Av Bit Rate v Constant Quality

General questions or discussion about HandBrake, Video and/or audio transcoding, trends etc.
Post Reply
Brasstacks
Posts: 1
Joined: Wed Jun 16, 2021 8:16 am

Av Bit Rate v Constant Quality

Post by Brasstacks »

I ripped my blu ray tv shows to pc so i dont have to handle them as much.
they are black & white and 4:4 Aspect Ratio
each episode is 30min 3.5gb in raw form from blu ray

some results are 1.75gb and some are as low as 600mb
the average bitrates vary from each one after reencoding

question is:
using Constant quality is supposed to be better then average bitrate.
why do some of these videos use a lot less bitrate then others?


example:
Video #1 before = 3.52GB 20mbps average & 36mbps peak
Video #1 After = 542MB 2.8mbps average & 13mbps pake

Video #2 before = 3.54GB 20mbps average & 36mbps peak
Video #2 After = 1.24GB 6.7mbps average & 16.5mbps peak

settings:
Constant Quality 20RF
encoder preset veryslow
encoder tune Film
Encoder Profile High
Encoder Level 4.1

I want the best quality out of these 1080p episodes
I have DVD episodes in a larger file sizes then some of these...
rollin_eng
Veteran User
Posts: 4011
Joined: Wed May 04, 2011 11:06 pm

Re: Av Bit Rate v Constant Quality

Post by rollin_eng »

Could you please post your HB logs, instructions can be found here:

https://handbrake.fr/docs/en/latest/hel ... y-log.html
User avatar
JohnAStebbins
HandBrake Team
Posts: 5608
Joined: Sat Feb 09, 2008 7:21 pm

Re: Av Bit Rate v Constant Quality

Post by JohnAStebbins »

A number of things affect bitrate when using constant quality encoding including motion, video noise, and scene detail. The larger encodes likely had more of one of those.

Given that the video is B&W, I'm guessing these are older TV shows. They probably have a significant amount of noise, so you might want to try adding a denoise filter like NLMeans.
Post Reply