January 17, 2021, 04:18:42 pm



Frame rate setting

Started by fhutt, November 15, 2020, 01:17:05 am

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I use Avidemux mainly to upscale some videos.
I notice that if the Frame rate is not exactly the same as the original, the video jerks when there is panning. the solution I found in other upscaling/resizing apps is to set the Frame rate to "Original"

This option appears to be missing in Avidemux in any direct way. However, I think that there must a way to ensure that the jerking doesn't take place. So, I was wondering what settings need to be set to prevent the jerking?


First of all, please use the latest build from https://avidemux.org/nightly/ available for your operating system.

Regarding frame rate, it all depends on properties of the input and the output. In general, Avidemux tries to keep the source time base or at least to remain compatible with it, but again, this all depends on the input, the filter chain and the selected muxer.

To assess the situation, please provide some info, e.g. if you run Avidemux on Windows, please load a source video exhibiting the issue, close Avidemux and attach admlog.txt from %localappdata%\avidemux\ to your reply. Additionally, please mention the muxer in Avidemux you use to save the output.


I am using Windows 7  Ultimate and Avidemux V2.7.6

The settings in Avidemux I use are:
Video Output Mpeg4 AVC (x264),
Configure - General/Encoding Mode Average bit rate (2 pass),
Average bit rate 1500K for 720p and 2500K for 1080p,
Crop filter pixels set for a 16/9 aspect ratio,
Change FPs try to set to same as source,
swsResize to 1280x720 or 1920x1080 with Lanczos-3,
Resize Method Lanczos,
Audo Copy
Output format Mp4 muxer

I have only been using Avidemux for a few days. I do not have an example at this stage because I have been trying to set the FPS to the same as the source each time. From previous experience I know the problems using a different FPS for the output from the source. Sometimes it is difficult to determine exactly the FPS of the source. I do now notice that the output setting in the Change FPS filter tries to follow the source. If this is the case, maybe I don't have a problem with Avidmux.

Could you please confirm that Avidemux actually tries to set the output FPS to the same as the source in the filter.


Don't insert changeFps unless you know what you are doing (else it will cause progressive A/V desync).

Quote from: fhutt on November 15, 2020, 11:36:40 pmCould you please confirm that Avidemux actually tries to set the output FPS to the same as the source in the filter.

Avidemux tries to keep the original time base when possible and always tries to keep timing of frames (eventually with a uniform delay to account for B-frames). But I have to repeat that generalizing statements don't make sense. Such problems are mostly tied to issues of the source video, see https://avidemux.org/smif/index.php/topic,19297.0.html

If you have a video which becomes jerky when re-encoded with Avidemux, please provide the log (it may be necessary to get a part of the actual source video to analyze the issue).

For better experience, please use the latest nightly build.


Thank you for your help.
The link you supplied was interesting.
If I find any problems I will send the log and sample.