Question about 10bit and bit rate.

[NunoMCastro]

Hello there. I know this isn't about Premiere Pro specificaly, but it's about video editing and rendering, so, can someone please help me? 

So, during confinement we had to start working somehow and luckily my wife job can be done remotely using a video platform (fitness professional). So we started to record her doing her classes and trainings.

Since I'm at home without anything to do I started to try to up a bit the video quality of her recordings and started to research about it (my job has nothing to do with video). But that research lead to sooo many questions.... 

I have a camera that can record h.264 or Hevc at 8 or 10bit.

The place has great lightning (its indoors, but I can use the lowest iso and the double shutter speed with no problem) and it's a white wall with some color and lights at the sides. But not that so much color.

So my first question is... 1) Is it worthy to record at 10bit? I mean, the camera is static and there is not that much color in the scene. And is there any point of recording in 10bit, and then export from the video editing program in 8bit?

Plus, I would like to record in hevc because files in h.264 and 4k can get massive and storage will become a problem in the near future. But, the video platform she uses advises to use h.264 (it accepts hevc as well, but it advises the older one). So, 2) should I render the files in h.264 even if they are recorded in hevc?
That raises two questions...

3) If I lower the bitrate when recording in Hevc, how does the ramping up of bitrate when converting to h.264 works? Will the video be limited to the hevc bitrate? Because the point of me using hevc is to have smaller files, so, lower bitrate... But h.264 needs a higher bit rate...

Thank you for all your help and I'm so sorry if those are very basic questions...

[chrisw44157881]

10 bit can hold more dynamic range and enables more grading refinements without as many artifacts. You can live without it if you use color profiles in the camera that don't stretch outside 8 bit color and your shooting inside 11 stops dynamic range. just make sure you white balance perfectly because there's less room to fix white balance in 8 bit in post.

h.264 and h.265 are just containers. they don't specify resolution, bit depth, bit rate. chroma sub-sampling etc.

I don't know what you mean but rendering in h.264 from HEVC sources. What are you trying to accomplish? smoother editing or smaller files sizes? You can use prores proxies to edit smooth and then premiere will render the native file upon export with zero generation loss.

It would be up to the cloud how it re-encodes your video. They all have a FAQ that says recommended encoding upload filetypes and resolutions. And it's not like you're working in a black box. Just upload 10 sec. of each and choose the best looking one. Usually its Prores anyway, it handles re-compression a lot better.

[NunoMCastro]

Thank you for your reply. 

As you can see, my knowledge on this matter is very sparse. 

As for the part of rendering in h.264 from hevc... If i record in hevc (so i can have smaller initial files) and then render the file in premiere pro (after editing it) in h.264 to be more compatible with the platform she uses, will I have some problem with the final product? Like loss of quality. I honestly don't understand very well how bit rates work, but when i record in hevc the bit rate is lower when compared to h.264. For example, lets say the video recorded in hevc is 40mbps... And when exporting in Premiere Pro to h.264 I use 60mbps. How does that 20mbps difference works? It's irrelevant? Or the h.264 file will be limited to the initial 40mbps? 

I will research the Prores suggestion you gave. Thank you. 

[chrisw44157881]

afaik, premiere doesn't let you choose the chroma subsampling. i think its default 4:2:0 for h.264. so your first impression would be to match the bitrate and that may get you close, but its doing a little lossy compression even with the same bitrate so you always want to go a little higher with exports like +20%. prores seems to show less artifacts overall, but its still lossy compression. you just don't see it.

[Andy 1968]

HEVC uses h.264/265 video codecs. Some h.264/265 codecs are hard to playback, even on a 24 core CPU.

[NunoMCastro]

Well... So far my computer is handling it well... To render a 40'ish minutes video it takes about 50 minutes. What I notice is that when Media Encoder reaches 100% it stays there lots of time. 

[Andy 1968]

You are probably are not editing one of the harder variations of H.264/265. H.264/265 can be 8 bit, 10 bit and even 12bith with 4:1:1, 4:2:2, :4:4:4; and 4:2:0 chroma sub sampling methods. Some variations of H.264 are supper easy to edit. Same with Pro Res. Some Pro Res files are hard to playback but then again some are easy.

[R Neil Haugen]

For control of final images, it's best to record in the highest bit-depth and bitrate you can. Within reason, of course. For your needs, you don't need a 12-bit file at 300Mbps ...  😉

But I would still suggest recording in 10-bit and a higher quality setting on the camera ... pretty good bitrate.

Then it's easy to do your corrections, and when you export to a compressed 8-bit H.264 files, it will still look great.  And I do know people who look at their projects, go "This will never need re-doing" ... keep the 'master' final export and dump the originals. Shocking yes, but ... some do!

Either that or dump the export once delivered as they have the originals and project therefore can re-export over the next couple years if needed.

