Getting 4k video from the Sony a6000

At an end result, can you actually have 4k video from the Sony a6000?

The Sony a6000 in XAVC S format records 1080p video at a bitrate of 50 Mbps. It cannot do 4k, however is 50 Mbps enough video data to upscale to 4k?

Using FFmpeg and the upscale parameters i gave it a go.

My source video file was

Bitrate: 51,344 kb/s size: 756MB video settings: 1080p 30fps

This was taken with the A6000 and the Sigma 16mm f/1.4 lens.

I upscaled the source footage to 4k using the 3 main sampling methods which are:

  • Bilinear
  • Bicubic
  • Lanczos
bilinear time: 414.612s Bitrate: 28231.7kbit/s Speed: 0.347x
lanczos  time: 391.033s Bitrate: 32241.0kbit/s Speed: 0.372x
bicubic  time: 420.894s Bitrate: 31330.9kbit/s Speed: 0.343x

The FFmpeg command used was

ffmpeg -i input.mp4 -vf scale=3840x2560:flags=METHOD output.mp4

In a comparison video i used the Lanczos file because the lanczos method combines sharpness with smoothness to make the footage look better overall, Avoiding blocky footage from over sharpening. Its a popular choice.

1080p up to 4k

Looking at the screenshots below i found that upscaling the clip in FFmpeg did infact make it appear sharper than just a regular Premiere Pro upscale to 4k. The blades of grass look a little bit softer in the upscaled source as does the palm fronds.

Upscaling with a dedicated video software library (FFmpeg) instead of doing it in Premiere Pro which at the same time is encoding it, makes a lot more sense.

Obviously upscaling takes time and computing power but if you want some more “realistic” 4k than a PP upscale it is the way to go and does seem somewhat authentic.

Examples

Here is a video sample with screenshots below:

Screenshots from FFmpeg

C0405 source 1
C0405 source 1
C0405 lanczos 1
C0405 lanczos 1
C0405 bilinear 1
C0405 bilinear 1
C0405 bicubic 1
C0405 bicubic 1
C0405 source 2
C0405 source 2
C0405 lanczos 2
C0405 lanczos 2
C0405 bilinear 2
C0405 bilinear 2
C0405 bicubic 2
C0405 bicubic 2
C0406 source 3
C0406 source 3
C0406 lanczos 3
C0406 lanczos 3
C0406 bilinear 3
C0406 bilinear 3
C0406 bicubic 3
C0406 bicubic 3

Screenshots from Premiere Pro with crop

source 3
source 3
lancoz 3
lancoz 3
bicubic 3
bicubic 3
bilinear 3
bilinear 3
source 2
source 2
lancoz 2
lancoz 2
bicubic 2
bicubic 2
bilinear 2
bilinear 2
source 1
source 1
lancoz 1
lancoz 1
bilinear 1
bilinear 1
bicubic 1
bicubic 1