[Mp4-tech] Timing question

[Gary Sullivan]

I'm not sure you would really want to hear my advice about what to do with platform-specific Mac environment issues.   :-)
Maybe you should get that advice from Dave Singer, who is also on this list.
Best Regards,
Gary Sullivan
+> -----Original Message-----
+> From: Nicolas El Hani [mailto:nicolas505 hotmail.com]
+> Sent: Wednesday, January 23, 2024 8:47 PM
+> To: Gary Sullivan; Ram; mp4-tech lists.mpegif.org
+> Subject: RE: [Mp4-tech] Timing question
+>
+>
+> Thank you so much, so basically it is a good idea to with
+> anything else than baseline, and you really suggest me to go
+> with "high" rather than "main". As I'm a Mac User and do a
+> lot of my work on Final Cut and encode in Quicktime Pro, I
+> have my two (last) questions hopefully!
+>
+> 1. Is there a difference between h.264 in a .mp4 container
+> or a .mov container?
+> 2. Quicktime Pro allows us to export only with the baseline
+> or main profile, what program would you recommend for a Mac
+> to be able to encode in the "high" profile?
+>
+> Thank you so so much for all your help!
+>
+> Nick
+>
+> ----------------------------------------
+> > From: garysull windows.microsoft.com
+> > To: nicolas505 hotmail.com; rramani gmail.com;
+> mp4-tech lists.mpegif.org
+> > Date: Wed, 23 Jan 2024 14:29:14 -0800
+> > Subject: RE: [Mp4-tech] Timing question
+> > CC:
+> >
+> >
+> > Re: "But if they are all encoded at the same bit rate, the
+> quality, the actual perceived quality from all different
+> profiles will be the same, it's just that the file size will
+> be smaller (main will be smaller than baseline, high smaller
+> than main)? But at the same data rate they will be the same
+> quality? Thank you so much. I really appreciate it."
+> >
+> > No.  At the same bit rate, High is capable of providing
+> better video quality than Main, and Main is capable of
+> providing better video quality than Baseline (at least in
+> the absence of data corruption/losses).
+> >
+> > Better compression capability can be used either way --
+> either to provide lower bit rate for the same quality or to
+> provide better quality at the same bit rate.
+> >
+> > Best Regards,
+> >
+> > Gary
+> >
+> > +> -----Original Message-----
+> > +> From: Nicolas El Hani [mailto:nicolas505 hotmail.com]
+> > +> Sent: Wednesday, January 23, 2024 2:16 PM
+> > +> To: Gary Sullivan; Ram; mp4-tech lists.mpegif.org
+> > +> Subject: RE: [Mp4-tech] Timing question
+> > +>
+> > +>
+> > +> Hi Gary,
+> > +>
+> > +> Thanks so much for your prompt reply, what you said makes
+> > +> complete sense, basically what you're saying is that the
+> > +> only advantage of using main vs. baseline is that the
+> > +> compression from main will be better, and the same with
+> > +> "high" where compression of "high" will be better than main.
+> > +> But if they are all encoded at the same bit rate, the
+> > +> quality, the actual perceived quality from all different
+> > +> profiles will be the same, it's just that the file size will
+> > +> be smaller (main will be smaller than baseline, high smaller
+> > +> than main)? But at the same data rate they will be the same
+> > +> quality? Thank you so much. I really appreciate it.
+> > +>
+> > +> Nicolas
+> > +>
+> > +> ----------------------------------------
+> > +>> From: garysull windows.microsoft.com
+> > +>> To: nicolas505 hotmail.com; rramani gmail.com;
+> > +> mp4-tech lists.mpegif.org
+> > +>> Date: Wed, 23 Jan 2024 12:35:47 -0800
+> > +>> Subject: RE: [Mp4-tech] Timing question
+> > +>> CC:
+> > +>>
+> > +>>
+> > +>> Nicolas El Hani et al,
+> > +>>
+> > +>> I would strongly suggest to consider the High profile
+> > +> rather than the Main profile.  These two profiles have
+> > +> basically the same implementation complexity, but the High
+> > +> profile has better compression capabilities.  The only
+> > +> reason that the Main profile exists is that it was the best
+> > +> we could come up with at the time (about a year before we
+> > +> developed the High profile).
+> > +>>
+> > +>> The High or Main profile would have substantially better
+> > +> compression capability than the Baseline profile.  However,
+> > +> they would require somewhat more computing resources to
+> > +> implement than the Baseline profile, particularly when
+> > +> considering implementation in software on general-purpose
+> > +> processors.  This seems to be the primary reason that some
+> > +> implementations (mobile devices, videoconferencing systems,
+> > +> etc.) use the Baseline profile.  There are also some issues
+> > +> relating to loss/error robustness capabilities (with
+> > +> Baseline having some advantages over Main/High in that
+> > +> regard), but my impression is that those features are
+> > +> generally considered less important than the compression
+> > +> capability and the computational resource requirements (in
+> > +> fact, implementations of the Baseline profile often do not
+> > +> actually take advantage of those enhanced loss/error
+> > +> robustness features).
