With b-adapt 1 (Fast), a larger number of max b-frames doesn't impact encoding performance much - if your playback devices doesn't have trouble with large numbers of consecutive b-frames, set it to the max, 16.
Similarly, b-pyramid barely impacts encoding performance (when using b-adapt 2, it apparently slightly increases performance when enabled). No need to turn it off unless your playback device has compatibility issues.
Direct Auto reduces performance a bit; if you optimize for encoding speed, it's hardly worth it (stick to the default, spatial).
Other than that your settings look fine. Though to get almost 300 fps on a DVD source with these settings, you must have a fast computer (i.e. quad-core or better).
@Rodeo
thanks for your advice.
Now i use bframes=16 direct=spatial and turn pyramidal to default.
It slow the encoding time a bit, but still very fast. I have PC with intel i7-920.
Still I didn't see any difference in quality, but i'm sure that it quality must be better now.
@mduell
in fact, with all 30 DVDs i have already encoded by now, i've only seen one of those that need to be decombine?
Isn't it better to set decomb/detelecine to off if it not necessary, because it blured the result somehow.
pringles wrote:@mduell
in fact, with all 30 DVDs i have already encoded by now, i've only seen one of those that need to be decombine?
Isn't it better to set decomb/detelecine to off if it not necessary, because it blured the result somehow.
No, it's better to default them on. They won't do anything if the frame is clean.
pringles wrote:@mduell
in fact, with all 30 DVDs i have already encoded by now, i've only seen one of those that need to be decombine?
Isn't it better to set decomb/detelecine to off if it not necessary, because it blured the result somehow.
No, it's better to default them on. They won't do anything if the frame is clean.
True (especially about decomb). However, both filters aren't well threaded. I doubt you can reach 300 fps on DVD input with either filter enabled, no matter how fast your processor is.
In some cases, quickly checking the source before encoding, guessing whether decomb is needed, encoding, and reencoding whenever the guess was wrong is faster than encoding everything with decomb enabled.
Does that mean that decomb does things even if not needed? I don't care about speed, but I don't want something decombed that shouldn't be (and your implication is that if you have it on default it might do something that you don't need). Right now I've just been using the High Profile preset (which has decomb on default) -- almost 100% of my sources are movies (and most of them are blu-ray M2TS and not DVDs).
Does that mean that decomb does things even if not needed?
It checks to see if the current frame is combed, in order to check whether it needs decombing or not. If you have a source that's progressive, then you know it won't need to perform that step. However, just checking is a lot quicker than actually applying the decombing filter.
Okay, then just to absolutely beat this dead horse, you're saying if I leave it at "default" it will check but not do anything to sources that don't need anything done, and thus the only thing I lose is some (small amount) of time? If so, I'll just leave it there because I'd rather have it check on those rare occasions I actually do need it (otherwise this old man would forget to turn it on).
(And, if so, don't bother replying because I then get it :>)
Rodeo wrote:However, both filters aren't well threaded. I doubt you can reach 300 fps on DVD input with either filter enabled, no matter how fast your processor is.
FWIW, I was under the impression I couldn't get past 80 fps with decomb and DVD sources on my 2.2 GHz Core 2 Duo MBP, but I ran a test with x264 ultrafast settings on an 8-minute 720*480 test clip, and got 101 fps (decomb default) vs. 116 fps (decomb off) - that was a progressive source, so 0 frames deinterlaced or blended.
That's still a good 15% difference, but not as dramatic as I expected. I don't know how well decomb would scale with more cores (though probably poorly - IIRC, jbrjake said it only supports up to 3 threads), but maybe it's worth trying to see exactly how much of a slowdown we're talking about.
Okay, but yet once again this begs the question -- is the detelecine filter doing anything if it doesn't need to?
IOW, is the only thing I lose speed if I leave it at default for my sources (which are nearly always movie sources). The secondary question is: does it really cut the speed in half like this poster is finding to have it enabled when it doesn't need to be?
Theoretically, no. In practice, I found that, on default settings, it was more prone to false positives than decomb. On the few sources I have which have some leftover telecine, enabling the detelecine filter resulted in jerkier motion than just decombing (while, theoretically, detelecine is the better approach). IIRC, I also had issues when leaving detelecine enabled for interlaced sources. But YMMV.
Regarding speed, it only halves the framerate because it's very high to begin with - when using slower settings that result in less than 130 fps without the filter, I bet its impact will be much less noticeable.
There are two parts to filters like detelecine and decomb. An analysis phase and a rendering phase. The analysis phase decides whether or not to engage the rendering phase. There is no way to avoid the analysis phase.
