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apaige

Member

Registered: 2008-06-15

Posts: 96

caudec, a multi-process command-line audio transcoder

I'd like to introduce a little program I made.

Caudec is a BASH script that transcodes audio files from one format (codec) to another. It leverages multi-core CPUs with lots of RAM by copying input files to a tmpfs mount, and running multiple processes concurrently (one per file and per codec).

• Supported input codecs: WAV, FLAC, WavPack, Monkey's Audio, TAK, Apple Lossless.

• Supported output codecs: WAV, FLAC, Flake, WavPack, Monkey's Audio, TAK, lossyWAV, LAME, Ogg Vorbis, Nero AAC, Musepack.

• Optimized I/O: input files are copied onto a tmpfs mount sequentially, so as to get the best performance out of the underlying medium (e.g. a hard drive). Transcoding however is done concurrently. Example: file 1 gets copied. When that's done, transcoding of file 1 starts. Meanwhile, file 2 gets copied, etc… Very little time is lost reading the files.

• Transcoding to several different codecs at once is possible. In that case, decoding of input files is done only once.

• Metadata is preserved (as much as possible) from one codec to another.

• Uses existing, popular command line encoders/decoders.

Here's the AUR package, enjoy!

apaige

Member

Registered: 2008-06-15

Posts: 96

Re: caudec, a multi-process command-line audio transcoder

It just occurred to me that I left out one of caudec's main selling points: it's fast. It sounds obvious to me, but maybe it isn't so much. I was never a sales person. It might also not be obvious that it works best on somewhat large sets of files (e.g. a whole album with one or two CDs, one file per track).

Encoding ABBA's 2CD The Definitive Collection (148 minutes, 37 tracks) from WAV to FLAC --best, with one process, on a Core i7 @ 2.2 GHz: 46x real time.
Same as above, with 8 processes: 186x

Just for kicks, FLAC -5 (default setting) with 8 processes encodes at 569x, TAK -p2 at 743x.

soupcan

Member

From: ?

Registered: 2008-10-25

Posts: 268

Re: caudec, a multi-process command-line audio transcoder

This looks great! I'm currently using whatmp3, but I'll definitely give this a run. I've been looking for something to replace dbPoweramp for a while now- if this is as speedy as you say I think I've found it.

apaige

Member

Registered: 2008-06-15

Posts: 96

Re: caudec, a multi-process command-line audio transcoder

whatmp3 is nice, though it has a somewhat different aim: creating BitTorrent files for sharing. caudec is marginally faster by design in common usage, faster yet if you use more than one codec at a time, and much faster by default (as whatmp3 uses only one process by default). That requires a lot of RAM, however. whatmp3 will be faster for those with less RAM. caudec, however, is more flexible, supports more codecs, and has better output.

I just released version 1.3.0, which adds support for resampling of stereo files, corrects a RAM hogging bug, amongst other things. Give it a try, and see which of caudec or whatmp3 suits you better

Last edited by apaige (2012-02-23 00:44:31)

12oz.oleg

Member

Registered: 2012-02-03

Posts: 7

Re: caudec, a multi-process command-line audio transcoder

hi, apaige. thanks for great tool.
can you add option to your script to turn off preserving of metadata when converting, to get just audio stream without any tags in result?

apaige

Member

Registered: 2008-06-15

Posts: 96

Re: caudec, a multi-process command-line audio transcoder

Sorry for taking so long to answer your question, I wasn't watching this thread anymore. Such an option would pretty much go against what I'm trying to do with caudec. There are tools that allow for complete removal of metadata in audio files ('metaflac --remove-all-tags', 'id3v2 -D', for instance).

I just released version 1.4.3 today, see the list of changes.

apaige

Member

Registered: 2008-06-15

Posts: 96

Re: caudec, a multi-process command-line audio transcoder

I've discussed that feature with some people and I've changed my mind. Latest SVN has a new -C switch that's like -c, except that metadata won't be preserved. It will be included in the next release.