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MSU Video Codecs Comparison. Frequently Asked QuestionsMSU Graphics & Media Lab (Video Group)
Frequently Asked Questions
Q: Why do you use exactly PSNR metric in the comparison?
A: There are several important reasons for it:
- First, PSNR is THE ONLY GENERALLY ACCEPTED metric nowadays used for codecs comparison. To become certain of that you may look through any scientific articles or drafts of the new standards (H.264, for example). So using PSNR measures provides clear and unique interpretation by any professional in the codecs scope. Actually we use special non-standard metrics in our researches. Moreover we create metrics ourselves. But if we presented all the measures in some "MSU metric-3" it would far not improve clearness and value of the comparison.
- Second, along with having several drawbacks PSNR can be calculated rather quickly. This is very essential, because all other metrics that more or less reflect visual perception need much more time for calculation (up to dozens of times more). We've spent 11 days to perform all the calculations for the first test using PSNR and we are not ready yet to spend something like 110 days on it :) Of course it is possible to reduce the number of the testing video sequences but it would make the adequacy of the estimation worse.
Q: Why don't you consider some certain types of video in the comparison?
A: We haven't had time to do it yet. Till this moment we've covered with tests only different types of DVD ripped movies and have left animation and video received from tuner without attention. We'll try to increase the variety of tested videos if we find time and free computers to perform calculations.
Q: You've mistakes in the comparison!
A: Yes, this could have happened. Please be so kind and report about them to ! We'll appreciate it a lot.
Q: You should have performed the comparison in another way!
A: Your approach might also make sense, but we don't have a possibility now to implement it. Try doing it yourself! We can even place your results on our site if they prove to be good.
Q: There are some graphs for some sequences in the comparison but there are no same graphs for another sequence. Can I somehow get to see them?
A: Alas, if we had placed graphs for ALL the measures that we had done for the comparison, we would have got a difficult-to-read 1000-paged document. That's why we used only a subset of all the graphs in the comparison. But we have all of them in our laboratory and we can share them and other additional information that hasn't been included in the comparison with those people who in their turn help us. These are, for example, the companies that had provided their codecs for the testing or people who have sent a lot of remarks. We won't be sending anything for nothing, we have no time for it! We are busy working on the new projects and performing new tests.
Q: Why being dated September 2004 did the first test appear much later?
A: The first test contained too much information and it took us long to study the results, and to choose what to include in the final document. However we're going to release further results with some delay as well. But this time the reason will be different: we want to give companies that have provided us with their codecs a chance to fix bugs that we find in the codecs during the testing. (We find bugs rather frequently during the testing and report about them to the codec's producer.)
Q: It's all clear to me, you've described all the codecs in details, thanks a lot! But which codec is the best after all?
A: Thanks for your warm words :) But the question "what codec is the best" is not correct and the comparison clearly illustrates this fact. Different codecs with different settings provide best results for different type of video. There are no any universal codecs that would outperform all other codecs for any given video sequence. We propose just a detailed report of the testing which other companies usually provide only for money. All the conclusions you should make yourself.
MSU video codecs comparisons resources:
- Introduction to Video Codecs Comparison
- Lossless Video Codecs Comparison 2004 (October 2004)
- MPEG-4 SP/ASP Video Codecs Comparison (March 2005)
- JPEG 2000 Image Codecs Comparison (September 2005)
- First Annual MPEG-4 AVC/ H.264 Video Codecs Comparison (January 2005)
- Second Annual MPEG-4 AVC/H.264 Video Codec Comparison (December 2005)
- Subjective Comparison of Modern Video Codecs (February 2006)
- MPEG-2 Video Decoders Comparison (May 2006)
- WMP and JPEG2000 Comparison (October 2006)
- Third Annual MPEG-4 AVC/H.264 Comparison (December 2006) (All versions for free!)
- Lossless Video Codecs Comparison 2007 (March 2007)
- Fourth Annual MPEG-4 AVC/H.264 Comparison (December 2007) (All versions for free!)
- Options Analysis of MPEG-4 AVC/H.264 Codec x264 (December 2008)
- Fifth MPEG-4 AVC/H.264 Comparison (May 2009) (All versions for free!)
- Sixth MPEG-4 AVC/H.264 Comparison (May 2010)
- Seventh MPEG-4 AVC/H.264 Comparison (May 2011)
- Eighth MPEG-4 AVC/H.264 Comparison (May 2012)
- Ninth MPEG-4 AVC/H.264 Comparison (Dec 2013)
- Tenth Video Codec Comparison (HEVC) (Oct 2015)
- Eleventh Video Codec Comparison (HEVC) (Aug 2016)
- Twelfth Video Codec Comparison (HEVC) (Aug 2017)
- Thirteen Video Codec Comparison (HEVC) (Aug 2018)
- Fourteen Video Codec Comparison (HEVC) (Sept 2019)
- Cloud Encoding Servoces Comparison 2019 (Dec 2019)
- Fifteen Video Codec Comparison (HEVC) (Dec 2020)
- Codec Analysis for Companies:
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Project sponsored by YUVsoft Corp.
Project supported by MSU Graphics & Media Lab