Lua: Create Snap Offset at maximum peak in first second of take

[mpl]

Hi, guys.
I wrote a script to automatically create Snap Offset on maximum peak value on first second of take. Seem to be something wrong with audioaccessor (sometimes changing item selection does not affect to values, like REAPER leave last used accessor in the memory and didnt get new accessor). Sometimes it works, sometimes not, don`t know why. Can anyone confirm is it works or not? And if not, where I was wrong?

PHP Code:

item = reaper.GetSelectedMediaItem(0, 0)
take = reaper.GetActiveTake(item)
source = reaper.GetMediaItemTake_Source(take)

accessor = reaper.CreateTakeAudioAccessor(take)
samplerate = reaper.GetMediaSourceSampleRate(source)
channels = reaper.GetMediaSourceNumChannels(source)
start_pos = 0
samples = samplerate
buf_size = samples -- first 1 second
buffer = reaper.new_array(buf_size*channels)

reaper.GetAudioAccessorSamples(accessor, samplerate, channels, start_pos, samples, buffer)

sample_max = 0
for i = 1, buf_size do
 sample = math.abs(buffer[i]) 
 sample_max = math.max(sample, sample_max)
 if sample_max ~= sample_max0 -- if max peak value is changed
    then max_peak_sample = i/channels end
 sample_max0 = sample_max
end

snap_offset_position = max_peak_sample / samplerate
reaper.DestroyAudioAccessor(accessor)
reaper.SetMediaItemInfo_Value(item, "D_SNAPOFFSET", snap_offset_position)
reaper.UpdateArrange() 


[spk77]

Hi,
It seems to work here (if a take source has 1 channel).

[mpl]

Strange... Sometimes buffer return extremely small values, even if i don't change code and just run script again.
I understood that samples going to buffer from same position one channel after another, so i put

PHP Code:

max_peak_sample = i/channels 


.
But I have a feel something wrong here (or there is a deep bug in accessor api not reproducible simply).

[alex_]

Very useful script, thanks mpl!
Is it possible to set the snap offset at the peak of the entire file instead of the first second?

Also the script only sets the snap offset to the first of the selected files. It would be great to be able to do that for all the selected files at once.

[vala]

Originally Posted by alex_

Very useful script, thanks mpl!
Is it possible to set the snap offset at the peak of the entire file instead of the first second?

Also the script only sets the snap offset to the first of the selected files. It would be great to be able to do that for all the selected files at once.

I am interested as well in this behaviour, please!

[TabbyCat]

Originally Posted by vala

I am interested as well in this behaviour, please!

If you don't need the 1 sec time constraint, there are built-in Actions (via SWS) that will do this:

SWS: Move cursor to item peak sample
-then-
Item: Set snap offset to cursor

Combine those two into a Custom Action. I have one that I constantly use for this very application.

If you don't want the cursor to move, run these at the start/end of the Action, respectively, and it will appear that the cursor never moved:

SWS/BR: Save edit cursor position, slot 01
SWS/BR: Restore edit cursor position, slot 01

[vala]

@TabbyCat:
oh yes, lovely! thank you!

[alex_]

great, thanks