Quantizer in Alltoavi

[drstew]

What does the Quantizer in Alltoavi do, and how is it different than setting a bit rate? What other programs use a quantizer? Conversion using the Quntizer seems to take a long time.

[redwudz]

Both Divx and Xvid codec have quantizer settings. Encoding in quantizer mode means that the encoder will encode the video with constant video quality. The lower the setting, the better the quality. Usually below 2 will be the same quality as the source. The downside is that the output file size is unpredictable. One pass quantizer mode is usually one of the fastest for encoding.

Setting the bitrate will be fine for some scenes. But it may be more bitrate than needed for static scenes and not enough bitrate for fast action scenes. The files size is predictable. One way to help this out is to use 2 pass encoding. The first pass creates a log file of the needed bitrate for each scene, then the second pass uses that to vary the bitrates. This takes longer to encode, but the results are better if you have a long video or need to use lower bitrates to conserve space. It also has the advantage over the quantizer mode in that the final file sizes are predictable.

These are both encoder settings, not program settings for the program that is running the encoder. But programs may give you access to them. I haven't used AlltoAVI.