Forgive newb question: syncing video

[Krishach]

This has been frustrating me for a while now.

I have some WONDERFUL videos, full length, to use as backgrounds for step-charts, all of which was created by artists better than I.

However, I cannot get the damn things to syncronize properly with the step chart and music.

I have resorted thus far to adding empty space to the beginning of the videos, or credits, to allow them to display properly when I try them in Step Mania play.

2 problems with this:
1) the sync is NOT always consistant ><
2) the sync in the TEST AREA is always correct without video editing. It starts the vid where I tell it to, based on the simple options available in the stepmania editor. However, the PLAY area starts the video MORE THAN 8 SECONDS BEFORE the listed start time. So its not starting at 0:00 on the vid. Except in the test area for making it ><


I don't know code, and this shouldn't be that hard. I am not trying to sync or move or transition through multiple images or movies: I just want ONE video to start when the music starts, and stay synched throughout at 100% speed (the step chart was made from the audio in the video, so that should not be the issue). Even worse, this is not something I can jury rig on MY machine, I am making this for someone else, so it has to work on HIS PC, and any DDR arcades he brings it to.



What am I doing wrong? Do I need to add the 8-9 seconds of dead space to make the video line up? WILL THE SYNC BE RIGHT ON SOMEONE ELSES MACHINE? Please help.


Lastly, despite reading the excellent BG thread by TheFlyingSquirrel, I am still lost when it comes to any coding, and so I am doing this through the visual step-chart editor inside Step Mania as a BGAnim add.

Thanks


EDIT: Ok, I finally wrapped my head around the way the .sm file is coded for background changes. I added the lines in the .sm file, and tried as "#BGCHANGES:0.001=Krishach - Halloween 2008=1.000=0=0=1;"

also, used the original editor added line
#BGCHANGES:0.001=Krishach - Halloween 2008=1.000=0=0=1,
99999=-nosongbg-=1.000=0=0=0 // don't automatically add -songbackground-
;

Still has the same time lag. Again, the problem is the video starts at SECOND NINE, instead of the beginning, and I have to add blank spots to the video itself to get it to line up. However, having done this, it doesn't sync the same on other machines.

[chaotixmaster]

Originally Posted by Krishach

This has been frustrating me for a while now.

I have some WONDERFUL videos, full length, to use as backgrounds for step-charts, all of which was created by artists better than I.

However, I cannot get the damn things to syncronize properly with the step chart and music.

I have resorted thus far to adding empty space to the beginning of the videos, or credits, to allow them to display properly when I try them in Step Mania play.

2 problems with this:
1) the sync is NOT always consistant ><
2) the sync in the TEST AREA is always correct without video editing. It starts the vid where I tell it to, based on the simple options available in the stepmania editor. However, the PLAY area starts the video MORE THAN 8 SECONDS BEFORE the listed start time. So its not starting at 0:00 on the vid. Except in the test area for making it ><


I don't know code, and this shouldn't be that hard. I am not trying to sync or move or transition through multiple images or movies: I just want ONE video to start when the music starts, and stay synched throughout at 100% speed (the step chart was made from the audio in the video, so that should not be the issue). Even worse, this is not something I can jury rig on MY machine, I am making this for someone else, so it has to work on HIS PC, and any DDR arcades he brings it to.



What am I doing wrong? Do I need to add the 8-9 seconds of dead space to make the video line up? WILL THE SYNC BE RIGHT ON SOMEONE ELSES MACHINE? Please help.


Lastly, despite reading the excellent BG thread by TheFlyingSquirrel, I am still lost when it comes to any coding, and so I am doing this through the visual step-chart editor inside Step Mania as a BGAnim add.

Thanks


EDIT: Ok, I finally wrapped my head around the way the .sm file is coded for background changes. I added the lines in the .sm file, and tried as "#BGCHANGES:0.001=Krishach - Halloween 2008=1.000=0=0=1;"

also, used the original editor added line
#BGCHANGES:0.001=Krishach - Halloween 2008=1.000=0=0=1,
99999=-nosongbg-=1.000=0=0=0 // don't automatically add -songbackground-
;

Still has the same time lag. Again, the problem is the video starts at SECOND NINE, instead of the beginning, and I have to add blank spots to the video itself to get it to line up. However, having done this, it doesn't sync the same on other machines.

hmm does your video have audio also if it does just throw your mp3 file in the trash and use the video file....

