@Richard-Broughton

Hi and welcome to the forum.

The issues you are having suggest that the issue could be with the imported video format.

Download and install MediaInfo and analyse one of the clips causing the issue and post the results, see this tutorial on how to setup MediaInfo and analyse a video clip for all the data required.

Is the Program settings, Playback Tab, Spacebar stops at current playback position option checked?

. . . . Force it to rebuild frametable . . . .

This is unnecessary and could make issues with timing worse.

As @Former user has commented, your system specification and MEP version number as found under Help, About would help.

John EB
Forum Moderator

The issues you are having suggest that the issue could be with the imported video format.

 

Thanks - the plot thickens on this one. There's certainly something going on with the video format but it's far from clear. I've done a great deal of experimenting and here's my current findings.

Background

First - a bit of background. I have source video captured at 4K with a H265 codec. The organisation I was sending to couldn't view those, so I transcode to H264 and reduce to 1080p. I've been doing that either with FFMPEG or VirtualDub (to also do a basic time slice). Trying to do some more sophisticated edits in MEP on these transcoded clips is where it is falling apart.

Experiments

I have now done a lot of experimenting with settings for the video compressor. For the example, I took one of my source videos which is 4K 30fps HEVC. Examining the file, this is Keyframe every 15 frames and everything else is a forward predictive frame. The source video seems to work fine in MEP - no issues in the editor.

The options I tried out of VirtualDub/FFMPEG on a time slice:

1 - simple stream copy. This seems to cause no issues in MEP

2 - x264 transcode, output video has KF every 150 frames or so and the sequence mainly bi-directional predictive frames. This glitches in MEP (but see below)

3 - x264 transcode, as above but forcing KF every 30 frames. Only difference in output video is the additional KF. This seems to cause no issues in MEP

4 - x265 transcode. This glitches in MEP (but see below)

Plus variations on a theme with quality and starting/not starting on an existing KF from the source video.

How is it glitching.

If I load in the video and let MEP play it through to the end (the test is only a 9sec clip) - then the editor seems rock solid, I can scrub back and forward with no problems.

If I load the video and scrub from start to end and then back again - the editor 9 times out of 10 is then rock solid.

If I load the video and do a random scrub or try to position the cursor somewhere in the middle of the file, I get the glitching. The glitch is mostly (but not always) around frame 100. Stepping forward/backward or scrubbing forward/backward through that point the glitch usually (but not always) shows frame 100, then frame 1 then frame 102 (but sometimes it's a longer sequence from somewhere else in the timeline).

If I have a "broken" file, removing it from MEP, restarting and then reloading the clip it remains broken whatever.

If I have managed to avoid the glitch, removing the file, restarting and then reloading the clip it remain unbroken whatever.

If the file is broken/unbroken, removing it from MEP, deleting the H0 and HDP files, restarting and reloading the clip is OK - unless I do the scrub which then "breaks" it or I let it play through which "fixes" it.

Longer files

Armed with this potential workaround - I went back to one of my old transcoded files that is 2500 frames. Let it play through in MEP and crossed my fingers. Unfortunately the workaround didn't work for this on file and as soon as I tried scrubbing it was glitching - this time the glitches being somewhere in the middle of the file.

I then pushed the broken file through FFMPEG to force KF interval and this time the editor seems rock solid again.

Conclusion?

So it appears it may be something to do with Keyframes but it's not exactly clear what. I could recompress my old files and force in the additional keyframes but this could be a lot of processing for a "hunch" as to what the issue is.

It also appears to be just a problem in the timeline view itself. If I export a movie from a glitching file, the output is correct.

Mediainfo

As far as MediaInfo goes, there is no difference (apart from overall bit rate which is a bit higher) between the x264 forced KF interval and the x264 default.

This file glitches in the timeline
General
    Complete name                            : TEST\12 - x264 no KF - no Force.mp4
    Format                                   : MPEG-4
    Format profile                           : Base Media
    Codec ID                                 : isom (isom/iso2/avc1/mp41)
    File size                                : 35.6 MiB
    Duration                                 : 9 s 657 ms
    Overall bit rate                         : 30.9 Mb/s
    Writing application                      : Lavf57.79.100

