Maximizing Youtube SD quality for super 8 footage

[Josh Gladstone]

They are not merely calling it 1080p for no reason, they are calling it 1080p because the files have a resolution of 1920 pixels by 1080 pixels. I don't know what else to tell you, and I'm really done arguing about it.

[Phil Rhodes]

 

 

Merely calling it 1080p and feeding it with a highly compressed stream is not the way it works.

You cannot have proper 1080p from a 6mbps stream. It just like upscaled DVD of 10 years ago.

Much as I agree that 6Mbps for 1080p material is often going to be rather inadequate, that's not really the case. The compression will, to whatever extent it possibly can, maintain high frequency detail to an extent that is likely to exceed what standard-def is capable of in all but the most absurdly low-bitrate scenarios. Now, what comprises an "absurdly low-bitrate scenario" is rather dependent on scene content, particularly motion, but describing it as an "upscaled DVD of 10 years ago" is inaccurate.

P

[Perry Paolantonio]

Merely calling it 1080p and feeding it with a highly compressed stream is not the way it works.

You cannot have proper 1080p from a 6mbps stream. It just like upscaled DVD of 10 years ago.

 

I understand what you're getting at, but you're bringing a quality judgement into the definition of 1080p that simply doesn't belong there. "HD" does not define the quality of the image - it defines frame rate and picture size. That's all it does, nothing more. Within that image you have a range of possible qualities and that range is broad (HDV vs HDCAM, for instance). But in all cases, if it's 1920x1080 and it's progressive, it's 1080p.

 

That said, you're incorrect about the quality/bit rate correlation. Yes, 6mbps MPEG2 looks terrible in HD. Yes, 6mbps AVC isn't as good as 20mbps AVC, but it can still look very good. In the early days of DVD, you couldn't encode at lower than 7mbps (SD MPEG2) and have it look good. Now you can encode below 5mbps and have it look just as good or better than the old encoders at 7mbps, because the encoders have matured significantly in the past 15 years. Same with H.264/AVC - the quality of the picture gets better as encoders get better, and that means lower bit rates.

 

New codecs come into being all the time, in pace with new hardware that can handle it. These codecs all have the same goal: better quality at lower bit rates. H.264 promised to deliver the same quality as MPEG2 at about half the bit rate. And it pretty much does that - maybe it didn't at first, but once the encoders matured it did. H.265 is making similar promises in relation to H.264 - same quality, half the bit rate. But it also supports 10 bit color, which is a massive leap forward in picture quality (goodbye, banding!). Give it a little time and I'm betting you'll see 1080pHD streamed video that's practically indistinguishable from the original, in H.265 at extremely low bit rates.

 

Have you actually watched Netflix streaming in "SuperHD" mode? (that's their marketing for 1080p at the two highest H.264 bit rates they support - the max being something like 5.85mbps). It's not perfect, but it's pretty damned good looking. From normal viewing distances without any network congestion it can look nearly as good as Blu-ray (this is content dependent, of course).

 

-perry

Edited December 18, 2013 by Perry Paolantonio

[Carl Looper]

Yes, the pixel dimensions are not in any way altered by the compression scheme.

 

What is altered is the quality, but by this word "quality" is meant how much of the original image frequencies (sharpness/softness) is retained, rather than what YouTube means when it uses that word. On YouTube they use the term "quality" in relation to pixel dimensions - which can cause confusion when otherwise using the word to mean the visual quality of the compression.

 

An image is composed of a large number of frequencies, from the very soft to the very sharp. It is the sharp frequencies (sharp edges, fine detail, grain) which occupy more bandwidth than the low frequencies (such as a cloudless sky) and are consequently more difficult to compress. And as a result can suffer more in terms of visual quality.

 

So a video encoded at 1080p can end up looking softer than it otherwise should at 1080p. It can end up looking as if it was 720p blown up to 1080p. Or worse.

 

But this depends entirely on image content and how much the image changes from one frame to the next. A video of a perfectly stationary scene (eg. a still photo), will compress far better than a scene in which there is a lot of different motions occuring and a lot of sharp details likewise. The visual quality varies even thought he pixel dimensions don't. In other words it is not the compressor which is doing this - it is the content of the video provided, in relation to a particular compression, that is doing this - and it's independant of the pixel dimensions.

 

This is also why grain is a very real problem because grain has the highest frequencies in an image, is across the entire frame (rather than occupying some small area), and is completely different from one frame to the next. So it is the worst case information for a compressor to deal with.

 

C

Edited December 19, 2013 by Carl Looper

[Anthony Schilling]

I'm not too savvy as to how You-Tube works, but when i post a video to the internet I usually render a separate MP4 to upload. I suspect that larger files get auto squashed by the channel?

[Perry Paolantonio]

I'm not too savvy as to how You-Tube works, but when i post a video to the internet I usually render a separate MP4 to upload. I suspect that larger files get auto squashed by the channel?

