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Topic: Darn. A good reason NOT to use AAC. My adventure. (Read 5342 times) previous topic - next topic

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Darn. A good reason NOT to use AAC. My adventure.
I've lurked on HA for a long time but created an account just for this. So much great information here -- always found what I needed in search. (One of these days I'll figure out why the AAC parameters for EAC don't work as specified in the WIKI but I digress.)

I read the following thread with a great deal of interest because the issues discussed described some of the dilemmas I've been going through: https://hydrogenaud.io/index.php/topic,106755.0.html

What lossy format? What encoding rate? What encoder? Could I hear the difference? Etc.

I started down the road of going AAC because the "prevailing wisdom" is that it's more efficient than MP3 for lossy encoding. I ABX'd FLAC / AAC in FB2K to find my threshold of transparency. (Turns out with my ears 128 works 99% of the time. 160 would be my paranoid setting.)

But the whole time I never really COMPLETELY thought through the reasons I needed lossy in the first place. Yeah I can RIP everything to FLAC and my 2 TB drive should handle it all. BUT, it's all my stupid devices. And yes on-the-fly conversion is OK, just really time consuming. Still, I was pretty close to settling on AAC because it worked fine on my phone, played great in all my media players (FB2K, MM, MusicBee, Groove, etc.) and file sizes were generally about 25% smaller than mp3.

Then I realized, crap. I forgot my cars. I like just plugging a USB stick into my radios. It's simple, doesn't glitch like Bluetooth and doesn't drain my phone battery. So I did a quick test. I threw an m4a, mp4, aac (file extensions only) AND mp3 file on a memory stick. Totally surprised at the result. My almost brand new 2016 Hyundai Tucson Sport with the full voice-operated media center ONLY RECOGNIZES MP3 files. Seriously? It will control an iPod for playback but it won't play AAC-encoded files natively? Nuts right?

Then I tested the same stick in our other car which has a much older Jensen VX aftermarket head. No problem with m4a, mp3 or mp4. Played them all fine.

The lesson I learned is, when considering lossy, look at ALL of your possible uses for it. AAC may be more widely supported than ever but that doesn't mean there aren't outliers that you need to consider.

So I guess I'm doing 192 VBR mp3 from now on. I'm not THAT paranoid. And thanks HydrogenAudio for all the fish.  :))
  • Last Edit: 15 April, 2017, 09:16:12 PM by Sven Golly

  • lithopsian
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #1
Yeah, cars suck. Media support is patchy, often obsolete, and very poorly documented. BTW, I also like the USB stick approach, again not as common as it should be in car.

  • Leo 69
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #2
I will now have to refrain from buying  2016 Hyundai Tucson Sport. Lack of AAC support is a critical drawback.

  • halb27
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #3
...
So I guess I'm doing 192 VBR mp3 from now on. I'm not THAT paranoid. And thanks HydrogenAudio for all the fish.  :))
That's a wise decision IMO. The main advantage of AAC is with rather low bitrate like ~100 kbps. With today's storage media most people can easily allow for ~200 kbps, and at such a bitrate you don't have to worry using universal mp3. Quality is great.
lame3995o -Q1.7
opus --bitrate 140

  • Apesbrain
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #4
Yeah, cars suck. Media support is patchy, often obsolete, and very poorly documented. BTW, I also like the USB stick approach, again not as common as it should be in car.
Agreed.  My parents bought a 2016 Honda Civic and it reads the USB key in the order the files are written!  You have to pay more for the premium audio system to have it sort by tags as we all would expect.  I fixed things for them using FAT Sorter, but really how hard would it have been for Honda to just do it right in the first place.

Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #5
I settled with bluetooth playback pretty much because of the reasons stated here. The performance is pretty good on the current MZD Connect system and I don't have any dropouts.

I always wondered why the hell cheap/car players read the files from the FAT instead of the filename, it just seems that the latter functionality is always implemented even on the barest of OSes, while the former would have to be separately implemented... unless I'm horribly wrong about it.

Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #6
I always wondered why the hell cheap/car players read the files from the FAT instead of the filename, it just seems that the latter functionality is always implemented even on the barest of OSes, while the former would have to be separately implemented... unless I'm horribly wrong about it.
The two are a lot more similar than that. The only difference is that one sorts the files and the other doesn't.

The trick is that sorting the files is relatively expensive on embedded systems (in terms of hardware and/or programmer resources) compared to not sorting them.

  • Palladium
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #7
In-car audio players and other hopelessly outclassed tech like standalone consumer GPS units/portable DVD players etc where the vendors just simply gave up improving them any further once they saw $130 octacore smartphones came.

Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #8
I always wondered why the hell cheap/car players read the files from the FAT instead of the filename, it just seems that the latter functionality is always implemented even on the barest of OSes, while the former would have to be separately implemented... unless I'm horribly wrong about it.

At least the Tucson AND the Jensen head both read tags from MP3's and there's a shuffle feature plus folder support so no problems there with the USB stick. It still surprises me that the Tucson audio is less capable than my 6 year old Jensen head.

Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #9
I settled with bluetooth playback pretty much because of the reasons stated here.
There are some odd things about Android music playback to car audio Bluetooth - especially with the voice driven media system that make it less desirable than direct playback via USB stick or even MP3 CD. ;-) Even the Aux cord solution is better. One annoying thing about my Nexus 6 is that Google Play Music drops the volume a LOT when the EQ is active. Thus I leave it off.

  • andy o
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #10
Yeah, if you got a smartphone, and you're determined enough to get a reasonable experience for playback that your new car choice has this as a priority, your best bet is Android Auto. Maybe followed distantly by Apple's CarPlay. Car manufacturers for the most part have had to been dragged kicking and screaming to modernity, with still some holdouts promoting their dumb terrible expensive user-hostile systems. There are some like Hyundai though, that embraced it early and widely. Now Honda cars come with AA/CP, and Mazda has even announced retrofitting some recent models with it.

You can also use the Android Auto interface on the phone itself, so that's a plus. I use that with BT without much problems, although Google Maps is not as well featured as either the normal AA interface, or the non-AA phone interface, but that's another thing.

I settled with bluetooth playback pretty much because of the reasons stated here.
There are some odd things about Android music playback to car audio Bluetooth - especially with the voice driven media system that make it less desirable than direct playback via USB stick or even MP3 CD. ;-) Even the Aux cord solution is better. One annoying thing about my Nexus 6 is that Google Play Music drops the volume a LOT when the EQ is active. Thus I leave it off.
I think it drops the volume in order not to clip. If you don't raise the EQ freq levels, the volume doesn't drop.

  • Klimis
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #11
Heh! I recently installed a head unit on my car. Guess what? It plays wav, mp3, wma, ogg, flac, ape, opus, wavpack BUT not aac. There might be a possibility that it has something to do with licencing or something.

  • tycho
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #12
My car stereo also has mp3 only USB interface. Last year I also bought a cheap Onkyo mini stero because of the need for DAB+ radio as they turn off FM broadcast in June where I live. It only supports mp3 via USB as well, but has bluetooth/NFC connection. I prefer having a USB-stick plugged in, so music is readily available. Both players continues where they left off last time.

So still in 2017, MP3 it is. Here is what I do:
  • Convert from replaygain-tagged FLAC-files, and apply gain when converting to mp3 in foobar2000.
  • Consider using CBR, e.g. -b 192 when converting: Many of these mp3-devices have flaky music search in VBR files.
  • After copying the files to the USB, use a FAT sorting program to sort the files, e.g DriveSort


  • Last Edit: 18 April, 2017, 12:22:32 PM by tycho

  • shadowking
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #13
Going for the lowest common denominator you will end up with CBR 'stereo' just like in 1999, In order to get bug free playback. Even then there there may still be bugs like the stupid FAT issue and not reading ID3 tags at all or partially.

This is due to poor and buggy 'support' of the MP3 format. Do you not use HD video  because support for SD / DVD is more 'widespread' ?  Or not use ODF because RTF is more 'supported' ?

