SAWStudio Video from 30 non drop to 29.97 non drop

[DavidandMary]

Hey,

How do I take a video that is 30 non drop to 29.97 non drop after I finish the audio in SAWStudio? The Video program wants 29.97 non drop. But, the actual video sent is 30. Basically, the guy is doing tutorials with Camtasia to capture the screen of his PC. He then narrates it. Now, he wants me to edit the audio, use the Levelizer and give him a 29.97 non drop AVI file. That way he could take it to Sony Vegas or whatever and add text, titles, etc. How would I help him?

[DominicPerry]

I think you need, in the Video Viewer: File -> Stamp New Avi File Frame Rate
I don't know how it works, and I can't find anything in the helpfile. Try changing the frame rate and then working on it, or do the work and then change the frame rate. Or wait for Bob to give you the right answer.;)

Dominic

[DavidandMary]

Will do Dominic and thanks for the point. I am reading up on that section of the helpfile again. It's probably what you said though...

[DavidandMary]

Something interesting to me... Let's say that I start the project in 29.97 non drop. Then, I import the 30 Non drop AVI file into the MultiTrack and ignore the warning that the framerates do not match. The Video still plays! So, maybe I should just not worry about it? Any advice is appreciated. Video seems to be its own animal...

[Bob L]

If the framerates do not match, SAWStudio will auto conform the video playback to the new rate set in the timeline... this will drop or duplicate frames as needed to match the overall framerates for the final results...

On a screen capture video, this will probably not be noticed as only very few frames will actually be adjusted.

So... if you want to render the final video to DV (which forces 29.97), then set the timeline to that rate at the start and do the audio... otherwise the audio and video will drift apart by the end of the project.

Bob L

[Dave Labrecque]

I think you need, in the Video Viewer: File -> Stamp New Avi File Frame Rate
I don't know how it works, and I can't find anything in the helpfile. Try changing the frame rate and then working on it, or do the work and then change the frame rate. Or wait for Bob to give you the right answer.;)

Dominic

FYI... I think the 'stamp new frame rate' thing is for fixing mis-stamped headers, not for changing frame rates of video files. Careful... it'd could end up being like changing the sample rate setting in the header of a 44.1 WAV file to 48. It'll playback at the wrong speed for the content. I think.

[DavidandMary]

If the framerates do not match, SAWStudio will auto conform the video playback to the new rate set in the timeline... this will drop or duplicate frames as needed to match the overall framerates for the final results...

On a screen capture video, this will probably not be noticed as only very few frames will actually be adjusted.

So... if you want to render the final video to DV (which forces 29.97), then set the timeline to that rate at the start and do the audio... otherwise the audio and video will drift apart by the end of the project.

Bob L
OK Bob! Thanks for that good information. Very helpful...:)

[DavidandMary]

FYI... I think the 'stamp new frame rate' thing is for fixing mis-stamped headers, not for changing frame rates of video files. Careful... it'd could end up being like changing the sample rate setting in the header of a 44.1 WAV file to 48. It'll playback at the wrong speed for the content. I think.

Good to know Dave...:)

[Gary Ray]

Here is something I just grabbed off the internet. www.csif.org/html/dropframe.html (http://www.csif.org/html/dropframe.html) --a concise and short tutorial.

Some simple math that is helpful for me to see what is happening.


Frame Rate/Audio Sample Rate = New Frame Rate/New Audio Sample Rate

-or-

30fps / 48,000 sample rate = 29.97fps / 47,952 sample rate

Your client may end up with more frames than he actually thinks he will have at the end of the project. These frames are not lost. Only the counting mechanism is different and therefore, the playback speed changes ever so slightly.

At 30fps, 60 seconds of video has 1,800 frames. At, 29.97fps, 60 seconds of video has 1,798.2 (drop the .2 cause you can't play .2 of a frame) frames. - To carry this one step further -

30fps 60 Seconds of audio has 60x48,000 = 2,880,000 samples -and-
29.97fps 60 seconds of audio has 60x47,952 = 2,877,120 samples

-or- just forget the above and follow what Bob has said.

[DavidandMary]

LOL Gary! They always said that music was math... Thanks for the article. i did not know that drop frame did not drop frames but was actually just a different way to count the frames. That was interesting. Drop frame seems a good way to go...

[Gary Ray]

David-
Something you might consider. Instead of getting into the video codec issues, ask the client to provide you with the total sound track audio file. Also ask for the total numbers of video frames of the project. Also ask for the correct sampling rate of the audio in the video he has produced.

The point of this is that every time you process (render) through a different codec (inspite of being in the digital domain) there is a minor but perceptible degradation of the video signal. If however, it is the exact same codec, then it probably isn't worth fussing about.

With the info above, you can down or up sample and let him worry about 29.97 or 30 or 30.03 frames per second. Do you really want to be in the video business?

Ohhhh.....there will be some feedback on this one.

[Bob L]

You will not have to down sample if you are doing the audio on the SS timeline as I mentioned in my message.

If he is giving you audio tracks to start with... then you would adjust those to the new rate... but if you are handling all the audio to silent screen grab video... if you follow my advise... you will have to do nothing special to the audio for the final results.

Bob L

[Dave Labrecque]

David-
Something you might consider. Instead of getting into the video codec issues, ask the client to provide you with the total sound track audio file. Also ask for the total numbers of video frames of the project. Also ask for the correct sampling rate of the audio in the video he has produced.

The point of this is that every time you process (render) through a different codec (inspite of being in the digital domain) there is a minor but perceptible degradation of the video signal. If however, it is the exact same codec, then it probably isn't worth fussing about.

With the info above, you can down or up sample and let him worry about 29.97 or 30 or 30.03 frames per second. Do you really want to be in the video business?

Ohhhh.....there will be some feedback on this one.


Gary -- hush! You're scaring the children. Children like me. :p

I used to find all this stuff very intimidating. I've found that the less I know about it, the better. And it's very rarely been a problem. Seriously, SAW does what it needs to to keep the audio doing what it's supposed to with the video (and vice versa), so long as the frame rate in the video file header is correct and the sample rates in the audio file header(s) is (are) correct. You don't even have to have the frame rate or sample rate set right in SAW! It may sound funny, but the sync will remain intact.

Stop thinking! ;)

[Gary Ray]

"I'm All Hushed Up" --I think that was Elvis, right?

[Dave Labrecque]

"I'm All Hushed Up" --I think that was Elvis, right?

Deep Purple, I think.

[DavidandMary]

I am glad that it is so simple to do as Bob suggested. I am working on it now Bob! :)

[Carl G.]

"I'm All Hushed Up" --I think that was Elvis, right?

That might have been from a post mortal release album, "I'm All Stiffed Up".