When you first start PowerVCR, the default position will be the Recorder (or simply click on the Recorder). Press the Recording Profiles, and then select from the Profile List a suitable description for your recording needs.
The first selection, Basic Profiles, are for novice or even
intermediate users. The remaining Profiles located below are for advanced
users.
Generally, use MPEG-1 for low resolution (normal usage) and MPEG-2 quality
recording for high resolution. Keep in mind the recommended system requirements
for recording high resolution (Pentium III 650 MHz ). Finally, if you will be
writing to a CD (making your own CDs), choose the VCD Profiles.
When a profile is highlighted, the Content box (upper right) will display its settings. Click on the + signs for more selections in the Profiles' List. General recommendations and suggestions are located in the bottom half of the dialog box. Below are brief descriptions for each profiles' content:
Only two choices are available: Constant Bitrate or Constant Quality. The difference is that for Constant Quality, PowerVCR will guarantee the quality of the video content while Constant Bitrate guarantees the bitrate, which in turn gives you more control over the memory that's consumed.
If you wish to edit and often utilize the random access (FF/Rew) capabilities, Constant Bitrate is recommended. If primarily for viewing and normal playback, select Constant Quality.
Measured in kilobytes per second, the higher the bitrate the more memory consumed but with better quality. The range for Video Quality is 2-4. Refer to the above Video Compression section for differences between quality and bitrate settings.
This determines the frame size when recording. The available sizes are 352x240, 352x288, 720x480 or As Source, which is dependent on the driver's automatic settings. The bigger the size, the more memory it will consume but with better quality for larger frames.
The frame rate setting allows you to set the frames per second (FPS) for recording. The more frames the better for capturing video content with motion.
A MPEG compression technology, GOP concept reduces the temporal redundancy across frames (from frame to frame) for video content. There are three types of frames involved in the GOP concept:
· I-Frame (Intra pictures): I-frame is the first frame of each GOP, is moderately compressed, and serves as the reference points for random access and can be likened to images.
· B-Frame (Bi-directional pictures): B-frames' predictions are forward, backward and bi-directional which is relative to the other I-frames and P-frames. Compression is at a high level.
· P-Frame (Predicted pictures): P-frames are coded with reference to past pictures, predict in a forward direction, and moderately compressed.
Layer 1 is best suited for recording audio bitrate levels around 128 kbps. For example, Philips' Digital Compact Disc Cassette (DCC) uses Layer 1 compression at 192 kbps per channel.
Layer 2 contains more efficient codes for representing bit allocation and performs better than Layer 1. Possible applications for this layer are the storage of audio sequences and content on CD-ROM or VCD audio tracks.
Stereo is the default for all the profiles which ensures the
best audio quality. The MPEG-1 audio standard definitions:
· Mono is a single audio channel for lowest bitrate consumption.
· Dual is two independent channels (left/right) with half the total bitrate and is generally used for multilingual audio programs.
· Stereo (default) includes two independent channels but bitrate remains constant while the channels' split may vary. The encoder uses this flexibility to improve quality by allocating more bits to the channel with the higher dynamic signal. Use Stereo for best audio quality at higher bitrates.
· Joint Stereo exploits stereo redundancy. It shares certain bits between high-frequency left and right channels which improves compression efficiency with a slight loss of stereo separation. Lower frequencies are treated as normal stereo. Joint Stereo is best for obtaining the best quality as compared to lower or mid-level bit rates.
Like its video counterpart, this too is measured in kilobytes per second (kbps). The higher the bitrate, the more memory it will consume but with better quality.
When encoding, the trade-off parameter consists of speed versus quality. '0' is for the fastest speed with the lowest quality, and '3' is for best quality and the lowest speed.
Now, if you would like to make your own profile, press New and go directly to next section, Making your Own Profile. Otherwise, press OK after you have made your selection.