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View Full Version : In xvid_encraw, do I need to specify bitrate in the first pass?


orion44
26th September 2021, 09:58
Just discovered that there is a command line version of Xvid codec when I looked into the Xvid folder.

When doing a two-pass encoding with xvid_encraw, do I need to specify bitrate in the first pass,
since in vfw version it is disabled in the first pass?

Why is imin, pmin, and bmin set to 2 by default, when in vfw version it is set to 1?
I would like to change this setting to 1.

Asmodian
27th September 2021, 01:45
If I remember correctly, yes you need to specify the bitrate for the first pass. It does try to do some rate control for first pass. This is why three pass offers some very slight improvements; the bitrate for the second pass is a much closer to the target so the data is more accurate for the third pass.

The minimum QPs set to 2 instead of 1 usually results in smaller files without quality loss because QP 1 is extra huge. However, people got annoyed when Xvid didn't hit their bitrate targets so some tools default to a min QP of 1. If you want extra size without a significant quality boost feel free to lower the min to 1. :)