Audacity Forum

I have a number (>2000) of 90 minute lectures I want to compress to 80 minutes.

Fortunately the lecturer pauses frequently, and many of those pauses are several seconds long. I tried using truncate silence to remove silence longer than 1200ms and have managed to reduce a 90m lecture to 78m. (This involves several hundred silences that are shortened).

Unfortunately, I sometimes find that the last few seconds of processed audio are the wrong audio, i.e. in place of the last few seconds of the lecture there are several seconds from another part of the lecture. I noticed a similar post:( http://audacityteam.org/forum/viewtopic ... nce#p10520 ) but It seems that it couldn't be reproduced. I have tried several times with the same file and the results are the same.

I am running
Windows Vista Home premium
AMD Athlon 64 dual core processor
3G memory
Audacity 1.3.5

I imported a wav file
12db noise reduction
truncate silence 1000ms -25db

The original wav file is 380 MB

I installed ubuntu and audacity 1.3.4 and had the same problem

ssiegfri wrote:I tried using truncate silence to remove silence longer than 1200ms and have managed to reduce a 90m lecture to 78m. (This involves several hundred silences that are shortened).

The problem may be due to the number of edits that the effect is doing, causing memory locations to be overwritten, or something like that. Try splitting the track into 2 and running the effect on one half, then repeating on the other half, and see if the problem is still there. (This is just a guess as I can't reproduce the problem).

When I did half the track at a time, I didn't see the problem on either half. (I didn't listen to the whole thing though just the end of the modified section of track:)

This problem is reproducible, I believe; here's why:
1. Whenever I open this file (I named it e27.wav) and do truncate silence (1000ms -25db) the last few seconds are from somewhere else.
2. I installed ubuntu linux and audacity 1.3.4 and saw the same exact issue with this same file.

I understand your line of reasoning. I estimate that there would be around 1,000 edits over the course of the track.
I would send the file but it is 380MB. I exported to ogg and it is 25.8M however I couldn't reproduce the problem using the ogg vorbis file.
I could try splitting all my files and doing them in two parts, however it will become impractical when I have to do hundreds or thousands at a time.

I have a similar problem. When I use truncate silence (1200 ms -45db) on my 38 min lectures a bit at the end get cut away. The file was shortened from 38:48 to 37:20. About half of that was from shortening of the file by the truncate, the other half was an unintentional cutaway. The end of the file was lost. When I marked 10 minute parts of the clip and used truncate on those, I didnt discover any problems. Does this indicate a memory problem?

I run 1.3.5 Audacity on a 2 gb internal memory, Vista system.

Now I noticed that when I marked 10 minute parts and did truncate silence on them. An extra bit got cutaway at the end when I marked the last 8 mins of the file.

Strange.

The file I do this on is a 38 mb mp3 file that was recorden in stereo, but I droppen one track and edit the original left channel as mono.

Bjorn, again