Neil

[NunoMCastro]

Thank you for your help. 

Normally i keep everything. 😄 That's why I'm afraid that storage it will become a problem in the near future. She is recording 24 classes every month plus a lot of individual exercises for her Personal Training clients. Thats something like 16-17 hours of video per month. At 4K and high bitrate it will consume my 2 x 4TB external drives in a few months. That's why i was thinking of recording in HEVC and lower bitrate when compared to H.264. Because in H.264 and around 130mbps, im getting around 1GB per minute. But i can get that down to around 500MB per minute in HEVC with similar quality. Thats a huge difference in storage. 

My fear was that if i'm recording in, lets say 50 mbps in HEVC and then, when exporting at 70mbps in H.264, from where those 20mbps come from? Or that is irrelevant? If the initial video is capped at 50mbps, how can he then transmit 70mbps in H.264?

[Steve Griffiths · Accepted solution]

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@NunoMCastro wrote:

So my first question is... 1) Is it worthy to record at 10bit? I mean, the camera is static and there is not that much color in the scene. And is there any point of recording in 10bit, and then export from the video editing program in 8bit?

I would suggest that, yes it's worthy to record in 10bit. A static camera and white wall with some colour at 8 bit is going to show some 'banding' in any shading on the wall. 10 bit will not exhibit this. 

Plus, I would like to record in hevc because files in h.264 and 4k can get massive and storage will become a problem in the near future. But, the video platform she uses advises to use h.264 (it accepts hevc as well, but it advises the older one). So, 2) should I render the files in h.264 even if they are recorded in hevc?

HEVC (H.265) is an encoding fomat that provides 'as good' image quality at lower datarates than H.264 ... so you can either get better image quality at the 'same datarate' (compared to an older codec) or the 'same/similar image quality at lower datarates' than H.264.

The downside is HEVC requires more processing power to work with. It *may* strain your system i.e. choppy playback while editing ... or not, depending on your system.

Should you export/encode to HEVC for the host platform, possibly - might be worth experimenting and see if there are any issues.

That raises two questions...

3) If I lower the bitrate when recording in Hevc, how does the ramping up of bitrate when converting to h.264 works? Will the video be limited to the hevc bitrate? Because the point of me using hevc is to have smaller files, so, lower bitrate... But h.264 needs a higher bit rate...

When (and 'if') encoding/exporting H.264 you will need to use a higher datarate than your original footage was shot at to maintain the same quality. How much higher will likely be trial and error. 15Mbps may be enough (for HD) and you might get away with anything down to about 10Mbps (for HD), considering this is a fairly static camera to encode. And no the original HEVC recording datarate will not constrain your H.264 datarate ... you can set your H.264 datarate to whatever looks good (though likely a higher datarate than your original HEVC).

Are you outputting/uploading HD or 4K? 4K will need higher datarates than HD.

As others have pointed out - your uploads may be recompressed by the host system - so it's important to review how they look playing back on the host system and adjust your export encoding datarates to suit.

Thank you for all your help and I'm so sorry if those are very basic questions...

Not basic at all!

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[NunoMCastro]

Thank you very much for the help. 

I think i will record in 10bit. If there is nothing shady happening when compressing to 8bit I have nothing to lose. 
I'm a photographer and the more shades of colors i can get from my raw images the better, so i guess that applies here as well. 😄 

"HEVC (H.265) is an encoding fomat that provides 'as good' image quality at lower datarates than H.264 ... so you can either get better image quality at the 'same datarate' (compared to an older codec) or the 'same/similar image quality at lower datarates' than H.264.

The downside is HEVC requires more processing power to work with. It *may* strain your system i.e. choppy playback while editing ... or not, depending on your system.

Should you export/encode to HEVC for the host platform, possibly - might be worth experimenting and see if there are any issues."

I tried to upload a few 1 minute videos with different setting and in both h.264 and HEVC and it worked just fine. I noticed that with HEVC and 10bit the image is slightly darker, but that could be the color space? 

If the only problem is getting a bit darker, i can live with that and work intirely in HEVC. 


Oh and I'm recording and publishing in 4K. If i record in H.264 i can go up to around 150mbps, but i don't know why, the camera keeps the bitrate at 130'ish if i record inside without my colors or contrast. If i record in HEVC i can get the same quality (at least i dont see any difference) arou 50-60mbps. Thats a huge space saves. Because she is recording about 17 hours of videos per month. 

Again, thank you for your help. 

[R Neil Haugen]

Most screens your stuff will be viewed on are actually only 8-bit. So delivering in 8-bit is normally ok, it's the bitrate you want to keep relatively high for better quality. But past X point, the streaming service dumps bitrate. How do you figure this out? Test. Does it make a difference after uploading when viewing on things from large TVs to phones ... ?

Neil