tyconvert and tyc.c pack header question

[willieb9000]

I had this conversation with Charlie Payne and then Dale Reed a while 
back. Here is what Dale said for what its worth...



"I don't think it does a /2.5. It just hard codes it. Looking
through the code, the *ONLY* place the mux_rate comes into
effect is putting the mux_rate into the header. I think this
is nothing more than a "hint" as to what the mux rate is, not
a "this is what follows" type of thing."


If I recall I changed this around to several diff numbers -- even 
tried TMPGenc's favorite (which is something like 2870.20) and I 
never noticed a difference in sync or playback or anything, so I just 
figured Dale was right...



--- In ExtractStream@y..., "Rick Weldon" <rick@n...> wrote:
> Hey all,
> 
> I don't know if anyone has noticed that tyconvert has the program 
mux rate
> set to best quality by default (its hard coded in the source), and 
oddly
> enough tyc.c for unix boxen has it set to medium quality by default 
(at
> least the copy I snagged did). This value gets set in the mpeg pack 
header
> that is created and written to the resultant system mpeg file that 
is
> created when converting from ty stream to system mpeg.
> 
> My question on this is how important is it that the pack header be 
correct.
> If you record on your TiVo at best quality (5800 kbps) and then set 
the
> pack header to medium (2600 kbps) what effect will this have on 
playback? Or
> vice-versa, you record at medium but tyconvert sets the pack header 
mux rate
> to best.
> 
> Anyone know what will happen under these circumstances? Could this 
be a
> source of audio sync problems? As in the decoder is trying to play 
at one
> rate and its really recorded at another.
> 
> Of course you have nothing to worry about if you record on your 
TiVo at best
> quality and use tyconvert on windowz. You may want to check this 
value if
> you use tyc.c under cygwin or on Unix boxen prior to compilation.
> 
> Rick