fps confusion after muxing

[adom]

hi,
the original is 1080i50.

After demuxing I got 264 video:
Frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First

To make explanation shorter I won't mention anything about audio in following part (just assume it's there all the tome and makes no problem).

if I use videoRedo to mux it back (into matroska) and then I play it with mPlayer I got a msg saing it's 25 fps - and it plays fine.
if I use mkvMerge (with default fps 25) the vido plays twice slower but mplayer again shows 25fps (when I advance frame by fame then I can count only 12 frames to make 1 second - ?)
same story after using mp4Box (to make it into mp4) - 25 fps but twice slower speed.

Here comes media info for resulting video:
Frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First

EXACTLY as the original one but plays twice slower.


To solve this I have to enter 50fps for video source in mkvToolnix then the speed is ok and mplayer says 50fp

media info:
Frame rate : 50.000 fps
Original frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First

- looks almost the same but one line (Original frame rate : 25.000 fps)

can somebody explain to me what is happenig here - and why videredo can make mplayer show 25fps and play it fine and the others just can't.

Thanks.

eta: when muxing into ts/m2ts everything is fine - only mkv and mp4 behave like above.

[manono]

i50 is 50 interlaced fields per second. That's the same as 25 interlaced frames per second (the 25fps all the information programs give you). I have no idea how you or the muxers screwed up the playback speed. Maybe someone else can help with that. Why do you have to do anything with it when the original plays fine and still plays fine after the editing in VideoRedo and muxing into Matroska?

[adom]

I have some videos that videoRedo cannot mux correctly - after some cutting (inside videoRedo) there is a short "jump" (sorry but don't know english word for this) somewere near the beginning of a video after which audio gets out of synch or the playback is totally "jumpy" - at least mpc-hc (with every possible filters combinations) cannot play this fluently (and thats my default player + mplayer) - that is the reason I was looking for other muxers.

Why changing to matroska? - thats just mosty as an exercise to play around with videos to get some experience with it.

...I have no idea how you or the muxers screwed up the playback speed...

belive me I did nothing - just opend gui, put 2 files inside (264 and ac3) and pressed mux - and it didn't work as should.

I'll try to post a short part from one of my recorded videos and the "broken" one (after muxing inside videoRedo)

[adom]

https://forum.videohelp.com/attachment.php?attachmentid=8896&stc=1&d=1317258303
you can download short sample from this link - there is a short "freeze" around 2-3rd sec.
the same file can be demuxed and used inside mkvmerge or mp4box to check if after muxing it gets wrong frame rate as well.