Jerky Quicktime playback on mac pro 3.2 Ghz

[wizb98y]

I generated a full HD 1920x1080 mp4 video file and tried
playing it back using Quicktime. The playback was very jerky.
The same file played beautifully using VLC. So I don't think
it is cpu horsepower issue. Anybody have similar problem
playing back mp4 HD materials using Quicktime? Any ideas?

Mac Pro 3.2 Octo with 10 GB Mem and 4.5TB diskspace.

 

[TheStrudel]

What compression settings were you using? Quicktime is better optimized for some things than others.

 

[wizb98y]

What compression settings were you using? Quicktime is better optimized for some things than others.

I was using the standard H.264 HDTV 1080p 29.97 preset in the Adobe
encoder (VBR, 1 pass, target 32, max 40 mbps). I also tried using
24fps, same problem. What I don't understand is that VLC played
the same files very smoothly - doesn't VLC uses/shares the underlying
decoders OSX provide to Quicktime. Granted, I am just speculating as
I don't know how these things work.

 

[grue]

QuickTime sucks harder than a sorority girl on a friday night. God only knows why.

 

[TheStrudel]

Actually, I don't think quicktime does use the same decoder. But it's worth pointing out that you can optionally install a different decoder - I can't remember where from - that might perform better. Quicktime's performance does leave something to be desired. That's something that could benefit from some GPU acceleration (especially now that most cards support HD decoding of one sort or another in hardware...but probably not in OS X).

 

[elvisizer]

it'd be helpful to know more about the actual h.264 settings the adobe encoder is using. quicktime tends to choke on some high profile specific features- pyramidal b-frames, or just too many b-frames in the first place are two that'll make it choke.
do you know what settings the encoder used?

also, VLC uses it's own decoder, not quicktime's, and doesn't have these issues with high profile h.264

 

[davidfastolfe]

I have the exact same problem, I can play my HD MP4 video in VLC but the playback jerky in Quicktime. No matter how the MP4 is encoded, Quicktime is unable to correctly play HD MP4.

I will not spend my time looking for a new codec or whatever it takes to correct this problem. If Quicktime can't play it well I will be using HDTV MPEG 1080p or WMV.

One more thing. From Itunes you can convert MP4 to M4V The playback is perfect then. But it's 720p not 1080p Depending on your needs it can be an option.