Video Codec
Apple iPods support either MPEG4 or H.264 video files. Generally H.264 is of higher quality, but at the expense of the time it takes to encode the video.
Bitrate (k/bits)
This parameter controls the video bitrate. If you want a higer quality video file, then choose a higer video bitrate, but at the cost of a larger file size.
Video Size
You may override the video profile with dimensions you wish to output your video file at.
Frame Rate
This option sets the Output frame rate of the encoded video file. Please see the section at the end of the help file relating to this.
Filter
Allows you to specify a De-Interlace or Inverse Telecine filter to the output file. Use this option if your output file has a combed or lined effect.
Higher Quality
This option, when ticked, will try and create a higher quality video output at the expense of the encoding time being longer. Visible output results may vary depending on the source video.
Don't Skip Frames
This option tells the encoder not to skip any frames. You should NOT normally have to use this option, but it may help where the output source Video and Audio are not in sync.
Maintain Aspect Ratio
This option if selected will create a video file, with the veritcal size of the video correctly matched to the horizontal size of the video. For example
a widescreen 16:9 PAL DVD which is 720x576, may end up being 720x404, as this is a near match for a 16:9 video resolution.
Automatic Aspect Ratio
This option if selected will flag the resulting output file with the aspect ratio marked in header, leaving the video resolution untouched.
Keyframe Interval
Is the maximum interval between keyframes in frames (default: 250 or one keyframe every ten seconds in a 25fps movie. This is the recommended default for MPEG-4). Most codecs require regular keyframes in order to limit the accumulation of mismatch error. Keyframes are also needed for seeking, as seeking is only possible to a keyframe - but keyframes need more space than other frames, so larger numbers here mean slightly smaller files but less precise seeking. 0 is equivalent to 1, which makes every frame a keyframe. Values >300 are not recommended as the quality might be bad depending upon decoder, encoder and luck. It is a common for MPEG-1/2 to use values <=30.< /FONT>
Keep Audio in Sync
Only use this option if you are experiencing Audio sync problems.
Keyframe Interval
Keyframes are used as pointers for searching in a video file. The more keyframes you have, the higher precision you can position a video to, but at the expense of larger files. The default of 250, gives you a keyframe every 250 frames, which for a PAL video is every second.
Two Pass Encoding
This option will perform two passes on the Title and Chapter selections you have made. The first pass gathers statistical information about the video stream. The second pass uses this information to make a better encoding filter. You generally will end up with a higher quality video file and potential a smaller file size. But it will take considerably longer to process.
Forced Subtitles
This option will allow the forced subtitles from a DVD to be shown in the output movie file. A typical example of this, is a film with an English dialog, but some parts may be spoken in another language. This foreign dialog can be shown as a subtitle. Please note, not all DVD's create forced subtitles in the same way. Some DVD's simply have a seperate subtitle track that has the non-english subs in.
