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blue hell
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 Posted: Sun Jan 01, 2006 3:29 pm Post subject:
Editing mp3 files without loss of quality |
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I don't know if this is possible at all ... but does anyone know of a tool for simple editing on mp3 files without the need for decoding and re-encoding ?
I just need to trim off material from the beginning and ends of tracks and to recombine tracks.
When lossless volume justifications are possible that would be nice as well.
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also .. could someone please turn down the thermostat a bit.
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ian-s
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blue hell
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blue hell
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| Posted: Sun Jan 01, 2006 6:45 pm Post subject:
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Using FooBar to fix mp3 headers seems to solve some problems. This might turn into full blown mp3 restauration course. Damnit why me :-)
Howard's track is still troublesome, this damned VBR thing again I guess, it's about the third time today that one pulled me a leg.
Still ... somewhat ot maybe ... streamripper did a good job in tracking a somewhat flimsy stream, which changed format all the time and dropped out on times. I picked it by accident, and didn't compare against other tools, be it seems pretty ok. Ehh http://www.oddcast.org , by head.
I'm now going to try the easy way out. Not normalize Howard's track but make it normative instead.
Then going to look further into cropping, foobar has some options for that I believe.
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also .. could someone please turn down the thermostat a bit.
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blue hell
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| Posted: Mon Jan 02, 2006 8:23 am Post subject:
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Just found http://www.mptrim.com/ seems promising. Going to try it.
Another interesting link is http://www.reverberate.org/computers/thesis/LosslessEditing.pdf
Edit :
damn mptrim has a filesize limit ... it costs some 60 or 70 bucks to get past that (for the pro version). Apart from that I'd need another tool to find the frames on which to trim ...
Ok, I tried something like 10 tools or so, one crashes on this another on that, I found nothing usefull for me.
AudioScissors, mp3Butcher, mp3Cut, mp3Knife, mp3Splitter, mp3Trim, mp3Utility, mp3 frame editor .. stuff like that.
Also I tried mp3Tidy which is supposed to clean out all the tags from mp3 files, unfortunately that one gave me sonic artefacts. |
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egw
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| Posted: Mon Jan 02, 2006 3:32 pm Post subject:
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Audacity lets you edit mp3 files.
I don't know if it actually converts them to wav first though. |
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blue hell
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| Posted: Fri Jan 06, 2006 7:35 pm Post subject:
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Yes, I know about Audacity, but it will convert first AFAIK ...
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blue hell
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| Posted: Fri Jan 06, 2006 7:51 pm Post subject:
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And next ... forget about all this .. it won't work ...
I've decided to convert everything to WAVs, which was hard enough already as some of the files ... aargh .. the jono track f.i. had to make an analog outboard trip and re-recording before it got usable. It was partly tagged as mono, reported by some toolsas VBR by others as CBR, the bitrates could be 64k or 8k, or 18h as another tool made out of it. The reported length could be anything between 5 minutes and an hour. The only player that would play it was Foobar (tried WinAmp, QT, WMP, Zinf, VCL, CoolEdit, Audacity and I'n sure I forgot some)
Unfortunately 'll have to convert to mp3 again in the end, and that's going to cost I noticed, in quality.
Anyway, this lossless mp3 editing seems a theoretical possibility only, too bad.
Next time I hope I won't forget to upsample everything before I start moving and chopping. Maybe I can still do that and I'll try, but I'm too far into it now to go a step back again.
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also .. could someone please turn down the thermostat a bit.
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ian-s
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| Posted: Fri Jan 06, 2006 8:22 pm Post subject:
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| Blue Hell wrote: | | Anyway, this lossless mp3 editing seems a theoretical possibility only, too bad. |
The way I understood it was that an MP3 file has no file header as such but is simply made up of short, independent blocks, each with it's own compact header. So VBR is not so much a file format but rather an encoding technique that takes advantage of the fact that each block can have an independant bitrate. Large VBR encoded files are a pain in car mp3 players because the player never finds the exact (or even approximate sometimes) location to resume at after a stop.
How a player determines format and length of these files would be dependant on how many blocks it takes as a representative sample I guess.
Re-encoding shouldn't be too bad. Once the DCT has done its thing once, quality reduction is minimal.
Never get as good as the original though. Maybe next time all the performers can organise recording what they do prior to encoding at 64K, is that possible with these pluggins? |
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blue hell
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| Posted: Fri Jan 06, 2006 8:48 pm Post subject:
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| g2ian wrote: | | Blue Hell wrote: | | Anyway, this lossless mp3 editing seems a theoretical possibility only, too bad. |
The way I understood it was that an MP3 file has no file header as such but is simply made up of short, independent blocks, each with it's own compact header. |
Thats what I make of it as well, most software seems to screw up though when it gets to see too many different blocks. Foobar and VCL seemed to perform best in this respect, but both could not convert that one difficult file. BTW my car mp3 player won't play that thrack either, it gets skipped entirely.
This whole concept of independent blocks should make it possible though to do do all kinds of lossless operations on mp3's, including (limited) compression. To make tools for it you wouldn't need to handle any deep encoding related stuff and so probably there would not be any patent licensing issues either.
Not only car mp3 players ar troublesome with VBR, most PC playerrs make up fantasy times for it, like saying 10:50 of 3:10 for progress.
The blocks sohehow do not seem to be completely independent, saw some mysterious notes about that on the web. Also I tried to delete frames from the beginning of mp3 files, which at first seemed to work but gave much trouble with skipping later on in the file I tried it on. Even Foobar got confused by that, although I'm pretty sure i correctly identified the block's starting points (sync patterns)
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egw
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| Posted: Sat Jan 07, 2006 10:59 am Post subject:
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Here's something I came across that looks like it does lossless mp3 editing.
I haven't tried it.
| Quote: | | mpTrim is a simple and easy to use MP3 editor. It can do a number of useful things. You can use it to trim MP3s (for removing silence or unwanted parts), adjust the volume of MP3s with volume normalization, fade-MP3s in/out MP3s (to fix abrupt beginning/ending), and clean-up junk from MP3s. mp3Trim keeps the music quality intact, no matter how many times you process an MP3, because it works directly in the MP3 format without having to decode/re-encode, this also makes it very fast. |
http://www.mptrim.com/ |
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blue hell
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| Posted: Sat Jan 07, 2006 12:03 pm Post subject:
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| egw wrote: | Here's something I came across that looks like it does lossless mp3 editing.
I haven't tried it. |
But I did :-)
It was one of the more usefull programs I tried, but it choked on some of the mp3s I had. The user interface is not super, but good enough for simple trimming off of some unwanted material from beginning and/or end. From reasonably clean mp3s.
There are some more programs like this, but mp3trim was the best IMO.
Another nice program, but a bit of a weird user interface, and apparently more meant for mp3 dj-ing was mp3butcher.
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