52.  2. 3 / 52.  2. 3
  libavfilter   1. 74. 0 /  1. 74. 0
  libswscale    0. 12. 0 /  0. 12. 0
found ssm_source..|2ÿ½
udp_resolve_host: Temporary failure in name resolution
found ssm_source..|2ÿ½

Here you can see that the ssm given above is not that in the SDP - not
even a valid IP address. After a few trials, the key thing that causes
this to happen seems to be changing the RTP type in the sdp file from
96 to 33.

Can anyone suggest why this is failing? Both SDP files have been
tested and ar working if passed into VLC from the same machine...
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[rogerdpack2]

> FFmpeg version git-b319052, Copyright (c) 2000-2011 the FFmpeg developers
>   built on Aug 15 2011 16:42:18 with gcc 4.1.2 20070626 (Red Hat 4.1.2-14)

Is the problem the same with newer builds of ffmpeg (i.e. latest trunk?)
0r
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[Ben Barker]

I have tried it with 0.8.3-4, which is the latest in the mint repositories

This gives me a slightly different error:


[mpeg2video @ 0x958f160] mpeg_decode_positinit() failure




On Mon, Jul 16, 2012
at 8:51 AM, Roger Pack <[hidden email]> wrote:
>> FFmpeg version git-b319052, Copyright (c) 2000-2011 the FFmpeg developers
>>   built on Aug 15 2011 16:42:18 with gcc 4.1.2 20070626 (Red Hat 4.1.2-14)
>
> Is the problem the same with newer builds of ffmpeg (i.e. latest trunk?)
> 0r
> _______________________________________________
> ffmpeg-user mailing list
> [hidden email]
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
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[Ben Barker]

I tell a lie...it DOES throw the below error, repeatedly, however it also
successfully joins the stream after some seconds!

On Tue, Jul 17, 2012 at 10:55 PM, Ben Barker <[hidden email]> wrote:

> I have tried it with 0.8.3-4, which is the latest in the mint repositories
>
> This gives me a slightly different error:
>
>
> [mpeg2video @ 0x958f160] mpeg_decode_positinit() failure
>
>
>
>
> On Mon, Jul 16, 2012
> at 8:51 AM, Roger Pack <[hidden email]> wrote:
>>> FFmpeg version git-b319052, Copyright (c) 2000-2011 the FFmpeg developers
>>>   built on Aug 15 2011 16:42:18 with gcc 4.1.2 20070626 (Red Hat 4.1.2-14)
>>
>> Is the problem the same with newer builds of ffmpeg (i.e. latest trunk?)
>> 0r
>> _______________________________________________
>> ffmpeg-user mailing list
>> [hidden email]
>> http://ffmpeg.org/mailman/listinfo/ffmpeg-user

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[rogerdpack2]

> I tell a lie...it DOES throw the below error, repeatedly, however it also
> successfully joins the stream after some seconds!
>
> On Tue, Jul 17, 2012 at 10:55 PM, Ben Barker <[hidden email]> wrote:
>> I have tried it with 0.8.3-4, which is the latest in the mint repositories
>>
>> This gives me a slightly different error:
>>
>>
>> [mpeg2video @ 0x958f160] mpeg_decode_positinit() failure

Hmm. If you have a reproducible test case then submit a trac I suppose.
-r
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