[Mp4-tech] MPEG4, MPEG2, and MPEG1

[Bharat Soni]

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
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