Trying to understand video quality from bit size and compression type

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Bubbabob
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Joined: Sat Apr 03, 2021 1:05 pm

Trying to understand video quality from bit size and compression type

Post by Bubbabob »

I'm trying to understand the basic quality of a video from looking at the compression types and the video bit rates. I have zero doubt that I'm confusing unrelated concepts, but let's take the following videos...

1. AVC. Video bit rate: 8000
2. HEVC. Video bit rate: 4000
3. HEVC 10 Bit. Video bit rate: 2000.

Based on the above, is it obvious which video would produce the higher quality? If the question is confusing or just stupid sounding, it's because I don't even grasp how video bit rate affects the final quality. So far I know that "Higher bit rate is better than lower bit rate, hevc is better than avc, and hevc 10 bit is better than regular hevc" and there my knowledge stops.

Anything you can say to clear this up for me would be appreciated.
rollin_eng
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Re: Trying to understand video quality from bit size and compression type

Post by rollin_eng »

While newer codecs are generally better than older ones there is no “best” bit rate. This is why most people have switched to quality based encoding.

https://handbrake.fr/docs/en/1.3.0/work ... ality.html

https://handbrake.fr/docs/en/1.3.0/tech ... mance.html
Bubbabob
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Joined: Sat Apr 03, 2021 1:05 pm

Re: Trying to understand video quality from bit size and compression type

Post by Bubbabob »

rollin_eng wrote: Thu Jun 03, 2021 5:38 pm While newer codecs are generally better than older ones there is no “best” bit rate. This is why most people have switched to quality based encoding.

https://handbrake.fr/docs/en/1.3.0/work ... ality.html

https://handbrake.fr/docs/en/1.3.0/tech ... mance.html
So to be clear, if I were to take three videos with equal codecs, the different video bit rates wouldn't necessarily tell me anything about the quality of the video? I understand how moving the rf setting affects the quality; I'm just unclear on what part the resulting video bit rate plays in the quality.
rollin_eng
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Re: Trying to understand video quality from bit size and compression type

Post by rollin_eng »

Correct, a bitrate itself does not tell you anything about the quality of a video.
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JohnAStebbins
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Re: Trying to understand video quality from bit size and compression type

Post by JohnAStebbins »

Bubbabob wrote: Thu Jun 03, 2021 5:47 pm So to be clear, if I were to take three videos with equal codecs, the different video bit rates wouldn't necessarily tell me anything about the quality of the video? I understand how moving the rf setting affects the quality; I'm just unclear on what part the resulting video bit rate plays in the quality.
Unfortunately, when speaking of quality there are a lot of general statements you can make and very few concrete statements.

Newer codecs generally provide better quality given the same bitrate. But not always.

Different encoders for the same codec often have dramatically different quality.

Hardware encoders usually have much lower quality than software encoders because they cut corners for the sake of simplicity and speed.

Different encoders will behave differently for different scene types. I.e. one encoder will handle motion better than another.

The same encoder will handle different scene types differently given different settings for that encoder.

So ultimately, you can't look at the bitrate and codec to tell you anything but a generalization about the quality. You have to know pretty much everything about how it was encoded (encoder, settings for that encoder, other filters that were applied, etc).
mduell
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Re: Trying to understand video quality from bit size and compression type

Post by mduell »

AVC at 8000 kbps by a long shot, assuming equal encoding time.
rollin_eng
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Re: Trying to understand video quality from bit size and compression type

Post by rollin_eng »

I’m not sure how encoding time would be of any help as different setups will take different times to encode.
mduell
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Re: Trying to understand video quality from bit size and compression type

Post by mduell »

On the same hardware, of course.
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