NetShow Overview

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Illustrated Audio Production Hot Topics

The illustrated audio hot topics contains tips and techniques to enhance your audio and image files for your NetShow presentation. Topics are arranged into two categories:

Illustrated Audio Production Tips

Create your .asf file in the Microsoft NetShow T.A.G. Author using your selected audio and image files. Then add the URLs to your .asf file where you would like the URL flip to occur.

 From the Edit menu, select Script Commands and then select Add.

 Specify the time you want the URL flip to occur.

 Define as TYPE URL.

 In the parameter box, type in the URL you want to flip, followed by the frame name.

 To call up the Microsoft Web page in your designated frame called showme you would type in the parameter field.

 Save your .asf file.

Create your Web pages using HTML. A demonstration of this is available. Use the View Source option on your browser for the HTML source code.

The quick answer: It depends.

Different codecs work better for different types of audio. Some codecs work better with complex sound like music. Others work best with less complex sounds like a single moderated voice. Some codecs also work better with male voices rather than female voices.

So to speed your process of content creation, we tested the NetShow audio codecs with different types of content -- music, voice, voice and music, male, female -- to see which responded best in different situations. We concentrated on the lower bandwidths, since that's where it matters the most. You can find this information in the Audio Hot Topics section.

If you are working with several audio files destined for the same ASF, you should join them into a single file before performing any edits. This will ensure that they join exactly as you wish and that they have uniform volume and quality. Always combine audio files into a single file before adding them to the Microsoft NetShow T.A.G. Author project.

Reducing the size of an image is possible in a number of ways:

 Reduce the image dimensions.

 Reduce the bit depth.

 Reduce image resolution.

While reducing your file size as much as possible, keep in mind that your aim is to preserve as much image quality as possible.

If you are already working with images for the Web then you are familiar with both .gif and .jpg file formats. Using JPEG compression you can make your image files smaller and store full color information 24 bit/pixel (16 million colors). JPEG works well with scanned photographs and in images with variation in color. It will not work as well on lettering, cartoons, or line drawings. GIF works better on images with few distinct colors. It stores 8 bits/pixel (256 colors or sometimes fewer colors).

The method you choose will be determined by the images you are working with and the presentation you have in mind. Although Media Player will accommodate larger images, a size of 320 x 240 is recommended. You may wish to edit your present images in an image manipulation software program such as Microsoft Imager, Adobe PhotoShop, Corel Draw, or Paint Shop Pro.

You can compare the quality and image file size of the various compression rates using these JPEG images. They've been divided into photo images (continuous tone) and graphic art (line art original) images. These images have been made into ASF files for quality, size and rendering time comparisons as well.

One thing you'll notice as you compare these images and their corresponding ASF files: those that were saved at low and medium-quality JPEG compression rates all increased in file size when converted to LT JPG in the Microsoft NetShow T.A.G. Author. Yet the images saved at high quality actually decreased in size when compressed using the Microsoft NetShow T.A.G. Author. While the high-quality images are clearer and sharper, the file sizes and rendering times can be significantly higher; if file size (bandwidth) is your main consideration, any of these compression rates will do to keep file sizes to a minimum and still maintain image integrity and quality

JPG Image Quality and File Size: Photo

Image Options
Baseline Optimized
Quality 2 LOW
(+ 6.2k)
Size: 35KB
Rendering Time: 16.5 seconds
Low Quality ASF

Image Options
Baseline Optimized
Quality 6 HIGH
Size: 41KB
Rendering Time: 19.5 seconds
High Quality ASF

Image Options
Baseline Optimized
Quality 3 MEDIUM
Size: 37KB
Rendering Time: 17 seconds
Medium Quality (3)ASF

Image Options
Baseline Optimized
Quality 4 MEDIUM
Size: 39KB
Rendering Time: 18.7 seconds
Medium Quality (4) ASF

JPG Image Quality and File Size: Graphic Art

Image Options
Baseline Optimized
Quality 2 LOW
Size: 21KB
Rendering Time: 10.2 seconds
Low Quality ASF

Image Options
Baseline Optimized
Quality 6 HIGH
Size: 23KB
Rendering Time: 11.1 seconds
High Quality ASF

Image Options
Baseline Optimized
Quality 3 MEDIUM
Size: 22KB
Rendering Time: 10.4 seconds
Medium Quality (3) ASF

Image Options
Baseline Optimized
Quality 4 MEDIUM
(+ .6k)
Size: 23KB
Rendering Time: 10.7 seconds
Medium Quality (4) ASF

It is recommended you save your images whenever possible as JPEGs before adding these to the Microsoft NetShow T.A.G. Author. However, if this is not possible, you can add your files and convert or resize them in Microsoft NetShow T.A.G. Author. GIF files that have been imported into Microsoft NetShow T.A.G. Author need to be converted to JPEGs, Loss Tolerant JPEGs or DIBs using other available compression methods, a list of which will appear in your drop down menu. Converting GIF files to JPEG may result in very poor image quality as you are converting an 8-bit image and it will not look as good as a JPEG made from a 24-bit image.

When creating .asf files for broadcast on the Internet, it is recommended that you convert all files to Loss Tolerant JPEG consisting of images with dimensions divisible by 16.

Yes, in a way. GIF files can be imported into the Microsoft NetShow T.A.G. Author, however the files are converted to JPEGs, Loss Tolerant JPEGs or DIBs during the import process. Converting GIF files to JPEG may result in very poor image quality as you are converting an 8bit image and it will not look as good as a JPEG made from a 24-bit image. It is suggested you convert GIF files to JPEG files in an image editing program prior to importing them into NetShow Author.