Video
    ID                                       : 1
    Format                                   : AVC
    Format/Info                              : Advanced Video Codec
    Format profile                           : High@L4.1
    Format settings                          : CABAC / 4 Ref Frames
    Format settings, CABAC                   : Yes
    Format settings, Reference frames        : 4 frames
    Codec ID                                 : avc1
    Codec ID/Info                            : Advanced Video Coding
    Duration                                 : 9 s 634 ms
    Bit rate                                 : 31.0 Mb/s
    Width                                    : 1 920 pixels
    Height                                   : 1 080 pixels
    Display aspect ratio                     : 16:9
    Frame rate mode                          : Constant
    Frame rate                               : 30.000 FPS
    Color space                              : YUV
    Chroma subsampling                       : 4:2:0
    Bit depth                                : 8 bits
    Scan type                                : Progressive
    Bits/(Pixel*Frame)                       : 0.498
    Stream size                              : 35.4 MiB (100%)
    Writing library                          : x264 core 157 r2935M 545de2f
    Encoding settings                        : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=abr / mbtree=1 / bitrate=31000 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
    Color range                              : Full
    Matrix coefficients                      : BT.709
    Codec configuration box                  : avcC
    
This one does not
General
    Complete name                            : TEST\13 - x264 no KF - Force 30.mp4
    Format                                   : MPEG-4
    Format profile                           : Base Media
    Codec ID                                 : isom (isom/iso2/avc1/mp41)
    File size                                : 36.2 MiB
    Duration                                 : 9 s 657 ms
    Overall bit rate                         : 31.4 Mb/s
    Writing application                      : Lavf57.79.100

Video
    ID                                       : 1
    Format                                   : AVC
    Format/Info                              : Advanced Video Codec
    Format profile                           : High@L4.1
    Format settings                          : CABAC / 4 Ref Frames
    Format settings, CABAC                   : Yes
    Format settings, Reference frames        : 4 frames
    Codec ID                                 : avc1
    Codec ID/Info                            : Advanced Video Coding
    Duration                                 : 9 s 634 ms
    Bit rate                                 : 31.0 Mb/s
    Width                                    : 1 920 pixels
    Height                                   : 1 080 pixels
    Display aspect ratio                     : 16:9
    Frame rate mode                          : Constant
    Frame rate                               : 30.000 FPS
    Color space                              : YUV
    Chroma subsampling                       : 4:2:0
    Bit depth                                : 8 bits
    Scan type                                : Progressive
    Bits/(Pixel*Frame)                       : 0.498
    Stream size                              : 36.0 MiB (100%)
    Writing library                          : x264 core 157 r2935M 545de2f
    Encoding settings                        : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=30 / keyint_min=3 / scenecut=40 / intra_refresh=0 / rc_lookahead=30 / rc=abr / mbtree=1 / bitrate=31000 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
    Color range                              : Full
    Matrix coefficients                      : BT.709
    Codec configuration box                  : avcC    

Hopefully my Profile info will populate. If not:

Movie Edit Pro Premium Version 20.0.1.80

Windows 10 Home 64-Bit Version 21H2 OS Build 19044.1889 Experience Pack 120.2212.4180.0

Intel Core i7-4790@ 3.6GHz 16GB RAM

GPU NVIDIA GeForce GTX 1050 Ti - Driver v31.0.15.1659 (23/06/2022)

@Richard-Broughton

Hi

. . . . it may be something to do with Keyframes but it's not exactly clear what. I could recompress my old files and force in the additional keyframes but this could be a lot of processing for a "hunch" as to what the issue is . . .

h.264 and h.265 video the standard settings for a GOP (Group of Pictures) are either 0.5 x or 1 x the video framerate, by setting GOP (KF) length to 150, you are creating a 'long GOP' which is not suitable for video editing, hence the preview and editing issues.

The only time you 'may want to use' a long GOP is on final export for streaming over the Internet from your own website without using Youtube or Vimeo embedding. I use a GOP length of 100 for this.

There is usually no need to change any of the export preset parameters, as they are optimised for best perceived quality vs file size.

HTH

John EB

@Richard-Broughton Hi,

'Driver v31.0.15.1659' - I think that is an old driver, the latest is 516.94 , download GeForce® Experience that will help you get the latest, people on here seem to use the Game driver, I use the Studio driver https://www.nvidia.com/en-gb/geforce/geforce-experience/

There is usually no need to change any of the export preset parameters, as they are optimised for best perceived quality vs file size.

John EB

Thanks.

Unfortunately, the default out of FFMPEG (and hence out of VirtualDub) is for x264 and x265 to create keyframes when it detects a scene-change. I have to manually add a parameter to force a shorter GOP.

As it happens - I have now got to the actual root of the problem (and I'm slapping my hand to my head here because I was convinced I never had this problem before the reinstall).

In the program settings in MEP, I noticed that the "Hardware acceleration for playback if possible" was checked on the Import/Export tab.

I unchecked the box and now all my videos seem to be well-behaved in the timeline editor - no glitches so far this afternoon.

I'm also going to head off the problem in future by changing my x264 FFMPEG slicer to force keyframes at least once per second.

@Richard-Broughton If you updated your GPU drivers perhaps Hardware acceleration would work correctly.

