Audio and Video Sync Problems

[bob_moody]

I have been working on capturing video of our display this year (1st year video, 1st year editing ... TOTAL NOOB...)

I have captured 3 or 4 songs already and had no problem getting them to sync up. I took a portable radio with me on the tripod and turned it up so the camera would capture the audio and give me a point of reference when overlaying the actual music.

Now I have been working on two songs. What I do when editing is put on a pair of headphones and put the audio from the camera in one ear and the music to sync with in the other ear. I can get them right on the money.

The issue is that while it starts out perfect it seems to drift as time moves on. By the end of the song I am no where even close. The lights are in sync with the camera audio. I dont know/understand what is happening.

Is it my playback computer?

Is it the camera (JVC Everio GZ-MS110)

Editing software (Vegas Video HD 10)

Is it LOR or the audio clips I'm sync'ing these songs with.

I have done songs with MP3 and WAV files and until now they are perfect. Both of these are MP3's are the same file that I'm using for playback.

The ONLY thing that I can think of between these 2 songs that wont stay in sync and the others are they were BOTH edited in Audacity. But then again, its the same file that is being played back in LOR.

I'm looking for help. I really want to get the display filmed before its time to teardown .

Thank you ... Long post .. I know..

PS. Videos I have been working on VIMEO. You can get there from our website:
http://moodychristmas.weebly.com/

Bob

[bob]

I'm not sure I understand what you're doing, but: Are the MP3s variable bit rate?

If they are, I suggest converting them to constant bit rate, or to WAV files.

[bob_moody]

Bob,

I have recorded video of my display and i'm in the process of editing the video. I use a radio next to the microphone of the camera to capture the audio so I can hear the music being broadcast from the FM transmitter.

Then when I edit the video, I can add the original sound track in and replace the audio soundtrack on the video.

The issue is only with two songs both of which were edited with Audacity. The kicker is that the sequence playback from LOR and the recorded audio are in sync. The issue arises when I try to replace the videos audio track with the original soundtrack used to create the sequence. Its time drifting.

I am thinking it has something to do with the Audacity edit and playback via WMP in LOR and the playback via Vegas Video Software. The audio file is MP3.

How do I determine if MP3 is variable bit rate?

What I dont understand is that non-edited audio either MP3 or WAV do not exhibit these issues.

Thanks,

Bob

[Paul Roberson]

Just a thought. Try opening the mp3 in question in audacity and export it as a .wav file.

Use the wave file to sync up to your video and see what happens.

[bob_moody]

Paul,

I did what you suggested and I still cant keep the sync from end to end.

How do I tell if the MP3 is variable?

How much damage would I do to the sequence to trade out the MP3 to the converted WAV?

Thanks,

Bob

[Paul Roberson]

bob_moody wrote:

Paul,

I did what you suggested and I still cant keep the sync from end to end.

How do I tell if the MP3 is variable?

How much damage would I do to the sequence to trade out the MP3 to the converted WAV?

Thanks,

Bob

It should not affect the sequence at all. I have traded out MP3, WAV, and WMV files in the same sequence. The WAV and the WMV files were made from the MP3 file that the sequence was programmed with.

If you converted the MP3 to WAV and you inserted the WAV file in your video you are trying to make and it did not sync all the way thru I would say there is some other problem other than VBR.

I have heard you can open a MP3 in winamp and play the file and watch the kbps under the title and see if it changes or is constant.

There is probably a better way, but I do not know of it.

[Brian Mitchell]

It sounds to me that your camera may have a slight speed issue with playback. Perhaps a weak battery is causing it to record or play back at a slightly slower speed. That would make synching it almost impossible without some professional equipment.

This used to happen all the time back in the dark ages. (before digital)

[bob_moody]

I THINK I have found the problem. I went back videoed a song that was done originally with a WAV file, not editied, and that I had already done sucessfully. (Sandra's idea)...

As I was watching the display, I saw a hiccup on the MERRY CHRISTMAS sign as it was scrolling across the roof. It actually stopped for just the slightest of moments.

When I brought the raw footage to the editor, I found the spot and sure enough there was a pause. For several nights now I have been hearing a progressively worse popping and crackling noise over the radio during playback. I thought at first my FM25B was starting to fritz. But I unplugged it and the audio glitches were coming from the computer itself. However I didnt think it was affecting the show. It was just annoying.

Well lo and behold, it is affecting the show however it is almost unnoticeable becasue it appears that LOR has time sync with WMP that regardless of what happens, LOR stays in sync with the time code from the audio.

Unless I was creating a video and trying to lock the sync back I would have never seen or noticed the issues.

So. It seems I will rebuild this laptop (Dell Inspiron 1300) and see if that fixes the problems. However, I think I have nailed the issues.

Thanks for all the help...

Bob

[bob_moody]

Found the problem. Flakey power supply to the laptop.

It was bouncing back and forth between AC and Battery causing power surges.

Fixed the PS and the problem appears to be solved.