Error message

Deprecated function: The each() function is deprecated. This message will be suppressed on further calls in menu_set_active_trail() (line 2404 of /home/aliakuser/

isadora links


export / save to disk in isadora - some tips


Optimizing Isadora(R) for Speed

There are many factors that influence Isadora's video processing
speed, including the speed and type of your processor, amount of RAM
installed on your computer, hard disk speed, the format in which the
video files are stored, and several other factors. This section
details several tips to help you get the very fastest frame rates from
Tip 1: Use the fastest computer you can

Much of the code inside Isadora is optimized for these the SSE /
Altivec processors that are part of most contemporaray Intel or
PowerPC chips. Using these processors will result in significant speed
increases when compared to G3 or non-MMX processors.

Tip 2: Add as much RAM (Random Access Memory) to your computer as possible.

Modern MacOS and Windows computers use a feature called "virtual
memory". When the computer senses that some data that resides in your
computers RAM (i.e., the extremely fast internal memory linked to your
processor) has not been used for a while, it will write it out to disk
to make more RAM available to other applications. This is called "page
swapping" and can adversely affect performance.

The best way to solve this problem is to add more RAM to your
computer. As a general rule, 512 megabytes is a good amount. 1
Gigabyte is even better. Page swapping will often take place on a
128-megabyte machine with more than one application running.

Tip 3: Don't run other applications at the same time as Isadora

Every running application consumes system resources. So,
especially when using Isadora for a live performance, don't run any
other applications at the same time. Even if they aren't "doing
anything" they get some of the processor's time, and thus slow down

Tip 4: Store Video Files at a resolution of 320 x 240 or 400 x 300

A full sized frame of Digital Video has a resolution of 720 x 480.
That's a total of 345,000 pixels that each video effect must process –
a substantial number for even the fastest computers. By reducing the
resolution of your movies to one-half (i.e., 320 x 240) you reduce the
number of pixels that must be processed by 75%, resulting in an
equivalent speed up in processing.

You may also have noticed that 360 is exactly half of 720 (the
standard DV-NTSC width), so why not store your movies with a
horizontal resolution of 320 and not 360? This is because you want the
"aspect ratio" (the ratio of width to height) of the video image and
the output device (i.e., a video monitor or video projector) to match.
The aspect ratio of a DV frame is 3 to 2, while a second monitor or
projector attached to your computer will almost always have an aspect
ratio of 4 to 3. A video with a resolution of 320 x 240 has an aspect
ratio that matches the output device, allowing Isadora to use
optimized code to render the image to the screen.

If you would like to have a bit more resolution, you can compress
your movies at 400 x 300. But this means that you should also set your
output device to 800 x 600 to get the highest rendering speed (see

You can use a number of software tools to convert your 720x480
DV-NTSC files to a 320 x 240 format. But perhaps easiest is the Pro
edition of Apple's QuickTime Player. See Tip 10 for instructions on
how to use QuickTime Player to compress your video.

Tip 5: Compress your video files using the Photo JPEG codec.

In addition to changing the resolution of your files,
recompressing them with the Photo JPEG codec (compressor/decompressor)
offers further speed improvements when playing video from your hard
drive. While the files will not be as small as with other codecs, the
Photo JPEG compressor offers several advantages. The first, and most
important, that it requires less processor power to decompress the
images when compared to many other codecs. Secondly, it is enhanced
for the G4 processor on Macintosh computers (many other codecs are
not.) Third, because each frame is compressed as an individual
picture, it is very fast when jumping to an arbitrary location within
the clip (i.e., when using the position input of the Movie Player) and
it plays just as well backwards as forwards.

You can use a number of software tools to convert recompress your
files using the Photo JPEG codec But perhaps easiest is the Pro
edition of Apple's QuickTime Player. See Tip 10 for instructions on
how to use QuickTime Player to compress your video.

Tip 6: Set the resolution of your output to an even multiple of the
video being processed by Isadora, and use the 'direct' option in the

When the resolution of the output device (i.e., the second video
output on your computer) is an exact multiple of the video being sent
to it, Isadora uses highly optimized code to render the video. If the
video images being processed have a resolution of 320 x 240, setting
the output resolution to 640 x 480 (i.e., exactly double in both
dimensions) allows Isadora to use this special code. If you render
your movies at 400 x 300, set your video output to 800 x 600 to enable
this optimized code.

IMPORTANT: To take advantage of this feature, you must set the
'mode' input on your Projector actor to 'direct'. The 'mode' input is
set to 'copy' by default because 'direct' works on almost every
computer, but not absolutely every one.

Tip 7: When capturing live video, set the Video Capture Size to Half
and make sure the Force 4:3 Aspect Ratio menu item is checked.

