[FFmpeg-devel] [PATCH] MMS wrapper

[Don Moir]

----- Original Message ----- 
From: "Stefan Gehrer" <stefan.gehrer at gmx.de>
To: <ffmpeg-devel at ffmpeg.org>
Sent: Saturday, July 14, 2012 12:11 PM
Subject: Re: [FFmpeg-devel] [PATCH] MMS wrapper


On 07/14/2012 01:41 PM, Michael Niedermayer wrote:
> On Sat, Jul 14, 2012 at 01:10:24PM +0200, Reimar Döffinger wrote:
>> On Sat, Jul 14, 2012 at 07:34:23AM +0200, Stefan Gehrer wrote:
>>> On 07/14/2012 01:30 AM, Don Moir wrote:
>>>> ----- Original Message ----- From: "Stefan Gehrer" 
>>>> <stefan.gehrer at gmx.de>
>>>> To: "FFMpeg development discussions and patches"
>>>> <ffmpeg-devel at mplayerhq.hu>
>>>> Sent: Friday, July 13, 2012 4:41 PM
>>>> Subject: [FFmpeg-devel] [PATCH] MMS wrapper
>>>>
>>>>
>>>>> attached patch implements a simple wrapper for handling mms:// URLs.
>>>>> It first tries to open using mmst protocol and on failure tries
>>>>> using mmsh protocol.
>>>>> I found some streams on tunein.com which either support only
>>>>> mmst or only mssh, with this patch applied both kinds can be
>>>>> played back with just specifying mms:// as protocol.
>>>>> This should fix ticket #998, the mms URL given there also works.
>>>>> mms://live1.wm.skynews.servecast.net/skynews_wmlz_live300k
>>>>>
>>>>> Stefan
>>>>>
>>>> Thanks
>>>>
>>>> Would mmsh be more common then mmst and maybe should be tried first 
>>>> even
>>>> if mmst is more efficient ?
>>>
>>> Yes, mmsh seems to be more common. But mmst usually fails after a
>>> minimal communication with server (connection on port 1755 refused)
>>
>> I don't know if it is common, but if port 1755 is blocked it might
>> actually hang until a timeout. This is less likely for port 80...
>
> a small timeout could be added to the 1755 connection attempt to
> ensure it fails quickly if it fails.

>I haven't seen this yet, but of course trying to connect to that port
>could time out. Current tcp default timeout seems to be five seconds.
>What would be appropriate? Two seconds?

This all probably depends on your use case on which should be attempted 
first.

In the general sense, it seems to be that http connections may be far more 
common then tcp connections for mms streams but I do not know that for sure.

How often is mms delieved by tcp versus http ? If you can answer this then 
you will know.

Clearly an mmst connection would be preferred, but how often will it 
timeout. Some corporations block tcp sockets all together.

For my own server code I always attempt tcp first and then http and I get 
about a 90 percent hit rate on tcp but thats special purpose and not related 
to mms.