Output Video Quality

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A standard-compliant DVD supports a combined data rate of 9800 Kbits/second (Kb/s). This includes Video, Audio Tracks (if any), Subtitles (if any) and less than 1% of overhead transmission and control data. At this rate, a standard DVD-5 (4.7GB) can hold at most (about) 135 minutes of video (with accompanied audio and subtitles) but no more. Since most discs also have menus, bonus material and extra features, as well as more than one audio track, the main attraction (the main movie) is usually encoded at a lower rate. So in practice most discs have video encoded at 5000-6000Kb/s.

 

DVD's utilize the Mpeg-2 video compression standard to compress the video. Mpeg-2 is twice as efficient as Mpeg-1. That is, Mpeg-2 can produce almost identical quality video to that of an Mpeg-1 at 50% the filesize. (Notice that the inverse might not be true: Mpeg-2 at the same bitrate of Mpeg-1 might not produce a video at twice the quality!) Similarly, Mpeg-4 is twice as efficient as Mpeg-2. Of course this comparison assumes the same input video.

 

Example: A video encoded using Mpeg-1, Mpeg-2 and Mpeg-4 SP, Mpeg-4 AVC can have almost identical quality, but the Mpeg-2 file will be 50% the size of the Mpeg-1 file and the Mpeg-4 SP will be 25% the size of the Mpeg-1 file and 50% the size of the Mpeg-2 file and Mpeg-4 AVC will be about 13%.
 
While the DVD and SVCD standards utilizes the Mpeg-2 format, VCD utilize Mpeg-1. iPod supports both Mpeg-4 Simple Profile (SP) and Advanced Video Coding (AVC). Mpeg-4 AVC when used at its full power is expected to be twice as efficient as Mpeg-4 SP. However, iPod uses only the most basic features of AVC and thus the quality or efficiency of AVC output is not as impressive as it could be.
 

DVD supports video resolutions of up to 720x480 pixels @ 29.97 frames/second for NTSC and 720x576 pixels @ 25 frames/second for PAL.

 

Notice that since increasing the source video resolution increases that amount of information in the input, the video quality will suffer more as a result, unless you higher the encoding bit-rate (if possible.)

 

VCD Video Quality

 

The VCD standard utilizes the Mpeg-1 video compression standard. VCD was designed to replace VHS cassettes. Their goal was to include about 74 minutes of video (with audio) on a single CD (650MB) at the same quality of the source (VHS cassettes.) So a VCD's video quality will be at best that of a VHS cassette, in practice, a little less.

 

The VCD standard support a maximum of about 1150Kb/s of video. Easy DVD Ripper & Converter has an internal Mpeg-1 encoder and when VCD is selected for output, the internal encoder will be utilized. The internal encoder uses the maximum allowed bitrate by the standard. You cannot set any video settings for VCD in Easy DVD Ripper & Converter other than the video resolution. Notice that when you enlarge the video resolution, the quality will suffer as a result, but lowering the resolution will help increase the quality a little, at the expense of lower details resolution, although the output file(s) will not be VCD standard compliant and might not play on most VCD players.

 

VCD supports video resolutions of only 352x240 pixels @ 29.97 frames/second for NTSC and 352x288 pixels @ 25 frames/second for PAL.

 

SVCD Video Quality

 

The SVCD standard utilizes the Mpeg-2 video compression standard. SVCD was designed to address the market needs for a high-quality digital video standard and to offer a more practical solution to those unsatisfied with what VCD had to offer. By utilizing Mpeg-2 for video compression, they offer higher-quality video at similar bit-rates.

 

The SVCD standard support a maximum of about 2600Kb/s of video. Easy DVD Ripper & Converter has an internal Mpeg-2 encoder and when SVCD is selected for output, the internal encoder will be utilized. The internal encoder uses the maximum allowed bitrate by the standard. You cannot set any video settings for SVCD in Easy DVD Ripper & Converter other than the video resolution. Notice that when you enlarge the video resolution, the quality will suffer as a result, but lowering the resolution will help increase the quality a little, at the expense of lower details resolution, although the output file(s) will not be SVCD standard compliant and might not play on most VCD players.

 

SVCD supports video resolutions of only 480x480 pixels @ 29.97 frames/second for NTSC and 480x576 pixels @ 25 frames/second for PAL.

 

AVI Video Quality

 

The AVI format is not a standard and it is designed by Microsoft for use on Windows platforms. AVI does not specify a Video compression format, but instead specifies methods to utilize any format. You need to use a CODEC (Coder-Decoder pair) to store video in AVI files. In Easy DVD Ripper & Converter you may select the video codec for AVI output from a list of available (installed and compatible with the source video) codecs. Each codec has it's own settings and quality parameters, and you must set them from the codec's windows and dialogs. You can reach to the selected codec's settings window from the 'Configure' button on the 'Video Codec' setting window (please refer to the Video Codec setting section in this help for further information.) Since each codec has a different set of settings, you must refer to the codec's help system to find out the best settings for your target quality/filesize.

 

Since in AVI the video resolution as well as the encoding settings are set by the user, the output quality may be disappointingly low if they codec and its settings are not selected carefully. As a rule lowering the video resolution almost always results in higher-quality output than leaving the default full-size resolution.

 

When encoding in DivX remember to select the appropriate profile for the source video. If you are converting at the highest video resolution, the 'Home Theater' or 'High Def' profiles must be selected. Also, depending on the type of video (fast motion, action movie or slow motion movie) you will need to select the bitrate. Faster-motion video require higher-bitrates, while slower-motion ones can be encoded in lower bitrates. But for the highest video resolution, setting the bitrate to 2000 or 2500Kb/s or higher will give good output quality. Also, remember that setting the 'Performance / Quality' bar toward the right (slowest) will give better results, especially if the video resolution is high and/or the bitrate is low. For the best results please refer to the DivX help files and to any of the multitude online forums for help.

 

When encoding in XviD using the default settings, selecting an appropriate bitrate will usually give very good quality output, even for high video resolution. Although for best results an understanding of the different settings is usually necessary. Please refer to the help files and to any of the multitude online forums for help.

 

In all events, when blockiness, or pixerlization is noticed in the output video, it is usually solved by highering the bitrate. Regardless of all other settings, the highering the bitrate will result in higher quality output.