I want to find a human-logic in video settings

It’s out of my mind why rendering video is so complex and I trying to figure out how to do a simple things. So, I want to find a truth and get some more intelligence :slight_smile:

1. How to take 2 videos and make 1?
I just want to merge two videos in one. But it’s not simple. Each video I maded has lowered quality. I cannot figure out why there is no tool in shotcut which just merge two videos without quality losses. Does it means that each time when I need to merge just two videos I need to dive into original settings and manipulate with codec and video settings to make simple operation of merge?

2. How to properly handle with quality and not losing it?
There is a situation. I have original video:

I exporing it with the next settings (as for me it should be only one slider named “quality loss” from 100% to 0%):

And here is the result:

Why it get so much data rate? It’s much more that original video which has only 33k. Why it cannot just take quality from the original video and make the same? I look at the result - it’s really nice. But with data rate 80k the 1 min of video take 0.5Gb. Is it means, that I can make codec settings “Quality” lower from 85% to get data rate in result video about 55k (this data rate value is approximately the highest for all of my recorded videos) and have no quality losses?
Also audio bitrate lose almost half of quality if I properly undestand the stats: original video has bitrate 390 kbps, rendered - only 216 kbps.

3. Why shotcut require to convert video to Edit-friendly if I can edit it anyway without converting?

It really bad for me! I losing video quality for converted videos and spend additional harddrive space, but receive really nothing. It not speed up my work, I can just put non-converted video in video-line and work with it without any problem. I read that video can be not syncronized, but I edit hours of videos and get no problem with desyncronization. Everything is ok.

If you are fussing about matching codecs then you are basically thinking about it wrong due to the way multitrack video editing and video compression works. See this post in our FAQ on the subject:

as for me it should be only one slider

You chose to delve into the Advanced settings to reveal very many options. Your Shotcut Export Frames/sec does not match the value in Explorer Properties. Settings > Video Mode > Automatic exists precisely to match “video settings.”

Why it get so much data rate?

Because you set the quality % too high.

Why shotcut require to convert video to Edit-friendly if I can edit it anyway without converting?

It does not require it as you already know you can skip it. We must warn users of potentially problematic sources. However, the threshold is simple, and we cannot figure out how bad the potential problem is without some additional engineering that would make you wait probably at least the duration of whatever you imported to do analysis. Why do you ask about something for which you already have the answer (the dialog tells you) and know you can skip? If you want to ignore the dialog because you are confident it works for you, you can, and that is why I designed it to be dismissable.

I apologize in advance for stupid questions. It is difficult for me to ask smart questions without having a point of reference. I’m new to video editing. I tried searching the FAQ for answers to my questions, but it seems the topic is too complex. I didn’t find a simple answer to the question “why I can’t merge two videos into one with one-click?” At the moment, it seems to me that the shotcut cannot predict how similar two videos are and each video is considered unique. It is unusual for me that a program cannot take the parameters of the best video and make one video out of two.

Well, looks like it require to go deeper to FAQ.

Shotcut does not provide a simple function to join two videos without re-encoding. There are some other tools (not multitrack video editors) that can do that, but there are very many pitfalls to that approach due to the way digital media works. Shotcut only offers the foolproof way of re-encoding, and if you use the defaults (i.e. automatic video mode and default export settings) and don’t bother with the details it is super simple.

Let me share my experience with default settings of Shotcut.

I made 2h length video (resolution 3840x2160). The original videos was 40k+ data rate. Some of videos was long enough and I cut it with Shotcut to two pieces, because videos longer than 25 minutes became too slow for editing (especially with undo operations) for my i7-6700K.

So, some of cuts was edited twice - first time cutted and second time rendered as final file.

As a result I got 18 Gb file (I expect it 35 Gb) and it was summary 21k data rate. The quality was dramatically decreased, as for me. Dark areas has stepped color gradient instead of smooth like in original. It’s not terrible quality loss, but a little sad.

Then I followed to settings and found that by default codec has only 55% of quality (there also was calculated value crf - I don’t know what is it but will find in FAQ soon). But looks like it not means 55% quality from the original video, but something else (yeah, still need read all the FAQ).

It taked 6 days to make a final version and something about 14 hours to render it. So, that’s why I’m trying to find now how to make it better.

If you want a simple solution (but only for beginners) you can just change the Rate control (in Advanced export options) to Average bitrate (so it won’t be a percentage - which has nothing to do with original file btw, it’s just from minimum to the maximum of the codec - read about CRF for mor details) and input your original file bitrate + 20%.

The quality will be about the same (but keep in mind ANY export will lower the quality a bit unless you deal with lossless codecs; the +20% helps with this loss in quality but it can’t be identical unless you use ffmpeg concat outside of shotcut).

For just splitting a file or joining files of same origin, I happily use Avidemux. I even use it if I just want to reduce resolution for disk-space reasons. So this should at least cover one of the steps in a lossless way. But maybe I’m missing a point here.

Adjust to 67% and re-examine the exported video. That is supposed to give something close to “visually” lossless.

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