[Udpcast] Udpcast for streaming data.

Jorge Muñoz Castañer jorgem at enigma.det.uvigo.es
Wed Sep 2 12:19:29 CEST 2009


Jorge Muñoz Castañer escribió:
> Alain Knaff escribió:
>   
>> Alain Knaff wrote:
>>   
>>     
>>> On 07/22/09 18:36, Jorge Muñoz Castañer wrote:
>>>     
>>>       
>>>> Hi list,
>>>>
>>>> I was looking for a tool to send a stream of data with FEC where the 
>>>> client/receiver can connect even if the stream has yet begun. I haven't 
>>>> found anything but Udpcast that can do anything similar. I think that 
>>>> maybe an "streaming" option can be added so the sender sends Hello 
>>>> packets at the end of a block of slices+FEC so a receiver can hook to 
>>>> the UDP stream.
>>>>
>>>> What do you think about this? Can this be made modifying Udpcast without 
>>>> broken it all? Is there another software that I can use?
>>>>
>>>> Greetings,
>>>>
>>>> Jorge M
>>>>
>>>>       
>>>>         
>>> Sounds like a good idea. I'll consider adding this for the next version.
>>>
>>> Regards,
>>>
>>> Alain
>>>     
>>>       
>> I just released version 20090830, which has support for this idea.
>>
>> You can now add a special flag (-Z or --streaming) to the sender, which
>> makes it retransmit HELLO packets during the transmission, which
>> receivers can then use to "jump onto" the ongoing transmission.
>>
>> Regards,
>>
>> Alain
>>
>> _______________________________________________
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>> Udpcast at udpcast.linux.lu
>> https://udpcast.linux.lu/cgi-bin/mailman/listinfo/udpcast
>>   
>>     
> Hi Alain,
>
> Sounds great! Thanks Alain. I'll test it and tell you anything.
>
> Jorge M
>
>   
Hi again,

It works great. We are using UDPCAST to send multimedia data that can be 
played from any point of the stream so the "streaming" option is very 
near of what we need. We also use the Asynchronous mode in order to 
avoid great latency.

There may be another functionality that can be useful with this option. 
If the FEC correction is not enough to correct a slice udp-receiver 
stops. This is useful when you are transmiting data files where there 
must be integrity, but in most multimedia streamings it is not very 
important to loss a small percentage of packets. Can I suggest a 
"multimedia" option which keeps udp-receiver active even if there are 
unrecoverable slices?. These slices can be marked as "no recovered" in 
the receiver slices queue and are not written in the output file or 
fifo. What do you think?

Regards,

Jorge M

-- 
---------------------------------------
         Jorge Muñoz Castañer
     e-mail: jorgem(en)det.uvigo.es
  Grupo de Tecnologías de la Información
   Departamento de Ingeniería Telemática
           Universidad de Vigo
          ETSI Telecomunicación
         Campus 36310 Vigo SPAIN
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