Question / Help Problem analyzing log file

[keybounce]

So I attempted to run a log file through the analyzer, and it failed.

Log file: https://gist.github.com/bec0beda0ffdc42e0650

Analyzer:
Slower preset in use

You have changed the default preset to fast. Using slower presets can result in late frames and high CPU usage / low FPS. You should only change the preset if you are sure you have the CPU power to spare.

This does not appear to be a complete OBS log. Please make sure you include the entire file.

I'm seeing a large number of skipped frames, but very few dropped frames. I'm not sure what a skipped frame is.

This was an attempt to send 1024x640@20fps; normally I'm sending 854x480@30fps.

 

[Lain]

The analyzer doesn't fully work with multiplatform logs (yet). It's meant for the old version of OBS still, not much effort has been made to port it yet.

That being said, you shouldn't use the fast preset with that computer. It's lagging almost all of your frames. It's barely able to even transmit anything properly. It most likely looks like a slideshow with what the log file was reporting. Set it to veryfast.

 

[keybounce]

...

2014 macbook, 8 core, ... and it can't do any of the quality improvements of the better settings?

I have a ton of unused CPU; is there any way to spend more CPU to improve stream quality?

 

[dodgepong]

I actually don't think it's an issue with encoding. There is something funky going on with the rendering that is preventing you from even encoding anything (which is why you have unused CPU). Probably has something to do with the repeating OpenGL errors in the log, but I don't know what causes that.

 

[Lain]

If you happen to have time some time I'd like to run some tests on your system to determine what's causing the issue. It's quite unusual. You'd have to come by chat some time though and ping my name, or message me for some other way to get in contact.

 

[keybounce]

Sure; where is your chat?

EDIT: Found, ping'd ya

 

[keybounce]

Test video: http://www.twitch.tv/keybounce/v/16070981
Corresponding log file: https://gist.github.com/dad019bcc155635e4928

That was "very fast", streaming. Constant bit rate, but actual bitrate was about half of what i specified; see last minute or so.

EDIT:
17:09:04.573: Output 'adv_stream': stopping
17:09:04.573: Output 'adv_stream': Total frames: 11300
17:09:04.573: Output 'adv_stream': Number of skipped frames: 353 (3.12389%)
17:09:04.573: Output 'adv_stream': Number of dropped frames: 2022 (17.8938%)

I know my upload speed peaks at over 4000 (4500 to 5000, depending), so ... why so many dropped frames? As I said, actual bitrate was around 1500-2000.

 

[Lain]

Dropped frames are due to network congestion of some sort. If it can't send out data as fast as you specify, it will "drop" frames being sent to the server to try to reduce network bandwidth and keep the stream from buffering and getting continually delayed.

Note that you can change your bitrate (with x264 at least) while streaming, so if you need to turn down your bitrate you don't have to turn off the stream to do so.

 

[keybounce]

What I don't understand:
1. Why are there so many skipped frames? There's plenty of spare CPU; I'm using display capture.

2. Why so many dropped frames? Actual observed bandwith used was 1500-2000 (see the test recording; end shows the bandwidth numbers).

Again, actual bandwidth tests in the 4.6 to 4.8 Mbits range (dslreports.com).