For the same reasons listed above, having the live video appear at
half resolution makes everything run faster. To do this, from the
Capture menu choose Video Capture Size > Half. Turning on the Force
4:3 Aspect Ratio ensures that the live video is in the same ratio as
the recorded clips, again saving processing power.

Now, on some cameras (notably the Apple iSight) the resolution of
the camera is actually double that of a DV Camera. (You can see this
by looking at the image in the Video Preview window.) In this case,
you may need to set the Video Capture Size to Quarter.

Tip 8: Turn off the Video Capture when you're not using it.

The Capture Control actor in Toolbox Group 7 allows you to turn
live video on and off from within an Isadora scene. If you are not
using live video in a section of your piece, then use this actor to
turn it on and off at the appropriate moment.

Note, however, that turning on the live video capture can take as
long as 1/3 of a second, and this may result in a visible glitch in
your video output.

Tip 9: If you only need to capture video and not sound, then use Start
Video Only Capture and vice-versa.

If you only need the video coming from the camera, and not the
audio (i.e., you're not using the Sound Level Watcher or capturing
live sound to disk) then just enable the video capture and not the
audio capture. Similarly, if you only need the sound input but don't
need video, use the Start Audio Only Capture.

Tip 10: How to use Apple's QuickTime Player (Pro Edition) to
recompress your movies.

As mentioned above, movies stored using the Photo JPEG codec at
resolution of 320 x 240 will give excellent performance when they are
played back in Isadora. Below are instructions on how to use the
Apple's QuickTime Player to store your movies in this format.

You can recompress a movie to this format using QuickTime Player
if you have the Pro version of QuickTime. To export a movie to the
Photo JPEG format, follow the following steps:

1. Open the movie in QuickTime Player.
2. Choose File > Export – the Movie Settings dialog will
appear. (If the Export item does not appear in the File menu, you
don't have the Pro Version of QuickTime. You can purchase it for $30
from Apple Computer.)
3. In the Export pop up menu at the bottom of the dialog,
choose "Movie to Quicktime Movie".
4. In the Use pop up menu at the bottom of the dialog, choose
"Most Recent Settings".
5. Click the Options button to show the Movie Settings dialog.
Then follow these steps:

Video Section:

1. Make sure the check box labeled "Video" at the top of the
dialog is checked.
2. Click on the Settings... button
3. In the first pop-up menu in the section labeled "Compressor"
choose Photo - JPEG
4. In the section labeled "Quality" use the slider to set a
compression factor of Medium or High. Using Medium produces somewhat
smaller files, but is more grainy. Using High produces less grainy
files, but they are somewhat larger.
5. In the section labeled "Motion", make sure the edit box to
the right of "Frames Per Second" has no number in it. This will cause
the exported movie's frame rate to match the source movie. Note: you
can choose a lower frame rate (i.e. 12 or 15, etc.) to reduce the size
of the movie and increase performance – but do this only if you have
problems playing movies at the normal frame rate.
6. Click on the Size... button to show the Export Size Settings
dialog box
7. Click the button labeled "Use Custom Size"
8. Set the Width to 320 and the Height to 240
9. Click OK Export Size Settings dialog.
10. Click OK in the Movie Settings dialog.

Sound Section:

1. If your movie does not have sound, make sure the check box
over the section labeled "Sound" is not checked and skip to the
section below called "Saving the Movie". Otherwise, check it and
follow the instructions below
2. In the section labeled "Video" click on the Settings... button
3. In the pop up menu labeled "Compressor" choose None.
4. Set the Rate pop menu to 44.1 KHz
5. Set the Size radio button to 16.
6. Set the Use radio button to Stereo or Mono, as appropriate.
7. Click OK

Saving the Movie:

1. In the edit box below the text "Save Exported File As:" type
the name for your new movie.
2. Choose destination folder for your new movie using the file
selector near the top of the dialog
Click Save.

A progress dialog box will appear as QuickTime player exports your
movie. When the dialog disappears, your movie is done compressing.

To see the difference in size between the original movie and the
newly compressed one, do the following:

1. Bring the original movie to the front by clicking on its window.
2. Choose Movie->Get Info to show a window that gives
information about the movie.
3. Choose ?Movie? from the pop-up menu on the top left.
4. Choose ?General? from the pop-up menu on the top right.
5. Look at the ?Data Size? and ?Data Rate? in that window. Take
note of the values.
6. Close the window by clicking on its close box in the top
left or by choosing File->Close.
7. Now bring the new movie to the front by clicking on its window.
8. Follow the same procedure starting at Step 2 to show its
Data Size and Data Rate.
9. You'll see how much smaller the movie is and how its data
rate has been lowered through the resizing and compression process.

::: location: