VisualHub - why do some AVI videos drop some frames when they are converted?

Discussion in 'Apple TV and Home Theater' started by M. Malone, Dec 10, 2008.

  1. M. Malone macrumors 6502a

    M. Malone

    Mar 11, 2004

    VisualHub has worked great for me, but some videos I convert to watch on my AppleTV drop some frames and become jerky during playback, this only happens to some videos, and not all.

    can this be fixed?
  2. M. Malone thread starter macrumors 6502a

    M. Malone

    Mar 11, 2004
  3. Nimiety macrumors regular

    Sep 6, 2006
    Too many possibilities.

    Could be frame rate issues - if the original file was at 25 or 29.97 fps (frames per second) and it was converted at 23.976 - it will look like it has a regular stutter. Solution: open file in quicktime, go to the movie inspector, manually set visualhub to convert at that framerate.

    Could be networking issues - start any show or movie and if you're (for example - could be many causes) wireless G, you may see the show start and then pause for a few seconds, stuttering if you quickly chapter forward to a random point. Solution: go wired, set up a wireless N network, or pause movie or show for a few extra seconds before trying to watch it.

    Could be a movie pushing the appletv to it's limits - 720p movies can be fine, but regardless of what the manual says, it is possible to convert 720p shows at 25 fps or higher and have them be fully compatible, but if so, they may stutter depending on file complexity (ie processing power required by the appletv).

    Hope that helps somewhat!
  4. M. Malone thread starter macrumors 6502a

    M. Malone

    Mar 11, 2004
    Thank you so much for your reply,

    it definitely isn't a performance issue of the Apple TV or my network, as the video isn't in HD and my network is wireless N.

    I just checked the movie inspector on QuickTime and the original AVI file is 25 FPS while the converted MP4 is 23.98 FPS, I will use visualhub again and set the FPS for the movie.

    What I'm wondering though is, how come out of the many movies I converted that are 25FPS, only this one dropped frames down to 23.98 while all the rest kept the 25FPS even when converted?
  5. bsmith1 macrumors newbie

    Jan 5, 2008
    I have the exact same problem...was going to start my own thread and luckily saw yours first.

    80% of my visual hub encodes of mkv's to mp4's play fine on my ATV. I have ben trying to figure out why the other 20% convert fine but drop frames or sporadically stutter when playing on ATV. My ATV is connected by a wired network...and it made no difference if I streamed the movie or synced it first.

    I will do the quick time frame check, encode at same rate and post my results over the weekend.

    Any other suggestions or tips, please let me know.

  6. bsmith1 macrumors newbie

    Jan 5, 2008
    Ok, it is not related to frame rate. 2 of the movies that I have dropped frames, skipping on are mkv's at 23.97 frame rate.

    Any other possibilities?
  7. M. Malone thread starter macrumors 6502a

    M. Malone

    Mar 11, 2004
    ok I may have found a solution, I had 4 movies which had the dropped frame rates, so I took these 4 movies into VisualHub and in advanced settings, I set the framrate to 29.97 (according to the VisualHub Manual, this is NTSC video, I didn't care, I just used it cause it's higher frames per second than any of my movies) The movies came out with 29.97 frames per second and they all worked perfectly and without the stuttering or jerkiness.

    I'm yet to find an issue with this method, but so far so good, let me know how it works for you bsmith1 :D
  8. Simon Bishop macrumors newbie

    Simon Bishop

    Aug 25, 2009
    I Too Had That Issue, And Fixed It The Same Way. I Made Sure To Check The Frame Rate Prior To Converting, And Converted It To My Desired Format With The Original Frame Rate.

    For Example: MyMovie.wmv @ 29.97fps --> MyMovie.avi @ 29.97fps = No Dropped Frames.

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