Wednesday, February 23, 2011

Video Storage: Kaltura considerations

Captured video storage options in preparation for transitioning to a
Kaltura-like video upload tool:

Currently instructors are creating FLV videos at 320x240 frame size when
capturing VHS tapes or DVDs. It is recommended that videos uploaded to
D2L be less than 40 minutes in length. These parameters create videos
that run smoothly in the browser using a Flash-based player. The entire
process is easy for instructors to learn and complete on their own.

Access to a high quality copy of the digital video file will be
necessary when the instructor transitions to Kaltura-like video upload
tool. While it is recommended that instructors keep a copy of the
original AVI file produced during the capture process, this file is very
large and offers storage challenges. As a result many instructors have
chosen not to keep the original AVIs as archive files.

In order to prepare for the eventual transition to Kaltura-like video
upload tool, we need to emphasize the need to save some type of archive
file. The options below will help instructors make decisions about how
they will store the video files they capture.


Option 1: Store the AVI files on an external hard-drive.

Advantages: AVI files stored on an external drive can be readily
accessed if the instructor needs to edit the film. The file can also be
readily accessed for uploading directly to the Kaltura-like video upload
tool. In addition, the AVI file is already created as part of the
capture process, therefore no additional time is required to prepare the
file for upload.

Disadvantage: AVI files require a significant amount of storage space.
Very often, the captured AVI files are larger than 4.7GB and cannot be
stored on a data DVD. If the AVI files are stored on the instructor’s
working computer, the space required can cause performance issues. This
is why it is recommended that the files are stored on an external drive.
With external storage there is always the risk of disk failure and the
loss of data. As with all data, it is recommended that the video files
are backed-up.

Additional decision points: This option is especially useful for
instructors who believe that they may need to edit the videos, or take
clips.


Option 2: Burning the AVI files as a media DVD.

Advantages: Once burned onto a DVD, the digital video file does not have
to be stored as data. The media DVD will be of high quality when played
in a DVD player. The AVI is produced as part of the capture process so
no addition time is required to create the DVD-ready file.

Disadvantages: Once the AVI is burned to a media DVD it is no longer
formatted as an AVI. In order for the media on the DVD to be accessible
as a digital video file, it needs to be “ripped” off the DVD, requiring
a significant investment of time.

Additional decision points: This option is most useful for instructors
who believe that they will not need to edit the video again or pull
clips from the video. It is also a very good option for instructors who
anticipate playing the DVD in a face-to-face classroom or as they
preparation to teach concepts in the video.


Option 3: Rendering an MP4 file for storage on a data DVD, computer, or
hard drive.

Advantages: Files rendered as MP4 with a 640x480 frame size are of high
quality, but require significantly less storage space than an AVI. They
can be burned onto a DVD as data, which means that they can be readily
accessed if the instructor needs to edit, or to upload the file to a
Kaltura-like tool.

Disadvantages: Creating an MP4 would require additional steps and
additional time. An MP4 is not produced as part of the capture process,
nor is it the file format that is rendered for direct upload to D2L
(FLV). This choice would require more time immediately, whereas storing
the AVI on DVD would require more time later, when transitioning to the
Kaltura-like tool.

Additional decisions points: If the instructor has edited the video
after it was captured, the file will need to be rendered as an “archive”
file in order to retain the edits. Normally, the archive video file is
rendered as an AVI, however, it could be rendered as an MP4 at 640x480
instead. If the instructor did not edit the video after capturing,
creating an MP4 would be an additional step requiring additional time.


Option 4: Uploading the FLV file to the Kaltura-like video upload tool.

Advantages: The FLV file is created as part of the current process. It
would not require additional steps. Since the video is uploaded to D2L,
the file can be downloaded from D2L when the instructor is ready to
transition to the Kaltura-like tool. Because the file can be downloaded
from D2L, the instructor does not need to archive/store an AVI or an MP4
file.

Disadvantages: The FLV file that is created as part of the current
process is of lower quality. Since the video needs to directly from D2L,
the FLV file must be rendered at 320x240. The small file does not take
advantage of the Kaltura-like tool’s ability to deliver high quality
video at a large frame size over the web. In addition, the FLV file may
degrade in quality when converted during the upload process. Because of
these issues, it is not recommended that instructor use the FLV file as
a storage solution. However, it is an option of last resort if no other
archive file is available.

AM

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