Slow Exporting!

Hello! I have a recent issue with the latest version of Shotcut. (As of 2023/06/23) The issue being that my exporting is way slower than it ever has been! Hopefully I can explain everything that can be explained.

Unfortunately, I’m not 100% sure what the issue is. I read other forums that described a similar issue, such as the Corner Pin being the culprit. While I had a Corner Pin filter used, I removed that filter, and then removed the file that had that filter to be sure that it was gone, but no luck. I’ve yet to try Parallels, but I’ll give it a shot the next time I export something and it slows on me.

The video itself isn’t too demanding, and I have exported longer videos with more special effects. Older exports took about 30 mins to an hour, with the content of the videos being around 10 minutes to an hour. Theo ne I’m currently exporting is a 20 min video with added audio, occasional spurs of overlaid videos/images, and of course a multitude of filters; mostly Text Simple & Zooms, with the biggest being the beginning having a handful of filters to imitate a retro VHS look, (though I removed that as a test and the export speed was about the same) and it’s exporting at a crawl, with the program estimating it will take 2-3 hours to export. While I’m unable to give my PC specs at the moment, I surely will in a reply update.

Something of note is that I’ve exported a handful of smaller content previously using a version either just before 2023/06/14, or the version itself, with the biggest being a 1-2 minute long advert. That exported as fast as I figured it would so that’s why I’m so stumped about this. It might be a filter that I’m not aware of?
Edit: I have the video exported, and something more interesting is that the overlaid videos have a chance of not showing up in the final product. To further explain, the aspect ratio of the original clips is 4:3, and I didn’t want the black sides to go unused, so I had a copy of the footage overlaid underneath the original clip, increasing it’s size by 150% and blurring it so that there’s some footage across the entire video. Perhaps this may be the problem?

If there’s anyone with a solution, please let me know! (And sorry for the very long post, I just like to be thorough!)

Hello everyone,

I also notice slowness. I mainly used SC for a while to transform the mkv encoding (of movies that cause problems with fast forwarding or stopping, when I sent them from the pc to the smart TV) in HEVC which removed this problem and compressed the order of three.
Last week I wanted to do the same thing (no filter applied, just the export) the operation took more than two and a half hours.

If there is only one track in the timeline and it has no effects, only slicing, enabling the “use hardware encoder” option can greatly speed up the rendering process. For example, my test fragment (30 seconds of white noise), without a hardware encoder, the encoding process takes more than a minute, if you turn on the hardware encoder, the time will be reduced to 4 seconds. I have a laptop with an old Nvidia 1050TI graphics card, nvenc encoder.

Here’s a posted update of some progress, and it only gets more confusing.

So, I tried a different method of video exporting. A singular video that is an hour and 21 minutes long. No editing what so ever, just the .mkv to an .mp4 process. The video itself is 60 frames, and I’m converting it with the settings below! Without Parallel Processing, the video takes 2 hours & 16 minutes long to export. With it, it takes even more time, 2 hours & 40 minutes, which definitely worries me. I hope someone can give me an answer, but otherwise I’ll just be rolling back and hoping older versions are the solution.

Not sure if you’re using OBS to record with.
There is a Remux option after you get done recording.
For a 22-minute video, Remuxing took 3 seconds.

If you do use OBS and once remixed to MP4, do you have the same issues?

Apologies, it’s not the format that is the issue… Maybe I will give it a shot tomorrow! I’m only hesitant to try since I have multiple Audio Tracks and from what I’ve seen changing the format like that may end up breaking the audio tracks in editing. But yes, I am using OBS!

If I wasn’t clear, my issue is seemingly how painfully slow the export process is. For all I know, an unedited clip that’s an hour & 20 minutes long being exported for an entire hour longer could be normal? I haven’t got anything to compare it to other than past exports that usually took about thirty minutes to an hour, depending on the footage.

I just want to know if A. This is actually a normal amount of time it takes to export something, and if not then B. What I could do to speed it up, outside of the options that I have tried and mentioned above.

I did some testing on different versions of the shotcut. There is no difference in encoding speed between 12.22.21 and the latest version (within the margin of error). The only setting that negatively affects rendering speed is enabling GPU Effects. I still don’t understand this absurdity, but with GPU effects disabled, shotcut works and renders much faster.

