FPS just dropped over 50%; what did we do wrong?

Anything and everything to do with DCP-o-matic.
MalibuFilm
Posts: 2
Joined: Mon Nov 06, 2023 9:15 pm

FPS just dropped over 50%; what did we do wrong?

Post by MalibuFilm »

We actually have a few questions, so any/all suggestions are appreciated:

1. Running Windows 11 Pro 64 on an MSI Pro Z690A with i9-12900KF CPU, we were encoding at up to 33FPS by setting 22 threads to DOM and 2 to the DOM encoder server (just using the basic openjpeg). However, we started to get overheating system shutdowns -- which we tried to resolve by replacing the stock CPU cooler with a DeepCool Assassin III. The only bad news: that cooler's design required removal of the second DIMM (Viper 4 Blackout DDR4), reducing RAM from 16G to 8G -- after which encoding dropped by 2/3rds (to ~11FPS). It doesn't seem like the reduction in RAM would be responsible for this level of performance drop, so I can't think of what might have just happened. With 24 threads, what would be the optimal assignment for DOM vs. DOM Server Encoder?

2. Aside from the image quality differences, do bitrate and/or encoding format/container matter?

2A. Of the following options, which would deliver the fastest encoding performance?
MPEG 2 (MPG), up to 49766kbps
h.264 (MP4), up to 16000kbps
AVC (MP4), up to 21000kbps
AVCHD (M2TS), up to 35000kbps

3. For outputting to XYZ colorspace, should we leave DOM at the default Video 16-255 or switch over to Full 0-255?
Carsten
Posts: 2665
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: FPS just dropped over 50%; what did we do wrong?

Post by Carsten »

8GB is most probably your problem with so many threads. Every thread eats RAM.
Probably the best solution would be to fit a larger capacity RAM DIMM into that usable socket. Or get another cooler. Is this 2K or 4k work?

The source format is not that relevant here.


Most standard video format as those you listed uses limited range (16-235), so leave it at that default. Only if you positively know that your video is full range, use the other option.
MalibuFilm
Posts: 2
Joined: Mon Nov 06, 2023 9:15 pm

Re: FPS just dropped over 50%; what did we do wrong?

Post by MalibuFilm »

Many thanks for the response. This is only for 2K, specifically for the creation of a trailer reel shown before each of our screenings at a local theater.

Unfortunately, replacing the cooler may have finally resolved the overheating issue (the system is automatically overclocking up 5.3MHz with DDR4 at 3600MHz without a hiccup). But somehow I bolloxed the motherboard and/or second DIMM (which I could only fit into the slot below the fan by removing the heat spreader -- the underlying DIMM stick appears to be intact but simply doesn't work). I even tried a new 16Gb DIMM set, but the system refused to boot with the two sticks slotted into either A1&B1 or A2&B2. My system will now only run with the single (unmodified) stick in A2.
Last edited by MalibuFilm on Wed Nov 08, 2023 3:40 am, edited 1 time in total.
Carsten
Posts: 2665
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: FPS just dropped over 50%; what did we do wrong?

Post by Carsten »

Under these conditions, you may try to find a thread# setting that gives best fps results. Of course it is unsatisfying.
Does this system use a system SSD, or spinning disc? When it get's into swapping because too much RAM is required, an SSD will of course still deliver better results than a spinning disc.

Also, I would in this case not activate the additional encoding server.



- Carsten
MalibuFilm
Posts: 2
Joined: Mon Nov 06, 2023 9:15 pm

Re: FPS just dropped over 50%; what did we do wrong?

Post by MalibuFilm »

The system has two SSD's plus one NVMe (no HDDs).

How do we disable the encoding server?
Carsten
Posts: 2665
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: FPS just dropped over 50%; what did we do wrong?

Post by Carsten »

The encode server is a separate app - if you don't start it (or have it in autostart), ist should not be running.