Again, it depends!

If you plan on using Loss Tolerant JPEG compression in the Microsoft NetShow T.A.G. Author your images need to have dimensions divisible by 16. If you have images of various sizes you can set the Window Size to Use Largest in the File, Properties, Bit Rate Properties dialog box. If however, your file dimensions vary greatly you will notice the smaller images are stretched to sit in the window.

It is suggested that you resize all images to the desired dimensions of your presentation before you add them to your ASF project.

JPEG is a "lossy" compression method used to reduce the file size of still images. Lossy compression provides a greater compression ratio, but the decompressed media may not appear exactly as did the original, uncompressed media. JPEG was designed with the knowledge that the human eye will perceive small color changes less accurately than changes in image brightness.

When streaming multimedia over the Internet or an intranet it is possible for image, audio or video data to get lost. Converting your image data to Loss Tolerant JPEG increases the chances that your image will arrive at it's destination. There may be a significant reduction in quality but it will be rendered to some degree. Images that are not converted to Loss Tolerant JPEG will not render on the user's machine.

The Microsoft NetShow T.A.G. Author:

You cannot edit an .asf file directly. To make changes that are reflected in your .asf file, open the .aep project file in the Microsoft NetShow T.A.G. Author, edit your image or audio files and build the new .asf file.

The Microsoft NetShow T.A.G. Author will create a default ASF file name based on the name of the Microsoft NetShow T.A.G. Author Project (AEP) project. To change this name (particularly important if you want to create multiple ASF versions from a single AEP), click File/Properties/Bit Rate Properties and enter your filename in the "Output File" box. Then click OK.

Before you can build an .asf file you must save your project file .aep. Select File, Save as and enter the name of your project file. You can now Build you .asf file.

Presentation Assistant enables you to synchronize your images with your audio track by simply playing the audio file and allowing you to drop an image where you'd like it to appear on the timeline.

When using Presentation Assistant, you can specify the images from the content window or from the time range in the edit window. When selecting images from the content window, they will be placed in the same order as they appear. Rearrange the images in the content window or have the Presentation Assistant use the correctly placed images from the edit window.

The Microsoft NetShow T.A.G. Author has a default end time of 1 minute. To extend this, you must first extend the timeline window beyond the desired end time. There are a couple ways to do this:

 Import a sound file. This automatically extends the end time to the length of the file and the timeline to just a little longer than that.

 To increase the timeline without importing a sound file, you must first click-and-drag the end of the timeline (in your editing window) beyond the point of your desired end time. Don't drag your arrow beyond the edge of the Microsoft NetShow T.A.G. Author window. If, while dragging, the timeline stops lengthening, just jiggle your mouse side to side in the small space along the right edge of the window. It will get there eventually.

Third-Party Software

In Adobe Premiere, you can use either of two ways to save your images:

To export a frame as a bitmapped file:

 In the Clip Window, select the single frame you want to save as a bitmapped image.

 In the File menu, choose Export and then select Frame as Bitmap.

 Save the file as .bmp, .dib, or .rle.

You can also use the Make Movie command to compile a movie clip and save it as a sequence of numbered bitmapped images by choosing Save as Bitmap Sequence or Tiff Sequence. With either of these methods, you can now modify the files in an image editing application such as Adobe PhotoShop.

When using audio from an existing video source, all you need to do is make a copy of the video's audio track and then synchronize frame captures to it.

To export an audio clip to a waveform file in Adobe Premiere:

 In the clip window, select the audio clip you want to export.

 In the File menu, choose Export then select Waveform File.

 Choose the options you want for audio rate and save as a .wav file.

PowerPoint for Windows 95 makes use of the free add-in PowerPoint Internet Assistant to output the PowerPoint slides to JPEG images. These images can then be used to build an .asf file using Microsoft NetShow T.A.G. Author. You can also record audio with your slides in PowerPoint, but you may want to have a separate audio track that you will combine later in the Microsoft NetShow T.A.G. Author. To convert your PowerPoint slides, you use the Export as HTML option in the PowerPoint File menu. Then proceed as follows.

 Open the PowerPoint presentation you want to convert.

 In the File menu, select Export as HTML.

 In your HTML Save Options, select JPEG as your output format. Here you can also select the compression quality level for the JPEG format.

 Save the images to your work folder.

Publish to ASF is an option in the Office 97 version of PowerPoint that you can use to output a PowerPoint presentation directly to an .asf file that's ready to stream.

 In the Tools menu, select Publish to ASF.

 The Publish to ASF wizard converts your images to JPEG.

 You can then select the target network you're are publishing for, which sets the playback quality, and the minimum network speed required.

 Save the .asf file.

Open your image file in PhotoShop 4.0. You may also want to make some changes to your image at this stage, resizing, or tweaking the color and quality of the image. When you're satisfied with the image save it as a .psd PhotoShop file. This enables you to return to this image later if you need to edit the image further.

To save as a JPEG:

 From the Layer menu, select Flatten Image.

 In the File menu, choose Save as.

 Select JPG from the drop-down menu and enter a file name.

 Choose Image and Format Options from the JPG Options dialog box.

These options allow you to trade off the file size against the image quality. The lower the quality you select the smaller the file size will be. You may want to save your JPG at different settings and compare the quality and file size. View a sample.