29.6 fps is not a standard frame rate at all so it doesn't surprise me that the mp4 export fails. But why it works for some clip lengths and not others is a mystery. It may be that your phone skips a frame or 2 in the last part of the video, which is not uncommon. Have you looked at other videos from taken your phone?

If you don't care about the size of the exported video you might try exporting to JPG, which creates a series of still images. You could then use a separate program to combine the JPG files into a single video.

Unfortunately the quality of exported videos is never very good and there is little I can do about it since it depends on the Xuggle video engine presets :-(




> Re: Error while exporting video
>
> Hi!
>
> First time poster here...
>
> I made an analysis
> (Tracker-Zip @ https://www.dropbox.com/sh/jt814gp6mp4hc2h/AACuGhFOWyOGhgYW3ydtCmkMa?dl=0)
> but
> when i try to export the Video with the lines and
> angles, in the end it throws an error:
> "Could not
> encode video"
> and a second error-Window
> "Timebase
> not supported by mpeg 4 Standard thread"
> See attachmen
>
>
> PC was Windows 8.1
>
>
> I tested it on my Laptop as
> well (Win10) with the same problem.
> The FPS is 29.6fps
> and straight from my phone... Should be a valid MPEG4
> i think...
>
> So... What can i do to export the video?
> What even is the problem, as 29.6fps is a valid fps
> for MPEG4, no?
>
> also tried to save it to an USB-Stick
> in case of write-problems. Same.
>
>
> Puzzled...
>
>
> Edit
>
> Oh... The console throws this:
>
>
> CONSOLE: 16:43:00.443
> [AWT-EventQueue-0] ERROR org.ffmpeg - [mpeg4 @ 0x288fedb0]
> timebase not supported by mpeg 4 standard
>
>
> CONSOLE:
> 16:43:00.443 [AWT-EventQueue-0] WARN  com.xuggle.xuggler
> - Error: could not open codec (../../../../../../../csrc/com/xuggle/xuggler/StreamCoder.cpp:686)
>
>
> CONSOLE:
> 16:43:00.513 [AWT-EventQueue-0] WARN  com.xuggle.xuggler
> - Attempting to encode when not ready (../../../../../../../csrc/com/xuggle/xuggler/StreamCoder.cpp:1194)
>
>
> CONSOLE:
> 16:46:20.201 [AWT-EventQueue-0] WARN  com.xuggle.xuggler
> - writeTrailer() with no matching call to writeHeader()
> (../../../../../../../csrc/com/xuggle/xuggler/Container.cpp:734)
>
>
> CONSOLE:
> Exception in thread "AWT-EventQueue-0" java.lang.RuntimeException:
> could not write trailer to output file
>
>
>     at org.opensourcephysics.media.xuggle.XuggleVideoRecorder.closeStream(Unknown
> Source)
>
>
>     at org.opensourcephysics.media.xuggle.XuggleVideoRecorder.reset(Unknown
> Source)
>
>
>     at org.opensourcephysics.cabrillo.tracker.ExportVideoDialog$5$1.run(Unknown
> Source)
>
>
>     at java.desktop/java.awt.event.InvocationEvent.dispatch(Unknown
> Source)
>
>
>     at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown
> Source)
>
>
>     at java.desktop/java.awt.EventQueue.access$500(Unknown
> Source)
>
>
>     at java.desktop/java.awt.EventQueue$3.run(Unknown
> Source)
>
>
>     at java.desktop/java.awt.EventQueue$3.run(Unknown
> Source)
>
>
>     at java.base/java.security.AccessController.doPrivileged(Native
> Method)
>
>
>     at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown
> Source)
>
>
>     at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown
> Source)
>
>
>     at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown
> Source)
>
>
>     at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown
> Source)
>
>
>     at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown
> Source)
>
>
>     at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown
> Source)
>
>
>     at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown
> Source)
>
>
>     at java.desktop/java.awt.EventDispatchThread.run(Unknown
> Source)
>
>
>
> Edit:
> weird... If i export only up to frame
> 35, all is OK... Only if i export up to 182, the error
> occurs...
> up to frame 99: error
> [unknown region]
> up
> to frame 76: Success
> up to frame 50: Success.
>
>
>
> Edit:
> Hu? If i export to WMV, all works (except the quality
> of the video is shit after export... Blocky as hell...
>
> I added the WMV to the Dropbox link from above...
> Some idea on how to improve the video-quality?
>
> Post
> edited November 14, 2018 at 11:19 AM EST.