Norman Black
Forum Replies Created
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Mainconcept AVC does not seem to be very accurate in hitting the average bitrate we specify. They are always under by some amount that varies by source.
A simple workaround is to have the average bitrate enough higher than the target average you want.
Sony AVC is much more accurate. Some say Sony AVC is CBR but looking at a bitrate graph shows it does vary but not by a lot.
Since your MAX and average bitrates are nearly the same you may as well eliminate the use of two pass and save the encode time. 1Mbps out of 30ish is not very much. The only reason for two pass is to allow the encoder to use widely varying bitrates depending upon scene complexity and still get an average of some specified value.
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You can download some sample videos here, and try for yourself on your machine.
I downloaded and tried this. 2.9Ghz core i7.
Interesting that these files playback better than my GoPro Black files. My GP 1080p60 30Mbps files do not play smoothly. The GH3 1080p60 50Mbps file does play smoothly. Both are CABAC and supposedly Long GOP. The 72Mbps All-I format also plays smoothly for me, 1080p25. I am jealous.
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The NewBlue titler does support fully justified text.
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Also, remember you can set the length of time for the cursor preview in video prefs, Editing tab.
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Yes, when you render from a lossy format to a lossy format you do get loss. This is technically true, but you may not be able to see it. Maybe only if you freeze frame and pixel peep. A far cry from viewing at 30p or 60p frame rates. You are also using very high bitrates which minimizes damage. Rendering through multiple generations is more likely to have damage but you are only doing one extra render.
So lossy -> lossy does damage, but if you cannot see it then should you really care? You can do a quick test for yourself.
Take a clip A. Render it out at your settings from your source(s). Now bring clip A in and render clip A again at the same settings. Now compare the first generation to the second.
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Xvid is a simpler codec which is easier to decode and is therefore less likely to have a playback problem at high bitrate and frame rate. Xvid will not have the same quality at the same bitrate as AVC. It will be close.
I use Media Player Classic Home cinema on my machine, 2.9Ghz core i7, and it plays my GoPro 1080p60 30Mbps files fine as far as I can tell. A little less bitrate than your file. This is with a pure software decode. There are options to enable DXVA hardware decode but it is not necessary on this machine with anything I do. I don’t bother with any other players.
On my nettop (Atom CPU) everything AVC must use hardware decode (DXVA) for smooth playback. This is playback to my TV via HDMI.
HDMI should not be a bottleneck in any way. Computer monitors can be hooked up via HDMI. The bottleneck is really how fast is the CPU to decode on playback given the high bitrate and framerate combination you have chosen.
My only suggestion, beyond a power CPU, is to enable DXVA hardware decode in the software decode seems like it has an issue playing smoothly. How you do this depends on the player. Some might do it automatically and some manually. In my MPC install it is controlled in the LAV video decoder options.
The only other possible suggestion is to back off the 59.94 down to 29.97. This cuts some frame overhead and you can cut the bitrate. Both helping playback.
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Better/best are subjective, but the best AVC/H.264 encoder out there is the x264 encoder. However at the higher bitrates you are using I doubt you would see much difference. The better encoders are obviously better at lower bitrates but most are very similar at higher bitrates.
One tweak you could try that I did not previously mention is to change the number of slices to 1 from 4. 4 slices is only needed if you are going to burn a Blu-ray at level 4.1.
The jumpy nature of your playback may have been due to the player not able to decode at full speed and so it stuttered briefly. You are at very high bitrate and 60p which takes a lot of power to decode.
What were you playing back on? PC, player, player settings like DXVA decode.
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The Mainconcept AVC encoder is actually three separate encoders.
CPU, OpenCL and CUDA.Each is independent code and there will be quality differences. The differences should have nothing to do with frame rate. Only the quality level within the frames.
The highest quality is the CPU only encoder. The OpenCL and CUDA encoders are similar and not as good. If you really want to know the ugly details. Note that any visual differences will only show at lower bitrates.
It’s kinda a waste to use two pass and have average and max bitrate the same. Just use one pass in this case. With two pass and average much lower than max bitrate, like the default templates, you allow the encoder to use lower bitrates when it can so it can save bitrate for those portions it needs a higher bitrate to preserve visual quality.
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If you want to deliver 29.97, then your project properties should probably be set to that. In this way any resampling, and its effects, of your 59.94 source will be visible in your preview window.
If you have a 59.94 source and your target is 29.97 I would disable resampling on the events. In this case Vegas will use every other frame from the source for the output. No ghosting.
As for output. If you are targeting the common internet video servers, then the Internet 1080p template, which is 29.97, is probably good enough. You might tweak it for one slice, high profile and two pass for a little better quality.
The AVC encoders in Vegas are not as good at low internet type bitrates as the x264 encoder which is commonly used by the online video servers. All this means is that the bitrate you upload to them should be a bit higher than what they re-encode to. You want what you give them to be higher quality than they deliver. In this way their re-encode will be as good as it can be.
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If you used one of the “internet” templates unaltered, then your source needs to be resampled from 59.94 to 29.97. Vegas smart resample should be smart enough to just toss every other source frame in this circumstance. If it is not smart, then you can get ghosting when Vegas blends two frames into one in the resample. You can avoid this by turning resampling off.
By setting your project settings at 59.94 you are telling Vegas that is your probable output frame rate. In that case you should render as at 59.94.
As previously stated all the online video servers I am aware of will resample your upload down to 30p at most and who knows what algorithm they use.
IMO since internet bitrates are so low, you should abandon 59.94 for streaming internet delivery. Download delivery is another matter.