Video file type and frame rate question

[efxmaster]

ok, so I have a video that had it's audio and video recorded on different computers. The video was recorded at 1080i 59.94. Recorded in final cut pro. The audio was recorded in Protools and the session's time code rate was set to 29.97. So I exported the video as an Apple Intermediac codec 1080i and 720p. When played back on catalyst, with the video and audio synced, the video after about 3 minuets starts to look off. It gets worse and worse as time goes.

I changed the catalyst play rate to 29.97 and that seemed to make it worse.

Any ideas?

Thanks for the help.

[Marty Postma]

Are you playing this back as two files?
If so I would recommend putting the audio and video together as one file and then play the single file back.

Hope this helps. :)

[efxmaster]

I would love to, but can't. Basically I have a video that plays along with a song, and a live band playing that song. The band has a few loops and things that they also play with, and so, even if i put the video's audio in with the video file, then other audio might get off.

Protools is sending sysex commands to a hog3 which controls the catalyst. That is how I was syncing it.

[NevBull]

Hi there

can you not chop the content up into verse/chorus/middle8 etc and get the hog to trigger the sections throughout the song? Or is it too critical to get cues in the right place?

More programming needed, but alot more flexible

Nev.

[Marty Postma]

+1 to what Nev posted.

It would be easier to have "loopable" sections of content and trigger them at the appropriate time in the audio track. This way if it is a bit faster or a bit slower you are at least always in the proper "section".

If you need more "precise" sync I would recommend having Protools output MTC (MIDI Time Code) to your Catalyst, and use the Sync to MTC Playback mode in your cue on the Hog.

Hope this helps. :)

[efxmaster]

I wish I had that option. Basically it is a person singing a song, and the band on stage playing the song. Can't really chop the video.

I already tried the midi sync to Protools, and that was cool, until it jumped from one point to the other in the video and back. I think that might have something to do with the crappy midi to USB I got for the catalyst. Man it would have been nice had High End finished the midi on the CIB.

Any other ideas? Thanks!

[Marty Postma]

In that case it definitely sounds like you need MTC to make this work properly.

If you saw "skipping" then there was either a problem with the signal coming from Protools or a problem recieveing on Catalysts' end.

I would suspect the Protools output or cables first.

What device are you using to recieve the MIDI on Catalyst?

With MIDI it is always critical to keep your cable distances as short as possible.

If you need to go longer distances, try these boxes:
http://www.kissbox.nl/products_new.html#midi

Hope this helps. :)

[prodigal2]

I take it that you are requiring either lip sync or certain elements of content to happen at a certain exact points. The only way to do this is IF the band is playing to click, is to get the protools rig to send you LTC(audio timecode).

In FCP i would make sure that your re-conformed mov is accurate to the audio track as when you reconform without audio there is a potential over a 3 min clip for considerable frame drift, cut and add frames as needed. I would recomend that in the sequences settings you set the timeline to the timecode you are working to. There are lots of little points in the work flow that if you don't do it just so, you will come unstuck. If you can install FCP on you catalyst system you can run FCP ref movs, that you have edited on that machine, and test and test till it is right and you can play back accuratly.

Freerunning clips if you need to be frame acurate will always end in tears.

email me if you want a more detailed explaination.

Phil
Philip G Haynes
Live Visual Design and Direction

[SourceChild]

This is a bit more of an explanation that what Phil had mentioned but basically on the same lines.

There are a few factors to consider. First, have you verified that the audio and video are in sync in from the post software that you output from? Sounds like a stupid question but worth checking. I'm sure you probably have.

Something else to look at is the machine performance. When you run this, are you only running one layer? What is the resolution? What kind of hardware? It may not be a hardware issue though and your performance could be fine. Then, it's simply a slip of the video from the audio.

Consider that the video portion of the media is playing at one speed and the audio at another. Here's why:

A media file has two parts, the audio and the video. While they are read at the same time, they are not linked except at their starting point. Think of it like a 10 meter steel cable and a 10 meter bungie cord connected to the same place but both have a weight on them at the very end The longer the lengths the greater the difference in the bungie versus the steel cable.

In a computer, audio is given highest priority, comparable to a steel cable. It will run frame accurate at the rate it was recorded. However, the video will not run at its default frame rate unless deliberately specified. It's like the bungie cord.

The video runs at multiples of the refresh rate of the video card. Basically 60hz means 30fps. This is, unless you force it by using the speed control in catalyst. Or if you're using a devices that genlocks the frame rate exactly as its specified.

We know a media server is not 59.94. It's 60. (actually not exactly 60 but definitely not 59.94 either).

Here's an explanation of what you might be seeing. If the video is 5 minutes long (300 seconds) and the post software outputs the final at 29.97fps progressive then it would have 8991 frames.

