[Mp4-tech] Poor H.264 PSNR Results with JM73

[Gary Sullivan]

I think the clue here is the word "mobile".  Are you using this with
some packet loss or data corruption?  The reference software is
primarily intended for the error-free case.
What encoders and decoders do to provide robustness to loss or
corruption of data is outside the scope of the standard.
I don't know what AHM20 is.
-Gary
+> -----Original Message-----
+> From: mp4-tech-bounces lists.mpegif.org 
+> [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of 
+> Michael Igarta
+> Sent: Thursday, October 09, 2023 10:57 PM
+> To: mp4-tech lists.mpegif.org
+> Subject: [Mp4-tech] Poor H.264 PSNR Results with JM73
+> 
+> 
+> Hello,
+> 
+> I am performing some test encodes of mobile CIF (300 frames) using 
+> latest the JM 7.3 reference software.
+> The resulting PSNR settings and visual quality seem much 
+> worse than I 
+> should be getting:
+> 
+> I/P Frame QP=30, B Frame QP = 32: PSNR(Y) = 30.79 dB
+> I/P Frame QP=38, B Frame QP = 40: PSNR(Y) = 25.15 dB
+> I/P Frame QP=46, B Frame QP = 48: PSNR(Y) = 20.22 dB
+> 
+> Using AHM20 with rate control gives me much better numbers.  
+> Can someone 
+> tell me what I am doing wrong with the
+> constant QP?  I changed the following in the default encoder.cfg:
+> 
+> InputFile = "mobile.cif"
+> LastFrameNumber = 299
+> FramesToBeEncoded = 299
+> SourceWidth = 352
+> SourceHeight = 288
+> 
+> 
+> Thanks you very much for any advice.
+> 
+> 
+> 
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