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trimming silence from the ends of a large batch of mp3s, looking for a free program for this, with a few settings at least
raygrote
post Oct 23 2013, 00:05
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Hi all,
I know this has been asked several times on here and other places, but I still could not find a definitive answer with a quick Google search, so I'm posting here.
Recently I've noticed that some of my mp3 encodes have a bit of silence on both ends. The silences are anywhere from a half second to 2 seconds in length. I am only concerned with digital silence, which there is quite a lot of. I don't want to touch anything else. I know the mp3 format isn't gapless, but that much silence isn't the result of the encoding process... normally I don't see any more than 50 MS on either side if I trim the original before encoding. And before you ask, I don't have originals anymore so I can't re-encode it the way I would like.
The files are VBR... hopefully that won't affect things too much.
I was wondering what program would be best to remove these silences. Preferably, I would want to keep a small amount in the order of a few frames to make sure that no audible data is lost. Hopefully that amount could be adjustable. If you cut too close to the data you want to keep, you can damage the beginning of the useful part. So I have no problem giving it a few frames of silence to keep the audio sounding as good as it did before.
I am just getting to know MP3 Direct Cut. While I could easily remove most of the silence manually, I don't yet know how to do it automatically, or if it can be done in batch. So far the only other programs I have seen that can do it are shareware. I would hope that this wouldn't be so hard to do for free, however. Especially since mp3 Direct Cut is free and can do way more than that. So far as I can tell, it has pause detection which for some reason refuses to work for me, probably because I can't understand how to get it to do what I would like. I can't find a feature which auto trims the data, or at least tries to. The manual is brief so there are some parts I don't quite get. Any ideas here?
Thanks for reading and I look forward to your advice!
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Hotsoup
post Oct 23 2013, 00:48
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The only tool I'm aware of that could do batches at a time is dbpoweramp, using the Trim Silence DSP effect. However, without the original source disc/file, I'm afraid it would force you to RE-encode your MP3s. That probably wouldn't have an audible effect, but is usually frowned upon for reasons I don't quite understand. Spoon, one of the developers, is around here all the time and might have better advice. Oh, and that's a paid program license, so not free... (easily worth it though IMO, one of the best music softwares I've ever had!)
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raygrote
post Oct 23 2013, 01:33
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Hi,
Hotsoup, Thanks for your answer. I could easily do that with Gold Wave and its auto trim effect. In fact that is what I am doing with my lossless files. But I will attempt to explain why I dont' support this with my mp3s.
Codecs work by taking advantage of the frequency ranges we are less able to hear clearly. Any distortions that the algorithms produce are carefully distributed in such a way that we cannot hear it. If you compress multiple times, the codec does not know how the original signal sounded, so it will be analyzing its own distortions as opposed to a clean signal. Perhaps one transcode won't kill the quality, but it will certainly make the quality worse. Whether I can tell the difference or not isn't so important... and i certainly don't want to find the best transcode settings. For one thing, codecs are nowhere near being able to transcode well from a technical standpoint, and any audiophile wouldn't want to develop a codec capable of transcoding in the first place, as we would essentially be building a codec that would worsen the fidelity of something which already sounds worse than the original. The very nature of lossy compression is to throw away and approximate things even at their highest bit rates. I hope I haven't come off as harsh, but I am trying to explain clearly and in a way that is easy to understand... I once thought the same thing about transcoding as you did, until I had a few bad experiences with it. I'll only transcode as a very last resort now.
Since mp3 Direct Cut can manually do what I want it to do, all I need is a tool to automate the process.
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Hotsoup
post Oct 23 2013, 03:32
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No, not harsh, it's cool. I knew transcoding was something to avoid, I just didn't know why exactly... Anyway, if it weren't for the transcoding part, dbpoweramp would trim your MP3's like a boss. You could do them all at once and trim pre- and post silence in one swat. I was hoping Spoon would chime in because I thought there was a way to pass them through the DSP without transcoding but after a couple of searches I came up blank. Good luck!
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JJZolx
post Oct 23 2013, 05:15
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QUOTE (Hotsoup @ Oct 22 2013, 17:48) *
The only tool I'm aware of that could do batches at a time is dbpoweramp, using the Trim Silence DSP effect. However, without the original source disc/file, I'm afraid it would force you to RE-encode your MP3s.


Why couldn't a program just examine the frames at the end of an Mp3 encoded file and tell if the audio contained is less than some db limit? And then simply remove those frames without re-encoding the whole file.

A quick google search turned up a program called mp3DirectCut, which claims that it can do it.

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phofman
post Oct 23 2013, 08:42
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I would take a loot at http://mp3splt.sourceforge.net/mp3splt_page/home.php too.
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Hotsoup
post Oct 23 2013, 13:56
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QUOTE (phofman @ Oct 23 2013, 00:42) *

That seems to be the ticket right there.
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