Since the video card counts single frames of playback at 30fps then you will complete 8991 frames in 299.7 seconds. Not 300. This means that you see a 9 frame difference between the audio and the video after 5 minutes.

If you're running through an image processor, scaler, switcher, etc then you loose a few frames already. It would definitely be noticeable after a few minutes.

If you can render the file again from the post software so that the video is exactly 30fps then it should work. Basically what this would be doing is introducing one new duplicate frame every 33 frames (1.1 seconds).

I've actually done this manually in the past just experimenting. Literally adding duplicate frames to a video I didn't have the source to anymore.

[SourceChild]

I already tried the midi sync to Protools, and that was cool, until it jumped from one point to the other in the video and back. I think that might have something to do with the crappy midi to USB I got for the catalyst.

FYI, you can use the audio input for SMPTE.

For MIDI though, I use the M-Audio MIDISPORT 2x2 or 4x4. They have been relatively solid. The 1x1 and Uno are a nightmare though.

[efxmaster]

Here is everything I am doing with the catalyst. I have a triple wide screen, blended with catalyst and a triple head 2 go. The computer is a mid 2008 Mac pro with I think an Nvidia 8800. I have a 32GB SSD hard drive for content playback, and a decklink extreme hd 2 for video input.

Ok so at this point I have a video that is a background. It was rendered as a triple wide image. I don't know the exact resolution or what it's codec is. Then I have my other video that I am trying to play over that. This video was recorded at 1080i 59.94. I have exported it at a photo-jpeg at that resolution. I have also done an AIC at 1080i and 720p, and both get off. It is around a 1.9GB file. Then I have 3 layers looking at the video input which just has lyrics from another source coming in the sdi line.

I know that Protools was set at 29.97 when we recorded it. I will check to make sure that the video and audio line up by themselves, but that might be a little hard. 2 computers in 2 different rooms.

The midi device I have for catalyst is a cakewalk um-2g. I don't think it is very good, but it is what I have right now.

Is there anyway to force the catalyst to make my video top priority?

Thanks

[SourceChild]

Is there anyway to force the catalyst to make my video top priority?


NO. There is no way to change the priority of video over audio. In computer standards, audio is presumed to be a higher priority because your ears will hear a defect before your eyes would see it.

This isn't just a fact of Catalyst. It's true at the root level of any computer or digital playback device. Trust me though, this is a good thing because there are all kinds of hidden things 99% of people aren't aware of that need this.

[SourceChild]

Here is everything I am doing with the catalyst. I have a triple wide screen, blended with catalyst and a triple head 2 go. The computer is a mid 2008 Mac pro with I think an Nvidia 8800. I have a 32GB SSD hard drive for content playback, and a decklink extreme hd 2 for video input.

This system will run several layers of HD footage in AIC. Depending on your compression level (about 70% or lower) the PhotoJPEG will also play several layers of HD.


Ok so at this point I have a video that is a background. It was rendered as a triple wide image. I don't know the exact resolution or what it's codec is.

You can check the info on this clip and see what it is, the codec, and the size. I will say though that a 3072x768 image is a big image and you wouldn't be able to run very many layers.

I think it would be a very good idea to verify that it is rendered AIC simply because it running could interfere with other layers being able to run well without dropping frames.



Then I have my other video that I am trying to play over that. This video was recorded at 1080i 59.94. I have exported it at a photo-jpeg at that resolution. I have also done an AIC at 1080i and 720p, and both get off. It is around a 1.9GB file.

Once again, re-rendering this files as Progressive at exactly 30 frames would be a very good idea. Anything interlaced looks terrible on a media server.

In regard to this I want to clarify a few things.

Many times people say 1080i or 720p loosely. In the realm of media servers you do not want to say or to used 1080i or 720p.

More exactly you want to specify:
1920x180x@30fps or 1280x720@30fps (25fps for other locals).

Without getting too lost in detail, the terms 720p or 1080p actually refer to faster frame sampling and the use of anamorphic pixels. These are not characteristics that translate to a media server (at least not yet).




Then I have 3 layers looking at the video input which just has lyrics from another source coming in the sdi line.

Video Capture Layers won't cause issues with the playback.

[SourceChild]

In reading though your post again, I thing I noticed something.

From the way you wrote the post, I believe we all presumed you were playing back the audio of the file on Catalyst.

Reading again now, I don't believe this is the case, right?

You're just playing the video portion along side the audio coming from another system, right?

If this is the case, a test you can do is to enable audio mode on the file and run it with the timecode from the audio dept and see if the audio stays matched near the end. If it doesn't then it means the file you're using is playing at a different time base.

[efxmaster]

Thanks for all the help with this. I have one additional question. I have a 32GB SSD hard drive for my content playback. Would I be able to play more if I had a second SSD drive and split the content between them? Or would I reach the limits of the hard drive bus in the computer?

Thanks