@Richard-Broughton Hi,

'Driver v31.0.15.1659' - I think that is an old driver, the latest is 516.94 , download GeForce® Experience that will help you get the latest, people on here seem to use the Game driver, I use the Studio driver https://www.nvidia.com/en-gb/geforce/geforce-experience/

Thank you - good spot.

Just downloading 516.94 now and will see if that makes a difference.

I generally don't like having things like GeForce Experience and other automatic updaters hanging around but i'll certainly get the updated studio driver.

Interestingly after installing this - Driver version string is from Device Manager and it hasn't changed. I checked back through my files and the previous version I had installed was 516.59 according to the NVIDIA install file - so wasn't that old. Begs the question of what version info is Device Manager actually looking at.

@Richard-Broughton I presume you have restarted the PC? Mine shows correctly, Geforce Experience isn't automatic, you have to manually update & i like having it because Alt+F9 records the screen & Alt+F1 takes a screen capture, for me that's easier than Win+Shift+S to take a screen capture & I don't have other software that records the screen without fannying around with programs like Capture in MEP (+ I don't have Stereo Mix in audio, so MEP doesn't capture the sound),

PS like i say people on here (Magix) seem to prefer Game Driver but i use Vegas also & Studio seems to work better for that, You'd have to Google Studio vs Game driver & read for yourself, Geforce Experience makes it easy to switch between the two so you can test n see, although you do have to install one or the other, you can't just 'switch', you'll see 👍

 

Gid wrote on 8/13/2022, 3:00 PM

@Richard-Broughton If you updated your GPU drivers perhaps Hardware acceleration would work correctly.

Sadly not - but I admire your optimism. I'll be leaving the checkbox unchecked . . .

@Richard-Broughton I presume you have restarted the PC? Mine shows correctly,

Yes - restarted and Device Manager still tells me it's 31.0.15.1694 (21/7/2022). Digging around in windows this seems to be the version number for dbInstaller.exe in the NVIDIA folder in DRIVERS in SYSTEM32. I deleted the device and did a clean install and it still insists on this version string

I like having it because Alt+F9 records the screen & Alt+F1 takes a screen capture, for me that's easier than Win+Shift+S to take a screen capture & I don't have other software that records the screen

OK - I don't need that functionality

@Richard-Broughton Hi, that's a bit confusing, 31.0.15.1694 is the latest (last four numbers 5.1694 = 516.94) , before you said 516.59 ('31.0.15.1659') & now you say 'still tells me it's 31.0.15.1694' that it hasn't changed, but it has changed,

@Richard-Broughton You could if you're willing share that file that glitches on the timeline on Google Drive, then we can see if it's your PC or the file?

@Richard-Broughton

Hi

. . . . the default out of FFMPEG (and hence out of VirtualDub) is for x264 and x265 to create keyframes when it detects a scene-change . . . .

This occurs with all h.264 and h.265 encoders when they encounter a sudden change of scene - it is not unique to FFMPEG.

The default setting for GOP length in VirtualDub is 250 frames, at 30 fps that theoretically means there is one I frame very 8.33 seconds.

When editing the further the edit point is from the preceding I frame the potential for poor quality increases.

Persoanally I use Handbrake to convert videos when necessary, it produces correctly formatted h.264/h.265 video with no issues when editing.

John EB

@Richard-Broughton Hi, that's a bit confusing, 31.0.15.1694 is the latest (last four numbers 5.1694 = 516.94) , before you said 516.59 ('31.0.15.1659') & now you say 'still tells me it's 31.0.15.1694' that it hasn't changed, but it has changed,

I really need to wear my glasses . . .

The default setting for GOP length in VirtualDub is 250 frames, at 30 fps that theoretically means there is one I frame very 8.33 seconds.

Persoanally I use Handbrake to convert videos when necessary, it produces correctly formatted h.264/h.265 video with no issues when editing.

John EB

So for x264 output I can force a lower KF interval in VirtualDub which seems to be working nicely.

I took a quick look at Handbrake. The main drawback for my purposes is the lack of ability to have more than 1 input file.

My specific use case is to take the 4K H265 source and produce a 120second clip at a certain point in 1080p H264.

My action camera, however, produces files of 300 seconds. This is fine if the point I need is less than 120 seconds from the end of a given file - but when it spans the end of one recording and the start of another recording I need to produce the output from 2 input videos, which I can do quite easily in VirtualDub. (I can change the length of the captured files - up to a point - but there is always the possibility of the section I want spanning 2 files)

I think with Handbrake I'd need to have something join the files beforehand, if needed.

As the issue I had seems to be a combination of long GOP length output from VirtualDub (which I have fixed going forward) and the use of Hardware Acceleration in MEP (which I've now turned off) I think the problem is solved for all practical purposes.