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render settings for music video


Yannick Willox

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Hello,

I have a specific question, which google did not answer yet ...

I have to render a big orchestral video project. I need manageable filesizes but correct motion (timing of the image on the music is essential). Are there settings that give better/worse results ? CBR/VBR ? The amount of keyframes ?

I am quite in the dark concerning these rendering settings.

Thanks !

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Render settings do not add a delay to the footage, they just determine the quality. You did not mention what resolution (4K or 1080P), or what destination platform (YouTube, Vimeo, DVD, etc), or frame rate. But anyway, below is what I use for 1080P with a YouTube or Vimeo Destination.

For your project since there is not much fast moving action, you can probably get away with a lower bitrate like 8Mb/s or maybe even 4Mb/s. The bitrate is the main thing that affects file size and quality. In the Davinci Resolve screenshot the bitrate is the 16000 Kb/s value. Not sure what NLE you are using but they all have bitrate options for rendering. 

I'm no expert on the whole keyframes, CBR/VBR, etc. I just experimented and watched rendering video tutorials until I got the settings that work for me. These days the only thing I change is the bitrate based on the project contents. As a reference point, DVDs have a video bitrate of only 9.8MB/s.

If I really need to conserve space for example a really big project, then I would render a small part of it, the part with the most movement, and keep lowering the bitrate with each test render until you start seeing a noticeable quality difference and macro blocking, then crank it back up a bit and you now have your lowest bitrate that will not affect the visible quality. That will get you the best file size without quality compromise.

DR-Render-Settings.JPG

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Thanks, I need to experiment more I guess. I am starting to think the amount of keyframes are the determining factor.

you say there is not a lot of movement, but 40 string players bowing happily is a lot of detailed movement. It is exactly there where things happen, and the conducter is unhappy, because where does Resolve decide to put keyframes ? The timing is very crucial here.

uploading in full hd to Youtube. What happens with keyframes there ? Anyway, youtube does not keep a tight sync between image and sound anyway, so all of this is a bit theoretical. I just need a good starting point.

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1 hour ago, Yannick Willox said:

Thanks, I need to experiment more I guess. I am starting to think the amount of keyframes are the determining factor.

you say there is not a lot of movement, but 40 string players bowing happily is a lot of detailed movement. It is exactly there where things happen, and the conducter is unhappy, because where does Resolve decide to put keyframes ? The timing is very crucial here.

uploading in full hd to Youtube. What happens with keyframes there ? Anyway, youtube does not keep a tight sync between image and sound anyway, so all of this is a bit theoretical. I just need a good starting point.

You actually want less keyframes not more, keyframes are mainly used for editing and help the video editing software do less work, that's why ALL-I compression is easier than LongGOP to edit even though ALL-I is typically 4x larger files. But you would never render a final project in ALL-I. 

When you say "it is exactly there where things happen" what things are you referring to? If you post a screenshot of what is going wrong myself and others may be able to help you better. Maybe it is something else that needs to be fixed somewhere else in the process.

Your example of 40 players bowing is still nothing LongGOP and a lower bitrate can't handle. Where you will start seeing artifacts or macro blocking with lower bitrates are scenes where nearly every single pixel changes in every frame like when a drone is flying at high speed over the ocean, a timelapse that was shot with large intervals between images combined with a field of flowers blowing in the wind, etc. 

If the final destination for the video is YouTube then I would recommend you simply look up the latest YouTube video formatting recommendations. It sounds to me like you are overthinking it...simply follow Google's YouTube chart (they do run YouTube after all) and leave it at that. Another option is to post it to Vimeo instead, maybe have the version that you want on the client's website hosted on Vimeo then the one for everyone else posted on YouTube, also does the source video look fine before you upload it to YouTube?

 

https://support.google.com/youtube/answer/1722171?hl=en

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Another trick that I have read about but not tried.....if the video is 1080P then upscale the whole thing to 2K or 4K, I have read that YouTube uses better codecs for anything higher resolution than 1080P. Also, keep in mind that YouTube also uses better codecs for popular channels; that's why music videos from celebrity names look better than yours ever will on YouTube.  It's part of the cost of free.

If the source video before the YouTube upload looks fine, then all you can do is try Vimeo, DailyMotion, follow the Google YouTube guide and tell the client that you can't control how badly YouTube is trashing your footage. Also let him/her know that YouTube has tiers of quality depending on the channels owner and popularity when they ask you why everyone else's looks so good.

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Ok thanks. I was mistaken that more keyframes = less motion interpolation = fast movement more in sync with the music.

As an example, some passages can have 3 times up and 3 down per second. 

The easy solution was to make the tutti camera (view from the hall) one frame early. It could be a visual/psycho acoustic thing, we are used to hearing sound late when viewing from a distance. I did not change the close shots, and they always seem fine...

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1 hour ago, Yannick Willox said:

Ok thanks. I was mistaken that more keyframes = less motion interpolation = fast movement more in sync with the music.

As an example, some passages can have 3 times up and 3 down per second. 

The easy solution was to make the tutti camera (view from the hall) one frame early. It could be a visual/psycho acoustic thing, we are used to hearing sound late when viewing from a distance. I did not change the close shots, and they always seem fine...

Ok got it, you would have benefitted from this thread then, we were just discussing this a few days ago. Yes keyframes have nothing to do with audio synch the timeline controls that. It sounds like you have a pretty demanding client audio wise, good luck.

 

 

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4 hours ago, Yannick Willox said:

Ok thanks. I was mistaken that more keyframes = less motion interpolation = fast movement more in sync with the music.

As an example, some passages can have 3 times up and 3 down per second. 

The easy solution was to make the tutti camera (view from the hall) one frame early. It could be a visual/psycho acoustic thing, we are used to hearing sound late when viewing from a distance. I did not change the close shots, and they always seem fine...

You may have read that more keyframes gives better motion cadence, which I suspect is true, but only on extremely extremely compressed files.  I tried to replicate motion cadence issues but failed completely to do so.  

Here's the thread:

The editing thread linked above showed that the difference between a cut one frame ahead and one frame on the beat is decent, but the cut ones frame ahead and the cut two frames ahead of the audio wasn't nearly as large, and there's a decent tolerance for thing being ahead, so I'd suggest doing a few test uploads and seeing how far ahead of the beat looks best.

BTW: YT moves the image one frame ahead of the audio when you upload, and seemingly more than one frame on smaller resolutions.  Check out the great videos by John Hess linked in the Editing thread above.

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