You will find there too the level of 'support' can be severely lacking and misleading.
wavpack 4.8 -b4x4s0.75c

  • o-l-a-v
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #14
Just get a stereo with AUX or/and bluetooth (aptx), and you don't have to worry about bad format support in car stereos. I think it's quite obvious why most stereos don't support that many formats, especially mp3 and aac: Royalty fees. In a ideal world car stereo producers would ship products supporting all free to use codecs, like vorbis, opus, flac. But they don't. So go for the best solution: Use your phone or dedicated pocket sized music player; it's way better for playback control, and you don't have to maintain multiple lossy libraries in multiple formats. You don't lose audio quality using AUX. You are just making it harder for youself sticking to USB sticks and old codecs.

  • eahm
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #15
Most people, me included, will never care enough to change the car stereo.

  • shadowking
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #16
Transcode straight into non-MPT devices and sticks . This is more efficient than keeping several collections . A universal compact setting would be something like lame -b160 -f or gogo -b 160 -q 7. Replaygain can be hardcoded and IDV3 tags set to v2.3-compat or 1.x  in foobar.

This has worked with everything legacy for me.
wavpack 4.8 -b4x4s0.75c

  • lithopsian
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #17
Then of course it is anybody's guess whether it will play gapless ...

  • Cartoon
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #18
I always wondered why the hell cheap/car players read the files from the FAT instead of the filename, [...}

Well, they don't. Filenames (and directory names) are stored in the directory table, not the file allocation table (FAT). When looking for files, the FAT filesystem implementation will read the directory table sequentially (and the directory table will point to the start of the FAT file allocation chain). Files are stored in the directory table as they are created and where ever there is a free entry. Over time the sequence of files will be random as files are deleted and directory entries are re-used.

Nowadays most people are used to files being in alphabetical order in a file browser window or even with the DIR command (DOS 3.0 iirc added the /O flag to sort files, like "dir /Ogn") and more modern filesystems like NTFS or HPFS have directory lists of files in non-sequential order, like b-tree and alike, and the files will always appear to be in binary sorted order even in the native APIs.

So an embedded stereo system using only the basic DOS API calls to read filenames from a directory table will return the filenames in the order that they appear in the table. Any sorting after that (for FAT) will have to happen in the code of whatever program that reads it and that takes space and time. Embedded systems usually have some space and time constraints, especially older generations typically found in cheap car stereos.

  • PoisonDan
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #19
Then of course it is anybody's guess whether it will play gapless ...
This!
Over thinking, over analyzing separates the body from the mind.

  • PoisonDan
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #20
Transcode straight into non-MPT devices and sticks . This is more efficient than keeping several collections . A universal compact setting would be something like lame -b160 -f or gogo -b 160 -q 7. Replaygain can be hardcoded and IDV3 tags set to v2.3-compat or 1.x  in foobar.

This has worked with everything legacy for me.
And by coincidence, the day after your post, Spoon announced TuneFUSION, which seems to automate exactly this (by syncing with a USB stick for the car, for which TuneFUSION "knows" it needs to be lossy in a specific format with specific constraints):
https://hydrogenaud.io/index.php/topic,113966
Over thinking, over analyzing separates the body from the mind.

  • JunkieXL
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #21
I am extremely glad that my Mazda 3 has iPod compatibility and can read its media library. 

This allows easy scrolling by artist, song, album, playlist, etc.

Not too mention it's an iPod classic with 160 GBs of music storage.

I'm sure most newer cars are capable of this as well, as I've used it 2015 Toyota Camry and VW Jetta and both were able to support it via a USB plugin.
JXL

  • loft
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Re: Darn. A good reason NOT to use AAC. My adventure.
Reply #22
Let me add that the just released Mercedes head unit doesn't read Vorbis. And there's no plan to add it in the upcoming yearly refreshes.
I don't want to mention what other ancient pieces of tech are used in this project as your heads will spin faster than a wind turbine.

PS: I'm working in the development of the mentioned system.