Having encoded a video using VidCoder (based on Handbrake I believe) I can see in the log that it is duplicating a frame to achieve CFR.
87657 frames output, 0 dropped and 1 duped for CFR/PFR
Should I be concerned about this? i.e. in terms of it posing an issue during playback. Will the video hang in the place where the duplicated frame is? Is it expected that the audio will go out of sync? Google gives mixed results as to how damaging duplicated frames are to a video. But I can't see anything having a quick skip through in VLC.
One curiosity is that running the same video through Handbrake gives 0 dropped and 0 duped. But VidCoder is a bit more suited to my needs for this particular video (I need to scale up slightly from 720x576 to 768x576 to achieve square pixels). The only explanation I can find for VidCoder producing the duped frame and Handbrake not is that it's an older version of Handbrake that I use (for the AAC FDK support) versus a newer version of VidCoder.
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Last edited by E King; 20th Sep 2021 at 00:22.
One duplicate frame out of 87657 is nothing to worry about. Even if it 1/framerate A/V de-sycn for the rest of the video it wouldn't be noticeable.
I've been getting this 1 duplicated frames on a few videos of the same type.
I was using this workaround: Put MXF source file through Handbrake to produce a H264 .mp4 file with 0 duplicate frames. Put the H264 file produced by Handbrake through VidCoder (no deinterlacing as already done in HB, constant frame rate + same as source) to achieve the desired 768x576 / 4:3 - Non-Anamorphic / PAR 1:1 - without any duplicated frames. However it's a bit of a pain encoding twice back to back like that.
You have reassured me that 1 duped frame is harmless. So I'm going to cut out HB and just use VidCoder for the encoding of these particular files instead.