[vebmetal]

Firstly, apologies to all for starting another Pioneer thread. But since the crux is totally different, I didn't find it appropriate to address this in other threads.

So here's the thing - I have a 8GB Corsair pen drive attached via USB to my Pioneer HU (6050UB). The initial scan time is excellent, and overall it works well. But it sort of hangs when attempting to play a certain few mp3s. It doesn't play the song, and doesn't show its info (i.e. name of song, artist etc.) and the pen drive's blue LED flickers as if it is trying to read it. But it never does (I have left it for a few minutes but to no avail). Then if I press "List" it loads the list slowly with each folder's name coming up after a 0.5 second pause, but when I do select another track that works, it goes back to operating smoothly. (That is why I said it "sort of" hangs).


At first I downloaded a program called mp3test, and did a little error checking and to my surprise a lot of my mp3s files had errors which were less than 1%. I have thrown these files at a number of things - winamp, media monkey, wmp, Microsoft Zune, Creative Zen, Ipods and every one of them plays them flawlessly. But for some reason the Pioneer HU doesn't.

Anyway, I thought that was the end of it. I would have to re-rip / re-download those mp3 again . I can tolerate that, annoying as it is. But to throw a whole wrench into it all, there are many songs that are not playing yet show no errors in mp3test. I tried examining whether there was a pattern as to ID3 tags / filename length / bitrates but there is no correlation. (especially since some of these tracks do work when re-downloaded, but some still don't).

HELP!

[low_bass_makker]

Check out the bitrate of those track. Some VBR tracks create problem sometimes.

[NetfreakBombay]

Can you upload any of "problem" MP3s somewhere (E.g. yousendit).com?

There might be something unusual. MP3, like most other MPEG standards is not implemented in the same way by everyone.

[DerAlte]

I have faced the problem too with other HUs and media players, especially with tracks that I had downloaded in 2000-01. They usually manifest themselves as intermittent chhik-chhik sounds on the players that were able to play the track. The one's that couldn't faced your problem, both on the PC as well on HU. There is a time-out implemented in all players, but it is rather large (about 60-90 secs).

mpeg decoding is usually in silicon nowadays, and the internal linking scheme causes problems with some tracks in some implementations. I had tried to crack this a few years back, but gave up as there was too little RoI.
At first I had thought that the problem was with CD scratches, but on checking back I had found that even the copy on the HDD was also faulty.
Let me check if I have some such examples in my repository.

[NetfreakBombay]

My guess (don't have not first hand knowledge)

Pio HU would be running some (almost)free Embedded system like VxWorks or Embedded Linux to reduce per unit royalty.

And these systems are typically 2 or 3 generations behind in terms of MP3 packages since they can't just take latest Linux version and compile for these systems.

So it is to be expected that they would be missing lots of bug fixes and patches for handling faulty files.

[DerAlte]

Originally Posted by NetfreakBombay

My guess (don't have not first hand knowledge)

Pio HU would be running some (almost)free Embedded system like VxWorks or Embedded Linux to reduce per unit royalty.

And these systems are typically 2 or 3 generations behind in terms of MP3 packages since they can't just take latest Linux version and compile for these systems.

So it is to be expected that they would be missing lots of bug fixes and patches for handling faulty files.

No they don't, and VxWorks is not at all free, even 'almost'. Most HU DON'T use an RTOS, and the ones that do use something with a much smaller footprint

You are comparing apples to oranges. For Linux and Windows, software CODEC implementations are not optimized for speed since they assume a very fast processor will be executing the algorithm. Quite opposite is the case with HUs, where there is an 8-bit CPU - hence the logic is implemented in dedicated silicon to achieve adequate speed.

And don't even start on "bug fixes and patches" - the embedded world doesn't work that way for obvious reasons.

[abhibh]

even Rs 3000 entry level JVC/Kenwood Plays the VBR files without any issue.

[hydrashok]

@veb, do the same tracks play when you play them from an MP3-CD?

In any case, the problem is most likely with the tracks themselves.

[NetfreakBombay]

Originally Posted by DerAlte

Quite opposite is the case with HUs, where there is an 8-bit CPU - hence the logic is implemented in dedicated silicon to achieve adequate speed.

And don't even start on "bug fixes and patches" - the embedded world doesn't work that way for obvious reasons.

8 bit CPU.. are you sure? Can you quote some source for that? If that is indeed the case it would be interesting to read about it.

Reason I am skeptical is, even 1000 - 2000 Rs devices have more power then that. We are talking about 9000 Rs device here.

Even a 1700 Rs Wireless router that I am using has a 32 bit MIPS processor (BCM3302) running at 200 MHz and runs VxWorks. SO VxWorks itself can't be expensive. Router is Netgear WGR614. Price :

eBay India: NETGEAR WGR614 Cable+DSL 54 Mbps Wireless Router WGR614 (item 150219954019 end time 04-Mar-2008 10:46:28 IST)

Hardware details :

Supported Devices - DD-WRT Wiki

It has 16 MB RAM.

My second PC was pentium 100 MHz with 8 MB RAM and it could do MP3

[greenhorn]

@ netfreak, while you can implement all this on a general purpose microprocessor, generally, as DerAlte said, a much simpler microcontroller is used, along with the decoding etc delegated to dedicated devices.
Single-Chip MP3 Decoder LSI for USB/SD Memory | New product new technology | ROHM Something like that

[NetfreakBombay]

I don't know if this would be a good idea for HU since it will need CD driver + CDROM filesystem support +USB host + FAT32 support + GUI. And if a 8 bit chip can handle all that.

But that gives me enough reason to start looking for second/third/fourth hand HU that I can buy for as close to free as possible and rip apart.

Hopefully they would not have obfuscated all chips .

[greenhorn]

why bother spending cash? get/download some service manuals. As a bonus , all the connections will be shown clearly, and you wont have to trace them out from the PCB

[BaCkSeAtDrIVeR]

There are applications like checkmp3 or mp3check on linux which show if the files follow the mp3 format. There are also applications like vbrfix which fixes incorrect vbr information in files. Corresponding applications may be available for Microsoft OSes, if that is what you are using.

[NetfreakBombay]

thats right.

do you know how to get hold on such manuals? searched on net but could only get "user" manuals :(

[greenhorn]

google is your friend

I found this
Audio : Service Manual free download,schematics,datasheets,eeprom bins,pcb,repair info for test equipment and electronics
It's not exhaustive, but then again, something's better than nothing!