Posted on 03/11/2023 10:38:10 AM PST by CptnObvious
Ripping: Video Jitters
You rip a video and it is fully of jitters. Every now and then the video pauses. Maybe for just enough to notice, but sometimes for what seems like a long time. What causes video jitters while encoding them?
The Number 1 Cause: Overclocking
Most of the systems we use today are built on gaming computers. The first core is built to handle the overclocking most folks give it. The subsequent cores can only handle the overclocking for shorter periods of time as the game gets more intense. When the limits are exceeded, either in watts and time and or temperature, the processor clock is backed way down.
But that is not what I believe causes the jitters. It is my belief that the jitter occurs when the processor(s) Interrupts all operations to record the event(s) (possibly in non-volatile ram). And the time it takes to record these events and get back to normal operation are the jitters we see.
However, when we do a video encode - such as with Handbreak, the cores are demanded non-stop. If overclocking is enabled, the subsequent core limitations will occur and produce jitters. Some of which will be seen it there are enough events and some won't be seen if not enough. And the warmer the system is the more jitters can be produced.
You know this is happening in Windows when the CPU clock gets backed off say from 4.5 GHz to 3.0 and seems to stay there.
Temperature limits which do the same things can be seen with programs like HWINFO, Throttlestop (Intel), Ryzen Master (AMD). The latter may be able to prevent these type of jitters.
However, a number of my systems resists all attempts at online intervention. In those cases, I have gone into the BIOS and turned off Overclocking (sometimes called Performance Boost and other euphemisms).
OTHER SUSPECTED JITTER PRODUCERS:
Sourcing over a WIFI:. Sometimes I download my Blu rays on one or more systems and then use multiple systems to encode them. I've noticed transfer speeds reduced to next to nothing at times. I've also seen failure to store files over a Wi-Fi.
So, I've gotten off the Wi-Fi and onto an Ethernet Switch for all my systems in this rig and noted a lot less jitters and no file losses.
Other Suspects:
A recent addition of a 4TB Backup share had some severe jitters on that system when the Hard drive would spin back up. I would touch a folder on it and everything would stop for maybe 10 seconds. Other stoppages occured when I heard it spinning up. I disabled it and only use when not encoding.
I suspect Hard Drives that severely thrash especially on the system volume. This is why I use SSDs for encoding exclusively.
I also noticed Windows anti-virus security using the highest priority in the scheduler. And I noticed scheduled defragging on my system and other SSD volumes during the daytime! UGH!
In short, anything that gives clean smooth operation is good!
PS: I HAVE TRIED VARIOUS FLAVORS OF LINUX. BUT LONG SHARE NAMES HAVE PREVENTED MY USE OF IT.
Some - OK: many — years ago I found that some programs call home several times an hour. The system clock was found to be online updating every few seconds.
memory cache overloads?
I don’t understand. On my Linux system, Debian 10, file names can be up to 255 bytes long, while full paths can be up to 4096 bytes. Of course, multi-byte characters (like UTF-8) can reduce the number of visible characters. So did the “long share names” exceed these limits, or was something else going on?
For example, assuming Windows was “sharing” the files, maybe the Linux client was the problem. Were you using a modern CIFS client or an obsolete SMB client?
How do you playback the encoded videos that jitter? If you are playing on a different machine from the one where the videos reside, the jittering could be a network problem.
When encoding, both the input and output are (or should be) sufficiently buffered so that no frames would be dropped if the CPU changes speed now and then.
When playing a video, on the other hand, it is important that the video data arrive, and are decoded, in real time to satisfy the 24/25/30/etc per second frame rate. Network delay and jitter can prevent this. That’s why YouTube tends to use methods like MPEG-DASH to reduce such problems.
Try playing back one of your jittering videos in VLC and look at the playback statistics to get more clues on what might be wrong. (Use Tools -> Media -> Statistics from the Menu Bar.)
P.S. WiFi (like other RF links) is especially susceptible to network problems, including interference from microwave ovens.
Maybe you just need to moderate your caffeine intake?
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