Beatles 24 Bit USB - Did I Screw Up?

[dmgbat]

Using Max, I converted my new Beatles 24 Bit USB Flac files (Green Apple thumb drive) to AIFF, and then imported the files to iTunes. The files are precisely the same size as those contained on the Redbook remasters, however, which makes me suspect that I managed to convert them incorrectly. Or perhaps the additional 8 bits doesn't add to the file size? Thanks for your input.

 

Best,

Danny

[Julf]

Using Max, I converted my new Beatles 24 Bit USB Flac files (Green Apple thumb drive) to AIFF, and then imported the files to iTunes. The files are precisely the same size as those contained on the Redbook remasters, however, which makes me suspect that I managed to convert them incorrectly. Or perhaps the additional 8 bits doesn't add to the file size? Thanks for your input.

 

That was one of the things I discovered when doing my hi-res listening tests - zeros compress very nicely. I used FLAC, not AIFF, but the algorithms are similar. The files should not get much bigger. But if they are *exactly* the same size, I would be a bit suspicious...

[goldsdad]

Using Max, I converted my new Beatles 24 Bit USB Flac files (Green Apple thumb drive) to AIFF, and then imported the files to iTunes. The files are precisely the same size as those contained on the Redbook remasters, however, which makes me suspect that I managed to convert them incorrectly. Or perhaps the additional 8 bits doesn't add to the file size? Thanks for your input.

 

Best,

Danny

 

AIFF is an uncompressed format, so the 24-bit AIFF should be very nearly 50 percent larger than the 16-bit AIFF for the same recording. The files contain metadata and things which prevent a precise 50 percent increase even when both files contain exactly the same count of audio samples. (File size in bytes is shown in Finder's Get Info).

 

The Max user has to set the desired output bit depth in the AIFF encoder settings. Settings can be "nicknamed" to be retained as custom presets.

 

 

[goldsdad]

I used FLAC, not AIFF, but the algorithms are similar

 

You must be thinking of ALAC, not AIFF, I think.

[Julf]

You must be thinking of ALAC, not AIFF, I think.

 

I had been reading about AIFF-C, didn't realize Apple still uses the uncompressed form. Just shows I don't know anything about Apple stuff.

[goldsdad]

I had been reading about AIFF-C, didn't realize Apple still uses the uncompressed form. Just shows I don't know anything about Apple stuff.

 

My (easily incorrect) understanding is that .aif or .aiff files created by most modern Mac apps are usually AIFF-C format but they're referred to as AIFF by most people. Before Apple switched to Intel processors, they chose to use AIFF-C in order to store big-endian samples. Standard AIFF is little-endian and has no provision for specifying byte order. I've not yet come across a Mac app that provides the compression options that are supported by AIFF-C.

[goldsdad]

Now I see that Audacity does provide compression options for AIFF (actually AIFF-C) in the "Other uncompressed files" export selector. They appear to be lossy compression, though.

[Julf]

Before Apple switched to Intel processors, they chose to use AIFF-C in order to store big-endian samples. Standard AIFF is little-endian and has no provision for specifying byte order. I've not yet come across a Mac app that provides the compression options that are supported by AIFF-C.

 

Ah! Thanks! Sounds like normal story - ended-ness and other portability issues don't matter until they matter

[Julf]

Now I see that Audacity does provide compression options for AIFF (actually AIFF-C) in the "Other uncompressed files" export selector. They appear to be lossy compression, though.

 

Hmm, wonder what codec it would be using.

[goldsdad]

Hmm, wonder what codec it would be using.

 

[Julf]

Ouch. Dynamic compression.

[Paul R]

Hey Owen - Does MAX pull the same trick as iTunes and input AIFF files only as 16bit values? That one bit me a while back, and is why I standardized on XLD.

 

-Paul

[goldsdad]

Does MAX pull the same trick as iTunes and input AIFF files only as 16bit values? That one bit me a while back, and is why I standardized on XLD.

 

 

iTunes correctly inputs and plays 16 and 24-bit AIFF. It's when exporting a 24-bit file as AIFF or WAVE that iTunes will truncate 24-bit to 16-bit.

