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Topic: Best Recomendations for Lossy-to-lossy transcoding (Read 945 times) previous topic - next topic

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  • guille350z
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Best Recomendations for Lossy-to-lossy transcoding
Hello, please consider my case:
I inherited a gigantic collection of music in mp3 and I had it on my hard drive for several years without problems. Now I'm running out of storage space and I'm considering doing a lossy-to-lossy transcoding.
The collection consists of thousands of mp3 files from different sources and their codification varies from 128kbps (~50% of total), 192kbps (~25%) to 320kbps (~25%). They are all coded in constant bitrate (with some few exceptions that are vbr v0).

I know, I know, I'm going to lose a lot of quality, and my sources are not very good (in addition to the low kbps they use not so recent lame versions), but I'm ok, I can accept any loss of quality until the differences are perceptible by my not so good ears.

Given all of the above what are you recommendations? What codec will be the best? I have no preference for any (vorbis, opus, aac, mp3 etc), as long as it is the best for this transcoding. The coding time is not a problem neither, I could leave the encoding for days if it was worth it.

Should I use the same solution to all the group of files? or should i need to use different for the 128kbps 192kbps and 320kbps?

Thank you for reading

P.S. I already tried to delete some, there was a lot of duplication but thanks to nice auto tagging software named Pickard I was able to find them  :)

  • KozmoNaut
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Re: Best Recomendations for Lossy-to-lossy transcoding
Reply #1
Honestly, I wouldn't even bother with lossy-to-lossy transcoding, I would simply buy more storage space. It's rather afforable, considering how compressed is MP3 already.

  • pdq
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Re: Best Recomendations for Lossy-to-lossy transcoding
Reply #2
The first thing you should do is losslessly convert your cbr files to vbr (someone help me out with the name of this tool). This will often reduce the size of the file by several percent by removing unused space.

The next thing you should do is buy more storage space.

  • Porcus
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Re: Best Recomendations for Lossy-to-lossy transcoding
Reply #3
losslessly convert your cbr files to vbr (someone help me out with the name of this tool).

http://wiki.hydrogenaud.io/index.php?title=MP3packer
With the -z option.

Caveat: could work suboptimally with quirky files. In particular, it could destroy gapless information, at least if that was written by a sufficiently stupid piece of software back in the stone age.

  • guille350z
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Re: Best Recomendations for Lossy-to-lossy transcoding
Reply #4
Thanks for your responses,
so it doest matter the codec i choose in this case?

Honestly, I wouldn't even bother with lossy-to-lossy transcoding, I would simply buy more storage space. It's rather afforable, considering how compressed is MP3 already.

The next thing you should do is buy more storage space.

Yes, I certainly do need some storage upgrade, It sound crazy but doing so will affect my monthly budget. I think the Venezuelan crisis has reached the hydrogenaudio lol.

I will try the MP3packer that you commented :)

  • pdq
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Re: Best Recomendations for Lossy-to-lossy transcoding
Reply #5
Deleting duplicates is a start, now try deleting ones that you will never listen to. Keeping something that you will never actually use is called hoarding.

  • DVDdoug
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Re: Best Recomendations for Lossy-to-lossy transcoding
Reply #6
I assume this means you don't have a back-up?  I hate to see you degrading your "originals". 

VBR should give you better results (for a given file size).  It tries to make the most of the available "bits".

Quote
I have no preference for any (vorbis, opus, aac, mp3 etc),
I'd stick with MP3 or AAC if you are not keeping the originals.  These are the most universal "play anywhere" formats.   

I don't know which will be better...  AAC is supposed to be better (if there's any sound quality difference at a given bitrate).  And,  AAC is supposed to be better with multiple generations of compression, but I don't think that applies to transcoding from MP3.

  • Porcus
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Re: Best Recomendations for Lossy-to-lossy transcoding
Reply #7
OK, so you are short on storage. What I would do:

mp3packer, starting  with the CBR 320s, as they are most likely to waste a lot of bits.  But:
Before you repack, remove embedded pictures you do not need. YMMV, but there might be a megabyte album cover embedded in each and every file of the album.
For each album, keep the un-repacked instead of the repacked if there is any sign of errors. Or at least listen then, if gaplessness is lost, before replacing with the repacked version.

If anything is to be transcoded or deleted, start with whatever you can acquire back at a later stage.
And, assuming that you have not given priority to backup: consider some cloud service, starting with whatever is the most scarce.

so it doest matter the codec i choose in this case?
There are quite a few threads around here:

2003: https://hydrogenaud.io/index.php/topic,9285.0.html
2004: https://hydrogenaud.io/index.php/topic,25671.0.html
2005: https://hydrogenaud.io/index.php/topic,32440.0.html
2006: https://hydrogenaud.io/index.php/topic,46062.0.html
2006: https://hydrogenaud.io/index.php/topic,48999.0.html
2013: https://hydrogenaud.io/index.php/topic,100067.0.html (hundred transcodings!)

and certainly more.

  • burkjavier
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Re: Best Recomendations for Lossy-to-lossy transcoding
Reply #8
This is just my opinion but I think you're going in the wrong direction on this.  If it were me I would:

1- Get more storage.  I don't know how big this collection is, but if we're talking about hundreds of GB's you can still buy an external hard drive at a pretty low cost these days.  Btw, I hope you have backups as a side-note.
2- Delete what you don't listen to.   I'm in a similar situation right now where my lossy collection has grown to the point where I really have to sit down and start deleting stuff.  My rule-of-thumb is that If I haven't listened to it in the last 10 years, there's a good change I never will.

As for the CBR / low bitrate question, you could leverage something like iTunes Match to "match" a lot of these and get better versions of what you have, but that will likely increase your storage space.  Except for the 320kps CBR MP3's as the matched AAC version will likely be smaller.  AAC isn't as much of a standard as MP3, but it's more supported than something like Ogg Vorbis.

  • doane2u
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Re: Best Recomendations for Lossy-to-lossy transcoding
Reply #9
I agree.. I wouldn't convert them at all, just get a bigger storage drive.. Every time you convert a lossy file to a different version you lose a lat of quality.. it's like copying a jpg image.  Stoarge is so cheap now, wheather solid state or portable drives, they can hold more data then you will probably ever need space for!  I rip all my CDs to FLAC files using the DBpoweramp utility. I organize all my media content using MediaMonkey as it has the most control for me. If I decide to burn a DVD or CD with music I can instantly convert it to any format or quality I want to on the fly.

  • jensend
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Re: Best Recomendations for Lossy-to-lossy transcoding
Reply #10
In many cases the dangers of transcoding are overrated. Especially if the lossy originals are high quality, the target codec is reasonably modern, and the target transcoded bitrate is low.

I wouldn't transcode any of your 128kbps files at all - lower quality sources mean more transcoding artifacts, and you wouldn't get significant bitrate savings. But transcoding 320kbps MP3s to 128 kbps AAC (or Opus), while possibly ABXable, seems unlikely to negatively impact your listening experience. I'm less sure what to say about your 192kbps files.

Here in the States, $70 is not a lot of money but can purchase a 3TB drive, enough to store 35,000 hours of 192kbps music (4 continuous years). So anyone here who transcodes lossy originals to lower bitrates for normal listening should archive the originals somewhere, just as others listen to low bitrate lossy but have their lossless FLACs archived somewhere. But given the crazy situation in Venezuela, do what you gotta do and best of luck riding it out.