Avidemux Forum

You can try re-muxing the file with mkvtoolnix.

Note that this is re-muxing, not re-encoding, the process should be very quick, as in seconds or maybe a minute or two.

You can even change the framerate to 25.000 fps, 24.000 fps, whatever you want.

Load your file, then select the default duration of 24000/1001, which equals 23.976 fps, the audio will remain unchanged.

If the resulting re-muxed file is of a different length or the audio becomes de-synced, further investigation would be required.

https://mkvtoolnix.org/

I dunno if this helps, or if it is still relevant some 8 years later(?), but, if you have a video that is in 25fps, the only option is to re-encode at 23.98, AND modify the audio filter to resample the audio "From PAL to FILM". This will keep the sync, but it will also extend the video a little and may sound "slower" - but in my experience with anything encoded in 25 fps, that is not the proper pitch for the audio anyway, and if you have a sharp ear, you can tell anything in 25 fps sounds a little "chipmunky" when compared to a proper 24 fps file.

Anyway, by the sounds of it, you have a perfectly good 23.98 fps video, but the audio tracks are somehow encoded to be in sync with a 25 fps speed, making them OUT of sync with your video, correct?

If so, try half of what I suggested, and COPY your video (as MKV or MP4) as you would, but use the AUDIO FILTER to change audio from "PAL to FILM"  and hopefully that will sync everything up without having to re-encode the video.

Alternatively, if you want to speed up the video to match 25fps audio, then you're looking at re-encoding the video.
I dunno why you would want to speed it up anyway? That "chipmunk" pitch is annoying and ruins a good movie.

I also recommend making sure the sample rate is set to 48 kHz (48000 Hz), if it isn't already, as I have had horrible results with 44kHz after copying/converting. 44kHz is great for audio music (CD) tracks, but not movie audio.

I posted about this in another thread, but let me try presenting this problem again, a different way :

Is there ANY WAY to MODIFY the FPS in a HEVC (H265) MP4 file, to a more specific rate (from 23·976215 to 23·976023)?   (Those last 3 digits have proven to make a crucial difference.)

I want to FIX my HEVC files that were somehow encoded with a 23·976215 framerate, causing defective results when trying to convert to AVC/H264. This framerate gets screwed up (whether converting to AVC/H264 or HEVC/H265) where it is automatically slashed to half (between 12 and 15 fps).

I tried doing the conversion in Freemake, but the video would not even be recognized and was automatically replaced with "visualizations". (Red flag right there!)

I tried doing conversions in VLC, but NOTHING ever works in VLC except playback. I even tried the "record" function while the file played, but the output was an MP4 with NO VIDEO, just audio.

I tried a Video Converter from NCH Software, but that cheap crap made the video look pixely and turned it into garbage.

Avidemux is the only program that does a decent job on most conversions (despite taking forever) - EXCEPT for this HEVC framerate issue.

While attempts to circumvent this problem in Avidemux have been futile, I came close with using the video filter to "Change FPS" from "23.98 Custom (default)" to "23.98 (Film)" - while the framerate correctly changes to 23.976023, the picture is now a bit stuttery/choppy. It's not as bad as other results, but it's noticeable enough to be annoying.

Why will the smoothness not be retained?
Why does this "215" value in the framerate cause ANY/ALL conversions to screw up the framerate so badly?
Why does modifying "215" to "023" still cause a slight stutter/choppy playback of the video?
In short : HOW DO I FIX THIS?

I know Avidemux is probably loaded with all kinds of settings, but they are in "proper editor terms" I don't understand, and I cannot find anything to "translate" them into layman's terms, so I can figure out what might fix these damn files that were encoded so poorly.

If there is a setting that will correct this discrepancy in the framerate and finally yield a smooth, quality AVC/H264 conversion output at a proper 23.98 (23.976023) fps without stuttering or jerking during playback, I would like to know.

Even if I have to convert the "bad" HEVC/H265 to a "good" HEVC/H265 before converting to AVC/H264 after, as long as I do not lose quality, I'll endure that extra step (despite more countless hours wasting my days away, cos these processes take so damn long).

I also use Windows XP, so my "conversion tool" software options are already limited.


