[mythtv-users] Using NetworkRecorder to watch TV streams

Robert Johnston anaerin at gmail.com
Wed Nov 19 03:25:46 UTC 2008


On 18/11/2008 5:54 PM, Nick Rout wrote:
> On Wed, Nov 19, 2008 at 12:19 PM, Robert Johnston<anaerin at gmail.com>  wrote:
>> On 18/11/2008 12:40 PM, António Santos wrote:
>>> Hi,
>>>
>>> I've been using Mythbuntu 8.04 with the latest version of MythTV
>>> (0.21). I've been trying to configure the backend to provide a couple
>>> of channels streamed out over the internet. I created the M3U file
>>> like this:
>>>
>>> #EXTM3U
>>> #EXTINF:-1,1 - cnn
>>> rtsp://cnn-cnnlive-1-primary.wm.llnwd.net/cnn_cnnlive_1_primary/
>>> #EXTINF:-1,2 - bbc world
>>> rtsp://a1482.v373745.c37374.g.vm.akamaistream.net/7/1482/37374/484f7385/clipdownloads.bbc.co.uk/windowsmedia-acl/news/n5ctrl/summaries/world/bb/video/world_bb.wmv
>>> #EXTINF:-1,3 - sky news
>>> rtsp://live1.wm.skynews.servecast.net/skynews_wmlz_live300k
>>> #EXTINF:-1,4 - extreme tv
>>> rtsp://195.122.130.133/Massive%20Mag_xtreme_10
>>>
>>> I configured the capture card ok, then the video source and the input
>>> connections, scanning for the channels which were correctly added to
>>> the channel list.
>>> In the frontend, I select Watch TV, but I get no image after a few
>>> seconds. A pop appears saying something like:
>>>
>>> You should have gotten a channel lock by now. You can continue...etc...
>>>
>>> Does the NetworkRecorder work with these streams? Or is it an issue
>>> with the MythTV internal player?
>> As I Understand It, RTSP is not supported (as it's not actually a stream
>> format, it's a stream control and setup format).
>>
>> Most RTSP streams actually use RTP to transport the stream. I'd suggest
>> using VLC to view these streams, and see where the actual streams are
>> coming from. The NetworkRecorder does support RTP (Again, AIUI).
>
> I thought there was rtsp support from something I read this morning
> when I did a little digging to help with this. I didn't come up with
> any conclusions so I didn't post anything.
>
> However on looking at the release notes for 0.21:
>
> "Improved FreeboxRecorder's RTSP support so that other transport
> methods can be used and fixes some bugs in the M3U channel parser"
>
> see http://www.mythtv.org/wiki/index.php/Release_Notes_-_0.21
>
> Also tickets like this:
>
> http://svn.mythtv.org/trac/ticket/5717
>
> support the proposition that rtsp is supported. However there could be
> some slippage of terminology and rtp/rtsp are often mistakenly used
> interchangeably. Finding and trying the rtp stream address might
> indeed be a solution.
>
> Another way to find that might be to use mplayer and take a good look
> at the (command line) output.

After doing some reading (Of the source, no less), it seems I was wrong. 
RTSP is supported, RTCP is not.

I'd suggest looking at the backend logs (Especially with "-v record" 
enabled), along with playing with mplayer to see what kind of problems 
you may be getting.

Something else I noticed while I watched those streams in VLC on Windows 
was that they're using WMV/WMA for the video and audio respectively. I 
don't know if WMV is supported in Myth (I think it is, as VLC supports 
it, and VLC uses ffmpeg too), but that could be related.
-- 
Robert "Anaerin" Johnston


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