Is there any way to get the Shotcut output file size down to anything close to the Avidemux size?


#1

A variation of the question has been asked last year, but the answer (if there was actually an answer) was too technical for me. And the difference in file size that I’m talking about is factor of ten.

I used a simple subject: one still image (1920x1080 JPG), repeated to yield a 15-second mp4 video. (In Shotcut, obtained by setting “Properties.” In Avidemux, obtained by using Copy and holding down the Paste key combination (Ctrl-V) until the desired length was reached.) No motion, no audio.

–Shotcut file size: 14MB-18MB, depending on settings. Smallest file (14MB) was Yadif temporal & spatial, Bicubic. All other settings (various combinations of Linear Blend, One Field, Yadif Temporal with Nearest Neighbor, Bicubic, etc.) yielded files 18MB-19MB in size.
–Avidemux file size: 1.68MB (medium quality), 2.78Mb(maximum quality)

Quality: no visible difference (except that Avidemux generated a more saturated image, with higher contrast).

Is there any way to get the Shotcut output file size down to anything close to the Avidemux size?


#2

When exporting, on the Codec tab:

  • Set Rate Control = “Average Bitrate”
  • Set Bitrate = “1M”

The output file should be about 2MB. Click “dual pass” if you want the extra quality boost. If you want an even smaller file, choose a lower bitrate.


Output file size - what am I doing wrong?
#3

Hi BG,

You might try running it through HandBrake after the export from Shotcut. I’m definitely a noob to Shotcut and video editing in general, but I’ve found this works well for me.

I just exported a small (6 minute) video and the file was 89,892 KB from Shotcut. All export settings were default based on the Automatic Properties of the first clip.

I then opened the file in Handbrake and left all the defaults as set in Handbrake and pushed the “Start Encode” and let it run. The finished file from HandBrake is 20,236 KB and plays just fine. I cannot tell any degradation in video or audio quality.

Tom


#4

Thanks, I’ll try this!


#5

Thanks. I’ve heard a lot about Handbrake but haven’t gotten around to looking into it. I don’t like to keep adding layers of processing because mp4 is lossy.


#6

I’ve tried several combinations on both Shotcut and Avidemux. Seems that at roughly the same level of quality, Avidemux files are smaller. But your advice has enabled me to get the Shotcut files much smaller and quite good. Thanks!


#7

That is a gross simplification. There is more than Quality % at play here. Quite likely Avidemux uses a longer GOP. The default GOP used by Shotcut is per YouTube’s recommendations, which is rather short, and which is resulting in people complaining about large files. I do not exactly know why YouTube wants such a short GOP, but it has something to do with how they transcode by breaking up a file in to many small pieces and converting each piece on many machines and then combine the results. Try changing GOP to 150, and you will get a smaller file with the same quality, and it will still upload to YouTube fine.


#8

Yeah, but maybe Youtube will degrade the video quality more thant with a smaller GOP?


#9

I’m not knocking Shotcut, just reporting on my own personal experience. Hence “seems that” and “roughly.” I don’t do YouTube so I was not commenting on that. I do 1080p to show on a 4k TV, approx 50in wide. I’m interested in what looks better (smoother, sharper) in that format and context. I admit to being to what some call a pixel peeper. Avidemux has very limited uses, anyway.