AIFF files will not play on iPod, will on iTunes

[kozikowski]

My newer iPod is a Touch -- I think the first one.

Apple picks a number, I think generally two major versions and then stops support. My older iPod dropped out of support years ago, but my Touch dropped relatively quickly because the first Touch didn't have a camera.

I remember when I bought it, I was thinking it would be fun to mess with the camera.....

Oh... shucks.

Koz

[waxcylinder]

There are several advantages to using compressed format on iPods. The two main ones are that you can fit a lot more songs into the device (for 320 kbps files you can fit more than 4 times as many songs), and compressed files improve battery life (because disk reads are relatively heavy on battery power). What a lot of iPod users do is to export from Audacity in WAV format, then use iTunes to convert from WAV to AAC and add metadata (iTunes has a very good AAC encoder). It's a bit more long winded than just exporting from Audacity, but apparently (I don't have an iPod) it produces very good quality files with metadata that works in the iPod, improved battery life, better "anti-skip" performance and uses less disk space on the iPod. Optionally the WAV file can then be archived on an external hard drive as a back-up.

*Like* If there was a "Like" button on this forum then I would have clicked it.

A an excellent summary of the manual's workflow tutorial - with the added benefit of the "why" - I think I may add some of this to the workflow intro
UPDATE: added to Exporting to iTunes and iPod and Sample workflow for exporting to iTunes

The only part I would dispute is your comment about it being more long-winded - the metadata has to be managed somewhere (assuming you want metadata - and most iPod users do) and I personally have always found it much easier to manage the metadata in ITunes rather than Audacity - apart, that is, from the track name that comes from the Audacity label track on using Export Multiple).

I also archive my WAVs onto two external hard drives - I have had a hard drive failure

WC

[steve]

The multiple export of Audacity is after al behaving correctly and compliant with the specifications.
However, I am not sure if those 3 extra text chunks are necessary - all information is in the ID3 tag too.

The three text chunks are optional.

One possibility would be to drop the text chunks, but my worry is that then we may get users of application xyz complaining that metadata has stopped working. I don't know which chunks are used by which applications, though I think that it is unlikely that there are many consumer applications on Mac OS X that use text chunks, simply because those chunks are not used by iTunes, but they may be used by pro-audio applications. The point being that it would be risky to remove these chunks unless we know for sure.

One advantage of the text chunks is that they occur before the SSND chunk (the audio data), so if the file is being downloaded by a media player across a network (the Internet) then the application will have that information when the download starts rather than having to wait until the download completes. The text chunks could be read from the beginning of the file before the file is parsed, which may be useful for audio library and sound archive applications. I don't know if applications do or do not use the text chunks in this way.

What should happen is that applications should skip chunks that they don't understand - that's why the name and size of the chunk are at the top of the chunk.

Gale will correct me if I'm wrong, but I think that the metadata is handled in Audacity by libid3tag which may be updated in the near future.

[Robert J. H.]

The multiple export of Audacity is after al behaving correctly and compliant with the specifications.
However, I am not sure if those 3 extra text chunks are necessary - all information is in the ID3 tag too.

The three text chunks are optional.

One possibility would be to drop the text chunks, but my worry is that then we may get users of application xyz complaining that metadata has stopped working. I don't know which chunks are used by which applications, though I think that it is unlikely that there are many consumer applications on Mac OS X that use text chunks, simply because those chunks are not used by iTunes, but they may be used by pro-audio applications. The point being that it would be risky to remove these chunks unless we know for sure.

One advantage of the text chunks is that they occur before the SSND chunk (the audio data), so if the file is being downloaded by a media player across a network (the Internet) then the application will have that information when the download starts rather than having to wait until the download completes. The text chunks could be read from the beginning of the file before the file is parsed, which may be useful for audio library and sound archive applications. I don't know if applications do or do not use the text chunks in this way.

What should happen is that applications should skip chunks that they don't understand - that's why the name and size of the chunk are at the top of the chunk.

Gale will correct me if I'm wrong, but I think that the metadata is handled in Audacity by libid3tag which may be updated in the near future.

In conclusion, text chunks would only make sense if the Audio is streamed, but who wants to do that with AIFF files?
I wouldn't download any file that hasn't the basic information in the file name itself or as an alternative text in the link. And no one says that the ID3 tag has to be at the end.
It should really be examined if it is common practice to avoid text chunks, beginning with Mac-OS and its applications.

Anyway, it is nonsense to speculate further as long as no more facts are available.
I am sure you'll find a solution, with or without those ominous chunks.

[Gale Andrews]

@audio_pete - when you get time, a couple of files for you to test-play here: http://forum.audacityteam.org/viewtopic ... 43#p220043 .

We'll let you know when Koz does some more testing if he encounters the same problems that you do, or different ones. He'll test the two files above so it would be good if you can do so too. We want to be sure there are not more problems than just export multiple with an odd number of characters in the metadata.


Gale

[steve]

In conclusion, text chunks would only make sense if the Audio is streamed,

It could also make sense when downloading files. Some media players can start playing a file as soon as a sufficient amount of data to fill the buffers has been downloaded, so while this is not strictly "streaming audio" it is a nice feature in some media players.

And no one says that the ID3 tag has to be at the end.

The IFF specification allows a lot of flexibility over the chunk order, but it is common practice for the "ID3 " chunk to be at the end. I'd not be at all surprised if some applications choke on files that have the ID£ chunk before the SSND chunk.

It should really be examined if it is common practice to avoid text chunks, beginning with Mac-OS and its applications.

It certainly seems to be common for Mac OS X consumer applications to not use text chunks. I've seen suggestions that some Mac OS X pro audio applications do use them, but nothing definite as yet.

Anyway, it is nonsense to speculate further as long as no more facts are available.

I agree. A summary of all this has now been forwarded to the Audacity developers.

It looks like Koz's old iPod may have an additional problem so we will continue to investigate that.

[steve]

Sorry Gale, our post crossed - bumping your post:

@audio_pete - when you get time, a couple of files for you to test-play here: http://forum.audacityteam.org/viewtopic ... 43#p220043 .

We'll let you know when Koz does some more testing if he encounters the same problems that you do, or different ones. He'll test the two files above so it would be good if you can do so too. We want to be sure there are not more problems than just export multiple with an odd number of characters in the metadata.


Gale

[kozikowski]

This version of the iPod software (3.1.1) is the current version.

I'm not shocked that the earlier versions had trouble with sophisticated file management. Remember how cutting edge these things were. When these were designed, AAC was still crawling on the floor wetting its nappies. As posted earlier, if you put full-on AIFF files on an early iPod, you'd get four songs on. They were always intended for delivery-only compressed music.

And yes, that confirms Pete's iPod is between my two, so I'm going to probably have all his problems in addition to some of my own.

Koz

[Gale Andrews]

Gale will correct me if I'm wrong, but I think that the metadata is handled in Audacity by libid3tag which may be updated in the near future.

I think the "ANNO", "NAME" and other optional AIFF chunks are actually controlled by libsndfile as they are not ID3 tags.


Gale

[Gale Andrews]

Hi audio_pete.

Here are a couple of files that are possible fixes we might make for the bug in iPod (if the developers agree).

b.aiff

(487.05 KiB) Downloaded 60 times

d.aiff

(535.13 KiB) Downloaded 60 times

They are both second files from an export multiple.

Could you see if your iPod will play either of them?

Also (important for whether we apply this fix or not), do your audio apps like Amadeus or Peak play them? Do they see any metadata in the files? Try all the apps you have, if you can.

If anyone else reading this can try the above files on Classic iPods or pro audio applications that would be appreciated.


Gale