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Live TV stutters when playing HD over browser


pylor
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I'd like to start by saying that this project looks very intriguing and you can see the care and effort put into it.  When I got my HDHR prime in Sep 2012 all that was really out there PVR wise was hacking at a mythtv installation to get it to work.  Things seem to have come a long way since then.

 

My current problem (and it's certainly far from crippling) is that live tv over an internet browser seems to have some buffering issues when playing HD data; it stutters for half a second every half a second or so, almost a micro stutter but too long to be considered such.  I notice a lot of people are using OTA type tuners, but I do have a cable subscription currently, and I'm using the cablecard-based HDHR prime so I'm not sure if the data rates will be different than with a typical OTA signal.  I'll list my setup first as it may be a bit exotic and I'll go into some details about what I've done to "troubleshoot" so far.

 

Server:

  • A hyper-v windows 7 VM running with 7 cores from an E3-1230V2 (not much CPU usage on this box) and 4 gigs of memory
  • The main system disk is a 40GB partition of an SSD, with a 1TB storage pool in RAID-0 partition for recordings, and another 250GB RAID-0 partition for cache/transcoding
  • serverwmc is running on this server as well, I've read a few places that it could run on a different machine but I've never looked into how that's possible

Current test machine is my laptop, it's running an I7-3630QM with 16GB of ram and switchable graphics that are currently set to use the processor's Intel HD 4000.

 

Things I've noticed and done to test whatever is causing this choke:

 

  • If I pause the stream in the browser, it will "buffer" and the stutter will go away till it catches up to the stream.  I'm on gigabit ethernet and can receive the raw mpeg-2 feed just fine so I don't think that network bandwidth would be my issue.
  • I was concerned with HDD contention so I set the transcoding to take place on the SSD (I didn't want to waste writes on transcoding) with no noticable difference.  I have NOT tried recording the WMC tv recording on the SSDs yet, as my HDDs seem fast enough
  • Watching TV on two clients (at the same time, different channels) via the XBMC wmcserver plugin plays flawlessly.
  • The transcode sits at around 24% CPU usage so I don't feel like it's CPU limited.  I can transcode 14GB MKV 1080P movies and they playback well enough for being transcoded on the fly.
  • The non-HD versions of channels do not have buffering issues (but they look hideous)

I'm attaching my logs, and it's midnight so I'm sure I'm forgetting something.  Thanks for reading my super-long essay and any help I can get.

ffmpeg-ac6d6587-43f3-4d2b-bbcc-ff9a7e6d7df6.txt

ffmpeg-b914cff8-ff8e-4565-a610-82f885962ad1.txt

server-63529717302.log

ServerWMC.log

Edited by pylor
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krustyreturns

When you test with xbmc to view these hd channels is it on the same laptop?

 

Does this stutter only happen with live tv, or does it happen when you play a wtv file too?

Edited by krustyreturns
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When you test with xbmc to view these hd channels is it on the same laptop?

 

Does this stutter only happen with live tv, or does it happen when you play a wtv file too?

 

Thanks for the response, to answer your questions:

 

  1. Yes, all the tests in my first post were done on this laptop.  When I attempted to view two live streams (non-transcoded) in xbmc I used my desktop pc in conjunction with the laptop.  Both played the non transcoded stream fine (at the same time no less).
  2. I didn't actually see the option at first to play recordings in the browser, but I checked and it occurs during recordings being played in the web browser as well.  I can post some more logs if you'd like.

 

I also tested last night on my desktop pc.  For whatever reason, firefox would crash every time I tried (I think it's because I have video card acceleration turned off for firefox, I haven't tested this though.  I can go into details about why I have it set this way but it'd be another paragraph of unrelated information).  Playing it in chrome it stuttered as well, however the stuttering lasted longer but so did the playing.  It was very analagous to buffering a slow youtube connection.  I still don't think it's network bandwidth related though as it occurs at 5mbps transcodes which are much smaller than uncompressed and I'm on a gigabit cat6 network.

 

My desktop pc has a 4770k @ 4.3ghz, 16GB of ram, and an AMD 7970 graphics card.

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krustyreturns

Yeah, based on everything you are saying it does seem like it is related to transcoding.  I can't really help on this since the transcoding is all mbs.  My desktop is a similar system to you and I'm using chrome, with stock mbs setup, and I am not seeing any stuttering for what its worth (not much).  I might be interesting to change the transcode parameters to see what difference it makes. 

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