15 votes

How to downsample 4k to 1080p using ffmpeg while maintaining the quality?

Convert 4k to 1080 (no change in codec) ffmpeg -i input4kvid.mp4 -vf scale=1920:1080 -c:a copy output1080vid.mp4 Convert h.264 to h.265 (no change in resolution) ffmpeg -i input.mp4 -c:v libx265 -...
KeshavDulal's user avatar
4 votes
Accepted

Why does 8K have 16 times the pixels compared to 1080p?

First off, 2K is not 1440p, it is 2048 x 1080p. 4K is 4096 x 2160p. (Note that UHD = 3840 x 2160p...4K and UHD are like US and Canadian dollars--they are both dollars, but they have different values....
Michael Tiemann's user avatar
4 votes

Why do cinema cameras cost too much?

Look at it from a data rate point of view: a GH4 records 4K at 100 Mbps. A RED Carbon Fiber WEAPON records at 300MBps. That's 24x the data rate. Look at how very much more expensive it is to ...
Michael Tiemann's user avatar
4 votes
Accepted

What is the origin of 4K term?

According to Wikipedia ,Digital Cinema Initiatives originated the term 2K in 2002 for a digital film format of 2048 x 1080. 2048 is commonly referred to as 2K in the digital world. It logically ...
Michael Tiemann's user avatar
4 votes
Accepted

.mkv file not playing in HEVC/H.265 supported player

Both files that don't play feature Opus as the audio codec. As per this site, Opus is not one of the supported audio codecs. Transcode the audio: ffmpeg -i in.mkv -c:v copy out.mkv
Gyan's user avatar
  • 33.2k
3 votes

Best render settings for broadcast/4k TV

The reason for mastering out to an uncompressed / minimally lossy format is so that you have a master copy, which you can then use to make other copies, without generation loss, or having to re-render....
stib's user avatar
  • 13.7k
3 votes

Tips to start making a little production

The minute you said "no lighting" you violate the premise of "look as professional as it could be and not too amateur". Lighting is not only about ensuring there are enough photons to actually record ...
Michael Tiemann's user avatar
3 votes

Downscaling 4K YUV420 to 1080p YUV444 with ffmpeg introduces red tint

I dug further and after reading the entire topic at Personal View, I found that user willyfan suggested to add in_range=full to both first scale arguments to correct a color shift that he also ...
kdarras's user avatar
  • 161
3 votes
Accepted

How to make Sony Vegas Pro 13 work on a 4K display

There's apparently a hack which alters the Vegas executable to solve this problem. There's a setting of dpiAware in the application manifest which falsely tells Windows that Vegas is DPI aware and ...
Gyan's user avatar
  • 33.2k
3 votes
Accepted

Downscaling 4k to 1080p in Premiere Pro, Image Zooming 2x

Changing the preference doesn't change any clip settings retroactively. But once you have set it, and then create a new project and a new sequence, and when you freshly import your 4K clip and drop ...
Michael Tiemann's user avatar
3 votes
Accepted

DJI Osmo X3 vs Canon 5D Mk III for easier chroma green screen keying

The key to pulling a good key is a clean separation between key and subject. All things being equal, higher resolution will give a sharper edge between key and subject, which is good. But that's ...
Michael Tiemann's user avatar
3 votes

Why do cinema cameras cost too much?

You are probably comparing cameras that record compressed 4k video with cameras that record uncompressed video, i.e. RAW footage. The ARRI ALEXA and RED Epic belong in the latter category. The ...
MoritzLost's user avatar
  • 5,412
3 votes

How should I encode my 4K video stream?

As mentioned by @Mulvya, I think the issue is the "slow" preset. One option is encoding a compressed stream that is also lossless. For example, the x264 encoder can do this using "-preset ultrafast -...
Michael Steinberg's user avatar
3 votes

Why do cinema cameras cost too much?

The image processing of cinema cameras is done with fairly inexpensive FPGA chips, that doesn't explain a 50.000€ price difference between I.e. a gh4 and a arri Alexa. The FPGA chip used in blackmagic ...
Hans Meiser's user avatar
3 votes

Is there a way to upscale without re-encoding?

To get from 1080p to 4K you're going to need to re-encode, but container won't matter (much), so 16bit png is overkill just for the sake of 4K. H.264 works fine. But before you spend the time to ...
Jason Conrad's user avatar
  • 4,504
3 votes

Simulating 1080p pan shot by cropping stationary 4K fisheye footage?

