Any way to convert 25 to 30 fps? ( 'cos YouTube is broken)

[MJ Peg]

Since December YouTube have been ruining 25fps 720p HD uploads by converting to 29.97
http://www.google.com/support/forum/p/youtube/thread?tid=12b19b1aff99d329&hl=en
http://www.google.com/support/forum/p/youtube/thread?tid=17607310c8c8806f&hl=en

While I wait for them to finally fix it, I wonder if I can convert from 25 to 30 with a 5:6 ratio method (and then drop frames to get to 29.97 perhaps), so that I can upload at a frame rate that they won't mess up?

I had in mind some freeware that would divide each 25fps frame into 6, upping the frame rate to 150 in effect, then sample 5 at a time, with blending, to reach 30.0 fps.
I.E. for each 5th of a second, the 5 frames A,B,C,D,E become 6 as follows:
1: A
2: 1 part A + 4 parts B
3: 2 parts B + 3 parts C
4: 3 parts C + 2 parts D
5: 4 parts D + 1 part E
6: E

Is there anything Open Source / Free/Shareware that would do that, please?
Thanks

[manono]

Is there anything Open Source / Free/Shareware that would do that, please?

Sure, AviSynth:

ConvertFPS(29.97)

http://avisynth.org/mediawiki/ConvertFPS
http://avisynth.org/mediawiki/Main_Page

Seems a shame, though, to wreck a perfectly good video by purposely blending it.

[MJ Peg]

Thanks! I'll look into that and have a play...

The shame is that YouTube have a bug reported for well over a month and still can't fix it!

Cheers

[manono]

And they never seem to be in a big hurry to fix their problems either. One of the posts in your links mentioned the problem they created with the audio and I got screwed over by that one. When they finally fixed it months later, I went back and reuploaded dozens of music videos.

[MJ Peg]

I've just tried it with a clip of a slowly rotating ceiling fan (AVCHD Lite 25fps) where the fan blades were already blurred, and the motion is perfectly smooth at 30.0 using :

testclip.avs

FFMpegSource2("testclip.MTS",atrack=-1)
ConvertFPS(30.0)

I'll take my chances with 30.0 for the exact 5:6 ratio rather than risk mucking it up with 29.97 - or am I being too cautious?

I need to experiment some more to see what artifacts it produces on other types of footage.
Thanks again

[jagabo]

I've just tried it with a clip of a slowly rotating ceiling fan (AVCHD Lite 25fps) where the fan blades were already blurred, and the motion is perfectly smooth at 30.0

Now try it with a medium speed, sharp, panning shot. Most frames will look like double exposures.

I'll take my chances with 30.0 for the exact 5:6 ratio rather than risk mucking it up with 29.97 - or am I being too cautious?

Yes. Although, with 25 -> 30 at least one frame out of every 6 will be a single exposure. With 25 -> 29.97 virtually all frames will be double exposures.

[MJ Peg]

Thanks
If my table above is correct, then 2 out of every 6 frames will be unaffected, but that transition from blur to no blur will be happening 5 times a second - so I'm expecting a flicker of some sort.

[jagabo]

If my table above is correct, then 2 out of every 6 frames will be unaffected, but that transition from blur to no blur will be happening 5 times a second

Yes, you're right, with your equations two out of very six will be clear. But AviSynth doesn't do it exactly that way:

[poisondeathray]

^ooooh psychadelic jagabo!

MJPeg, is using another hosting site an option? e.g. blip.tv, vimeo etc...I think they won't change the framerate. Keeping the native framerate is probably the best idea

Another option : motion interpolation methods should give smoother results , but take more time to process e.g. mflowfps in avisynth, pixel motion in AE ,etc...but have their own issues with artifacts

[jagabo]

^ooooh psychadelic jagabo!

Yes, I picked a very bad case example!

[MJ Peg]

Thanks, I've just tried a clip with a ceiling fan slowing to a stop, in a bright conservatory. The digicam had to use a short exposure time which doesn't make for attractive video, but is just the trick for this test as the fan blades are quite distinct in each frame.

As you have demonstrated, there is one clear frame every 6, with the 5 frames in between featuring leading or trailing ghosting. The middle one of each of the blended 5 is equally blended 50/50.

Anything stationary looks fine, and I can't quite make my mind up whether I can put up with the motion ghosting or not. It is an extreme case which didn't look great as it was at the original frame rate anyway, so I'd need to run some more tests on normal footage. I suspect that if the original footage is watchable (not too much panning about or zooming, but steady shots containing movement with a reasonable exposure time) then the converted footage wouldn't be too bad.

I would use a different website than YouTube, but the audience just isn't there, and I've tried Vimeo but it just doesn't play smoothly for me like it did on YouTube.

I'll probably give it a few more weeks.
Thanks

[MJ Peg]

After more testing, I can confirm that good steady video with minor movements in the frame looks fairly acceptable, but panning and zooming is shot to hell. I tend to do too much of that, so I'm stuck - it's 25fps or nothing. Conversions won't do.

I hope YT hurry up and fix their upload converter, but looking at the sheer number of unresolved problems on their help forums I don't know whether my optimism is misplaced

[MJ Peg]

I am pleased to report that my latest 25fps 720p upload test is playing smoothly at the correct 25fps after they've processed it.
Thank you YouTube!

[jagabo]

It's amazing that YouTube can be so incompetent.

[jman98]

I am pleased to report that my latest 25fps 720p upload test is playing smoothly at the correct 25fps after they've processed it.
Thank you YouTube!

Here in the USA we say "You get what you pay for". Considering that you aren't paying YouTube for what they do, you don't really have a lot of room to complain when they don't do it right.

[manono]

And since this thread originated I've learned of a better way to change framerates without also changing the video's length, other than ConvertFPS and ChangeFPS. It's part of the Motion.dll and is called BlendFPS. Something like (from the earlier 25fps):

BlendFPS(29.97,Aperture=0.1)#or 0.2

will create one new blended frame out of every 5 existing frames, a blend of frames on either side, and leave the rest alone.

http://avisynth.org/warpenterprises/files/motion_25_dll_20051212.zip

[MJ Peg]

Here in the USA we say "You get what you pay for". Considering that you aren't paying YouTube for what they do, you don't really have a lot of room to complain when they don't do it right.

Obviously I appreciate a free service, I don't believe I was whingeing like a spoilt brat, I was looking for a way around the problem.... expressed some frustrations because a service, as provided, raises a certain level of expectation... and, having found that the problem has been sorted, I expressed my gratitude. I don't know why you felt you needed to make an issue of that?

Manono, that's interesting, thanks for sharing that.