 

Max will correctly input and output 24-bit AIFF and WAVE. It currently does not automatically maintain bit depth when converting to AIFF and WAVE, though. The correct output bit-depth has to be set by the user. Encoder settings can be saved by "nicknaming" them as seen in my earlier image of Max >Preferences > Formats.

 

XLD will automatically maintain bit depth when converting to AIFF and WAVE, although the user can manually override that with a specific depth.

[Paul R]

In this case, Input = "IMPORT"/"RIP"/"TRANSCODE". iTunes will not correctly IMPORT or TRANSCODE a 24bit AIFF file, it will convert the output to 16bits. Not sure if iTunes truncates the bit depth or if it dithers it down. As you noted, it won't EXPORT one either, say transcoding a 24bit AIFF to a WAV - it will again produce a 16 bit output file.

 

I take it from your comment that MAX doesn't automatically select the output bit depth as equal to the input bit depth, but can be set manually and will then work properly?

[goldsdad]

In this case, Input = "IMPORT"/"RIP"/"TRANSCODE".

 

I don't understand why you want the term input to mean transcode. If you mean transcode then everyone will understand what you mean if you actually write transcode. Anyway...

 

iTunes will not correctly IMPORT or TRANSCODE a 24bit AIFF file, it will convert the output to 16bits.

 

Partly correct. I guess iTunes's labelling of its encoding settings as "Import Settings" when they actually apply to its file encoders is causing confusion. As I wrote, iTunes does correctly input/import 24-bit AIFF. Playback of such a file is verifiably bit-perfect (as long as the whole system is correctly set up) and export of that file to ALAC is verifiably bit-perfect. iTunes file export to AIFF (actually AIFF-C) format is limited to 16-bit and 8-bit. The AIFF bit depth automatic setting will result in a 24-bit source in any format being truncated to 16-bit on export to AIFF.

 

Not sure if iTunes truncates the bit depth or if it dithers it down.

 

It truncates, not dithers.

 

As you noted, it won't EXPORT one either, say transcoding a 24bit AIFF to a WAV - it will again produce a 16 bit output file.

 

It's the WAVE encoder, not the AIFF importer, that truncates in the same way as the AIFF encoder.

 

I take it from your comment that MAX doesn't automatically select the output bit depth as equal to the input bit depth, but can be set manually and will then work properly?

 

Yes.

[Paul R]

deleted

[goldsdad]

Summary

 

iTunes import

AIFF 16-bit good

AIFF 24-bit good

WAVE 16-bit good

WAVE 24-bit good

ALAC 16-bit good

ALAC 24-bit good

 

 

iTunes playback

AIFF 16-bit good

AIFF 24-bit good

WAVE 16-bit good

WAVE 24-bit good

ALAC 16-bit good

ALAC 24-bit good

 

 

iTunes export

AIFF 16-bit good

AIFF 24-bit not supported - truncates to 16-bit

WAVE 16-bit good

WAVE 24-bit not supported - truncates to 16-bit

ALAC 16-bit good

ALAC 24-bit good

[Paul R]

You must have gotten the email from the message I decided to post later in another thread. So ONLY "exporting" (and "transcoding") triggers the unwanted truncation. Thanks - Paul

[goldsdad]

You must have gotten the email from the message I decided to post later in another thread.

 

I haven't seen the email, but I'll go look for it now.

 

Edit: No, I don't have an email regarding the forum. I notice you deleted a post in this thread before I got a chance to read it, though.

[Paul R]

It was just basically asking the same thing you answered.

 

Thanks

-Paul

[dmgbat]

Ah, I suspect that while fooling around with Max output formats (call it audio nervosa) I somehow deselected the AIFF 24-bit depth setting. I'll report back. And glad that my probable screw-up provoked some discussion!

 

AIFF is an uncompressed format, so the 24-bit AIFF should be very nearly 50 percent larger than the 16-bit AIFF for the same recording. The files contain metadata and things which prevent a precise 50 percent increase even when both files contain exactly the same count of audio samples. (File size in bytes is shown in Finder's Get Info).

 

The Max user has to set the desired output bit depth in the AIFF encoder settings. Settings can be "nicknamed" to be retained as custom presets.

 

 

[ATTACH=CONFIG]536[/ATTACH][ATTACH=CONFIG]535[/ATTACH]