
1) Any option highlighted in red color is not supported by the selected encoder. For example, ffmpeg does not have a command line switch for setting the VBV Buffer size for XVID encoding. So the VBV options will appear red, when you select ffmpeg encoder. Note: Just because a particular encoder does not support some options does not mean that the quality will be bad. Most of these options are advanced options which can degrade quality if set to wrong values. Hence the encoder does not provide a command line switch for changing the default value.

2) xvid_encraw supports only AVS files as input. Non-AVS files are not supported.

3) MEncoder cannot transcode audio files. The source file MUST contain a video stream.

4) If you want to create OGG Theora videos then use ffmpeg2theora. FFmpeg is not very good at creating OGG theora files.

