Variable Frame Rate - Output on MP4 Problem

[TheMediaMaster]

AVIDemux - Output Video has Variable Frame Rate (VFR):





I Have tested using AviDemux v2.6.10 build 150607 win 64 Bit

&

AVIDemux Version: 2.6.10 (Lastest)

OS: Windows 8.1 Pro x64
AviDemux - 32 Bits
Version: 2.6.10.151014




TEST CONDITIONS:

Video Output: Mpeg4 AVC (x264)
Output Format: MP4v2

Checking the file with MediaInfo, you should find both a Minimum and Maximum
Frame Rate.

Input File: Frasier - Extras - Analyzing The Laughter.avi

Here are Pastbin links to the MediaInfo v0.7.78 (Current Version) Outputs:

Fraser Video - MediaInfo & PasteBin URL:
http://pastebin.com/3KvxSP27

Frasier Video - AviDemux MP4v2 OUTPUT - MediaInfo & PasteBin URL:
http://pastebin.com/bWfhQAiH

Dev - Tell me if you really want me to upload samples of the Frasier video to you for testing/analysis.



Specifying a Preset Frame Rate using the filters makes no difference at all.

Here are some URL's to previous references of this issue:

http://avidemux.org/smif/index.php?topic=11670.0
http://avidemux.org/smuf/index.php/topic,11384.0.html
http://newscentral.exsees.com/item/65a35e349112a7958c32c7739e295094-67e8e73ba7bcb505b8054771a7596493




DATE I CREATED THIS FILE: Thursday the 15th of October, 2015

[AQUAR]

Are you basing this purely on the info provided by Mediainfo?

[TheMediaMaster]

Of course, Why, do you suspect that MediaInfo is incorrect ?

[AQUAR]

Move past the first few I frames and check the duration of subsequent frames.
Are they constant as in the source material?

Mediainfo interprets frame rate parameters based on frame duration sampling.
Quite possible the first few frames have their frame duration changed during the transfer/transcode into a new container.
Don't ask me why (I don't know!).

[Porygon]

Hi all,
Sorry to bump and old topic but I had a similar problem and felt that the issue has not been addressed - at least for someone as ignorant as myself.
I am not an expert at all, and I barely know anything about video compression let alone Avidemux. Just fiddling with it for several uses.

I noticed that using the MP4V2 muxer generated files with variable framerate and variable audio bitrate. While a file might play ok with VLC, which would resync video and audio properly on playback, not only MediaInfo shows that the file has a variable framerate (I often get max. of 29.97fps and weird min. below 10, whether true or not) and variable audio bitrate, but sending the file over web applications (for instance Facebook messenger or Instagram), which don't like to process files with variable framerates and variable audio bitrates, will make the audio drift out of sync.

I noted that it worked fine with the MP4 muxer though, and the output video would have CFR and CBR for audio. Using the AVC x264 codec or Copy mode (original video being AVC). Audio in Copy mode seems to work too (original audio being AAC). This is not a general answer but a practical solution that worked in my case. The videos seem to be processed properly through messenger or Instagram too. Hoping this would help.

Best regards