Yes, you can do this successfully. I did it with an overhead 4K action camera with a fixed fisheye lens (YouTube video here). You'll want to remove the distortion in software to "square it up". Then ...
Carl Raymond's user avatar
2 votes

Why do cinema cameras cost too much?

In addition to the points above, keep in mind that cinema cameras also have a host of features not found in cell phones and lower-end cameras, such as removable lenses, better autofocus, better bodies ...
user1118321's user avatar
  • 2,156
2 votes
Accepted

Does it make sense to upgrade my set up to 4K from a (Canon) 70D set up?

It all boils down to "Do you need it" If you are shooting corp promos and your clients keep asking or are insisting on 4K then Yes you can look into it as you can justify the purchase as the work is ...
Adam Mann Pro's user avatar
2 votes

How to capture 4K screens?

As you know there are two solutions, one using your CPU, the other a dedicated GPU. CPU Solution As of today, the CPU solution exit for 4K content, at 60 fps, using x265 or x264 codec. x264 is ...
RawBean's user avatar
  • 163
2 votes
Accepted

Tips to start making a little production

Story Your film needs drama. That is normally created by conflict or tension. Keep the story simple. It is better for your first film to be too simple than too ambitious. But it must have drama. Shot ...
paulzag's user avatar
  • 308
2 votes

GoPro Hero 5 Session camera for long shot (crowd shot)

Yes, useful for wide crowd shots. Yes, you can crop down/scale up 1080p selections from the 4K to simulate additional camera angles. Consider using the gopro app or a wifi remote to stop/start the ...
alexh's user avatar
  • 703
2 votes

The 4k videos from Sony a7iii are quite large by default, suggestions on HQ ways to compress?

Well first, the a7iii at 100mbps is far from lossless or even minimally lossless. It's highly compressed in a 4:2:0 or 4:2:2 colorspace depending on your recording selection. The files are incredibly ...
McFlySoHigh's user avatar
  • 2,487
2 votes
Accepted

Is 4K 4.2.0 just HD 4.4.4

4:2:0 means that only the colour information is subsampled. So while that the colour is at a lower resolution the brightness information is at full resolution. This works because human vision is more ...
stib's user avatar
  • 13.7k
2 votes

Why is 4K downsampled so much better than 1080p at low bitrates?

First let me explain chroma subsampling, as this is the reason why 4k -> 1080p always looks better than native 1080p Consumer & pro-sumer camera gear, anything not super high end, cuts some ...
TravisO's user avatar
  • 153
1 vote

Can upconverting 1080p videos on 4k TVs, lower their quality?

Upsample by an integer ratio can be completely blameless, just repeating pixels and lines gets it done, no new information, and you get only the original resolution displayed, but no losses either. ...
Dan Mills's user avatar
  • 211
1 vote

Editing 4k footage in 1080p project and rendering in 4k?

To expand on @Dul32's answer: Below is the settings dialog for a new sequence. The settings for the preview (what you see when you're editing) are at the bottom, the actual pixels settings for the ...
stib's user avatar
  • 13.7k
1 vote

Editing 4k footage in 1080p project and rendering in 4k?

There is two option at sequence setting. Video and video previews. If the video set 4k, and the video previews set 1080, i shoud not be downscale at rendering.
Dul32's user avatar
  • 21
1 vote

Recording 4K H.264 from HDMI to External Media

Would you consider using a computer equipped with a 4K HDMI capture card like BlackMagic Intensity Pro 4K, to write to that SD card? This will be cheaper than buying a recorder and you will have full ...
Tony Sepia's user avatar
1 vote

GoPro Hero 5 Session camera for long shot (crowd shot)

Whatever camera you go with, keep in mind that 4K sensors run hot. I would run tests, under above normal room temps, you will likely want to run a small fan over the camera, overheating will shut it ...
McFlySoHigh's user avatar
  • 2,487
1 vote

Where can one find a current and definitive reference for video quality as it pertains to hosting HTML5 Videos?

What could do is show that Youtube transcodes to 4K at bitrates of ~20 mbps. You can use a tool like youtube-dl to check. Run youtube-dl -F URL So, your upload and download times will increase by a ...
Gyan's user avatar
  • 33.2k

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