QuickTime 7.5.5: H.264 playback stutters
Many QuickTime users use the H.264 codec to encode content, but under QuickTime 7.5.5, some users are experiencing stuttering upon playback of encoded video.
Apple Discussions poster Disctrict: "I've been encoding to H.264 for over a year...I most often use 720p25 format (1280x720 progressive, 25fps), at 6Mbps, encoding from a progressive source (Photo-JPEG or HDV 720p) in Compressor...watching the H.264 encode in QT Player (vsn 7.5.5) it stutters really badly."
When users have nudged through videos with this problem, its apparent the movie is only advancing every other frame in the forward direction, but seems to show every frame properly when nudged in reverse. This problem seems to affect other QuickTime-related players as well, since it has been reported in iDVD; however, the movies play fine in VLC and other players that do not rely on QuickTime. In addition, users have tried changing encoding settings, such as keyframes, bit rate, and quality settings, but still experience the problem.
This particular issue is related to an incompatibility with the Perian plugin that many users install to enhance their QuickTime installation by adding support for various popular video formats not native to QuickTime.
Fixes:
Update Perian The version 1.1.1 update for Perian is available here. While users have updated the plug-in, for some the stuttering came back; however, this was most likely due to the plugin not being properly updated. It is recommended that users download the Perian update and install it. Then right-click the Perian.prefPane file, choose "Show Package Contents", and navigate to the /Contents/Resources/Components/ folder and drag the "Perian.zip" file to the Desktop. Unzip the file and then drag the resulting Perian.component file to the /Macintosh HD/Library/QuickTime/ folder, replacing older versions. Doing this has fixed the stuttering issue for users.
Uninstall Perian If users are not actively using Perian then uninstalling it may be the best option to prevent any incompatibilities with future updates from affecting the system. To do this, remove the Perian.component file from the /Macintosh HD/Library/QuickTime/ folder.
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