Slow video playing every couple of seconds

I just bought ATVFlash and I´m trying to play a MKV file but every couple of seconds, the video plays like slow motion.
I know there are similar threats but I´m not sure if it´s the same problem. I´m not intended to duplicate threats.
I´m using an Iomega 250GB drive or SanDisk CompactFlash Ultra II to store the video and have the same problem.
The file is a 590MB MKV so there supposed to be no problem with the file size.
I read about the USB cable but I don´t think my USB cables are damaged.
The only thing that I can think right now is the HDMI cable that I´m using to connect the AppleTv to the TV, because it´s not a branded cable like Monster Cable, but this HDMI cable has been working fine with the other devices that I used it.
I tested the movie in the computer and there is no slow motion so the file isn’t the problem either
I will appreciate if some one can help me find what is happening, because I bought this app just for the possibility to play different movie formats than the iTunes supported, but watch a movie this those slow motion moments every couple of seconds is very annoying.
Thank you for the help.

Ok… I uploaded the same file I tried via USB but this time via ftp and I obtained same result… slow motion every couple of seconds… The video and the audio are synchronized but the video stops every couple of seconds.
Any help would be great
Thank you.

What resolution and bitrate does the mkv file have?

AppleTV can only handle low bitrate 720p, for anything higher you need to add a Crystal HD card to the AppleTV.

The files are 720p
Thank you for your response

Do you know the specs for your files? The AppleTV will support video files up to 5 Mbps, maximum resolution 1280x720 @ 24fps, 960x540 @ 30fps.

I´m not sure of the specs but I´m watching an episode of The Big Bang Theory I downloaded from tvunderground in 720p… and the movies that I have in the internal disk of the AppleTv and iTunes are same or more resolution and they play perfect.
Thank you for your response

If you do a ‘get info’ while playing the file in Quicktime (on a Mac) it will show you the relevant info for that file.

In the meantime, you may try toggling the ‘Apple H.264’ option in the Maintenance --> Settings menu.

I can´t play it in Quicktime (at least the standart version) because it´s a mkv, but VLC gave me this:

bitrate: 384 kb/s
Framerate: 23.976216
Resolution: 1280x720

I´m attaching other details.

I´m going also to try the ‘Apple H.264’ option. I will let you know
Thank you for your help.

Ok… I disabled the Apple H.264 option and the problem is still there.

I´m getting without options:

.- Disabled Apple H.264
.- ftp the file to the internal disk
.- File 720p with 384kb/s bitrate

Any additional idea?
Thank you for the help.

I have the same issue with this file

You may try the following.

1. Disable the 'Apple H.264' option through the Maintenance --> Settings menu.

2. Change 'File Playback Mode' to Quicktime through the nitoTV --> Settings --> General menu.

3. Play the file through the nitoTV --> Files menu.

As the movies starts, press the play/pause button and let the blue 'buffer' bar fill up. Once the bar fills completely press play/pause again to start the movie.

no better