[Daniel]

If the mp3 was directly ripped from the video the simfile should sync up automatically. However why are you using #BGCHANGES:0.001? You should be using #BGCHANGES:0.000

Was the mp3 actually created from the video? This may be a hardware problem if you are attempting an ITG2 hack. ITG2 hardware isn't totally powerful.

[TougaKiryuu]

part of the problem could be how the audio was ripped. I have occasions where if I rip audio, the program will put in a very brief moment of quiet which causes it to be off, you could always check the mp3 with goldwave and remove any silence if that's what happened

[Daniel]

Oops I forgot to explain how the offset of the video and the offset of the entire step chart has to be correct.

When you place a video at second 0 the chart itself more than likely does not start at second 0. The chart begins at -0.980 for example. Therefore the video has to have an offset to match the chart's offset. However the #BGCHANGE tag places videos based on beats and the #OFFSET tag places the entire step chart field based on seconds. We are going to need some algebra to convert seconds to beats.

Let's say the offset is -7.372. We need to know what that amount of time is in beats. Here is the formula...

((# of beats) / BPM) * 60 = # of seconds

If the BPM is 134.94 here is our math problem in the formula

((X)/134.940) * 60 = -7.372 <== offset

Here it is solved for example

0.445x= -7.372

-7.372/0.445

-16.566

Here is an except from my notes.

To solve this Algebra problem calculate the reciprocal of the BPM.

Multiply the reciprocal of the BPM by 60

Attach the variable to the BPM's reciprocal and place the equal sign
next to the offset.

Divide the offset by the BPM's reciprocal to reveal the variable.

Plug in the answer to see if it works.

Hope this helps.

[MdX MaxX]

Have you tried setting the video to start on a negative beat (manually through the SM file)? For example, if there are 5 beats of emptiness in the video you could set the video to start at -5.000 beats manually. I did this with BPMs so I assume it would work with BGVideos also.

[KyahRyorin]

Originally Posted by MdX MaxX

Have you tried setting the video to start on a negative beat (manually through the SM file)? For example, if there are 5 beats of emptiness in the video you could set the video to start at -5.000 beats manually. I did this with BPMs so I assume it would work with BGVideos also.

It does. I have several videos that are set at negative times to sync with the music. You have to make sure it matches correctly, otherwise you have a very off beat video to an on beat song. X3

[Krishach]

I've had to resort to doing that several times now, and the audio WAS ripped from the video. And in the TEST area, the video sync's correctly if set at 0.0000

In the PLAY area is where is way way off. And the two are drastically different.

Also, if you wouldn't mind, what scripting are you using to get the video to start play on a negative second? You have to make that sort of script in DWI if I recall. When I make it using the info provided on SM and DWI BG vids thread it doesn't change its timing, and I wonder if thats because I still have the line

#BGCHANGES:0.000=Krishach - Project=1.000=0=0=1,
99999=-nosongbg-=1.000=0=0=0 // don't automatically add -songbackground

in the SM file. Does that need to be removed or altered?

How do you write your script in DWI when your playing just one video?

[Krishach]

Would someone please post an example script for a single video, and tell me with clear words what changes need to be make to the SM file so the video write in the DWI file plays correctly?

[Akira]

okay... shameless plug

Aya Hirano - God Knows

what I did was actually edit the video to match the beat to where it starts. look at that file in the editor and see where I start them

also, I remove the audio from the video file and keep it in a low, but clear resolution like 320 x 240 to prevent lag. Also, use a more familiar encoding like DivX and XviD

[Krishach]

Thanks. If my projects finish, is it against this sites rules to post the DMI and SM files and link offsite to AMV.org, where the videos I have been given permission to use are?

The artist videos are freeform fan vids, but I believe its a free download. Not sure about rights though, however I personally bought the CDs for the songs in the vids (why do a vid/stepchart if you don't love the song, right?)


EDIT: it looks like you changed the beat that the video starts on. How do you change the Second that the video starts on? Like starting at -8.46 seconds, for example.

[Krishach]

sorry again for a bump, but I still need a little help changing what second the video itself starts on. The information previously provided let me change what BEAT it started on, but if I need to start the video itself on second 20 (video time 0:20, not song time) or on time -8.46, how does a string for DWI look to make that work? I tried writing the one for the FAQ on DWIs and starting that way, but I must have coded something wrong, because it doesn't seem to change anything.