PS :
Please don't get on me about why I still use XP. I have my reasons.
Let's stay on point with the topic, thanks.

Let me try this again, a different way :

Is there ANY WAY to MODIFY the FPS in a HEVC (H265) MP4 file, to a more specific rate (from 23·976215 to 23·976023)?   (Those last 3 digits have proven to make a crucial difference.)

I want to FIX my HEVC files that were somehow encoded with a 23·976215 framerate. This framerate results in screwy conversions (whether to AVC/H264 or HEVC/H265) where the framerate is automatically slashed to half (between 12 and 15 fps).

I tried doing the conversion in Freemake, but the video would not be recognized and was automatically replaced with "visualizations".

I tried doing conversions in VLC, but NOTHING ever works in VLC except playback.

I tried a Video Converter from NCH Software, but that cheap crap made the video look pixely and turned it into garbage.

Avidemux is the only program that does a decent job on most conversions (despite taking forever) - EXCEPT for this HEVC issue (this is why I despise HEVC and any compression formats).

While attempts to circumvent this problem in Avidemux have been futile, I came close with using the video filter to "Change FPS" from "23.98 Custom (default)" to "23.98 (Film)" - while the framerate correctly changes to 23.976023, the picture is now a bit stuttery/choppy. It's not as bad as other results, but it's noticeable enough to be annoying.

Why will the smoothness not be retained?
Why does this "215" value in the framerate cause any conversions to screw up the framerate so badly?
Why does modifying "215" to "023" still cause a slight stutter/choppy playback?
HOW DO I FIX THIS?

I know Avidemux is probably loaded with all kinds of settings, but they are in "proper editor terms" I don't understand, and I cannot find anything to "translate" them into layman's terms, so I can figure out what might fix these damn files that were encoded so poorly.

If there is a setting that will correct this discrepancy in the framerate and finally yield a smooth, quality AVC/H264 conversion output at a proper 23.98 fps without stuttering or jerking during playback, I would like to know.

Even if I have to convert the "bad" HEVC/H265 to a "good" HEVC/H265 before converting to AVC/H264 after, as long as I do not lose quality, I'll endure that extra step (despite more countless hours wasting my days away, cos these processes take so damn long).

I also use Windows XP, so my "conversion tool" software options are already limited.


PS :
Please don't get on me about why I still use XP. I have my reasons.
Let's stay on point with the topic, thanks.

CleanTalk was standing in alexstorm's way trying to post the following text he sent to me via PM:

================= (begin of quote) =================

Thanks RH, that is interesting that CleverFFMPEG_gui software works. There are several different subtitles types that can be embedded or as separate files.  Does this software work for all subtitles?

If this was requested in Post Production house, all edits would use a time code list that has all edit removal or additional drop in inserts, The editor would give the time code list to a subtitle person and they would also use separate software, like you mentioned, to fix the subtitle timing. Does it qualify as a new feature when you are the only person, I've ever seen to ask for it?

I think AVIDemux would need to first support Time Code lists.  Does that happen somewhere with a plug in?

Search for video edit timecode list online to find more info on how to work with timecodes.

================= (end of quote) =================

On my part, I explained it multiple times on many occasions what is required to add support for subtitle tracks in Avidemux – high quality patches are welcome (yes, I know that a few good pull requests in other areas are currently rotting awaiting merge, my fault due to lack of time and task overload).

If you absolutely cannot use the CLI application, e.g. because you need hw accel features (hw video decoders or encoders, OpenGL video filters), you can minimize the window of the graphical application using QtGuiWindowMinimize() method in Gui() class, e.g.

gui = Gui()
gui.QtGuiWindowMinimize()
There is no way to script default zoom value.

By the way, why not running Avidemux on a separate workspace / on another virtual desktop? At least on Windows. On Linux it will impertinently pop up on your current workspace right in your face when encoding is finished, at least with gnome-shell, unfortunately.

Hi

I usually use the View of Zoom 1:2 to reduce the application size but when running a script it keeps the view at 1:1 filling the screen.

Is there a way either to set the default View to Zoom 1:2 or set the View size within a script when converting a folder of files?

