Mailing Lists: Apple Mailing Lists
Image of Mac OS face in stamp
 
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Increased export times with QT6

Mea culpa. My posting is incorrect. We've since repeated the comparison of
export between QT5 and QT6 which invalidates my original posting. If anything
QT6 is marginally than QT5 on export.

As Kevin Marks indicated, the newer Codecs are faster. My V6 tests showed that
an export using the Sorensen 3 codec is about twice as fast as the Cinepak or
Indeo codec. Compared with the CinePak codec, it produces a smaller file size
and higher quality. For the Indeo 4.4 codec this is less clear - for the same
quality settings Indeo produces a smaller file size, but is also has lower
quality.

Unfortunately, since ours is a Window product we need to support exporting to
AVI so hints on how to speed up export are still needed.

Cheers,

Andrew

Andrew Friedman wrote:
>
> I'm wondering whether anyone else has noticed longer export times
> with QT6 versus QT5 and perhaps knows the cause.
>
> Our QA guy has done some preliminary testing of exports from our application
> using both QT5 and QT6. His results were that in most cases with the Cinepak
> and Indeo codecs that exports took longer. In some cases, the time was
> significantly longer. While file sizes were often reduced in QT6 vs. QT5 the
> decrease in sizes was not as great as the increase in time.
>
> In the worst case, a low res Cinepak encoding time doubled with no change in
> file size (i.e. 5 to 10 minutes for 35.2 Mb)
>
> Our source video is DV PAL. Guessing from the small set of data points I have,
> it may be that the presence or absence of transitions has a significant
> influence on export speed.
>
> He also noticed that QT6 does not load the CPU to same utilisation
> as QT5. He reports a wider variation in CPU utilisation of 40 - 100% for QT6
> vs. 90 - 100% for QT6.
>
> Sounds like QT6 is busy doing something else.
>
> Any thoughts?
>
> Cheers,
>
> Andrew
>
> P.S. Does anyone have any tricks to make QT export faster? I recently exported
> some video from VideoWave and was blown away by the difference in export speed.
> _______________________________________________
> quicktime-api mailing list | email@hidden
> Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/quicktime-api
> Do not post admin requests to the list. They will be ignored.
_______________________________________________
quicktime-api mailing list | email@hidden
Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/quicktime-api
Do not post admin requests to the list. They will be ignored.


Visit the Apple Store online or at retail locations.
1-800-MY-APPLE

Contact Apple | Terms of Use | Privacy Policy

Copyright © 2007 Apple Inc. All rights reserved.