MeGui Const Quality or 2 Pass?

[killerteengohan]

I been using 2 pass and specific bitrates to get episodes to always be 300MB.

I hear using Const Quality aka VBR gives better results and then I also hear its not as accurate with bits and just randomly guesses in one pass, while 2 pass carefully calculates before it does its job.


I do like to control the file size in the end but I also want the better looking video results.

Would 17.0 const quality be better or would the specified bitrate and 2 passes to get 300MB be better?

Sometimes I see 17.0 being less bit rate than my 300MB amount I would use and under 300MB and sometimes I see it being more than 300MB and more bitrate than I would use to get 300MB.

Its totally random sizes and bitrates in the end when compared to choosing a specific amount of kbps.


Which is going to get me the better output video?

[detmek]

At same output size (same average bitrate) Constant Quality and 2 pass mode with same settings will give you the same quality. So, if you can hit 300MB output with Constant quality mode it will look the same as if you used 2-pass.

Constant quality mode gives overall the same quality at different bitrate (filesize) while 2-pass mode gives same bitrate (filesize) with different quality. If you try to change CRF to get 300MB output file your quality will vary and will be the same as if you have used 2-pass mode.

So, if you want all your episodes at 300MB use 2-pass mode. Or, if you want same quality use CRF and forget about 300MB per episode.

[Asmodian]

At the same size the quality of crf = 2 pass. With crf you set approximate quality while with two pass you set size. If you want a specific size use two pass, if you don't care about size pick a crf you like the look of (via a few tests) and run with it.

It sounds like you care about the size so your two pass workflow is probably better for you. If you pick a crf that resulted in an average bit-rate of 300 kbps after encoding all episodes you would have better quality on average because easy episodes would be smaller while harder episodes would be larger. The easy episodes would be worse quality and the hard ones better, the hard ones would probably gain more quality than the easy ones lost. You could get the same result by splicing all the episodes together and encoding the entire thing with two passes targeting 300 kbps.

For some videos crf 17 would give better quality (and be larger) while with others it would give worse quality (and be smaller).