Chapter 5: RealMedia Recording Tips

RealEncoder comes with a variety of options that allow you to create the highest-quality streaming media.

Because there is no single best process for delivering all types of streaming audio and video, RealEncoder provides several ways in which you can customize and streamline your recording.

This chapter discusses how to:

• run RealEncoder more efficiently
• produce high-quality audio
• produce high-quality video

Improving RealEncoder Performance

RealEncoder has several features that allow you to improve performance and increase efficiency while recording your media clips.

Disabling Viewers

By disabling the input source window, the output source window, and the audio level meter during live recording, you can increase the frame rate of your recorded file and decrease the time it takes to record your clip.

To disable viewers during recording:

1. Choose the View menu from the main RealEncoder window.

   Viewers that are currently active are designated with a checkmark:

   • Input Source
   • Encoded Output
   • Audio Meter
2. Select a viewer to disable it.

Live Capture-to-File

If you have a real-time capture station, you can use it to capture and compress directly into RealMedia format. The output of an audio or video device can be recorded by RealEncoder to a RealMedia file instead of a live broadcast.

This process eliminates the need to create and store intermediate audio or video files, which are very large and can take considerable disk space. It is also the fastest way to capture content like breaking news clips when time-to-post is important.

Drag-and-Drop Recording

RealEncoder supports drag-and-drop recording.

To use drag-and-drop with RealEncoder:

1. Click an input file icon and drag it onto an open RealEncoder window.

   This opens a new session with path and file name information entered appropriately.

2. Enter any descriptive information (title, author, and copyright) and customize recording settings before clicking Start.

Producing High-Quality Audio

This section describes how to successfully create quality sound for RealMedia clips. It gives you overall audio tips, shows you how to use the audio meter, and how to adjust the volume during recording.

General Audio Tips

Follow these tips in order to get the best quality from your different audio sources.

• Use high-quality source files or a recording input device.
• If you are not doing a live broadcast, capture or "digitize" the sound to a supported file format such as a .wav or .mov whenever possible.

  This allows you to use a sound editor to adjust the amplitude of your signal to maximize the available dynamic range. If you do not adjust the signal, the resulting RealMedia file may sound flat.

• If your original audio file signal exceeds the acceptable amplitude range, the file may be "clipped." Clipping can give rise to clicks or pops on playback. If your source file contains a clipped signal, your final RealMedia file will have high-frequency background noise or static. Lowering the input volume will help reduce clipping.
• Eliminate any DC offset either while recording or later with an audio editor. This removes low frequency noise.
• When encoding live-source audio, you have less opportunity to manipulate your input signal. Be sure that volume levels are prepared and tested before encoding.
• Cut any unnecessarily long silences from the beginning or end of the output file to conserve space.

Using the Audio Level Meter

While you record RealMedia clips, you can monitor the Audio Level to be sure you are encoding the optimal dynamic range. Green indicates a normal reading. Red warns that you are close to an over-modulated input. The best sound quality will occur when the top red bar is often lit but the clipping indicator (the red light above the meter) is never lit.

The Audio Level Meter

Clear the clipping indicator during recording by clicking on it. This allows you to track if audio clipping is occurring without watching the audio level constantly.

Volume Control

While recording, you can adjust or monitor the volume using the Windows Volume Control window.

To adjust the recording volume:

1. Select Volume Control from the Options menu.

   The Volume Control window opens.

   

2. In the Volume Control window, select Properties from the Options menu.

   The Properties window displays.

   

3. Select Recording to adjust the input recording volume. (Playback adjusts the level of the volume you hear while you are recording, not the volume RealEncoder uses.)
4. Select from the list of volume controls the type of inputs you will be using and click OK.

   The Recording Control window opens.

   

5. Select which recording inputs to use by choosing the Select box for each input.
6. Adjust the sound level by moving the sliders up or down.

   Remember, if the volume is too high, the recorded sound may be clipped and appear distorted. If the volume is too low, it will be difficult to hear. Use the audio level meter in the RealEncoder window to monitor the level during encoding.

7. Close the Recording Control window and return to the RealEncoder.

Producing High-Quality Video

This section describes how to successfully create quality video for RealMedia clips. Follow these tips in order to get the best quality from the different types of video sources.

Existing Video Files

In order to get high quality output, your existing files should meet the following requirements. You can use any size image, but the height and width of the video will be automatically cropped to multiples of 16.

AVI files:

• AVI files should have a 24-bit color depth.
• The standard video frame size for the Internet is 176 x 144.
• The file should be uncompressed for best results.
• Indeo drivers must be installed on your machine for the encoder to be able to open .avi files created with the YUV9 format. The Indeo drivers are available from the Intel Web site (http://www.intel.com). However, if you captured an AVI file on the same machine as RealEncoder, the encoder typically has no problem opening it.

QuickTime files:

• Use 24-bit RGB QuickTime video files.
• Use 8-bit or 16-bit mono and stereo audio.

  	Warning
  	QuickTime files must be uncompressed.

External Video Sources

When using an external video source, you must start with the best possible quality. In particular, different video formats yield different qualities when captured (digitized). Additionally, video playback devices commonly have two types of video outputs, S-video and composite. S-video produces better results.

The common video formats in order of quality are:

• Betacam-SP, also known simply as Beta. This format is common among video production professionals.
• Laserdisc or DVD
• S-VHS or Super-VHS
• VHS

Image Size

RealEncoder supports any size image, but will automatically crop the height and width to multiples of 16. The most common sizes are 176 x 144 pixels or 320 x 240 pixels. An image size of 160 x 120 is also supported. Live capture image size is controlled through Set Video Format under the Options menu, and is dependent upon the video capture hardware installed.

Image Cropping

The cropping feature allows you to record any section of a video image that you wish. By cropping an image, you can reduce the overall bitrate of your recorded clip.

To crop a video image:

1. To edit the image cropping settings, select Crop Settings from the Options menu.

   The Image Cropping window displays a sample image from the session input. Notice the crop lines around part of the image. These lines show the portion of the image that will be recorded.

   

2. Use Left, Top, Width, and Height buttons to adjust the size and location of crop lines.
3. Click OK to return to the RealEncoder window.
4. Select Crop Enabled from the Options menu.
5. Click the Start button to start the recording process using the crop settings.

   The cropped image appears in the Encoded Output viewer.