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

Erik Slagter erik
Mon Mar 13 15:16:36 CET 2006

On Mon, 2006-03-13 at 13:32 +0000, M?ns Rullg?rd wrote:

> >  - 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.

Still "NTSC" is not a frame rate. There are regions that watch NTSC
modulated colour using 25 frames per second. I don't know from the top
of my head where, but I can dig if necessary. NTSC B or NTSC G or

> 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.

Okay, from a technical perspective it doesn't matter that much, I agree,
the computer won't mind using a crystal (eg) 0.001% different to
compensate for a "weird" frame rate. But personally I prefer having to
write 30 fps to 30000/1001, don't you?

> Interlacing is pure evil, though.

:-) It's a bit like marketing, it promises all sorts of things it
actually never completely meets.

> > 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.

I was talking of the colour modulation techniques, which they refer to.
Analogue TV gone -> colour modulation gone.

Over here (NL) at last digital TV is taking off, using DVB-S (been
available for ages) DVB-T (available for a few years) and DVB-C
(available since recently). Especially the last one seems promising, in
marketing terms, many people are considering it, and the cable companies
push it, because it's more profitable for them. DVB-T cannot be expanded
any further because the necessary frequencies are in use for analogue TV
distribution, so there is some pressure to stop broadcasting analogue TV
completely and re-use the frequencies for DVB-T. Although I am not too
enthusiastic about DVB-T (merely because of the horrible bitrate used
here) at least it's better than analogue.

So... analogue TV might come to an end (at least here) in the not too
distance future! Yeah!
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