quicktime movie preloader

initi's picture

Hi, is possible to preload QuickTime movie into RAM for better playback in quartz, pls? thx in advance

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cybero's picture
Re: quicktime movie preloader

Pre loading Quick Time files into RAM is usually thought of as referring to streaming of files and is simply set in the files options panel.

It will facilitate smoother streaming .

So for streaming into a composition, it will help.

I've just placed a 1.2GB clip into a 2g GB RAM disk, [another interpretation of your question], & run that alternately from its HDD location & RAM disk location and achieved the following results, note differences between asynchronous and synchronous results for both RAM & HDD.

The images below have not been taken at the same frame point, but the usual result I get is that there is arguably some improvement by running the movie from a RAM disk, but not much of one.

The RAM Movie Asynchronous

The HDD Movie Asynchronous

Then the RAM Movie Synchronised - sans audio

& finally the HDD Movie Synchronised

PreviewAttachmentSize
RAM-Movie.png
RAM-Movie.png29.89 KB
HDD-Mov.png
HDD-Mov.png30.23 KB
RAM-Sync_Mov.png
RAM-Sync_Mov.png47.53 KB
HDD_Sync_Mov.png
HDD_Sync_Mov.png46.06 KB

photonal's picture
Re: quicktime movie preloader

I'm having problems with forcing movies into RAM. I have 12GB RAM installed and am not getting good performance reading back a 45MB quicktime movie.

When loaded, I cannot skim through the movie smoothly since the 45MB is being read from Disk rather than RAM.

I even tried creating a RAM disk and reading it from there but still OSX insists on reading from disk.

When I installed the extra RAM this was one of the first tests I did and the QuickTime movies were being read from RAM then - however they are not now. Maybe an OSX update (QuickTime Update) has buggered this up? Anyone else have this issue?

Sometimes I miss the old RAM disks in OS 9 (I have an old Power Macintosh 9600 maxed out at 768MB) - that thing was so quick when the OS was placed in the RAM disk ;-)

So, I guess what I'm asking is - Is there a way to force a QuickTime movie into RAM?

Also : "Pre loading Quick Time files into RAM is usually thought of as referring to streaming of files and is simply set in the files options panel."

Where is this 'files options panel' that is referred to?

[Using QuickTime Player Pro 7.6.6 and the QuickTime X Player on OSX 10.6.7]

.lov.'s picture
Re: quicktime movie preloader

With just one movie, the ram disk will not show a much better result, thats my experience.

What kind of codec did you tried? If you want to 'skimming' a QT movie very smoothly, i think photo-jpeg or motion-jpeg codec is the best choise.

franz's picture
Re: quicktime movie preloader

I'm using EsperanceDV as a RamDisk, with QT movies compressed as PhotoJpeg 85%. Performance is great. Try using the built in patch in Asychronous mode, or try the v002 movie player as well. AFAIK, preloading is unsupported in QC.

Note that compressing a movie with H264 or equivalent codecs is not good for scrubbing. Prefer PhotoJpeg, MotionJpeg or Animation

photonal's picture
Re: quicktime movie preloader

Thanks for the infos. I'm using the animation codec btw. I'll try out the EsperanceDV RamDisk.

What's weird, is that the scrubbing was working fine the last time I tried it (which was around last Xmas when I got the extra RAM - I tested after installing it) - not any more though - not even using the QuickTime player. (Scrubbing forward is fine - but scrubbing backwards stutters).

photonal's picture
Re: quicktime movie preloader

Things are certainly working a lot better.

Putting the QT file into the RamDisk and using that path in RamDisk for the Movie Location works quite good now, Thanks!

bangnoise's picture
Re: quicktime movie preloader

photonal wrote:
Thanks for the infos. I'm using the animation codec btw. I'll try out the EsperanceDV RamDisk.

If you don't have an alpha layer you need to preserve, AIC or pjpeg will give you a much better data-rate than the Animation codec.