Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Lossless Dave]

I am unable to get MC12.0.400 to update tags in m4a lossless files.
The files are created by converting from flac using the external-encoder with a
call to itunesencode (and thus itunes). iTunes 7.5.0.20 is installed.

iTunes sees and plays these files and their original (EX FLAC) tags correctly.

iTunes can update the tags using the right-click/get info method.  Deleting them
from the iTunes library and re-importing them shows the updated tags.

mp3tag (V2.39) correctly shows the modified tags (via extended tags).  If I modify a tag via mp3tag
it shows in iTunes correctly.

MC12 will import these files BUT only shows the original (ex flac) tags
generally.  If I update the library in the MC12 it reports successful update of
the tags.   A subsequent update library from tags then reverts to the previous values.

Going through the file with a Hex Editor reveals the original and updated values
being carried in tags.

My WORKING assumption is that MC12 is not following modified pointers correctly.

Additionally it reports it is posting tag values but they don't appear in either the original or newer tags anywhere in the file.

As a final nail in this coffin the dbPoweramp shell Edit-IdTag tool is showing the same info as
iTunes and mp3tag.  I can then update the tags via Edit IdTag, which then show
correctly in iTunes/mp3tag but NOT MC12.

The result is that any re-import of files reverts all tag info to initial values.  Quite frustrating!

Audio playback is via the DC-Bass directshow filter.  I recommend this easy to install and use filter.

Regards
Lossless Dave

[Yaobing]

Thanks for the detailed reporting. Media Center does not write tag info to mp4 (including m4a) files. It can only read some tags from them.

[Lossless Dave]

Obviously that's not the answer I was hoping for !

In which case there are two obvious questions

1 - Why do I get a message - tag update successful ?

2 - Other software can do these tag updates. How about implementing in MC ?

Please consider that increasing capacities on iPods may now increase usage of the ALAC format.  Flac is the obvious example of a similar format with broad previous take up.

Regards
Lossless Dave

[schmoose]

increasing support of m4a/mp4 files should be a priority - both AAC and ALAC.

almost every DAP being released nowadays supports m4a (AAC) - even the Microsoft Zune!

why J River still refuses to provide tagging/encoding support is a mystery.

[glynor]

why J River still refuses to provide tagging/encoding support is a mystery.

I don't think they "refuse", I just think they've had bigger fish to fry.  I totally agree that I'd love to see both MP4 and MKV in-file tagging support, and I'd like to see it soon (I'd use it mostly for video files, but using it for audio-only MP4s would be nice as well). However...

Using ALAC-encoded files on an iPod is just a waste of space, especially with MC's automatic conversion method (which can cache the converted files so it doesn't have to re-do conversions it's already done).  The DAC on the iPod is no where near high enough quality to preserve the differences accurately between a high-quality lossy file (such as a V2 LAME MP3 or high-bitrate AAC) and the ALAC M4A file.  Neither option is going to be "true" on an iPod, so you might as well save the space.

I understand totally the desire to use lossless files on your computer.  Especially if you are using a high-quality external DAC or a high-quality add on sound board.  I'm very dubious about the iPod's support for ALAC files other than for convenience (to not have to convert).  With MCs auto-conversion method, even the convenience factor is of limited benefit and the space savings can be extreme.

[JimH]

[Lossless Dave]

Hi Guys,

Firstly - thanks for taking an interest . . . .  It is greatly appreciated.

Picking up your points

1 - I've tried the auto-convert (Flac to m4a lossless) on upload.  It takes roughly three times as long as loading a track already kept in m4a.  I seem to recall having tag issues with cover art also - I would have to retry this if you were interested. I was using the iTunesEncode shim from within the external encoder.  (Is this the optimal method?)  The cache is the work-around for some of these issues - if I had a spare 100Gb and rising fast as I rip CDs (400 still to go) on my PC.  This capacity may soon materialise - but I don't have it yet.  If I did have it the fast way forward would be a dbPoweramp "Apple Lossless" convertion at 4 times the speed of iTunesencode- and then an upload via one of various possible mechanisms - e.g. the very fine SharePod freeware program.  But this takes me away from having a MC based total solution and feels a rather fragmentary approach.

2 - I appreciate your comments regarding quality of output from iPod Classic to headphone socket - however I am hoping to get the digital signal out to use in docked situations to drive my premium quality DAC / HiFi system.  This is yet to be proven though !!!

3 - The PC is equipped with a Terratec DMX6fire 24/96 soundcard. I do take audio quality very seriously.

4 - Future opportunities to re-impement in new and better technology will only be easily implemented if I have lossless to start from.  You can never get back what you throw away in going lossy.  A complete re-rip is unattractive.

Hoping this gives you an insight into a lossless way of life . . .

Regards

Lossless Dave
==================

[glynor]

I totally understand your desire for the lossless output on an equipped PC.  MC fully supports this.  My only argument was with the need to transcode to the locked-down ALAC format for use on the iPod.  Maybe you can get full-quality digital output out of the iPod, but I sincerely doubt it without hacking the firmware on the iPod.  I haven't seen any successful reports that have been fully documented with bit-analysis showing that the output wasn't going through their crappy DAC.

Also... That increased time for the transcoding only happens once, because MC can cache the transcoded files and use the already-transcoded files next time.  If you really want to do this though, I'd just convert your whole library to ALAC.

