[FFmpeg-user] '-bsf setts=dts' has problems

[Mark Filipak]

On 08/06/2024 12.05, Paul B Mahol wrote:
-snip-
> If you do not explicitly set expression for both pts and dts options, they
> will be set to same value later.

Thank you, Paul. I see (and I'm surprised by it).

So this command:
-bsf setts=dts='if(eq(DTS\,2846606)\,2850360\,DTS)'
produces this:
0,    2846606,    2846606,     3753,   640646, 0x3a5a0c45,
0,    2854113,    2854113,     3753,   640646, 0x02208727,
(which is not intended and surprises me),

whereas this command:
-bsf setts=dts='if(eq(DTS\,2846606)\,2850360\,DTS)':pts=PTS
produces this:
0,    2850360,    2854113,     3753,   640646, 0x3a5a0c45,
0,    2854113,    2861621,     3753,   640646, 0x02208727,
(which is correct and what I intended).

So, PTSes can be rewritten, but DTSes cannot be rewritten unless PTSes are copied in the same setts. 
Therefore, the scope of setts=pts is only PTSes, but the scope of setts=dts is both DTSes & PTSes.

That's illogical.

It's also contrary to what the documentation says:
"Set expressions for PTS, DTS or both"

Nevertheless, you have really helped me. I thank you!

--Mark.