Digital Workshop

Hi,

When using the editor, have not yet tried publishing as I guess the same problems will display:

1.
I have an app with a number of AVIs. They are full screen (800 x 600).

When I navigate to a page with one of these monsters on it takes some seconds before the page displays.

Even when I remake the avi at 400 by 400, the smallest I can get it, it still takes ages to load the page.

Is there any way of speeding up the page load?

2.
Text shown on top of the AVI suddenly becomes very coarse when the AVI is played. Rendering it doesn't help prevent the coarseness. Can this be got over?

3.
When I use a full page AVI the page blacks out when going to another page - this doesn't look TOO bad, but if I use a smaller AVI, a black space suddenly appears where the AVI was - looks awful to the user.

I don't know if the solution is to use another format - but I don't want to have to rely on the user having other apps on their computer - hence my use of AVIs.

Any suggestions welcome.

many thanks

John

Hi,

Thank you for your enquiry.

In my experience, AVI files are not best suited for streaming purposes and the entire file must be pulled from CD-ROM before the media player can show the first frame, hence the delay you are experiencing.

You also state that you are using AVI files to ensure that your end-user does not need to install additional software to view the file, but this is a potentially flawed strategy. As you may be aware, AVI files are encoded and decoded using algorithms (more commonly known as codecs). You have obviously used one of the codecs installed on your system to encode the original video file, but are you certain that this is a standard AVI codec supplied with all versions of Windows? For example, many screen capture utilities (such as Techsmith's Camtasia - www.techsmith.com) use their own proprietary codec to create high-quality, but heavily-compressed, video, but unless your end-user has installed this same codec, they will be unable to view your videos.

A much better solution would be to use standard MPEG-1 video files. These should stream much more effectively from CD-ROM and can be viewed by all Windows users without additional software (as the Microsoft MPEG-1 decoder has been included in all versions of Windows since Windows 95). The only downside with MPEG-1 video is that the file sizes will be much larger than the same video in AVI format.

The black screen you are seeing when the page displayed is the video overlay onto which Media Player 'projects' the video data. If you wish to eliminate this, simply open the properties of the video object, select Change under the Video Type options and set the video mode to Rendered. This will allow Opus to use Media Player as a frameserver and treat each frame of the video as a separate image, which should ensure instant playback.

Kind regards,

Thanks Robin,

Very helpful - I'll experiment with MPEG-1.

Tried the MPEG-1 - works fine. However, you said

'The only downside with MPEG-1 video is that the file sizes will be much larger than the same video in AVI format.'

My cut down AVI was 7034KB, the MPEG-1 I converted it to ended up at 181KB - the direct opposite of what you said. I'm confused.


Any thoughts about why the text shown develops a coarse look?

John

I was going to ask Robin what he meant also. MPEG-1 files are compressed, and therefore much smaller than AVI files. In audio, it's like .wav files compared to .mp3.

MPEG-2 files are the standard for DVDs. If you have a computer/laptop capable of playing DVDs, then you can bring them into OPUS as a Video Object. They are larger, higher video and audio fidelity, but if your viewer's computer can't play DVDs -- they'll see nothing. I've actually put a Text Object UNDER a Video Object which plays MPEG-2 files. The text reads "Requires DVD playback capability." This is never seen, expect by non-DVD viewers.

My mistake...I recently converted some Camtasia AVI files to MPEG-1 format and the file size ballooned by about 400%, but I suspect that this may have been due to the audio encoding, rather than standard behaviour. After further experimentation, I see that you are correct - MPEG1 files are typically smaller than their AVI counterparts, although I'm sure users with a broader experience of video formats may be able to elaborate on this further.



Is the text part of the video or a text object you are showing on top of the video object?

If it is the former, have you made sure that the video object is exactly the same size as the video frame size? To do this, simply select the video object and click Arrange > Fit to Contents. Now preview the publication and see if the problem is still present.

If the text is a separate object being shown on top of the video, I suspect that Opus may be unable to correctly 'antialias' the text (i.e; smooth the edges of the characters) when placed on top of a video object. Try opening the properties of the text object, selecting the Text tab and setting the Antialias setting to None. Now click Apply and OK and compare the text shown in the editor to that shown in the previewed publication - they should now match.

Kind regards,

Regarding video file sizes:

A 320x240 MPEG-1 file created from a "standard" 320x240 *.AVI file is normally significantly smaller than the *.AVI source file. Depending on settings such as the data transfer rate, audio format & compression and so on, the difference may often be a factor of 9:1.

The TSCC (TechSmith Screen Capture Codec) saves a lossless-compression *.AVI file (note -- "lossless" is TechSmith's term, and I don't know if it's true -- my experience is that there IS a slight loss of detail). Lossless or not, a compressed TSCC *.AVI file is significantly smaller than other *.AVI formats for the same running time and playback size -- thus, an MPEG-1 file created from a TSCC file may indeed end up being larger than its source.

TSCC playback requires that the codec be installed on the player's PC, or else that the video play back through their player (their software provides a method of packaging video inside a TSCC player that will decode on the fly without installing the TSCC codec).

Thanks for the helpful clarification, Robert.

Kind regards,

Very many thanks for all the helpful comments.

I eventually went the way of MPEG-1 and set Video Type in properties to Rendered. This latter change prevents a noticeable darkening of the MPEG-1 when displayed, as compared to the background that part of it was cut from.

Quality of the final MPEG isn't as good as the AVI, but, not obviously noticeable when the end user isn't directly comparing one with the other!

John