objective software?

[vrpatilisl]

hi
Is there any software to measure the loss of quality in the output MKV/MP4.
Consider i converted dvd to mkv with megui. I want to measure the quality diff.between Input dvd and output Mkv.
Thanxs

[Taurus]

Every transcode/encode from a lossy source to a lossy format is doing harm to the original.
The only "objective" measure is a "subjective" one by eyesight :D.
There are some tools floating around which promise to do this on some mathematical assumptions.
But I dont use them. Even forgot the names of them.
Some websites are doing frame compares (russian?)

Do your own tests by eysight and use a good video monitor :D
Make a lot of snippets at different resolutions/bitrates/complexity
and you will get a sense of the look and feel of the different encoders.
No more numbers, sheer reality.
Sorry if this sounds a little bit sarcastic,
but for years at this forum every now and than people are claiming
they found the sweet spot for their encodes by SSIM comparions. Drives me nuts.

[Groucho2004]

I basically agree with Taurus, your eyes are the best instruments. If you really want to measure something try this:
http://avisynth.org/mediawiki/Compare

[LoRd_MuldeR]

Various "objective" quality metrics have been proposed, but none of these perfectly predicts the "subjective" quality, as perceived by a human viewer.

They all have their "pros" and "cons". Some are more useful as an overall quality indicator, some are less useful (or even misleading).

And most important: Basically all quality metrics that I am aware of assume the original source to be "perfect" quality and measure quality-loss as "error" between original and compressed video.

That's why these metrics get fooled by "Psy" optimizations, as implemented in x264: While Psy-optimizations can greatly improve the perceived quality, they'll hurt the metrics.


You'll find an overview about existing video quality metrics here:
https://ece.uwaterloo.ca/~z70wang/publications/SPM09.pdf

[setarip_old]

The authors of MakeMKV state that the streams contained in the .MKVs it makes from either DVDs or Blu-rays are bit-for-bit identical to those of the original discs...

[LoRd_MuldeR]

The authors of MakeMKV state that the streams contained in the .MKVs it makes from either DVDs or Blu-rays are bit-for-bit identical to those of the original discs...

Well, that applies to all tools that just rip and re-mux the streams without actually re-encoding them.

There's nothing to compare, quality-wise, in that case.

The OP, however, says that he is using MeGUI and wants to evaluate the quality of his encodes...

[vrpatilisl]

what you experianced guys think when 1 want to get transperant dvd rips which is better Make mkv(mpeg 2 container ) or crf 18 encoding in Megui or handbreak with x264 . Please dont consider size. Size is always low in h.264.

[hello_hello]

As far as I know MakeMKV doesn't re-encode, it just extracts the DVD contents and puts it into an MKV container. From that point of view you can't get better quality as it's the original video.
Of course if you want to crop the video then the only practical option is to re-encode it, in which case anamorphic encoding using a CRF value of 18 is a pretty good option. I use MeGUI myself.

[LoRd_MuldeR]

Please dont consider size. Size is always low in h.264.

Nope. As in every video format, the size directly depends on the chosen bitrate! High bitrate h.264 can produce the same size as any other video format. Make an CRF=2 encode and you'll see ;)

Though what you mean probably is: As h.264 (and x264 in particular) compresses more efficient than "older" formats, you usually will be able to get away with a lower bitrate (for the same quality) and thus with a smaller total file size.

Anyway, as MakeMKV does not re-encode, you won't get h.264 in output from a Video-DVD. It just wraps the existing MPEG-2 streams, that are found on the Video-DVD, into an MKV container. That's it!

And, as hello_hello said, you can't get a better quality than the original. Re-encoding can only hurt quality, it can never* improve quality! At best, re-encoding doesn't hurt the quality in a noticeably way (aka "transparent quality").

__________________
(*) There is one exception tough: In case your source video suffers from a specific "defect", you may be able to "repair" that specific defect with suitable filters, e.g. in Avisynth, and thus improve the quality. Such processing implies re-encoding, of course.