# another time scale

Hello again,

I am working with video that is 30 frames per second.
Audacity has many many options for choosing a time scale…
hh:mm:ss + hundredths, for example.
Also,
hh:mm:ss + 25 frames
Or, 24 frames, or 75 frames.
but not 30 frames.
So synchronizing is a little dicey.
Any ideas?

If you need to be sample accurate and the frame rate is exactly 30 fps; ensure that your sample rate is 48000 Hz and use hh:mm:ss + samples (1/30th second = 1600 samples @ 48 kHz)

If sample accuracy is not necessary, just use hh:mm:ss+ms (1 frame ~ 33 ms, 2 frames ~ 67 ms, 3 frames = 100 ms,…)

As Steve wrote, each frame (@ 30 FPS) is 33.33 mS.

So you could create bursts of noise every 33.33 mS and duration of the same.
Then create a block of 30 of them (lasting 1 sec), and copy and paste for the duration of your video.
Just mute the noise.

Example:

Create a new project, set the sample rate to 48 KHz, which is the default for audio used in video files.
Import the attached “block” of noise, copy and paste as many times as required.
(HINT: paste the first block at exactly the beginning, then use the right arrow key and paste, repeat).
Don’t forget to mute the noise track, it’s only there for visual reference.
Import the audio to synch up, on a track below.

Note that the noise duration and repetition rate is for 30 FPS and NOT 29.97 FPS drop-frame.
If you use it on drop-frame video, the error will accumulate and get progressively worse with time.

“Block” of 1 sec noise as shown above is attached.

Another method, use the “Regular Interval Labels”.
The only problem with this method is the limit on the numbering, 999 max ( 3 digits).

Example:

I’d have thought that the only time that this will be an issue at all is when selecting edit points, so all you would need is to create 30 labels starting from an exact second position such that the labels overlap the edit point (or 31 labels that start and end on an exact second):

It will depend on how the editing is being done.
For example the client/producer may want something (music for example) at a certain point.
They would normally specify it as HH:MM:SS:FF

Going to an exact hours, minutes and seconds point is easy, however, going to an exact frame location after that,
would involve some hunting around if there was no frame reference from the start.
The hours, minutes and secs could be found from the usual time line, then frames from either the “noise” method or,
using “Regular Interval Labels”.

For example:

Insert music (with 5 sec fade out) between 00:11:04:15 and 00:12:30:22
Leave silence for 20 frames (for audio FX inserted later with video wipe) at following locations:
00:05:11:10
00:06:22:27
00:19:04:04