[MEncoder-users] Determining proper frame rate

[Chris Capon]

L Lee wrote:
> On 11/4/09 4:13 PM, "Grozdan" <neutrino8 at gmail.com> wrote:
>
>   
>> 2009/11/4 Andrew Berg <bahamutzero8825 at gmail.com>:
>>     
>>> While we're on the subject, I have material that I know is telecined at
>>> 60000/1001fps and I want it at half that (it's on a network that does
>>> 720p at 60000/1001 and the material is originally 1080i at 30000/1001).
>>> -ofps 30000/1001 doesn't work. There's some discussion about 60fps
>>> telecined material on the list, but I didn't quite understand it and I
>>> think it's for getting 24000/1001fps anyway.
>>>       
>> Have you tried with filmdint? It can scale down frame rates with its
>> io option, eg filmdint=io=60:30 -fps 60000/1001 -ofps 30000/1001. Or
>> are you just trying to reduce the frame rate but preserve the
>> telecine?
>
> I was fooling around with some of this today. By default, using the scale
> filter for a size A:B (defaults to same as scale=A:B:0, I think) yielded
> deinterlaced output if I used -ofps 30000/1001. But I know my source is
> telecined, so to get output that's deinterlaced at the NTSC frame rate, I
> appeared to have two choices, neither of which I liked very much, because
> either way whenever there's smooth continuous motion in passages with the
> slightest amount of edge contrast, it's like getting slapped six times a
> second.
>
> Using most deinterlacing filters, I get two combed frames at the same
> position in every consecutive five, and using, for example,
> filmdint=fast=0/io=30:30, I get a pair of duplicate frames at the same point
> in every consecutive five. All my routines were using -ofps "30000/1001",
> but none contained "-fps". I don't really know if there's a way to get
> telecined sources to come out at 30 fps without either two duplicates or two
> combed frames of every five, but I doubt it. Maybe some filters or options
> can mask it better than others. (I haven't found a perfect one yet, but I'm
> all eyes if any of you know of one.)
>
> Anyway, all I had to do to get pullup using the filmdint routine was to
> change "30:30" to "30:24", and "-ofps 30000/1001" to "-ofps 24000/1001", and
> I didn't really have to change the -ofps value, because changing the
> filmdint value changed the output frame rate even without changing anything
> else, but I didn't want to leave the misleading "-ofps" option in the
> command line, of course.
>
> Laine Lee
>
>   
One way to get 30 fps from telecined content seems to work if you are 
using the -of mpeg encoder.

Use filmdint=io=30:24 -ofps 24000/1001 then add the -mpegopts telecine 
parameter.  This produces output which is encoded at 24 fps but then is 
soft scaled to 30 fps when played (so the output size stays the same).  
This allows telecined content to play on older DVD players which may not 
support 24 fps.