Hello, I’m starting to learn and work with ELAN 6.2 to analyse videos for my PhD (doing some annotations and counting events duration).
I’m currently having problems with “fast motion” control: when I try to increase the velocity of the video, the play button doesn’t respond anymore. Then, even if I comeback to normal velocity of play, it stills freeze. (I can still use the frame_by_frame or sec_by_sec buttons). Do you have any tip or suggestion to help me?
Thank you in advance!!
DETAILS: The operating system of my PC is Microsoft Windows 10 Enterprise. My videos were collected with a GoPro, and their format is .MP4 (around 17 minutes each, size around 3,66 GB).
Things I already tried (but didn’t work): -The same but with older version of software (6.0). -To play just a smaller “section” of the video (10 sec.). -To “compress” the size of the video file (from 3,66 to 1,98 GB).
So far, I haven’t been able to reproduce this problem and I don’t really have a solution for you, but here are a few suggestions for things you can try.
One thing I did notice, on my system, is that when the playback rate is changed while the video is playing, the player stops but the play/pause button is not updated. This is not really a problem, it has to be clicked twice to start the player again, but I do see some warning messages in the log (“failed to process the media event”) when changing the velocity that way. Maybe you already tried that, but does it make a difference whether or not you first pause the player before changing the playback rate?
After the freezing there might be error messages near the end of the log (View->View Log…), other than the one I mentioned. Is there anything that specifically refers the playback rate?
Whether or not slow or fast motion works at all sometimes also seems to depend on the type or encoding of the video. Do you observe the same problem with e.g. one of our example media sets?
Hi again, Thanks for the answer Han,
Yes, I forgot to say that I first pause the player before changing the playback rate (is the “playback rate” the button to speed of the video, right?)
I already tried you your examples, and it worked!! When you say that it could depend on the “type or encoding of the video”, are you speaking about “file format” like .MP4? Can you please explain that or tell me where I can check that?
I will keep trying what you suggest and cross fingers!
Thank you
One more thing: about Log view, I’m afraid I cant understand/ “replicate” what it says there, do you want me to copy/past that info somewhere else?
Well, I decided to do it here…I just copied the last part:
Thank you for your help and patience!
“”
WARNING: No plug-in cmdi metadata file found in analyzer-gloss-0.6.jar
Jan 19, 2022 12:10:36 PM mpi.eudico.client.annotator.util.AvailabilityDetector detectFromJar
WARNING: No plug-in cmdi metadata file found in annotyzer-lexicon-0.7-compound.jar
Jan 19, 2022 12:10:36 PM mpi.eudico.client.annotator.util.AvailabilityDetector detectFromJar
WARNING: No plug-in cmdi metadata file found in annotyzer-whitespace-split-0.9.jar
Jan 19, 2022 12:10:55 PM nl.mpi.jni.NativeLogger nlog
NATIVE: MMFPlayer.ProcessMediaEvent: setting rate failed, requested rate 2.000000, actual rate 0.000000
Jan 19, 2022 12:10:55 PM nl.mpi.jni.NativeLogger nlog
NATIVE: MMFPlayer.Invoke: failed to process the media event (-1072875824, 0xC00D36D0)
Hi, thanks or the part of the log; it confirms that changing the playback rate (indeed, the speed of the video, slow or fast motion) failed. Unfortunately it doesn’t tell why it failed. I assume you also tried other values between 100% and 200%?
Since our example video does work, the problem might be in the encoding of the .mp4. Indeed when I mentioned the type of the video file I was thinking of the format, mp4 or mpeg-1 etc. Within each format the video can be encoded in different ways and maybe some encoding parameters can prevent fast playback (with this media player). I actually have no idea which setting or settings could cause such problem, but you might try if re-encoding the video following the guidelines in this media encoding guide changes anything.
To be sure that it is not the size or length of the video, you might want to try if a shorter GoPro video has the same problem?
Thank you Han,
(Yes, I also tried other values between 100% and 200%.)
I’m currently doing that “transformation” of videos, cutting them into small pieces and it works like that. But I cant still be sure if its due to the smaller size, or to the “encoding parameters”. (actually I’m not aware of that parameters since the app I’m using does it automatically…). Well, at least it works like this!
So thank you for your answers!
Great, good that it works like that!
I guess it would still be interesting to know whether it is just the smaller size or the re-encoding that makes the difference, but I understand that this doesn’t have top priority :).
Han, for me its not because of being or not a “priority” - I really don’t know how to do correct “encoding of the .mp4”… even with “guide” you shared… sorry. But thank you! And the reason why I have no idea about whether or not I’m changing the file properties, it’s because I just tried to cut the video lenght/size with “Windows Photos”. And maybe this “cutting operation” is changing encoding as well, but I dont know how to find it out or where to look for that information. Anyway, I think that’s OK like this
and cross fingers!
sorry. But thank you! And the reason why I have no idea about whether or not I’m changing the file properties, it’s because I just tried to cut the video lenght/size with “Windows Photos”. And maybe this “cutting operation” is changing encoding as well, but I dont know how to find it out or where to look for that information. 
Anyway, I think that’s OK like this