[MEncoder-users] mencoder does not inverse telecine properly; inccorect ofps framerate

[Matt Kinni]

Hey Lobs.  Adding -ovc pcm and removing nosound still produced the same number of (short)
frames.  Would it make sense to do -vf pullup,softskip,harddup -ofps 24000/1001 or would
that be nonsensical?  Does ofps have any way of knowing to only discard the extra telecine
frames I don't need anymore?

On 02/21/2011 04:20 PM, Lobster wrote:
> On 22/02/2011 1:07 p.m., Matt Kinni wrote:
>> Hello, I have a telecined ntsc dvd that plays at 30000/1001 fps and is 6481.056 seconds
>> long.
>>
>> Mencoder's -vf pullup,softskip filters work perfectly, however I'm unable to maintain an
>> audio/video sync when changing the out fps to 24000/1001.
>>
>> For example:
>>
>> 24000/1001 fps * 6481.056 seconds = 155,390 frames that should be produced by mencoder.
>>
>> However,
>> "mencoder dvd.vob -vf pullup,softskip -ofps 24000/1001 -nosound -ovc raw -of rawvideo -o
>> /dev/null"
>> only produces 155,332 frames, which is 2.2 seconds too short (and audio/video sync fails)!
>>
>> If I keep the framerate the same as the source, it produces the correct amount of frames:
>>
>> 30000/1001 fps * 6481.056 s = 194237 frames
>> "mencoder dvd.vob -vf pullup,softskip,harddup -ofps 30000/1001 -nosound -ovc raw -of
>> rawvideo -o /dev/null"
>> does indeed produce exactly 194,237 frames, the same as the source, and the audio/video
>> sync is ok.
>>
>> The point with inverse telecining is that not only do progressive frames look nicer, but
>> discarding all the extra frames allows for a smaller encode.  It seams that mencoder can
>> inverse telecine perfectly, it just can't change the source framerate from 29.97 to the
>> desired 23.976.  Is there something I'm doing wrong?
>>
>> Thanks for your time
>
> Don't use -nosound
>
> Processing the sound with the video will allow av sync to be kept more easily, also use
> the harddup filter as the last video filter in your chain (if you need to duplicate
> frames to keep av sync it is very important)
>
> using -of rawvideo will discard any sound output, so you don't need to worry about it
> being included in the output file, you will still need to specify a -oac, pcm will
> likely be fine.
>
>
>
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-- 
Matthew Kinni
Cal Poly State University
2640 Canyon Circle
San Luis Obispo, CA 93410
Cell: 925-817-0934
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