Appreciate any assistance..
T

Bonjour,

Quote from: DWAM on December 10, 2025, 07:15:48 PMPensez-vous que ça vaille quand même la peine que j'essaie sous X11 ?

Je n'attends rien, mais, si possible, veuillez essayer.

Quote from: DWAM on December 10, 2025, 07:15:48 PM- que vous ne semblez pas vraiment motivé pour qu'Avidemux puisse fonctionner sur l'architecture arm64

Eh bien, il me faudrait d'abord acheter un RPI5. Malheureusement, même si je peux acheter du matériel, je n'ai toujours pas le temps nécessaire pour reprendre le travail sur Avidemux.

Quote from: alexstorm on September 02, 2025, 11:43:53 PMHandling subs is very complex to do well and it depends on what hardware and processing speed each end user has.  Very fast servers with hardware transcoding support can handle most embedded subtitles but even these server can fail to process in real time wen there are too many embedded subtitles for media coming from original blu-ray discs.  Blu-ray players are set to handle one sub at a time. Servers, even with hardware encoding support see all the subtitles and tries to handle them in sequence during the transcoding. Even a dedicated fast and hardware supported server may not be able to handle all he subtiles in real time.

Keeping many subtitles embedded in .mkv media including graphic subtitles .sub works fine with blu-ray playback but other players do not support .sub or some don' even do .ass files.  The .sub files need to be scanned, read by a optical character reader and converted to text based subtitles that the user's player, browser or TV app can accept.  This has to be done in real time or the sync goes bad or the media buffers before any playback starts.

This problem varies with every user, every hardware and every network / Internet connection speed and traffic.  In short, .sub graphic subtitles are fine for blu-ray and not really supported for video streaming.  Trying to support them would be pointless, because it depends on each user as to what bandwidth and hardware processing their hardware and software player can handle.

This type of subtitle support won't work with the current hardware.  In my opinion, there is no point in trying.  Take the embedded subtitles and convert them to text .srt.  Most players support this and there is no lag time for processing.  You are asking everything to be automatic so you don't have to prep anything, but video streaming that works smoothly has to be prepared and it is different than blu-ray playback.

There is software that can take out all embedded subtitles for all media in a directory and subdirectory.  It's possible to create a command line and point the software at 10,000 videos and the software will do them all when you click 'Enter'.  Average computer can do a 2 hour media remove embedded subtitles around 10 a minute.

The sync should be fine, but even if it needs adjustment there are online services that can adjust a subtitle in ms plus or minus in a few seconds.

The video collection is yours, so prep it correctly and remove the subtitles yourself with tools. MKVCleaver MKVtoolnix, full ffmpeg install.

Online services:
https://subtitletools.com/subtitle-sync-shifter
https://subtitletools.com/convert-sub-idx-to-srt-online

Online professinal sites that sell content make sure their playback has been prepped in this way with all sub converted ahead of time.  I do not believe any online streaming site includes embedded subtitles.  If someone knows of one, please do post it here.  These sites are running these support software to remove subtitles and convert them so their streaming playback works for everyone.  Doing it automatically is not reasonable to even attempt.

See my reply to WTWASP.

Quote from: WTWASP on August 17, 2025, 02:42:21 PMHave you done the SRT thing? SRTs will provide you the subs you need (for MP4s in VLC, anyway), and when editing the video, cutting parts out or whatever, well, you literally have your work cut out for you ; SRTs can be edited, but it's a lot of painstaking manual effort to change all the timestamps after the points of edit, and depending on how much dialogue there is, you could be looking at thousands of individual captions that need their timestamp adjusted to the new timestamp, post-edit.

I dunno if this helps you at all, or if I am even in the ballpark of your issue, but there it is, anyway.

I might not have explained things very well (my apologies) but the MKV files I'm working with already have a single, subtitle track (.srt). When I make cuts to the MKV file, those subs are instantly removed from the finished file.

CleverFFMPEG_gui can make cuts to MKV files and automatically fix the timing (and keep) the included srt subtite track but its' cutting isn't as good as AVIDemux and you have to enter exact time codes and cutting videos in AVIDemux is just so much easier.

If somebody could combine these two programs into one, that would be amazing!