will there be quality loss

[cns00]

if i shrink the file size of a 720p movie by using handbrake then there will be quality loss. if i convert a 1080p movie to a 720p movie by using handbrake then there will be quality loss. by quality loss i mean that part of the background will become blurry

i have some 4k 2160p movies that i need to convert to 720p without having any quality loss. i saw https://www.youtube.com/watch?v=C-R2egmc-MI and it said that i can convert the video resolution without losing quality by using wondershare uniconvertor. is this really true or no and it's just an advertisement?

if it's not true then is it possible to convert from 2160p to 720p without any quality loss?

[exekutive]

without any quality loss?

Impossible.

1st of all , you are down-sampling. You're throwing away pixels. It's like recording a Blueray onto VHS. Of course there will be quality loss.
2nd, you are transcoding. Anytime you do that, you are throwing away information. There will ALWAYS be quality loss (but you can minimize so as to be imperceptible)

[jagabo]

I took a list of 9 numbers and reduced it these three: 129 67 160 (similar to reducing 2160p to 720p). What where the original 9 numbers?

[Cornucopia]

without any quality loss?

Impossible.

1st of all , you are down-sampling. You're throwing away pixels. It's like recording a Blueray onto VHS. Of course there will be quality loss.
2nd, you are transcoding. Anytime you do that, you are throwing away information. There will ALWAYS be quality loss (but you can minimize so as to be imperceptible)

To clarify: it doesn't matter if you are downsampling or upsampling, as BOTH throw away some/most of the original numbers, and BOTH make guesses on the new numbers. Smarter algorithms may mean more educated guesses which means closer to possible truth, but none are exactly right, which means there is loss.

Also, transcoding to a LOSSY format will lose quality. Lossless formats do not, when transcoding. So "uncompressed ->lagarith->huffyuv->utvideo->uncompressed->magicyuv" might be lossless, assuming no other conversions are happening (color space & color subsampling conversions almost ALWAYS lose quality, and some of those happen behind the scenes so people often do not fully realize it).


Scott

[VoodooFX]

if i shrink the file size of a 720p movie by using handbrake then there will be quality loss. if i convert a 1080p movie to a 720p movie by using handbrake then there will be quality loss. by quality loss i mean that part of the background will become blurry

i have some 4k 2160p movies that i need to convert to 720p without having any quality loss. i saw https://www.youtube.com/watch?v=C-R2egmc-MI and it said that i can convert the video resolution without losing quality by using wondershare uniconvertor. is this really true or no and it's just an advertisement?

if it's not true then is it possible to convert from 2160p to 720p without any quality loss?

If your monitor is ~"720p" then you'll not see any quality loss. Anyway, Handbrake would produce better quality encode than that wondercrapshare.