[Mp4-tech] Re: PCR Discontinuity Issues

[Song]

Dear Mohit Agarwal
I think which packet contains the valid pcr value should be checked with PCR_flag in adaptation_field. If PCR_flag set 1, the PCR can be used.
So I think that the sequence can be modified with the following.
...
    <pcr_flag == 1, discontinuity_indicator = 0> 
    <pcr_flag == 0, discontinuity_indicator = 0> // old system time
   <pcr_flag == 0, discontinuity_indicator = 1> // new system time begin
  <pcr_flag == 1, discontinuity_indicator = 1> //  new PCR set.
    <pcr_flag == 1, discontinuity_indicator = 0>
 ...
Best Regards.
Song
> 
> Message: 4
> Date: Fri, 14 Jul 2023 15:54:46 +0530
> From: "Mohit Agarwal" <magarwal NeoMagic.com>
> Subject: [Mp4-tech] [MPEG2-SYSTEMS]PCR Discontinuity Issues
> To: <mp4-tech lists.mpegif.org>
> Message-ID: <004601c6a72f$bc76c680$841fa8c0 pcmagarwal>
> Content-Type: text/plain; charset="us-ascii"
> 
> Hi,
>  
> I have a doubt regarding  discontinuity indicator in the case of pcr
> packets, mentioned in section 2.4.3.5- discontinuity_indicator of H.222.0 
>  
> What I interpret from the Standard is:
>  
> <valid_pcr, discontinuity_indicator = 0> 
>  <valid_pcr, discontinuity_indicator = 0> 
>  <invalid_pcr, discontinuity_indicator = 1> //do not use this value
>  <valid_pcr, discontinuity_indicator = 1> //use this value
>  <valid_pcr, discontinuity_indicator = 0>
>    .
>    .
>    .
>  
>  
> The standard also mentions that there can be more than two packets with
> discontinuity indicator =1.
> But the question in this case is that how does one differentiate which
> packet contains the valid pcr value???
>  
>  
> Thanks
> Mohit Agarwal