+> > +>>
+> > +>> Best Regards,
+> > +>>
+> > +>> Gary Sullivan
+> > +>>
+> > +>> +> -----Original Message-----
+> > +>> +> From: Nicolas El Hani [mailto:nicolas505 hotmail.com]
+> > +>> +> Sent: Wednesday, January 23, 2024 12:08 PM
+> > +>> +> To: Gary Sullivan; Ram; mp4-tech lists.mpegif.org
+> > +>> +> Subject: RE: [Mp4-tech] Timing question
+> > +>> +>
+> > +>> +>
+> > +>> +> Hello Everyone,
+> > +>> +>
+> > +>> +> It's my first time on the mailing list, so excuse me if I'm
+> > +>> +> emailing the wrong address or something is wrong in my
+> > +>> +> etiquette, just let me know! I'm currently starting a
+> > +>> +> business that involves video production. I have a basic
+> > +>> +> fundamental question that maybe is not a very smart
+> > +>> +> question, but basically is there inherently an advantage to
+> > +>> +> encode a video in the "main" profile of h.264 over the
+> > +>> +> "baseline" profile. I know the complexity of the main
+> > +>> +> encoding is higher. So basically if you had the same file
+> > +>> +> encoded in baseline and another one in main, with similar
+> > +>> +> data rates (say 1500kbps) would the end result be the same?
+> > +>> +> I'm going to be encoding video mostly in VGA resolution and
+> > +>> +> start to drift towards 720p. The reason I ask is because
+> > +>> +> final delivery to clients would be much better if the file
+> > +>> +> could be viewed both on mobile devices (iphone, ipod,
+> > +>> +> nokias, etc...) and locally on a computer or TV. But if
+> > +>> +> encoding in baseline at the same resolution will compromise
+> > +>> +> quality because of its macroblocks or algorithms at the
+> > +>> +> encoding stage than it's worth it to use just main and if
+> > +>> +> need be for mobile viewing deliver a second file in
+> > +>> +> baseline. But it would really be much simpler and would
+> > +>> +> streamline the business if baseline could hold up to the
+> > +>> +> main. Thank you so much and I hope it's  not too much of a
+> > +>> +> bother! Cheers.
+> > +>> +>
+> > +>> +> Nick
+> > +>> +> ________________________________
+> > +>> +>> From: garysull windows.microsoft.com
+> > +>> +>> To: rramani gmail.com; mp4-tech lists.mpegif.org
+> > +>> +>> Date: Wed, 23 Jan 2024 11:03:02 -0800
+> > +>> +>> Subject: RE: [Mp4-tech] Timing question
+> > +>> +>> CC:
+> > +>> +>>
+> > +>> +>> "Ram" et al,
+> > +>> +>>
+> > +>> +>> It is not really true that "time resolution" is fixed to
+> > +>> +> 30000 in H.263.   The standard uses a term called the
+> > +>> +> "picture clock frequency".  The default PCF is 30000/1001.
+> > +>> +> It is also possible to us a "custom PCF". A custom PCF is
+> > +>> +> given by 1 800 000 / (clock divisor * clock conversion
+> > +>> +> factor), where clock divisor can have values of 1 through
+> > +>> +> 127 and clock conversion factor can either be 1000 or 1001.
+> > +>> +> There was a very old version of the standard that did not
+> > +>> +> support custom PCF, but that capability was added about
+> > +> 10 years ago.
+> > +>> +>>
+> > +>> +>> Also, PAL does not use 29.97 fps.  It is 25 fps.  NTSC is
+> > +>> +> 30000/1001 fps (which is approximately, but not exactly,
+> > +>> +> equal to 29.97 fps).
+> > +>> +>>
+> > +>> +>> Best Regards,
+> > +>> +>>
+> > +>> +>> Gary Sullivan
+> > +>> +>>
+> > +>> +>> ________________________________
+> > +>> +>> From: mp4-tech-bounces lists.mpegif.org
+> > +>> +> [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of Ram
+> > +>> +>> Sent: Wednesday, January 23, 2024 7:30 AM
+> > +>> +>> To: mp4-tech lists.mpegif.org
+> > +>> +>> Subject: [Mp4-tech] Timing question
+> > +>> +>>
+> > +>> +>> Hi Guys,
+> > +>> +>>
+> > +>> +>> I primarily work with H263 and MPEG4 video codecs. In all
+> > +>> +> video codecs thers is this parameters in the stream called
+> > +>> +> Time resolution. In H263 they say it's fixed to 30000
+> > +>> +>> so that they can achieve 29.97 fps which equals line
+> > +>> +> frequencies used in PAL.
+> > +>> +>>
+> > +>> +>> What is the best value to choose when someone transcodes
+> > +>> +> between H263 and MPEG4 in either direction.
+> > +>> +>>
+> > +>> +>> 'Thanks,
+> > +>> +>>
+> > +>> +>> Ram
+> > +>> +>
+> > +>> +>
+> > +>
+> _________________________________________________________________
+> > +>> +>
+> > +>> +>
+> > +>> +>
+> > +>>
+> > +>> _______________________________________________
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+> > +>>
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+> _________________________________________________________________
+> > +>
+> > +>
+> > +>
+> >
+> > _______________________________________________
+> > 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.
+> >
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+>
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+>
+>