Question about Handbrake's 'Constant Quality' setting

[Ronaldinho]

Hi,

I've been using handbrake for encoding for a few months now, but I've never used the Constant Quality setting, I've always just set the bitrate to what I want. But the thing is, I've recently decided not to worry about file size when I encode, because I just want the best possible quality, and lately I've just been setting the bitrate very high in order to keep the highest quality possible, and I was wondering if using the constant quality setting and putting it as high as it can go, will result in better quality with less overkill in terms of bitrate/filesize?

Because, I was thinking that perhaps I might be using too high a bitrate with no real need for it. I hope some of you can understand what I'm trying to say, I may not have worded it very well...

Basically, would setting Constant Quality as high as it can go, be better than choosing a bitrate that could possibly be too much?

And before anyone says "if you want the highest possible quality, then don't encode at all"... I have to encode these files, I have no other option...

Thanks to anyone willing to help

[jagabo]

I was wondering if using the constant quality setting and putting it as high as it can go, will result in better quality

Yes. But...

with less overkill in terms of bitrate/filesize?

No, more overkill. The highest quality setting is RF=0 -- that will get you lossless encoding and you will get gigantic files. Look for a better compromise setting. Most people settle for round RF 15 to 21. You'll always get the quality you want and the bitrate will be exactly what's needed for that quality. If you then go back and make a 2-pass VBR encode at that same average bitrate the two videos will be nearly identical.

[Ronaldinho]

okay, thanks.

But, is it really lossles encoding, or just close to? Because I thought h.264 was lossy...

What if I set it to CRF 5, would that be better? I know I will still have very large files, but maybe a little less so with close to identical quality?

[jagabo]

But, is it really lossles encoding, or just close to? Because I thought h.264 was lossy...

Except at CRF=0 where it's lossless (most hardware players will not play lossless h.264).

What if I set it to CRF 5, would that be better? I know I will still have very large files, but maybe a little less so with close to identical quality?

CRF=5 is still to high a quality. A Blu-ray source encoded at CRF 5 would be larger than the original.

You'd be hard pressed to see differences between the original and CRF=12 even looking at enlarged still frames. Like I said most people who want good quality use 15 to 21. Just run a few test encodes at different CRF values. Use a short video with a variety of shots. x264's weakest areas are dark shots with grain. You'll see posterization artifacts there first.

[Ronaldinho]

hmm... okay.

What about this...

Instead of using Constant Quality and setting it real high, what if I were to choose a bitrate that was about 2000 or 3000 kbps higher than the source bitrate?

For example, if I had a source file that was 1080i at 18 mbps, and I encoded it at 20 mbps, would that result in a file that is very close to, but not quite, original quality?

And yes, I know that would result in a file larger than the original, but it won't be as large as a file that was encoded at CRF 5 would it?

Thanks for all your help so far

[Ronaldinho]

ok, I've thought about what you said a bit more and I think you'd probably be right. Setting it at CRF 12 would probably be the best way to go... But since I always overestimate things, I think I will go with CRF 10, haha

[jagabo]

Instead of arbitrarily using 10 or 12 I highly recommend you run tests with different values and see what you can live with.

[Ronaldinho]

Instead of arbitrarily using 10 or 12 I highly recommend you run tests with different values and see what you can live with.

Yeah, probably a good idea.

Thanks, Jagabo.

[jagabo]

You're welcome. Write back and let me know what CRF value you end up using.

[Ronaldinho]

Sure, will do. But it probably won't be for a few days or maybe even a week or more until I do. I don't have anything to encode at the moment. I will bookmark this thread and you'll probably see it pop up again when I post back later.

[Ronaldinho]

Okay, I ended up using CRF 12, like you recommended, and I'm happy with the results.

However, I have a new problem that I'd like some help with if you don't mind... I've already posted a new thread for it, as it is a different kind of issue.

Thanks again