L-SMASH & 60fps footage

[Mounir]

I have a problem with LWLibavVideoSource
my camcorder footage is 60 fps interlaced and it's decoded as 30fps interlaced. Am i missing smtg ?
edit:
Well LSMASHVideoSource decode it correctly it seems as far as fps, ill do more test but last time i checked it wasn't stable on my computer (frames not decoded,frame accuracy etc..)

[hello_hello]

Sometimes for interlaced video you just have to tell it to convert the frame rate. ie

LWLibavVideoSource("E:\video.mkv", fpsnum=60, fpsden=1)

But it might also depend on the total frame count and duration as you don't want it duplicating frames unnecessarily. If the total number of frames is correct then following it with AssumeFPS(60,1) instead might be all that's needed.

[poisondeathray]

my camcorder footage is 60 fps interlaced and it's decoded as 30fps interlaced.

60fps interlaced ? (I know you mean 59.94 or 60000/1001), but that would be exceedingly rare, because that would mean 120 fields/second

More common would be 29.97 frames per second interlaced, or 59.94 fields per second

[Mounir]

right i meant 59.940 fps interlaced (typo..), it's not that rare in the camcorder world (as far as i know)

[poisondeathray]

right i meant 59.940 fps interlaced (typo..), it's not that rare in the camcorder world (as far as i know)

Are you sure ? 59.94 fps interlaced (119.88 fields/s) is not compatible with NTSC systems

I think you meant 29.97 fps interlaced ? (59.94 fields/s)

What camera model is it ?

[kuchikirukia]

60i is 30 interlaced frames per second.

[poisondeathray]

60i is 30 interlaced frames per second.


Yes, "30i" and "60i" actually mean the same thing, just different naming conventions expressed as frames vs. fields. Be he never used the term "60i", only "fps"

The confusion is the way the OP is expressed "my camcorder footage is 60 fps interlaced and it's decoded as 30fps interlaced." - it's not clear what he means by "fps" - frames or fields. But "fps" usually indicates frames per second. hello_hello assumed it meant frames, and I did too. If he was using it to indicate "fields" - that would mean decoded as 15 frames per second, and I doubt that is what he meant.

Eitherway it is better to be explicitly clear

[Mounir]

60i (59.940i) gives 30 progressive frames once the fields are recombined ?? i'm learning something here
It's an hybrid Fuji finepix i'm using to take photos and also shoot some video

[poisondeathray]

60i (59.940i) gives 30 progressive frames once the fields are recombined ??


Depends what you mean by "recombined"

When fields are not separated (ie footage straight out of camera), you have the original 29.97 frames/second (but that is not progressive, it's interlaced. Since fields are not separated you will see "combing" during motion) . When you bob deinterlace, essentially each field becomes a frame and you have 59.94 progressive frames/second

[hello_hello]

hello_hello did wonder about the frame rate originally, but decided to just go with it. I assumed, maybe incorrectly, it was one of those instances where L-Smash was decoding interlaced video incorrectly, or at the wrong speed, so fixing that was the objective rather than fuss over the terminology. As it's looking now, maybe the video was being decoded correctly after-all, but in my defence, the OP indicated LWLibavVideoSource and LSMASHVideoSource are decoding it differently, so I'd assume one of them must be getting it wrong.