HD streams are jittery/pixelated (SD plays fine)

[christo16]

So excited to get this installed and running, thanks for your effort. I'm seeing one issue with my setup, SD streams play fine, but HD streams fail to play. The streams will usually start and immediately become unresponsive and distorted.

Here is my ffmpeg log, any thoughts? Running on Ubuntu 12.04.

[mcqueena]

I'm having a similar problem, running on OSX. My problem might be related to the fact that my server is my laptop on wireless. I'll try tomorrow on with a wired connection.

[maddox]

You're never going to be able to have this work over wireless reliably. The raw mpeg2 streams are just too large for wireless to reliably do this kind of thing.

The rule of thumb is: never do anything with HD video over wireless. Heh.

On Jan 26, 2014, at 5:00 PM, mcqueena notifications@github.com wrote:

I'm having a similar problem, running on OSX. My problem might be related to the fact that my server is my laptop on wireless. I'll try tomorrow on with a wired connection.

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[mcqueena]

Ok, thanks. I thought so and will try it on wired. I'll report back.

[mcqueena]

I still have trouble with HD channels, even on the wired connection.

[christo16]

@mcqueena This replicates my experience, wired -> wired for HD channels failed to play.

[maddox]

What are the specs of the computer doing the real time encoding?

On Jan 27, 2014, at 5:04 PM, christo16 notifications@github.com wrote:

@mcqueena This replicates my experience, wired -> wired for HD channels failed to play.

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[mcqueena]

Model Name: MacBook Air
Model Identifier: MacBookAir4,2
Processor Name: Intel Core i5
Processor Speed: 1.7 GHz
Number of Processors: 1
Total Number of Cores: 2
L2 Cache (per Core): 256 KB
L3 Cache: 3 MB
Memory: 4 GB

[maddox]

yeahhhhhhhhh..... that might be too slow to be encoding 20+mbit mpeg2 streams in to h.264 in real time. It just might not work :/

You could try editing this line and swap out superfast for ultrafast. It'll make encoding faster, but at a loss of quality.

I should probably make this (and a lot of other things in the ffmpeg command) an option.

[mcqueena]

Ok, I'll try that. What would you say are the minimum requirements for SD and HD?

[tmm1]

You can also try lowering the default resolution and bitrate here.

[maddox]

You can also try lowering the default resolution and bitrate here.

I really need to make a setting for that in the web views.

[wTheOnew]

Have any other performance tweaks you could suggest?

Think adding "nice -n -15" or something similar to to the exec of ffmpeg up the priority of it would help?

Changin superfast to ultrafast did seem to make it smoother, but the quality is terrible. Dropping the bitrate down to 2000k didn't seem to help.

I'm running Wallop on a Ubuntu VM that has 4 cores of a 4GHz i7 dedicated to it and the HD streams are unwatchable. Either stuttering and pixelated or buffering 50% of the time. Wired gigabit Ethernet from the HDHR to Wallop and then wired gigabit or wireless to each Roku behaves the same. The VM seems busy when encoding, but not bogged down. 50-65% cpu utilization max.

[tmm1]

Bump the bitrate up, to 6000k atleast

[mcqueena]

Is it possible the problem is on the Roku end?

[wTheOnew]

I'll try a higher bitrate this evening. Seems like that would make it harder to stream though?

I guess it could have something to do with the specific channel, since I can stream much higher bitrates using plex. This is the Roku channel: https://github.com/computmaxer/roku-hdhomerun If you look at the videoScreen.brs file it's about as simple as it gets, it just sets up the stream and displays it. Know any way I can stream an m3u8 file in Windows to test it? VLC just does the audio stream for whatever reason.

Thanks to both of you.

Hate to junk up this thread if there's a better place to troubleshoot?

edit: Had a chance to do a bit more testing. It looks like it only pixelates and bufferes really bad on the wireless Roku. The wired one rarely buffers after the first 5 minutes. It's weird since I can stream stuff with plex at 12Mbps to either one. I can live with SD on the wireless one. Going to still play with it to see if I can make it better and I'll update this if I figure something out.