How do you lose quality when upscaling?.

[Felow]

Obsolete

[manono]

Filtering requires a reencode. Resizing is filtering. Reencoding degrades the quality unless you're reencoding using a lossless codec. You're not using a lossless codec. Therefore, upscaling, no matter how well you do it, degrades the video quality. It may or may not be noticeable, depending on how well you upscale and reencode.

I don't know if those you 'heard' saying that meant it the way I outlined it or not. I upscale from time to time myself.

[poisondeathray]

I've heard that you lose video quality when you upscale a video... I don't understand how, aren't you basically just stretching it the same way a media player would do? It's not like you're lowering bitrate.

You're usually re-encoding with lossy encoding when you upscale a video = some quality loss by definition

But upscaling is generally worse, because you need an even higher bitrate to achieve a given level of quality as compared to a re-encode of the same dimensions. It's not exactly like this; but a simple way to think of it is a given number of bits is spread over a larger area (larger dimensions) . So the image quality would be worse for a given bitrate when you upscale

If you're filtering, however, or using some exotic methods like neural network processing - then you might be able to increase subjective quality

[Felow]

I see, thanks for the clarification. I do upscale videos regularly to merge them with higher resolution videos so it's good to know.