@me_again Does it make any difference if you renecode to 24fps & not 25fps, as I understand it you're adding frames to make it up to 25.

There's 371 seconds in 6mins 11secs,

371 x 24.329 = 9026.059 frames

371 x 25 = 9275 frames

9275 - 9026.059 = 248.941 frames

248.941 frames @ 25fps = 9.95764 secs, that's your 10sec difference in time,

---------------

Reading that it sounds the wrong way around but it's too early for me to fathom or put in words 😂.🤔

------------------

25 - 24.329 = 0.671

In my mind you're loosing 0.671 of a frame every second when encoded to 25fps, so 0.671 x 371secs = 248.941 frames, that equates to 9.95764 secs lost.

@CubeAce

Greetings Ray,

In the General section it says 6mins 11 secs and in the Video section it says 6min 1 sec.

That's another dark art 😳

AndyW

@me_again

Hi Andy.

Have you seen the length of the produced clip as reported on the timeline?

I assume when these programs say there is no re-encoding that they mean there is no re-compression of the images within the existing frames and not that new frames are not produced or 'muxed' (is that a term for blending two frames to produce a new one? I don't know.)

Also if the original clip can be played back properly in a player that is capable, is the time played actually 6 mins 11 secs to account for the varying frame speeds?

I'm just curious as I don't have to deal with these types of files.

Ray.

@Gid I understand what you're saying re the fps difference but I didn't re-encode to 25 fps, that's what I don't understand. I use MyMP4Box to demux to the file's raw formats then put them back together without re-encoding.

The original file had variable frame rate of 24.329 average (4.998 min 25.619 max), demuxing then remuxing tidied that up to constant 25 fps.

MyMP4Box, can remux to different fps. I've repeated the experiment changing the output to 24 fps. The resulting file is 6 mins 16 secs.

The details are here https://www.videohelp.com/software/My-MP4Box-GUI

AndyW

@me_again 😁 Yeah that's what doesn't makes sense to me, the maths sort of makes sense & creates a 10sec difference but I don't know if new frames are added, or the orig amount of frames are distributed/divided amongst the new frame rate. Or if I'm just talking bollocks 😂🤦‍♂️

I tried drawing it to understand it 🤷‍♂️

@CubeAce

Greetings Ray, when I play the files in Media Player Classic or Films & TV the length for the original and the remuxed is shown as 6 mins 11 secs.

It's all very odd I know and I hope that someone can shed some light on this.

What I do know is that it's worked well for me, the project I've been working on looks OK considering the original material. The first draft I did with re-encoded files was really quite poor even with NeatVideo and friends.

AndyW

@Gid

I've put the files into MS2025, one under the other and the difference in length can be seen.

Not sure about you "talking bollocks", it makes sense. When I talk I roll my R's, my wife says I talk through it 😒.

AndyW

@me_again In the Duration at the top under General it still says 6 min 11 s but under the Video section it is 6min 1 s, Does this mean MediaInfo is reading the whole thing & the Audio is still 6min 11secs & so offset to the video now, Is MediaInfo reading Audio & Video to make the Duration in the top General box?

@Gid, No idea mate. The audio plays perfectly in sync is media players and in MS2025.

To complicate the issue, when I put the remuxed file into Exiftool (similar to Mediainfo but more info) it reads the file as 6 mins 12 secs.

Greetings,

Here's some more information, this time from Exiftool. The text file output is extremely long so I won't post it unless asked to. Here are the main differences I can find:-

In the QuickTime information section:-

1. Compatible brands: Original - isom*3gp4, Remuxed - isom*avc1
2. Timescale: Original 1000, Remuxed 600 (no unit associated)
3. The duration is 0:06:12 for both files
4. Track Duration: Original 0:06:11 & 0:06:12 ( shown in different areas of the file) , Remuxed 0:06:02 & 0:06:12 (again in different areas of the file)
5. Media Duration is Original 0:06:11 & 0:06:12 ( shown in different areas of the file) , Remuxed 0:06:02 & 0:06:12 (again in different areas of the file)
6. Media Timescale: Original 90000, Remuxed 25000 (no unit associated)
7. Pixel Aspect Ratio: Original 65536:65536, Remuxed NO ENTRY
8. Video Frame Rate: Original 24.329, Remuxed 25
9. Media Data Size: Original 100118022, Remuxed 100118022
10. Media Data Offset: Original 810040, Remuxed 122979 (no unit associated)

Pick out of that what you can 🤓. I was lost after Greetings.

AndyW

@me_again

Andy, can you share one of your recalcitrant files?

Greetings,

Recalcitrant files? Most of the ones involved young grandson / daughter so I'll not show those, however this one is from the same phone but a year later. No audio.

https://1drv.ms/v/s!Ajly6fulyLULhAjNcGKzjkxt_Fqn?e=IaZCAS

AndyW

ps it's been a long long time since I've used OneDrive but i think I've done it right.

@me_again

Hi Andy,

That is one bad video - frame rate 5.002 min, 30.060 max. Works fine in VPX16 with no treatment. One of the anomalies, I guess.

John CB

@browj2

I have to admit it's one of the worst of the batch. I've had better quality 8mm to VHS to AVI to MP4 as technology progressed. Unfortunately I didn't keep the originals of those.

Would it be possible for you to try the demux/remux with MyMP4Box to see if you get the same results as me - remuxes to 25 fps and is 4 seconds longer but plays exactly the same with no evidence of speeding up?.

AndyW

@me_again

Andy, I'll have a crack at MyMP4Box tomorrow but what exactly is the problem with these? This one plays and edits fine on my machine. As the "over the ditch" people would say, "it's smooth-as, bro!".

@AAProds

Al, unfortunately this is only a short video. Some of the ones I've been editing are 10+ minutes with usually only 2 or 3 minutes of yhem usable.

When they're cut, the audio goes out of sync a little bit. In most cases it's not noticeable because there's just laughing and screaming when running around as kids do, but one or two clips are priceless closeups of them talking - from out of the mouths of babes 😊 - and it's these that caused the trouble. Not insurmountable obviously but annoying.

When I found that the demux/remux hack seemed to make things easier by not re-encoding, and as I've run out of variable frame rate videos, I thought I'd ask the wider community if it is indeed a viable alternative to the re-encode option.

Nothing more, nothing less.

AndyW

@me_again Hi, as mentioned this plays without problems in MMS.

This is what VP21 shows, the offset at the end highlighted in blue is 12frames, MediaInfo has a different duration for Video & Audio but I haven't tried to work out ms vs frames 🤷‍♂️ Also VP21 has 'issues' so I can't fully trust it,

VP20 shows no offset but also shows different Field Order Properties & it shows an i at the end of the fr bottom left of the preview window.

I'm just sharing for the sake of sharing & more info the better yes 👍

Do you mind if I ask on the Vegas forum, I won't share your vid but I want to know which to trust,

PS there's an option that turns on Legacy AVC decoders, it srt of like rolling it back, that shows a different mix of the Properties. 😂

@Gid

Well now I'm totally confused. Ask away.

AndyW

@me_again 😂👍

@me_again

How are you using MP4Box? Are you opening the file on the Mux tab, then clicking Mux?