50p to 25p framerate conversion

cweb · 29th September 2009, 17:39

Hello
I need to convert from 50p (progressive) footage framerate to 25p...

What's a good present way of doing this in Avisynth (without desyncing audio of course)?

Should I use convertfps or is there a better way which I'm overlooking?

I was thinking perhaps this should work: AssumeScaledFPS(video,divisor=2)
thanks in advance

Guest · 29th September 2009, 17:49

SelectEven()

thewebchat · 29th September 2009, 17:54

Or SelectOdd() if you want to be a rebel.

Guest · 29th September 2009, 18:14

Or SelectEvery(2,1) to be extra rebellious.

cweb · 29th September 2009, 18:58

Thanks! I thought of that was being too obvious and I hadn't tested that yet. I tried it and it works....

cweb · 30th September 2009, 09:47

One thing seems to have happened though with the SelectEven, the video seems to be too fast!
I would like to keep the normal speed of my camera recording.
I'm using the latest MT avisynth posted in another thread.

cweb · 30th September 2009, 10:16

Hmm I think it was caused by my source.
My source is a camera video, an mts file which I convert to ts using tsMuxer. The latter by default uses vbr.
I access the ts file using directshowsource.
The speed was quite odd after going to 25fps...

I solved it by choosing the cbr option in tsMuxer, I created a cbr ts file instead, which seems to work well.
Thanks anyway.

Gavino · 30th September 2009, 10:19

What do you mean 'too fast'?
SelectEven does not change the video duration.
It halves both the frame rate and the number of frames, so there is no change in playing time.

Probably all you are seeing is that motion is less smooth at 25fps than at 50fps.

Edit: Ok, just seen your later explanation.

SeeMoreDigital · 26th January 2013, 12:41

cweb

Out of interest... Are you able to provide a sample of your 50fps source?

29th September 2009, 17:39	#1 \| Link
cweb Registered User Join Date: Oct 2002 Location: The Pandorica Posts: 528	50p to 25p framerate conversion Hello I need to convert from 50p (progressive) footage framerate to 25p... What's a good present way of doing this in Avisynth (without desyncing audio of course)? Should I use convertfps or is there a better way which I'm overlooking? I was thinking perhaps this should work: AssumeScaledFPS(video,divisor=2) thanks in advance __________________ PC specs for bug reports: Intel Core i7-4790K @4Ghz Win10(Linux VM) PCI express NVIDIA RTX 2060 SUPER graphics card http://twitter.com/cwebdesign Last edited by Guest; 29th September 2009 at 17:49. Reason: rule 12

29th September 2009, 18:58	#5 \| Link
cweb Registered User Join Date: Oct 2002 Location: The Pandorica Posts: 528	Thanks! I thought of that was being too obvious and I hadn't tested that yet. I tried it and it works.... __________________ PC specs for bug reports: Intel Core i7-4790K @4Ghz Win10(Linux VM) PCI express NVIDIA RTX 2060 SUPER graphics card http://twitter.com/cwebdesign

30th September 2009, 09:47	#6 \| Link
cweb Registered User Join Date: Oct 2002 Location: The Pandorica Posts: 528	One thing seems to have happened though with the SelectEven, the video seems to be too fast! I would like to keep the normal speed of my camera recording. I'm using the latest MT avisynth posted in another thread. __________________ PC specs for bug reports: Intel Core i7-4790K @4Ghz Win10(Linux VM) PCI express NVIDIA RTX 2060 SUPER graphics card http://twitter.com/cwebdesign Last edited by cweb; 30th September 2009 at 09:52.

30th September 2009, 10:16	#7 \| Link
cweb Registered User Join Date: Oct 2002 Location: The Pandorica Posts: 528	Hmm I think it was caused by my source. My source is a camera video, an mts file which I convert to ts using tsMuxer. The latter by default uses vbr. I access the ts file using directshowsource. The speed was quite odd after going to 25fps... I solved it by choosing the cbr option in tsMuxer, I created a cbr ts file instead, which seems to work well. Thanks anyway. __________________ PC specs for bug reports: Intel Core i7-4790K @4Ghz Win10(Linux VM) PCI express NVIDIA RTX 2060 SUPER graphics card http://twitter.com/cwebdesign

30th September 2009, 10:19	#8 \| Link
Gavino Avisynth language lover Join Date: Dec 2007 Location: Spain Posts: 3,439	What do you mean 'too fast'? SelectEven does not change the video duration. It halves both the frame rate and the number of frames, so there is no change in playing time. Probably all you are seeing is that motion is less smooth at 25fps than at 50fps. Edit: Ok, just seen your later explanation. Last edited by Gavino; 30th September 2009 at 10:21.

29th September 2009, 17:49	#2 \| Link
Guest Guest Join Date: Jan 2002 Posts: 21,901	SelectEven()

29th September 2009, 17:54	#3 \| Link
thewebchat Advanced Blogging Join Date: May 2009 Posts: 480	Or SelectOdd() if you want to be a rebel.

29th September 2009, 18:14	#4 \| Link
Guest Guest Join Date: Jan 2002 Posts: 21,901	Or SelectEvery(2,1) to be extra rebellious.

26th January 2013, 12:41	#9 \| Link
SeeMoreDigital Life's clearer in 4K UHD Join Date: Jun 2003 Location: Notts, UK Posts: 12,345	cweb Out of interest... Are you able to provide a sample of your 50fps source? __________________ \| I've been testing hardware media playback devices and software A/V encoders and decoders since 2001 \| My Network Layout & A/V Gear \|

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