I have other identical files, which all work fine. This one drifts, with the audio finishing a couple of minutes before the video in Audacity, Audition, and Premiere. Plays fine and in-sync in VLC and PowerDVD.Code:General Format : MPEG-4 Format profile : Base Media Codec ID : isom (isom/iso2/avc1/mp41) File size : 7.33 GiB Duration : 3 h 59 min Overall bit rate mode : Variable Overall bit rate : 4 387 kb/s Tagged date : UTC 2018-11-26 13:49:55 Writing application : Lavf56.19.101 Video ID : 1 Format : AVC Format/Info : Advanced Video Codec Format profile : High@L4 Format settings, CABAC : Yes Format settings, ReFrames : 3 frames Codec ID : avc1 Codec ID/Info : Advanced Video Coding Duration : 3 h 59 min Bit rate mode : Variable Bit rate : 4 284 kb/s Maximum bit rate : 5 500 kb/s Width : 1 280 pixels Height : 720 pixels Display aspect ratio : 16:9 Frame rate mode : Variable Frame rate : 29.772 FPS Minimum frame rate : 14.983 FPS Maximum frame rate : 29.970 FPS Original frame rate : 29.970 (30000/1001) FPS Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : Progressive Bits/(Pixel*Frame) : 0.156 Stream size : 7.15 GiB (98%) Audio ID : 2 Format : AAC Format/Info : Advanced Audio Codec Format profile : LC Codec ID : 40 Duration : 3 h 59 min Bit rate mode : Variable Bit rate : 92.8 kb/s Maximum bit rate : 99.8 kb/s Channel(s) : 2 channels Channel positions : Front: L R Sampling rate : 48.0 kHz Frame rate : 46.875 FPS (1024 spf) Compression mode : Lossy Stream size : 159 MiB (2%) Default : Yes Alternate group : 1 Text ID : 1-CC1 Format : EIA-608 Muxing mode : SCTE 128 / DTVCC Transport Muxing mode, more info : Muxed in Video #1 Duration : 3 h 59 min Bit rate mode : Constant Stream size : 0.00 Byte (0%) Encoded stream size : 0.00 Byte (0%) CaptionServiceName : CC1
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Frame rate mode : Variable
Frame rate : 29.772 FPS
Minimum frame rate : 14.983 FPS
Maximum frame rate : 29.970 FPS
Original frame rate : 29.970 (30000/1001) FPS
Basically you'd have to convert to CFR to edit it.
You're missing video frames. Video is shorter than audio , this causes the drift. In a media player, timecodes keep it in sync by displaying certain frames longer than usual. In a CFR version, there would be duplicate "placeholder" frames instead at those spots
WTF? All the others are CFR, I have no idea why this one is VFR.
Okay, looks like one other is also VFR, but it works fine in PP. Weird.
How do I convert this one so it co-operates?
Also I'm not sure I am missing video frames, as the audio always finishes early which implies added frames, not absent ones does it not?
If it's minimally variable, or just minor jitter in the timecodes, then you might not detect a sync issue . These aren't truly VFR, and can be treated as CFR. You might be able to remux it and fix those
Ones that have larger variations, will produce a sync issue for sure in PP or any editor
Newer versions of PP handle VFR slightly better
If the "assumed" CFR frame rate in PP is below the actual average framerate, the video might be longer. If the "assumed" CFR frame rate in PP is above, the video might be shorter. But it in both cases, they will still be in/out of sync in sections if you don't have one of the minimally variable cases
You can do the math. Look at the framecount and calculate the duration based on a FPS. 99% of timecode VFR cases will have missing frames
Use search, it's discussed often. Search for "VFR to CFR". There are several methods, several variations,none of them perfect, but it will be better than what you have now. For example, you can use avisynth to convert to CFR
DirectShowSource("video.mp4", fps=29.97, convertfps=true)
It's still out of sync after doing that.
Was the output file in sync in a media player? What format did you use, what does mediainfo say ?
The minimally variable ones where you can just assume CFR, usually have min/max like 29.95, 29.98 or something (ie. very little deviation, just jitter). But you have min 14.983 . But it might work , you can use mp4fpsmod to patch it to CFR. But I doubt it will work for that one, because it really is variable
I just told PP to interpret as 29.97 instead of 29.77, worked out how long that made it, reset it to original, and then used the rate stretch tool on the video. It's now synced at both ends, fingers crossed it's functional across the bit I need (which is only about 30-40 minutes of the four hours).