I have a wav file that is behaving stragnely when I import it.  I switched the timeline view to show me the source (button turns green), displayed the waveform, and selected a precise range.  When I cut this into my sequence, I ended up with a slightly shifted range -- i.e. a piece of audio that was CLEARLY cut off when I made the selection was not included in the segment in the sequence.  The timecode was correct, but the resulting piece of audio was a frame or two off.  In other words, the waveform I "saw" when selecting the audio was not correct.

I investigated a little further, and discovered that the problem occurs as I zoom into the souce clip.  I can actually see a sudden shift in the selected section of waveform when I zoom in beyond a certain zoom level.  For example, I see a one frame "pop" in the source clip (using the "source" view on the timeline), so I park on this pop and place in and out points on this single frame.  I then start zooming in.  When I zoom in to the point where a frame is about an inch or so wide on my screen, my current position and the in/out selection are suddenely one frame to the left of the pop according to the waveform display.  I zoom in more, and suddenely the in/out selection appears two frames to the left of the pop.  I zoom back out, and the waveform once again shows the pop as being selected.

Note that the "zoomed out" view is the "correct" one.  The audio I actually hear when playing the selection corresponds to what I see when zoomed out.  The zoomed in view does NOT reflect that audio section that will play.

When I cut the selection into a sequence, the issue stops -- i.e. it only appears to happen when viewing the source.  In the sequence, I can zoom in as far as I want with no "shift" in the waveform display.  The problem, however, is that this issue makes it more difficult to make accurate selections in the source.  If I'm zoomed in far enough, what I see will not be what I get.

Just a few extra pieces of information:  This audio was created in Audition at the same sample rate and bit depth as my project, and this is confirmed when I view the resulting properties in Avid after import.  Also, I only see this happening in a single file so far, but this file was created in the same program (Audition) with the exact same settings as other wav files that do not have this issue in Avid, and it was imported with the exact same settings.  I don't know why this file would be any different.

Once again, this does NOT happen when viewing the same piece of audio in the "sequence" display once it's cut in.  It's only the "source" display that does it.  I realize that this allows me to do accurate cutting once the clip is cut into the sequence, but I want to make sure that there isn't a bigger issue at play here that could cause other problems.

Thanks for any feedback on this,

Larry

UPDATE:

Apparently -- the issue DOES transfer over to the sequence in at least some situations.  I created a new sequence, cut in the entire clip, and I find that I cannot make accurate edits based on how I "see" the waveform.  I marked everything up to a one frame "pop" and lifted it out, and it lifted the pop as well, which was clearly not selected.

Does anyone know what can cause the waveform of a wav file to display erraditcally like this?

Thanks,

L

Another UPDATE:

The file in question was created by trimming another wav file (once again, in audition) and saving out a new file of just this smaller section.  When I went back and saved out the same file with the same processing but WITHOUT trimming anything from it (i.e. it was the full original wav file with some processing), it does NOT have this problem in Avid.  The issue is apparently related to trimming the fine in Audition first.

I also tried another troubleshooting test where I exported the (problem) file from Avid as a wav file and then imported the export.  It showed the exact same issue as the original import.

Thanks again for help with this.

L

I have to say this is an issue that a number have experienced. I've had it happen myself a number of times.

Basically the Avid waveform drawiong display has an issue or bug and the display is mistimed.

Never got to the bottom of how or why. Its not related to the source file creation as I've seen this on one track of a multiple file delivery. Its related to the content in some way. Its an uncommon issue and even less people report it so hard to troubleshoot.

Thanks for the response.  It makes me feel a bit better to know that I'm not the only one (i.e. not a problem with my sources or system), but it's quite disconcerting in general, and makes it VERY difficult to do normal audio cutting in Avid if one of these "problem" files is necessary.

L

Pat says that it is an uncommon issue.  Well, he is lucky then.  All the editors here have hit it multiple times.  We are currently running 8.5.2 on most workstations on Mac 10.9.5.

Sometimes forceing Avid to delete the waveform files it has created and therefore make new files helps.  But not always.

I can find no smoking gun as to why.  But it is really annoying.

Jef

I'm with jef, totally; the only workaround is to trash the waveform cache files, but eventually the waveform display shift will come back, and You'll have to trash the files again.

I don't even have any viable theories as to why this happens to certain files and not others.  I have a wav file that I edited in Audition that works fine -- no display errors.  If I cut a piece out of it and save it as a smaller section of the original file -- still in Audition -- the resulting file ALWAYS has the display issue.  I don't know why selecting a section and saving it as new file would have ANY effect on how it displays in Avid, but the smaller files always has this problem while the longer version does not.

Given that this issue appears to be relatively common, has Avid acknowledged it.

L

lalittle:

I don't even have any viable theories as to why this happens to certain files and not others

One suggestion could be in your Import Audio settings.  Do you have "Subframe Alignment to Broadcast Wave Start Time" checked or unchecked.  (could well contribute to differences between files saved and then imported as .wav compared to those saved and imported as Broadcast.wav) 

AndrewAction:

One suggestion could be in your Import Audio settings.  Do you have "Subframe Alignment to Broadcast Wave Start Time" checked or unchecked.  (could well contribute to differences between files saved and then imported as .wav compared to those saved and imported as Broadcast.wav) 

Yes -- I tried changing that setting, as well as some of the other import settings in Avid and export settings in Audition.  No differences -- the exact same behavior happens every time.

Thanks for the suggestion.

L

lalittle:

No differences

Pity. Last thought on that setting and you probably something you have tested already, Clearing the waveform caches between each test.
When I get a chance I will try inputing some original.wav files  and the same files taken into Pro Tools and the saved from there as BWF files with start times moved by a quarter frame and then again by three quarters of a frame. 

AndrewAction:

Pity. Last thought on that setting and you probably something you have tested already, Clearing the waveform caches between each test. 

When I get a chance I will try inputing some original.wav files  and the same files taken into Pro Tools and the saved from there as BWF files with start times moved by a quarter frame and then again by three quarters of a frame. 

I haven't tried that yet -- can you tell me where to find the option to delete the waveform caches?  I searched around but I'm not finding this information.

Thanks,

L

The editing application saves cached waveforms for projects. You will see a WaveformCache folder in the Avid Projects directory. The WaveformCache folder also appears in the Shared Avid Projects directory.

AndrewAction:

The editing application saves cached waveforms for projects. You will see a WaveformCache folder in the Avid Projects directory. The WaveformCache folder also appears in the Shared Avid Projects directory.

Just to clarify, is it a "one or the other" situation?   i.e. if I find the files in the project folder, do I just delete the files there, or do I have to delete files in two different locations?

Thanks.

I did both here with no ill effect. On the short test project I had available this morning.  

Disclaimer: With Pro Tools on the same machine able to use the local MC media I VERY rarely use waveforms with MC. My experience with these audio cache files is limited to testing tried after reading this thread and finding them via MC help.