 

Count on anything you upload being compressed again by the streaming service (whether it's YouTube or Vimeo). If you start with an already compressed source, you're reducing your chances of a good looking streaming version. If you can upload something that's got less compression (Uncompressed, ProRes, or extremely high bit rate H.264), you're going to get a better result when streamed. (I would avoid H.264/MP4 as a source though, since it's 8 Bit. ProRes is 10 and the upload time isn't too bad on 5mbps upload connection)

 

No matter what you do, they're making a bunch of different files from your uploaded video with different compression levels and different resolutions (always smaller than what you upload). That way, because the player and the server are talking to each other all the time, if the network bogs down they can more or less seamlessly start streaming a degraded version to keep things running without hiccups. Since you can't avoid them making new files from your uploads, it only makes sense to give them the highest quality you can so they're not working off of already compromised footage.

 

It can be painful to upload large files, especially on a slower connection, but it's worth it.

[Peter Woodford]

Hi folks,

Thanks for the tips. And thanks especially to Carl for the very clear explanation.

I'll definitely try ProRes to start (it's always music vids for really short songs so the file size isn't a huge deal for me).

Does anyone have an example of a grainy clip that they uploaded to YouTube using ProRes?

We're working on another vid, this time it's using relatively grainy Tri-X (you can see a few stills: here) so when it's done I imagine it'll be a YouTube SD torture test.

[Josh Gladstone]

Here's a grainy clip. I processed tri-x as a negative so it's even grainier and more contrasty than normal.

[Peter Woodford]

Thanks Josh. Even at 480 the grain looks pretty nice to me. It's a shame how lossy the compression gets for 360 and lower. Love it in HD! Great sound as well.

[Josh Gladstone]

Thank you so much, Peter! That really means a lot!

[David Cunningham]

So, I think I have discovered the solution to getting at least "good" looking Super 8 on youtube.

 

I have been working entirely in 2K from the ScanStation. If I then export to 4K (upres), it tricks youtube into using a higher bit rate expecting a real 4K stream.

 

So, if you upload 4K, and then view "full screen" or in the case it's "fit to screen" at 4K you actually get something that looks pretty close to my 1080p Prores output.

 

 

You need a hefty CPU/Video card to actually get this to play smooth.

 

Dave

[Peter Woodford]

Hi David,

That's a really interesting discovery. I don't think my internet connection is up to the task of streaming 4K but based on stills, it looks like the grain survived really well.

I also tried uploading Prores files to both Youtube and Vimeo and found it helped quite a bit. Long encoding time delay on Youtube though (and much longer upload times natch).

[David Cunningham]

Hi Peter,

 

Yeah, the upload time is definitely killer. And, like you say, the encoding time too.

 

Also, if you are a MAC user, Safari and youtube html5, in anything other than 720p, just don't get along. You'll have to use Chrome (on all platforms) to use HTML5 in 4K which delivers and even better result than flash 4K.

 

It definitely holds up "better" but still looks NOTHING like the Prores 4444 4K file I uploaded. It's very sad that Super 8 cannot truly be experienced over the web.

[David Cunningham]

FYI, HTML5 is way better. But, the grain still blocks up when it gets really heavy.

[Peter Woodford]

That's interesting about HTML5.

According to this: http://stackoverflow.com/questions/5845484/force-html5-youtube-video

you can use the ?html5=1 parameter to 'force' html5 playback on compatible systems. Not sure if it still works (youtube seems to deprecate and change these parameters all the time).

[Peter Woodford]

Hi folks,
Here are the results of my own tests, if anyone is curious.

Screenshots of Vimeo at 720p
my usual compressed upload (I deleted the original file but I believe I used H.264 w/bitrate set to minimum 9Mbps):
https://drive.google.com/file/d/0B-lCRsGpYuimRkJPZUZHRkNxR2M/edit?usp=sharing

prores422(LT) quality=80:
https://drive.google.com/file/d/0B-lCRsGpYuimVkFveS10cHN1YlU/edit?usp=sharing

Screenshots of Youtube SD
my usual compression:
https://drive.google.com/file/d/0B-lCRsGpYuimbHNXWG42Nkw0Tnc/edit?usp=sharing

prores422(LT):
https://drive.google.com/file/d/0B-lCRsGpYuimWlhTQi1wRmFHd0E/edit?usp=sharing

Final ProRes422 at Youtube

Final ProRes422 at Vimeo (HD=720p)

[David Cunningham]

Prores looks way better.... interesting. That's not even a different resolution issue, but a different encoding. Cool.

[Peter Woodford]

Yeah, I definitely think it helped. Vimeo in particular scolded in warning dialog that uploading a file with such a high bitrate could lead to playback issues. I have a lousy Internet connection so I can't really tell the difference. Can anyone tell if it seems to have slower or more stutter-y playback than usual for Vimeo?

[Alessandro Machi]

Yeah, I definitely think it helped. Vimeo in particular scolded in warning dialog that uploading a file with such a high bitrate could lead to playback issues. I have a lousy Internet connection so I can't really tell the difference. Can anyone tell if it seems to have slower or more stutter-y playback than usual for Vimeo?

 

The Vimeo image plays fine here, because it is a very small image I presume. When I clicked on full screen, it turned into a still frame music video, one frame per cut on average.

 

Ever considering viewing your footage on a CRT as well?

[Peter Woodford]

Thanks for checking Alessandro. Do full screen Vimeo vids usually play fine on your system?

What would be the benefit of checking on a CRT (I'm still a bit of a novice)?