Constant Quality vs Avg Bitrate at equal bitrates
Constant Quality vs Avg Bitrate at equal bitrates
I am in the process of converting all of my movies over to a smaller bitrate to allow for streaming on my Emby server using my limited bandwidth. To avoid the cpu strain of constant transcoding, I have used HB to convert all the movies to limit the bitrate, which has worked great. On all of the guides and advice I have read, Constant Quality is superior to setting an Avg Bitrate, as well as being much faster to encode. My question is, there are times when I have to go through and change the Constant Quality setting and reencode multiple times to get to my target bitrate limit. If I am already using CQ to get down below a bitrate such as 7000kbps, would there still be a quality difference if I were to have just set that bitrate using the Avg Bitrate setting in the first place? Thanks.
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Re: Constant Quality vs Avg Bitrate at equal bitrates
If you want a certain quality use CQ, if you want a certain bitrate use ABR.
A CQ encode that is 7000 kbps will be the same as a 2 pass ABR at 7000 kbps.
Could you please post your HB logs, instructions can be found here:
https://handbrake.fr/docs/en/latest/hel ... y-log.html
A CQ encode that is 7000 kbps will be the same as a 2 pass ABR at 7000 kbps.
Could you please post your HB logs, instructions can be found here:
https://handbrake.fr/docs/en/latest/hel ... y-log.html
Re: Constant Quality vs Avg Bitrate at equal bitrates
It's the other way around. Every source is different, so matching a bitrate will always give you a different quality.
If your home server has limited bandwidth, best thing is to limit vbv-maxrate, since that is what causes stuttering.
If your home server has limited bandwidth, best thing is to limit vbv-maxrate, since that is what causes stuttering.
Re: Constant Quality vs Avg Bitrate at equal bitrates
You should be using vbv to cap bitrate peaks for streaming, and letting the constant RF do what it needs otherwise.
Re: Constant Quality vs Avg Bitrate at equal bitrates
Thanks for the replies. I'm not having problems with studdering or anything. I'm just trying to limit the bitrate so I'm not over-taxing my internet connection, and my NAS doesn't have to transcode all the time. I am fine with some variations in quality as long as it is all still decent.
Re: Constant Quality vs Avg Bitrate at equal bitrates
This sounds like how I would like to handle it, but I'm not familiar enough with how to use the vbv parameter. Could you point me in the direction of a relevant guide? How does vbv work alongside the constant RF? If I set the quality higher, does it simply not go any higher than what the bitrate allows?
Re: Constant Quality vs Avg Bitrate at equal bitrates
VBV specifies a maximum bitrate and a buffer size. It will constrain bitrate spikes that constant RF would otherwise have during high motion/complexity/detail.
https://forum.doom9.org/archive/index.php/t-147460.html
https://forum.doom9.org/archive/index.php/t-147460.html
Re: Constant Quality vs Avg Bitrate at equal bitrates
It's all in the ffmpeg docs.
https://trac.ffmpeg.org/wiki/EncodingForStreamingSites
https://trac.ffmpeg.org/wiki/EncodingForStreamingSites