Video quality/snr

[mikehunt69]

Is there some tool that can analyse a given video file and give some quantitative measure of the resolution?

E.g., a 1080p video can have less resolvable detail than a 720p video.


Can this be determined in some way by some tool, with a view to determining the best resolution for the file?

[yoda313]

Are you referring to bitrate? That is essentially what you are driving at I think.

In general with everything else being equal a video with a higher bitrate will look better than the same video at a lower bitrate. Again with all variables being the same except bitrate.

In this case you can use mediainfo to get technical specs of the video file itself.

[mikehunt69]

No not really the bitrate. You can take a DVD, run it through handbrake at the highest possible quality settings, and the bit rate will increase, but the quality won't.

Like, if you scan an old movie recorded on high-quality film on a cheap film scanner at 1080p, and then release at 1080p, then that's going to give you an inferior result to scanning the movie on the best film scanner at 4k and transcoding to 1080p.


You can see comparisons of dvds of the same movie, and some are way more detailed than others.

[yoda313]

You can see comparisons of dvds of the same movie, and some are way more detailed than others.

I think now you are talking about restorations and the like.

They did that with the James Bond movies. The first "special edition" dvds of the original movies weren't that great looking. But they rereleased them after remastering them. Then they came out with the blurays that look that much better.

In that case you can only tell by the release edition not some quantative measure.

Garbage in garbage out.

There has to be a good source involved in order to get a good product out. Or else it has to be professionally and painstakenly remastered frame by frame.

[Brad]

Theory-wise: Modulation Transfer Function (MTF). For some reason this appears to be the closest Wikipedia article: http://en.wikipedia.org/wiki/Optical_transfer_function

[mikehunt69]

Does this tool do this?

http://compression.ru/video/quality_measure/vqmt_download_en.html

[poisondeathray]

Does this tool do this?

http://compression.ru/video/quality_measure/vqmt_download_en.html

Not really - It's one type of objective "quality" measure used in video (the free MSU version offers PSNR, SSIM, a few others) , but you need a reference SOURCE version to compare it with.

eg. if you have a DVD source, and you do an encode in handbrake, you can measure the handbrake encode compared to the orginal DVD source

There aren't any objective reliable or accurate measures in video that measure "effective lines of resolution" , and the "objective quality" measures such as SSIM, PSNR, typically used in video are questionable and problematic (there is only a moderate correlation with the human perception of "quality" )