This is one of many help and support pages that are available about the University of Nottingham's Moodle online learning environment. If you have any questions or queries concerning Moodle then contact information is at the bottom of this page. As a first step to finding the information you are looking for why not check out our FAQ - Your questions answered or try the SEARCH box below.
Video files can be too large to upload, and when this happens, one possible solution is to create a new smaller version by converting , which requires 'transcoding' the video from one 'encoding profile' to another aka 'transcoding'.
If you find when your video is uploaded (particularly when working on a Mac) that the audio disappears, then you will need to encode it in a different way - follow the instructions below to transcode.
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(see the novice guide for how to do that).
If your video file is too big then you may experience issues with slow upload, exceeding allowable upload size, or stuttering during playback.
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Moodle does not have rigid delivery requirements, however you are restricted by your internet connection, and the viewers viewer's computer system.
In this situation, it is wise to use a format that is widely compatible e.g. MP4 rather than something restricted e.g. WMV or MOV, and to deliver a moderate file deliver a moderate file size.
There are many software tools for this including Adobe Media Encoder, Apple Compressor, and FFMPEG, but this guide will use Handbrake as an example because it is free, straightforward, actively developed, and available on both Mac OSX and Windows.
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Video File Compression is for final delivery only, do not do this for your source media. If you experience stuttering video during editing seek alternative solutions, such as changing video playback quality, video proxy settings, using a separate scratch disk, or a faster computer. For specific video advice and support contact is-learning-team@nottingham.ac.uk. |
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Video file sizes are a function of duration x data rate.
Assuming the duration is fixed you need to reduce the data rate. This is achieved by transcoding the original video file to create a new one.
Data rate is often expressed in megabits aka Mb (lowercase b) and file size is often expressed in megabytes aka MB (uppercase b), which is often a source of confusion. There are 8 bits to a 1 byte.
A typical camera data rate could be 15 Mbps, which would be:
30 seconds x 15 Mbps 15 Mbps = 450 Mb 450 Mb = ~56 MB.
The data rate from motion graphics software or a different camera could be much higher such as 200 Mbps, which would be:
30 seconds x 200 Mbps = 6000 Mb = 750 MB.
You may wish to compress either of these to a data rate of 4 Mbps, which would be:
30 seconds x 4 Mbps = 120 Mb = 15 MB.
Needless to say, there are significant differences between 15, 56, and 750 .
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Handbrake on Windows:
Handbrake on OSX:
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Video Tutorial:
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MBs.
You will notice the transcoding software has numerous parameters, if . If you are interested to learn what they do, then start with the the Wikipedia page for video, move on to video codecs, and then read the Handbrake documentation.
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Within the above guide, the key variable for changing the data rate is "RF" which you can increase to generate a smaller file size (or vice versa to potentially improve image quality).
If you are experiencing issues uploading your video submission after following the above process then you may have issues with your source material, internet connection, or playback device.
If your video is taking forever to upload then be patient and be prepared to give it many hours (unless you know you should be getting better speeds).
If the recipient cannot play your video back, check they have received a working h264 file. You (or the recipient) can download VLC to establish whether a file is readily playable or not.
If you are having problems with stuttery video whilst editing or playing back, then you can try: faster computer, lowering playback quality in software, or transcoding media into a 'friendlier' format such as mpeg2 or mpeg4 depending on the situation - try both!
To query your source files as an issue: download some test footage, transcode test footage using the fore mentioned Handbreak guide, and check playback in softwareTo eliminate the source material as the issue, try downloading some test footage, transcoding the test footage using the above guide, and seeing if it will play back. If the test footage works ok then your source material needs troubleshootinginvestigating.
To eliminate the internet connection as an issue then try: changing the network; , using a wired connection; , or another computer. If non none of this works then we can presume the network connection is ok and the problem is something else.
To eliminate the playback deviceIf playback is an issue, try playing the video on other devices to determine if it's an issue limited to one device. If issues occur across multiple devices then we can presume it's not a problem with the deviceassume there is something fundamentally wrong that needs investigating deeper.
To eliminate this guide as the issue, try using a different piece of transcoding softwaresomething else to compare.
If issues persistspersist, make a note of your fault finding attempts (the above eliminations) and seek technical support, such as through the Digital Media Support Group.
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