Changing timestamps on an audio file
May 22, 2011 8:12 AM   Subscribe

Is it possible to change the timecode on an audio file?

I have an Olympus LS-11 (you can see it here)

I was wondering if it's possible to edit the timecodes that are recorded along with the sound? I set the clock wrong on the device and I need to adjust the timecodes to an hour later. Is there a way of somehow doing this without altering the recording?

The software I use needs to be able to sync the time from the audio file with a realtime text file I created. If I can get the two to match, then all should be well (but I need the text file timestamps to stay how they are!).
posted by stenoboy to Computers & Internet (8 answers total) 1 user marked this as a favorite
 
I don't know what that device is using for timecode since it doesn't mention anything about it on the product page, but It's probably easier to change the times in the text file.
posted by rhizome at 1:02 PM on May 22, 2011


What is the format of the actual audio file? It's likely that the audio file (mp3 or aiff or whatnot) simply has a start time somewhere in the metadata (tags) and doesn't have an actual clock time encoded throughout the actual audio stream data. That is the program justs sees the tag that says 'recorded YYYY/MM/DD HH:MM:SS TZ' and just uses that as the starting point for the time clock. It's probably pretty easy to just change the tag.
posted by zengargoyle at 3:36 PM on May 22, 2011


Is the 'timecode' a tag, or just the file creation date? The former can be edited with mp3tag while the latter can be modified by examining the file's properties.
posted by unmake at 4:37 PM on May 23, 2011


Response by poster: Thank you for the replies.

I should have mentioned the format I record in is PCM. The program I use cannot use anything else. Is there an mp3tag equivalent that will work for PCM?

Also, will altering the first timestamp alter those following by the same amount? That's the goal here, is possible.
posted by stenoboy at 4:18 PM on May 27, 2011


So...what software do you use for the sync'ing?
posted by rhizome at 6:08 PM on May 27, 2011


Response by poster: It's a court reporting software that's designed to make transcripts quickly. The software itself won't let you change the start of the audio file or the text file, although you can alter the timestamps within the text file to reflect, say, a videographer's timestamps.

The software requires in order for the text and audio to be synched that the file was started at the same time. This is fine if the computer took charge of the making of the text file and realtime steno, recording audio at the same point, but it's more difficult to sync when a file is 'brought from the outside'. The court reporting software has a limited ability to change the audio tracking with the text, but you have to plus or minus the amount of time difference to what was said and what's in the transcript. And this only works if the initial start times match anyway, so it's not useable in that respect.

I want to find a way to change the creation time of the sound file and then for all following times to match that change plus or minus the time as neccesary.
posted by stenoboy at 12:51 AM on May 28, 2011


The creation date is not a tag - PCMs and WAVs generally don't have that sort of metadata.

I don't know what OS you're using: on Windows XP, you could adjust timestamps by right-clicking a file and viewing its properties. This functionality seems to have been removed in Windows 7; SKTimeStamp looks like it adds it back in. This app appears to do the same on OSX.

There are probably some command line (terminal) was of accomplishing this as well.
posted by unmake at 1:30 AM on May 28, 2011


So your actual question is how to change the timestamp of the audio file?

Use "touch" on unix/mac, which is also available for Windows.
posted by rhizome at 10:35 AM on May 28, 2011


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