[Mp4-tech] [H.264] I_PCM mode available in all profiles?

[Gary Sullivan]

See below: 
+> -----Original Message-----
+> From: mp4-tech-bounces lists.mpegif.org 
+> [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of 
+> Fredrik Claesson
+> Sent: Wednesday, April 06, 2024 6:17 PM
+> To: mp4-tech lists.mpegif.org
+> Subject: [Mp4-tech] [H.264] I_PCM mode available in all profiles?
+> 
+> Dear Experts,
+> 
+> Is the I_PCM mode available in all profiles?
Yes.
+> 
+> It was my understanding that the I_PCM mode was part of the Fidelity
+> Range Extensions, and available only for the High 4:4:4 
+> Profile, as was
+> presented in "The H.264/AVC Advanced Video Coding Standard: 
+> Overview and
+> Introduction to the Fidelity Range Extensions" (Sullivan, Topiwala,
+> Luthra), SPIE Conference XXVII, August 2004, chapter 2.1.6.
You need to read what that paper was saying more carefully.  I apologize
if our writing style was confusing.
That section of the paper says that the "standard includes a PCM
macroblock mode... However, the PCM mode is clearly not efficient ...
When developing the FRExt amendment, it was decided that a more
effective means of lossless coding was desirable...  FRExt therefore
also includes a transform-bypass lossless mode which uses prediction and
entropy coding for encoding sample values.  When this mode is enabled
(which can only be in Hi444P use), the meaning of the smallest
selectable value of the quantization parameter is redefined to invoke
the lossless coding operation.  The new lossless mode of FRExt is a
fairly efficient lossless video coder..."
In other words, the original profiles had I_PCM already.  FRExt High
4:4:4 profile adds something new in addition to that.  The new thing is
called transform-bypass lossless mode (at least by me).
Best Regards,
Gary Sullivan
+> 
+> However, according to the latest Rec. H.264 draft, chapter 0.6, the
+> following added paragraph seems to indicate that the I_PCM mode is
+> available in all profiles: "With the exception of the 
+> transform bypass
+> mode of operation for lossless coding in the High 4:4:4 
+> profile and the
+> I_PCM mode of operation in all profiles..."
+> 
+> Best Regards,
+> 
+> Fredrik Claesson
+> 
+> _______________________________________________
+> NOTE: Please use clear subject lines for your posts. Include 
+> [audio, [video], [systems], [general] or another 
+> apppropriate identifier to indicate the type of question you have.
+> 
+> Note: Conduct on the mailing list is subject to the 
+> Antitrust guidelines found at 
+> http://www.mpegif.org/public/documents/vault/mp-out-30042-Ant
+> itrust.php
+>