Time markers move after cutting and pasting file -Sound Forge - PC

Subject:Time markers move after cutting and pasting file Posted by: anduin Date:12/22/2014 10:26:29 AM I am using Sound Forge Audio Studio 10. I have a techno track as an MP3 file, and I "mapped" out my track so that I have 62 segments of 16 beats each. I am turning the track into a series of loops (cut and paste each segment into a new, smaller file and save as) so that I can put them in Acid to manipulate the track. I finish mapping the segments, save the file, then cut and paste both the file and the metadata file into a new location. When I reopen the audio file, every single time marker is moved back to the left a fraction of a second, thus messing up the timing on my loops and rendering all of my previous work worthless. The loops are supposed to start precisely on the first beat of each segment, except now each loop has shifted back slightly. What happened? I used to use an old version of Pro, now I have this Studio version, but this never happened before. Is there a setting to prevent this? Did this happen because of the cut-and-paste action? Did it happen because I'm using an MP3 file and not something like a Wave? Any ideas would be greatly appreciated. I only want to "map" my file one more time! Message last edited on12/22/2014 10:28:45 AM byanduin.
Subject:RE: Time markers move after cutting and pasting file Reply by: SonySQAPete Date:12/22/2014 10:56:15 AM Yep - it's because you're using MP3. MP3 encoding both appends and prepends samples as padding, to the tune of ~1600 samples in total. (The exact number can vary from encoder to encoder.) It's best practice to never edit directly on a lossy encoded source. If you can't get a lossless source, at least convert to an uncompressed intermediary for the duration of your edits. Save re-compression for the finished mix. Doing this will reduce the number of compression artifacts that are introduced into your file.
Subject:RE: Time markers move after cutting and pasting file Reply by: anduin Date:12/22/2014 11:15:36 AM Wow thanks! It's good to know the risks of using MP3s :P So basically, if I start over and begin with saving as a Wave and making my edits that way, then I should be good right? Then, when I'm ready to save and transport the finished track I can resave as MP3 to save space?
Subject:RE: Time markers move after cutting and pasting file Reply by: anduin Date:12/22/2014 11:36:15 AM Also, would this be the reason why, when I work with beatmapping files in Acid, that the mapping is not accurate and the track "drifts" the further along the track goes? It's as if the track itself is not a consistent tempo sometimes. I have been working with MP3s only, however, not all tracks do that drifting thing, so I'm inclined to believe that those tracks actually have an inconsistent tempo (that would be horrible!), and not the fact that I'm using MP3s. But who knows?!?
Subject:RE: Time markers move after cutting and pasting file Reply by: anduin Date:12/22/2014 11:54:09 AM Well I just tried Beatmapping the file in Acid as a .WAV file and it still "drifted". Mind blown. I guess I'll go back and manually "map" the .WAV file in Sound Forge and see how it holds.

Subject:Time markers move after cutting and pasting file

Posted by: anduin

Date:12/22/2014 10:26:29 AM

I am using Sound Forge Audio Studio 10. I have a techno track as an MP3 file, and I "mapped" out my track so that I have 62 segments of 16 beats each. I am turning the track into a series of loops (cut and paste each segment into a new, smaller file and save as) so that I can put them in Acid to manipulate the track. I finish mapping the segments, save the file, then cut and paste both the file and the metadata file into a new location. When I reopen the audio file, every single time marker is moved back to the left a fraction of a second, thus messing up the timing on my loops and rendering all of my previous work worthless. The loops are supposed to start precisely on the first beat of each segment, except now each loop has shifted back slightly. What happened? I used to use an old version of Pro, now I have this Studio version, but this never happened before. Is there a setting to prevent this? Did this happen because of the cut-and-paste action? Did it happen because I'm using an MP3 file and not something like a Wave? Any ideas would be greatly appreciated. I only want to "map" my file one more time!

Message last edited on12/22/2014 10:28:45 AM byanduin.

Subject:RE: Time markers move after cutting and pasting file

Reply by: SonySQAPete

Date:12/22/2014 10:56:15 AM

Yep - it's because you're using MP3.

MP3 encoding both appends and prepends samples as padding, to the tune of ~1600 samples in total. (The exact number can vary from encoder to encoder.)

It's best practice to never edit directly on a lossy encoded source. If you can't get a lossless source, at least convert to an uncompressed intermediary for the duration of your edits. Save re-compression for the finished mix. Doing this will reduce the number of compression artifacts that are introduced into your file.

Subject:RE: Time markers move after cutting and pasting file

Reply by: anduin

Date:12/22/2014 11:15:36 AM

Wow thanks! It's good to know the risks of using MP3s :P So basically, if I start over and begin with saving as a Wave and making my edits that way, then I should be good right? Then, when I'm ready to save and transport the finished track I can resave as MP3 to save space?

Subject:RE: Time markers move after cutting and pasting file

Reply by: anduin

Date:12/22/2014 11:36:15 AM

Also, would this be the reason why, when I work with beatmapping files in Acid, that the mapping is not accurate and the track "drifts" the further along the track goes? It's as if the track itself is not a consistent tempo sometimes. I have been working with MP3s only, however, not all tracks do that drifting thing, so I'm inclined to believe that those tracks actually have an inconsistent tempo (that would be horrible!), and not the fact that I'm using MP3s. But who knows?!?

Subject:RE: Time markers move after cutting and pasting file

Reply by: anduin

Date:12/22/2014 11:54:09 AM

Well I just tried Beatmapping the file in Acid as a .WAV file and it still "drifted". Mind blown. I guess I'll go back and manually "map" the .WAV file in Sound Forge and see how it holds.