You can verify this.
Create a color layer 1 minute long (1920x1080x60fps)

With GPU Effects enabled - 1 minute 13 seconds.
With GPU Effects Off - 14 seconds.
In both cases I used h264_nvenc.

Using the Remuxer doesn’t change the format, it converts the existing MKV to a new file.
I create a 6-channel track short clip MKV and then remixed it to an MP4. All tracks are still there in Shotcut.
Note: By default per video track, only one audio track will be used.
shotcut_2023-06-24_05-17-31 shotcut_2023-06-24_05-18-52

I did read and understand what your issue is with slow exporting. I haven’t tested any exporting time to compare one version to the next. Every computer is different along with every video file.

A very long time ago (years) someone came up with a video to essentially benchmark-test various CPU’s with Shotcut. I’ve been trying to find that post, but can’t recall even the name of the video used. Even though I can’t find that post, I think it would be a great idea to come up with a video to test-bench Shotcut with.

I only mentioned remuxing because of the use case going from MKV to MP4.

Things to speed up the process:

  • Restarting computer before exporting
  • Only run Shotcut (no watching Netflix)
  • CPU cooling
  • Data Drives: NVME or SSD
  • Turning off Anti-Virus programs
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Regarding GPU effects being disabled, from what I’ve gathered, they became automatically disabled with later versions, so I believe what I’ve been experiencing has GPU effects off.

Otherwise, I appreciate the advice offered by Remuxing & ways to speed up Shotcut. I’ve done Restarting, only running Shotcut, and I cleaned my PC earlier to have the fans run better, so CPU cooling. The only Anti-Virus I have is Windows Security, but I’ll try to see if I can let the firewall bypass shotcut, and if not, I’ll turn off the antivirus and hope that it speeds things up.

Thank you very much!

Hi dimadjdocent,
the Nvidia GTX950M hardware encoder is enabled, as in other versions before 2023, strictly default settings. For the use described above, the processing of a standard 1h45 film was roughly a processing of 15-20 minutes, …
W10, 24 Go Ram, system and programs on SSD.

Please note that you have h264_qsv selected (qsv - QuickSync from Intel - is the hardware codec of the integrated video core in the processor). You need to select h264_nvenc - this is the codec of your discrete graphics card. To do this, click detect and make sure that the shotcut can see your video card and support for this codec. If it does not see it, make sure that you have installed the drivers for the NVIDIA video card.

I realize that you have put your finger on the problem dimadjdocent :ok_hand:. By using your setting h264_nvenc, I release a film in 32 minutes, which is certainly within the margin of what I obtained previously. So a big thank you.
However, and without any implication for the developers, knowing that my software machine configuration is the same (apart from windows updates) and that I know absolutely nothing about video and that for this reason, I don’t have fun modifying what SC offers me, was the detection of the hardware decoder correct and I no longer have it or another hypothesis?

I forgot, my laptop is programmed so that certain programs, greedy in graphics resources, use the NVidia card instead of the intel of the motherboard. Operation indicated by the mains indicator which changes colour, This is always the case with SC.

The Shotcut program, in my opinion, is aimed primarily at compatibility and stability, as evidenced by the fact that on a fresh install or reset, the hardware encoder and gpu effects are disabled by default. This was not done by accident. I find that with the software encoder and graphical effects disabled, the Shotcut app performs as best as the developers intended. For example, turning on graphical effects causes problems for me, but does not cause problems for other users, as well as a hardware encoder, for some it works very well, like me, for example, and for some it is difficult. Therefore, to enable these functions or not, everyone should decide for himself, based on the stability of your operating system and your equipment.

I understand what you’re talking about. This is the NVidia Optimus system, it automatically determines which of the video cards to use in a particular case. For shotcut, this only matters in one case - if you will be using gpu effects, then it is better to give preference to a discrete video card. If you do not plan to use graphical effects, it will not make much difference on which video card the interface is drawn. In my particular case, the integrated graphics render the shotcut interface, and this does not prevent me from using the hardware encoder of a discrete video card. It even to some extent uses two video cards, one for the interface, the second for encoding.

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