1080i to 720p: framerate issues

[flapane]

1080i 25fps source (sport) -> Avidemux H264-2.5Mbps -> yadif deinterlacer (temporal and space, top field first) -> resize to 1280x720 50p

source lenght: 9m37s
output lenght: 8m49s (why?)

Also, there are a lot of scenes in the output file (ie. when an athlete shakes his hand with another fellow, or when the supporters jump... they're clearly both vertical movements) where the movements seem to be somewhat accelerated.

Mediainfo shows a "VARIABLE" framerate on the output file:
Frame rate mode : Variable
Frame rate : 50.000 fps

Did I make something wrong while deinterlacing?
Any hints? Thanks

[Audionut]

Why are you encoding at a very small bitrate and then deinterlacing and resizing.

Skip "Avidemux H264-2.5Mbps"

Also, make sure your source is top field first.

Are you sure your source is constant frame rate?

[flapane]

Why are you encoding at a very small bitrate and then deinterlacing and resizing.

Skip "Avidemux H264-2.5Mbps"


Hi. Encoding is at the very end of the workflow, just after resizing. The bitrate thing doesn't concern the problem I explained in the first post. I need a 720p 2.5Mbps output. :)


Also, make sure your source is top field first.


How do I verify it?
edit: I tried using bottom field first: same result.
Also, the mode (0 or 1) seems to be irrelevant.



Are you sure your source is constant frame rate?

Mediainfo just says:
Frame rate : 25.000 fps
and while playing the video in MPC I notice that the framerate is always 50fps +- 0.01fps

[flapane]

Using Virtualdub with the same Yadif algorithm settings produces a flawless output. I wonder if the problem is in Avidemux 2.5 itself.

[poisondeathray]

Using Virtualdub with the same Yadif algorithm settings produces a flawless output. I wonder if the problem is in Avidemux 2.5 itself.


You can try a 2.6 build instead
http://avidemux.razorbyte.com.au/

[flapane]

I already tried it, but the bugs I already wrote 1 month ago in Avidemux thread still exist. Furthermore latest svn build couldn't even go past 1st pass, it produced a pop-up error message. Better luck with the builds coming out in early autumn, I guess.