[QLab] Increasing Video load buffer -- causing startup stutter
Allen Strand
| How do I increase the amount of video that the load function consumes? The buffer is too small which causes video startup stutter. I have a video that only needs about 1MB/second to play. During startup it stutters. That can happen regardless of whether there are follow on queues or not. I then loaded a .MOV that came from After Effects that needs a large amount of disk transfer i.e. 60MB/sec. When I play this in QLab the display plays extremely jerky. A this high rate, I wasn't surprised but unfortunately QuickTime and ProPresenter can play the 60MB/sec movie without issues. (Both can play my 1MB/second movie also). I am thinking that the system needs to pre-load some of the .mov data and I should be able to specify the pre-load cache size. I
noticed that the audio is cached for this very reason. Shouldn't the same capabilities exist within QLab? System information: Macbook Pro 15" that is less than 6 months old. |
Christopher Ashworth
To my knowledge QuickTime does not provide a way to control how much of the movie is buffered in a QuickTime object.
A few things to check:
- What codec are you using? I'd recommend trying PhotoJPG
- Is the video cue assigned to only a single screen? (Currently video playback is more optimum in that case.)
Best,
Chris
________________________________________________________
WHEN REPLYING, PLEASE QUOTE ONLY WHAT YOU NEED. Thanks!
Change your preferences or unsubscribe here:
http://lists.figure53.com/listinfo.cgi/qlab-figure53.com
Follow Figure 53 on Twitter here: http://twitter.com/Figure53
Ben Chaisson
From after effects you are probably making a an uncompressed quicktime animation.
At large screen sizes this codec eats up a lot of system resources. You should transcode the files to H264, but keep it in the quicktime file.
Though compressed the file will play much smoother in Qlab.
From: Allen Strand <arst...@yahoo.com>
To: ql...@lists.figure53.com
Sent: Sun, June 26, 2011 11:18:31 PM
Subject: [QLab] Increasing Video load buffer -- causing startup stutter
Allen Strand
| Chris, What is weird to me is that Quicktime plays the 1Mb/Sec video fine it is just QLab that stutters. 1Mb/Sec is small transfer rate (DVD is 6Mb). Interesting that QT doesn't allow buffering per your note -- but not surprising. Your questions -- -- I do not know what codec. It was done by FinalCut by someone else. -- Video playback was to one screen. Unfortunately, I just used ProPresenter for the videos since I couldn't get this working. There must be something wrong with QLab if ProPresenter and QT works flawlessly. Hopefully someone at QLab will figure this out since I have seen quite a few posts about having to recreate videos to solve this somehow. Thanks for the input. I will revisit this
challenge shortly because I really like QLab. --- On Mon, 6/27/11, Christopher Ashworth <ch...@figure53.com> wrote: |
Christopher Ashworth
> There must be something wrong with QLab if ProPresenter and QT works flawlessly. Hopefully someone at QLab will figure this out since I have seen quite a few posts about having to recreate videos to solve this somehow.
Hi Allen,
You're right, video performance is something I'm hoping we can continue to improve. There are definitely places that QLab could improve in this regard, if we can figure out how to improve it. That's something I'll continue to try to do better on, as best I can.
It's also true that different video programs are designed with different goals in mind, and thus different underlying architectures, so not all programs will necessarily perform the same way.
Best,
Chris