[ExtractStream] Crazy Audio Offsets?

[Roger Merchberger]

--- anddmx2001 <anddmx2001@y...> wrote:
> Hey guys,
> 
> Question for you. I'm doing an extract from my SA Tivo, and ran
> into something that got me thinking.

I hope you had a helmet... ;-)

> When I usually do an extract, I usually extract as 1 file. This
time 
> I decided to extract as multiple, smaller files. Now, when I Vsplit
> these files, this is what I got.... 
> 
> Part1- perfect
> part2- 6ms early
> part3- 9ms late
> part4- 1ms early
> part5- 17ms early
> part6- 6ms late
> part7- 17ms late
> part8- 9ms early
> part9- 4ms early
> part10- 15ms early
> part11- 17ms late
> 
> Is it normal for the offset to be diferrent from .ty to .ty? I have
> never extracted this way, so please ignore my ignorance. :)

AFAIK, but I've never extracted this way before either, but methinks
that this would be normal behavio[u]r. A chunk is exactly 128KBytes
(with the *real* definition of 1024 bytes... ;-) and AFAIK a chunk
does not have to keep to the boundries of MPEG data - so at the
beginning of every different extracted chunk [each part that you
extracted] you prolly had a certain amount of "junk data" which was
the tailings of the previous MPEG frame which gets tossed, then the
split utility grabs the PTS data from the next audio frame, and the
next video frame, and figgers it as close as it can, but cannot be
"perfect," hence each offset difference.

== Or, I might be "full of condensed milk" as my father-in-law was
wont to say... ;-) ==
You can extract as individual files just fine, but you need to
concatenate the files on the target machine before splitting to make
sure you keep good A/V streams, AFAIK.

Hope this helps,
Roger "Merch" Merchberger

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