[Mp4-tech] MPEG4, MPEG2, and MPEG1

[Gary Sullivan]

I was trying to convey a more complete picture than that.  For example,
there are four decoder chips today that can decode MPEG-4 AVC at HD
resolution (Broadcom, Sigma, ST Micro, and Conexant).  Three of those
four (all but the Conexant CX2418x) can also decode MPEG-2.
Best regards,
Gary Sullivan
+> -----Original Message-----
+> From: mp4-tech-bounces lists.mpegif.org 
+> [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of Bharat Soni
+> Sent: Monday, January 24, 2024 12:54 AM
+> To: Gary Sullivan
+> Cc: Kae Hsueh; mp4-tech lists.mpegif.org
+> Subject: Re: [Mp4-tech] MPEG4, MPEG2, and MPEG1
+> 
+> Hi Gary,
+> 
+> Is it not true that MPEG-4 video bitstream syntax is different than
+> MPEG2/1 bitstream syntax. Then would it not be more appropriate to
+> simply say MPEG-4 decoder can't decode MOEG-1/2 streams?
+> Correct me if I am wrong.
+> 
+> Regards,
+> Bharat
+> 
+> 
+> On Sat, 22 Jan 2024 00:32:12 -0800, Gary Sullivan
+> <garysull windows.microsoft.com> wrote:
+> > 
+> > +> Can I use MPEG2 decoder to decode MPEG1 streams or files?
+> > 
+> > In the case of video, the answer to this question is Yes.  
+> The MPEG-2
+> > video standard is a basically-straightforward extension of 
+> the MPEG-1
+> > technology, and this kind of compatibility is required in 
+> the MPEG-2
+> > video standard.
+> > 
+> > +> Can I use MPEG-4 decoder to decode
+> > +> MPEG1 or MPEG2
+> > +> streams or files?
+> > 
+> > 
+> > In the case of video, the answer to this question is ... Maybe.
+> > 
+> > To put it more precisely, the MPEG-4 standard does not 
+> require a product
+> > to have this capablity.
+> > However, MPEG-4 product makers may want their product to have that
+> > capability and would put it in their product voluntarily.
+> > 
+> > Best Regards,
+> > 
+> > Gary Sullivan
+> > 
+> > +> -----Original Message-----
+> > +> From: mp4-tech-bounces lists.mpegif.org
+> > +> [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of 
+> Kae Hsueh
+> > +> Sent: Friday, January 21, 2024 10:09 AM
+> > +> To: mp4-tech lists.mpegif.org
+> > +> Subject: [Mp4-tech] MPEG4, MPEG2, and MPEG1
+> > +>
+> > +> This might be a stupid question. Can some one tell me 
+> if MPEG2 is
+> > +> backward compatible to MPEG1? It means can I use MPEG2 
+> decoder to
+> > +> decode MPEG1 streams or files?
+> > +>
+> > +> Same go with MPEG-4. Can I use MPEG-4 decoder to decode
+> > +> MPEG1 or MPEG2
+> > +> streams or files?
+> > +>
+> > +> Kae
+> > +> _______________________________________________
+> > +> 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
+> > +>
+> > 
+> > _______________________________________________
+> > 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
+> >
+> _______________________________________________
+> 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
+>