Again, though, I'd just use the lossless files on your well-equipped PC and transcode to high-quality MP3 for the iPod.  Unless you can get the direct digital output working on the iPod then the whole thing is pointless and you might as well use lossy files on the portable.  And like I said, I haven't seen confirmation that this works without modifying the bitstream.   If it is digital but not direct but going through the DAC anyway, then that's useless.

[Lossless Dave]

Thanks Again Glynor

I didn't appreciate the lack of digital output from iPod.  I'll look into this but it doesn't sound hopeful (sigh).

So - going back to your suggestions.

It sounds like we agree that the PC / MC library has many advantages in being lossless.

BUT which format?

FLAC is fully supported by MC12 but needs transcoding on transfer to iPod (even to lossy AAC this is slow).  A cache needs circumvents this after the first upload but needs serious parallel/additional capacity (but possible).  A better/faster m4a encode option (a la dbpoweramp) would ease the pain here.

ALAC is easily and speedily uploaded , doesn't need additional capacity - BUT isn't supported for full write of tags back to the file unlike (most/many/all ?) other audio formats in MC12.

To an iPod owner it seems reasonable to go the m4a route.

I don't think we want to talk about WMA etc.

So - again and probably not for the last time

Full Tag support cannot be a big issue for the developers and will also bring benefits to the mp4 etc users.

I suggest it should be seriously considered.

Alternatively I could junk the iPod and go to a Flac supporting device (ouch).

PS MC12 still tells me it has successfully updated tags in ALAC files (naughty !)

Regards - in a calm and constructive way

Lossless Dave

[bspachman]

Dave,

Thanks for joining me in the wilderness! It's been a long time as the (apparently) lone voice looking for tag writing to MP4 containers....

I do exactly what you are (or are planning to). I keep dual entries for nearly all of my files. Home playback with Monkey's Audio (fully supported by MC); Portable/iPod playback with AAC files. I use view schemes and smartlists to deal with making sure the entries in MC's database match for both sets of files, and to make sure that only the lossy files get sent to the portable.

I, too, use the iTunesEncoder shim to transcode my APE files to AAC (m4a). However, I use foobar2000 as the engine since it is able to write the basic tags to AAC files. Basically:

1) Rip the CD to APE. Import into MC. Make sure all the tags are as I want them.
2) Fire up foobar2k. Use it to transcode to AAC.
3) Import the new AAC files to MC. Make sure all the tags match the APE versions. Do any cover art manipulations and audio analysis.
4) Repeat as needed!

Tags are the big stumbling block for me since MC doesn't seem to behave properly in getting the information to the AAC files. Then, I just cross my fingers and hope that I never have to change the AAC files' tags

brad

[JimH]

Tags are the big stumbling block for me since MC doesn't seem to behave properly in getting the information to the AAC files.

In the interest of clarity, MC doesn't natively support AAC.  It can play them by using the Quicktime engine.  That's the reason it can't write tags in the file.

The reason we don't support AAC is cost.   The licensing terms aren't friendly to small companies.  It's public information if you want to check.

http://www.vialicensing.com/licensing/MPEG4_fees.cfm?product=MPEG-4AAC

[glynor]

Jim - IANAL, and I hate to burst your bubble, but.... Those Via licensing fees are to cover patents (which are dubious enough as is) for the AAC codec.  This is the compression on the audio inside the container, not for the MPEG-4 Part 14 container (MP4, M4A, M4V, etc) itself.  You could certainly support MP4 tagging without paying those licensing fees.  Those fees would be needed to directly support ripping to AAC or to support direct AAC playback.  Native support for this would be completely unnecessary though, as external encoders and decoders are readily available and work perfectly well (as I've pleaded for before though, a nice "wrapper" GUI for the Nero AAC encoder would be superb).

In fact, even if you pay the Via licensing fee, you might not be in the clear on AAC (aka MPEG-4, Part 3 or MPEG-2, Part 7) because AT&T has recently been making noise over the fact that Via is actually violating some of their patents in the technology (and moved to sue Apple among others).  Who knows where this'll end up, and I'd definitely steer clear of implementing any built-in AAC encoding or decoding.

The MP4 container is a different story entirely, and you could certainly provide built-in tagging support for the container format.  People often confuse AAC in a MP4 container (most "apple" M4A files from iTunes) with MP4 itself, but they are not one and the same.

I should also say...

Thanks for joining me in the wilderness! It's been a long time as the (apparently) lone voice looking for tag writing to MP4 containers....

You are both not alone by any means!  I'd really, really like to see both MP4 and MKV in-file tagging support in MC and have posted on it many times.  MKV should be fairly simple for them to implement.  MP4 takes a bit more work, but should be easily accomplished given the effort.  I suspect that much of the problem stems from Jim's post above and a bit of confusion over the state of the patent world.

[JimH]

glynor,
When You Are A Lawyer, let us know.

For now, I plan to act as Switzerland would.

Jim

[glynor]

For now, I plan to act as Switzerland would.

What...?  Look the other way and laugh all the way to the bank?  (Glynor ducks from all the things the Swiss members throw at him.)

Eh.... MP4 is less important than MKV to me anyhow, and MKV is definitely patent and license free.

http://www.matroska.org/index.html

[schmoose]

how about at least passing MC's database fields to the external encoder plugin? currently none of these fields are transferred if we use an external encoder, and thus our resultant files end up tagless.

this way, at least we could use iTunesEncode or Nero to encode and tag APE/FLAC/etc. to AAC on the fly when transferring over to a handheld

[bspachman]

<bump>

Any further thoughts from the powers that be on tagging mp4 containers?

brad