mpeg-2 conversion out of sync?

[Chipsteruk]

hello, i have a 3ivx D4 4.0.4, 640 x 352 avi file with 5 channel ac3 audio i think. i'm trying to convert back to mpeg-2 dvd format. using ffmpegx but it always comes back out of sync! more than 30 seconds out of sync

is there a way of demuxing the 3ivx file and then remuxing the audio with the m2v file that ffmpegx created? nothing seems to demux the 3ivx file tho (bbdemux & ffmpegx there wont touch it)

cheers

[major]

Check the video framerate and audio sampling rate of your 3ivx file, and be sure to use the same values for encoding. Probably you will also need to disable the "3:2 pulldown" option.

[Chipsteruk]

Major,

not sure how you you make the video frame rate and the audio sample rate the same!

this is what my file reads:

3vid 640 x 352 24 bpp 13.98
fps 1494.8kps (182.5kbytes)
audiocodec: framecopy (format=2000
chans=5 rate 48000 bits= 0 bps
= 56000 sample = 1)

when you say framerate do you mean under video parameters?
i cant see one that matches! but i normally just use pal (25) with the auto size set to dvd pal 16:9 and use the high bitrate dvd pal in the quick settings.

as for the audio do i set it to .ac3 or just use pass through?

in options i have to uncheck set 3:2 yes?

thanx for your time Major

[major]

13.98 fps

This a really strange framerate value for a movie!

when you say framerate do you mean under video parameters?

Yes

as for the audio do i set it to .ac3 or just use pass through?

.ac3

in options i have to uncheck set 3:2 yes?

Yes

[Chipsteruk]

sorry did i write 13.98 fps it should of read 23.98fps does that sound more like it?

[Chipsteruk]

i also have another movie that gets the same sync probs this reads:
Divx 608 x 256 24 bpp 13.98
fps 863.0 kps (182.5kbytes)
audiocodec: framecopy (format=2000
chans=5 rate 48000 bits= 0 bps
= 16045 sample = 1)

do i do exactly the same with this file except choose mp2 in the audio part?

cheers

[major]

If it is 23.98, you should set NTSC FILM as framerate, and disable "3:2 pulldown" from the Options tab. This is because "3:2 pulldown" should only be set if the source is MPEG-2 (at NTSC FILM rate).

[tokyotony]

I'm getting the same synch problems when trying to convert my dv file to SVCD and CVD (using the Presets), even though I have converted it to VCD without any synch problems.

I try to click the Info button to find out the framerates, etc., but no info pops up. I would guess that changing the default framerates, etc. from the SVCD and CVD present would not be necessary if the VCD is working correctly??

[major]

You should disable "3:2 pulldown". This option is not applicable to VCD but will have its effect on SVCD and CVD.

[tokyotony]

Thanks. That did the trick. Any reason why 3:2 is the default? Would there be a particular use for this?

[major]

This is frequently applicable when the source is VOB/VIDEO_TS.

[Chipsteruk]

major,

that seemed to do the trick with the out of sync audio video. but the end result is a little jerky like to many frames are missing, it dont run smooth like the avi file. is this just the down side to converting back to mpeg-2

cheers

[major]

It should not be jerky. It's difficult to say what to do without testing. If you can put a clip online so as I can download it, I could give it a check.

[Larrybob]

I'm not sure how to disable "3:2 pulldown".
In the options tab I see two things:
1. Undo 3:2
2. Set 3:2
Each of those has a box beside them, both are unchecked. Should one of them be checked?

[major]

It's the second checkbox. Enable it to enable 3:2 pulldown flag, disable it to disable 3:2 pulldown flag.

The audio is still out of sync even with it disabled.

[major]

Are you using framerate=NTSC FILM and 3:2 pulldown flag disabled?