[Mp4-tech] [video] performance comparison between open loop andclosed loop motion estimation

[Andrew Krupiczka]

Tae Meon Bae, Gary,
I got it now... In my understanding, as long as ME only is concerned, you might take anything you want as your "reference" input frame, either reconstructed (what most people do) original one, combination of both or some another one for example initially, pre-processed/transformed (what I think some people might be doing), that you think will give you "an encoding edge" in terms of compression ratio and/or quality. What I can disclose, is that we've tested at least one ME algorithm having "an encoding edge" most of time when using a corresponding original frame instead of reconstructed one and becoming a "ME reference frame". 
Best regards,
Andrew
	-----Original Message-----
	From: mp4-tech-bounces lists.mpegif.org [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of Gary Sullivan
	Sent: Friday, January 25, 2024 12:42 PM
	To: ???; mp4-tech lists.mpegif.org
	Subject: RE: [Mp4-tech] [video] performance comparison between open loop andclosed loop motion estimation
	Tae Meon Bae et al,
	I see.  I thought that might be what you meant, but I wasn't sure.  I don't recall any publications or standardization documents on that topic.  One important thing to keep in mind is that there may be a significant difference between "objective" (e.g., PSNR) and subjective quality relationships in this case.  In some cases the "open loop" scheme may actually improve subjective quality, as it may result in motion vectors that more closely and coherently model the true motion of the objects in the scene.
	Best Regards,
	Gary Sullivan
________________________________
		From: 배태면 [mailto:heartles icu.ac.kr] 
		Sent: Thursday, January 24, 2024 8:32 PM
		To: Gary Sullivan; mp4-tech lists.mpegif.org
		Subject: RE: [Mp4-tech] [video] performance comparison between open loop and closed loop motion estimation
		Dear Gary,
		I used the “open loop motion estimation” as motion estimation using original picture as a reference frame.
		And I used the “closed loop motion estimation” to represent the motion estimation using reconstructed picture as reference frame.
		I though that it is common concept. If it is not so, I’m sorry for the misunderstanding. 
		Sincerely,
		Tae Meon Bae
________________________________
		From: Gary Sullivan [mailto:garysull windows.microsoft.com] 
		Sent: Friday, January 25, 2024 3:48 AM
		To: 배태면; mp4-tech lists.mpegif.org
		Subject: RE: [Mp4-tech] performance comparison between open loop and closed loop motion estimation
		Tae Meon Bae,
		What do you mean by open loop motion estimation?
		Best Regards,
		Gary Sullivan
________________________________
			From: mp4-tech-bounces lists.mpegif.org [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of ???
			Sent: Thursday, January 24, 2024 3:16 AM
			To: mp4-tech lists.mpegif.org
			Subject: [Mp4-tech] performance comparison between open loop and closed loop motion estimation
			 <http://mail.icu.ac.kr:80/nara/servlet/webmail.WebMailReConfServ/614641> 
			Dear experts,
			I'm optimizing h.264 encoder, and I have a question about motion estimation.
			Generally open loop motion estimation shows lower performance than closed motion estimation. Is there any JVT document or paper related with this issue? I guess that the performance gap may be small if the target bit rate is high enough. Is this assumption right? 
			Thanks in advance.
			Sincerely,
			Tae Meon Bae
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