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Author Topic: MP3 conversion seems slow  (Read 2796 times)

Frobozz

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MP3 conversion seems slow
« on: June 18, 2009, 05:36:35 pm »

I just started a big bulk conversion process to build my handheld conversion cache.  It's converting from FLAC to MP3 (LAME -V0).  12,000 files.  I have it configured to cache converted files via a stack and save the stack location to a specified directory.  At the rate it is going it is going to take over a 1.5 days to convert all of the files.  I have a dual core CPU and have the converter set to do 2 simultaneous conversions.

I did a quick test of several hundred files using the dBpoweramp batch converter to convert from FLAC to MP3 (LAME -V0).  Based on that very quick and dirty test it would take dBpoweramp less than 18 hours to do the conversion of all 12,000 FLAC files.

The batch conversion by MC13 seems slower than what is possible on my little computer.  Maybe MC13 is trying to play nice with the CPU and resources rather than process the files as fast as possible?
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Matt

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Re: MP3 conversion seems slow
« Reply #1 on: June 18, 2009, 05:55:45 pm »

Try using the converter tool instead of the stack system for maximum conversion performance.
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Matt Ashland, JRiver Media Center

JimH

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Re: MP3 conversion seems slow
« Reply #2 on: June 18, 2009, 05:57:26 pm »

A quick test isn't a valid test.

Why don't you do a test with the same number of files for both?

And use the same version of the same encoder with the same settings.
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Frobozz

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Re: MP3 conversion seems slow
« Reply #3 on: June 18, 2009, 06:31:58 pm »

I had a suspicion that caching via the stacks might slow things down.  I'll try a dedicated conversion using the converter tool next week as a comparison.  Right now I just want to get the conversion cache built so I can sync my iPod before a weekend trip.

I had always done conversions in much smaller batches so never noticed or cared about the speed.  This time I'm doing it all in one go and didn't expect it to take more than a day.  When I saw that it is going to take about 1.5 days I was surprised.  (I had to recover my music files from a backup after a HD crash and lost my existing conversion cache, so now I have to rebuild the cache from scratch)

The quick test against dBpoweramp was very very quick and dirty.  No controls and I'm not sure I'm testing against the same things or the same version of LAME.  I'll look into things more closely next week after my iPod gets synced and after my trip.

My CPU is cruising along at 50-60% utilization.  I wonder if bumping MC up to doing 3 simultaneous conversion processes would get things going faster even though it is a 2 core CPU (AMD X2)?
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Matt

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Re: MP3 conversion seems slow
« Reply #4 on: June 18, 2009, 06:41:19 pm »

My CPU is cruising along at 50-60% utilization.  I wonder if bumping MC up to doing 3 simultaneous conversion processes would get things going faster even though it is a 2 core CPU (AMD X2)?

I don't think it does simultaneous conversions when building the cache / stacks.  This might be a good feature addition.

You can do simultaneous conversions if you use the dedicated Converter tool in Media Center.  You still might not use 100% of your CPU since it could bottle-neck on the disk I/O, etc.
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Matt Ashland, JRiver Media Center

Frobozz

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Re: MP3 conversion seems slow
« Reply #5 on: June 18, 2009, 09:03:07 pm »

I don't think it does simultaneous conversions when building the cache / stacks.  This might be a good feature addition.

I took a look using Process Explorer (by SysInternals) and Media Center 13 is only launching a single instance of lame.exe even though I have simultaneous conversions set to 2.  Looks like it is only doing a single conversion process at a time when building the conversion cache.  That would explain why the conversion seems slow.  Only half of my CPU is getting put to work.

I'll put in my vote for a feature addition here.  Faster is better.   :)
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Frobozz

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Re: MP3 conversion seems slow
« Reply #6 on: June 19, 2009, 10:03:19 pm »

The conversion cache building process finished.  It ended up taking very close to 1.5 days of processing time.  Now I'll be able to sync my iPod with new songs before my weekend trip.  :)
The total was 6317 FLAC files converted, 5588 MP3 files (they were part of the cache building count even though they didn't get converted)

I did bump into an odd bug.  After the cache building was done I noticed 26 new MP3 files got added to my library.  These "new" files all came from the TEMP directory that MC13 was using for the conversion.  That TEMP folder is not in my library or part of my auto-import.  The files that got added are temporary mp3 files from the conversion process.

Only 26 temp files out of the 6000-some-odd FLAC files that got processed ended up getting incorrectly added to my library.  The temp files no longer exist.  If I had "fix broken links" enabled they would likely have been removed from the library automatically, but I don't have "fix broken links" enabled.

An interesting little odd bug.  Might indicate a race condition.

Settings:
Auto-import options are all off
Fix broken links: No

Conversion settings:
Encoder MP3 (LAME) VBR Extreme (-V 0 --vbr-new)
Source files FLAC and MP3

Conversion Cache settings:
Cache converted file (via a stack): YES
Stack location: I specified a directory
Cache directory rule: I specified a naming rule ([Album Artist (auto)] - [Album]If(IsEmpty([Disc #],1),,-PadNumber([Disc #],2)))
Then I selected "build cache for selected handheld"
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