[Ffmpeg-devel] [ bug ] converting png to dv gives solid black

Måns Rullgård mru
Mon Mar 13 14:32:06 CET 2006

Erik Slagter said:
> On Sun, 2006-03-12 at 15:06 -0500, Rich Felker wrote:
>> > Besides the fact that either 30000/1001 and 30001/1001 are completely
>> > stupid from a design point of view,
>> No they're not. Why don't you learn why the number is 1000/1001 (and
>> this an _exact_ 1000/1001, not a nice approximation of some physical
>> quantity)
> WTF are you talking about. Have you ever seen me using either 30 or
> 29.97 fps?
>> by reading the history of NTSC rather than making ignorant
>> comments?
> Actually I DO know something of the history of NTSC and this ignorant
> guy can tell you that:
>  - NTSC has nothing to do with frame rates

NTSC is the very committee that specified those frame rates.  The acronym
has subsequently been overloaded with a number of meanings.  Sometimes it
is used to refer to frame sizes, sometimes frame rates, and sometimes chroma
encodings.  In a sense they are all correct.  All these parameters were
part of the system defined by NTSC some 50 years ago.

>  - way back (indeed history) there was a reason for this stupid frame
> rate; there is no excuse for using it in digital video though,
> especially not in HD, same goes for interlacing.

Analog or digital, SD or HD, you still have to use *some* frame rate.  The
proper choice depends on the specific context.  The problems only arise when
you need to convert content to another frame rate.  If codecs, containers
and displays all support arbitrary frame rates the problem will go away.

Interlacing is pure evil, though.

> I really hope this silly technical artifact dies very soon, as will NTSC
> (and PAL and SECAM).

I'm afraid that won't happen all that soon.

M?ns Rullg?rd
mru at inprovide.com

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